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Diflubenzuron: control of the codling moth, Laspeyresia pomonella L., and the obliquebanded leafroller,… Anderson, Dale William 1980

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DIFLUBENZURON: CONTROL OF THE CODLING MOTH, Laspeyres  pomonella L., AND THE OBLIQUEBANDED LEAFROLLER, Chor i s toneura rosaceana (Ha r r i s ) B.Sc. ( A g r . ) , U n i v e r s i t y o f B r i t i s h Columbia, 1978 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF THE FACULTY OF GRADUATE STUDIES (Department o f P l an t Sc ience) We accept t h i s t h e s i s as conforming to the requ i r ed standard THE UNIVERSITY OF BRITISH COLUMBIA lALE WILLIAM ANDERSON by MASTER OF SCIENCE in December, 1980 @ Dale W i l l i am Anderson, 1980 In presenting th is thes is in pa r t i a l fu l f i lment o f the requirements for an advanced degree at the Un ivers i ty of B r i t i s h Columbia, I agree that the L ibrary sha l l make it f ree ly ava i lab le for reference and study. I fur ther agree that permission for extensive copying of th is thesis for scho la r ly purposes may be granted by the Head of my Department or by his representa t ives . It is understood that copying or pub l ica t ion of th is thes is for f inanc ia l gain sha l l not be allowed without my wri t ten permission. Department of PLANT SCIENCE The Univers i ty of B r i t i s h Columbia 2075 Wesbrook Place Vancouver, Canada V6T 1W5 DECEMBER 16, 1980 - i i -ABSTRACT D i f lubenzuron (D im i l i n ) was eva luated as a con t ro l agent f o r the cod l i ng moth, Laspeyres ia pomonella L. and obi iquebanded l e a f r o l l e r , Chor i s toneura  rosaceana ( H a r r i s ) . Laboratory t e s t s showed cod l i ng moth eggs to be extremely s e n s i t i v e to d i f l u ben zu ron , p a r t i c u l a r l y when t r ea ted t o p i c a l l y immediately a f t e r o v i p o s i -t i o n . L D 5 0 va lues f o r 0- to and 3 - day - o l d eggs were 1.1 and 17.2 ppm, r e s p e c t i v e l y . D i f lubenzuron was more e f f e c t i v e as an o v i c i d e when kept i n s o l u t i o n on egg sur faces f o r longer t ime pe r i ods . When the compound had d r i e d on f r u i t or f o l i a g e , r e s i dua l a c t i on was e x c e l l e n t aga ins t the eggs. Th is a c t i v i t y d id not decrease over a 10-day per iod and d a i l y spray ing of f o l i a g e w i th water d i d not s i g n i f i c a n t l y reduce o v i c i d a l a c t i o n . Tween 20, a s u r f a c t a n t , improved the d i s t r i b u t i o n and e f f i c a c y of d i f l ubenzu ron on f o l i a g e and young apples but not waxy mature app le s . F i r s t - and 2nd - i n s t a r c od l i ng moth l a r vae were su s cep t i b l e to d i f l u b e n -zuron when the compound was ingested from agar d i e t or apple f o l i a g e . On the d i e t , the LD 5 g ' s f o r the two i n s t a r s were 48.2 and 8.1 ppm, r e s p e c t i v e l y . Adu l t c od l i ng moths dipped in or fed d i f l ubenzu ron s o l u t i o n s showed no marked adverse e f f e c t s , a l though marginal reduc t ions in f e cund i t y or egg v i a b i l i t y were observed. The s e n s i t i v i t y o f the obi iquebanded l e a f r o l l e r (a r ep re sen ta t i v e l e a f -r o l l e r spec ies ) was a l s o examined under l abo ra to r y c o n d i t i o n s . Egg masses were i n s e n s i t i v e to d i f l ubenzu ron a t concent ra t i ons as h igh as 1,000 ppm. However, 100 ppm d i f l ubenzuron proved t o x i c to f i r s t - i n s t a r l a r vae and r e -duced l ongev i t y of adu l t moths. In f i e l d t e s t s , d i f l ubenzu ron s i g n i f i c a n t l y reduced l e a f r o l l e r damage to app les . However, a t comparable a p p l i c a t i o n r a te s (375 ppm), con t ro l was on ly 25% tha t prov ided by az inphos-methyl (Guth ion) . In c on t r a s t , aga ins t the cod l i ng moth d i f l ubenzu ron prov ided con t ro l equal to tha t o f az inphos-methyl i n orchards o f Golden De l i c i o u s and mixed apple c u l t i v a r s . The add i t i on of Tween 20 d id not enhance the e f f i c a c y of d i f l u ben zu ron . Leaf mi te-counts suggested tha t d i f l ubenzu ron was non- tox i c to predaceous m i t e s . The imp l i c a t i o n s of these f i n d i n g s are d i scussed i n terms of the poten-t i a l o f d i f l ubenzu ron in the i n t eg ra ted con t ro l o f apple pes t s . - i v -TABLE OF CONTENTS Raje ABSTRACT i i LIST OF TABLES v LIST OF FIGURES v i i LIST OF PLATES v i i i ACKNOWLEDGEMENTS i x INTRODUCTION 1 MATERIALS AND METHODS 12 A. Rear ing Techniques 12 B. Test Compounds 13 C. Tests on Eggs 16 D. Tests on Larvae 17 E. Tests on Adu l t s 17 F. F i e l d Tes ts 19 G. S t a t i s t i c a l Ana l y s i s 23 RESULTS 24 I . Laboratory S tud ies 24 A. Cod l ing Moth 24 B. Obiiquebanded L e a f r o l l e r 37 I I . F i e l d Tests 42 A. L e a f r o l l e r Test 42 B. Cod l ing Moth Tests 48 DISCUSSION 54 7 LITERATURE CITED 61 APPENDIX 68 -V-LIST OF TABLES Table Page I Percent hatch and con t ro l o f c od l i ng moth eggs t r ea ted 25 t o p i c a l l y w i th vary ing concent ra t i ons of d i f l u ben zu ron . II< Maximum l i k e l i h o o d t e s t s on, the t o x i c e f f e c t s of d i f l u - 26 benzuron to eggs of the cod l i ng moth. I I I Percent hatch of cod l i ng moth eggs t r ea ted t o p i c a l l y , . 27 w i th 10 ppm d i f l ubenzu ron a t va ry ing t imes from o v i - ' p o s i t i o n . IV Perpent hatch of cod l i ng moth eggs p laced in contac t 29 w i th 10 ppm d i f l ubenzu ron so l u t i on s f o r va ry ing per iods . o f t ime . 1 V Percent hatch of cod l i ng moth eggs t r ea ted w i th d i f l u - 30 benzuron s o l u t i o n s i n the presence and absence of Tween 20. VI . . . H a t c h a b i l i t y of c od l i ng 'moth eggs o v i po s i t e d on apples 31 which had been d ipped- in d i f lubenzuron/Tween 20 s o l u t i o n s . VII Hatchab i l i t y o f c od l i ng moth eggs o v i p o s i t e d on pear .< 33 f o l i a g e which had been dipped in' d i f l ubenzuron/Tween 20 s o l u t i o n s VI IT M o r t a l i t y o f f i r s t - and 2nd - i n s t a r cod l i ng moth l a rvae . 34 feed ing on agar medium con ta i n i ng var ious concent ra t ions of d i f l u ben zu ron . IX Maximum l i k e l i h o o d t e s t s on the t o x i c e f f e c t s of d i f l u - 35 benzuron to l a rvae of the cod l i ng moth 7 X Pene t ra t i on of apples and s u r v i v a l to 4 t h - i n s t a r by cod- 36 l i n g moth f i r s t - i n s t a r l a r v a e , a f t e r feed ing on apple f o l i a g e sprayed w i th d i f lubenzuron/Tween 20. XI Longev i t y , f e cund i t y and egg v i a b i l i t y of adu l t c od l i ng 38 moths dipped in d i f l ubenzu ron s o l u t i o n s . 'i • . . . XII Longev i t y , f e cund i t y and egg v i a b i l i t y of adu l t c od l i ng 39 moths dipped in d i f l ubenzuron/Tween 20 s o l u t i o n s . X I I I Longev i t y , f e cund i t y and egg v i a b i l i t y of adu l t c od l i ng 40 moths fed d i f l ubenzu ron s o l u t i o n s . " - V I -Table Page XIV Percent hatch of l e a f r o l l e r egg masses t o p i c a l l y 41 t r ea ted w i th va ry ing concent ra t i ons of d i f l ubenzu ron . XV Percent s u r v i v a l o f f i r s t - i n s t a r l e a f r o l l e r l a r vae 43 feed ing on pear f o l i a g e which had been dipped i n dif1ubenzuron/Tween 20 s o l u t i o n s . XVI Mou l t ing success of f i v e l e a f r o l l e r l a r v a l i n s t a r s 44 p laced on apple f o l i a g e sprayed w i th d i f l ubenzu ron / Tween 20 s o l u t i o n s . XVII Longev i t y , f e cund i t y and egg v i a b i l i t y of adu l t l e a f - 45 r o l l e r moths dipped i n d i f lubenzuron/Tween 20 s o l u t i o n s . XVIII Percent of harvested apples showing l e a f r o l l e r damage. 47 XIX Percent of harvested apples of mixed c u l t i v a r s showing 50 cod l i ng moth damage. XX Percent of harvested Golden De l i c i o u s apples showing 52 cod l i ng moth damage. LIST OF FIGURES F igure 1 Schematic r ep re sen ta t i on of the c od l i n g moth f i e l d -t e s t o r chards . 2 Schematic r ep re sen ta t i on of the l e a f r o l l e r f i e l d - t e s t o r cha rd . 3 Seasonal abundance of f ou r l e a f r o l l e r spec ies i n the t e s t orchard dur ing summer, 1980. 4 Seasonal abundance of the cod l i ng moth i n Summerland orchards dur ing summer, 1980. 5 European red mite numbers, per l e a f and per p h y t o s e i i d , i n the cod l i ng moth f i e l d - t e s t orchards dur ing summer, 1980. LIST OF PLATES P l a t e I Corrugated wooden s t r i p s used f o r c o l l e c t i o n of c od l i ng moth l a r v ae . II Ro ta t ing o v i p o s i t i o n cage used f o r c o l l e c t i o n of c od l i n g moth eggs. I I I Broad beans, used f o r r ea r i ng of l e a f r o l l e r s , growing i n a greenhouse s i t u a t i o n . IV Wax paper cage used f o r experiments on adu l t moths and fo r c o l l e c t i o n of l e a f r o l l e r eggs. V C l i p - c age used f o r t e s t s on f i r s t - i n s t a r cod l i ng moth l a r vae VI Apple f o l i a g e showing feed ing i n j u r y by cod l i ng moth f i r s t - i n s t a r l a r v ae . - i x -ACKNOWLEDGEMENTS The author wishes to express h i s s i n ce re app rec i a t i on to the members of h i s committee: Dr. G.W. Eaton, Dr. R.H. E l l i o t t , Dr. D.G. F i n l a y son , Dr. R.D. McMullen and Dr. V.C. Runeckles. A spec i a l thanks must go to Dr. McMullen and the other entomology personnel a t the Summerland Research S t a t i o n , f o r i n va l uab l e a s s i s t an ce w i th the f i e l d t e s t i n g . I am p a r t i c u l a r l y g r a t e f u l to my supe r v i s o r , Dr. R.H. E l l i o t t , f o r h i s adv ice and a s s i s t ance w i th t h i s p r o j e c t . I would a l s o l i k e to thank A g r i c u l t u r e Canada and Dr. E l l i o t t f o r p rov id ing my suppor t . - 1 -INTRODUCTION The c od l i n g moth, Laspeyres ia pomonella L. ( Lep idop te ra : O l e t h r eu t i d a e ) , i s gene ra l l y regarded as the s i n g l e most d e s t r u c t i v e pest of pome f r u i t s i n the wo r l d . S ince i t s i n t r odu c t i o n to North America v i a New England c a . 1750, the cod l i ng moth has spread to v i r t u a l l y a l l reg ions where pome f r u i t s are grown ( S l i n ge r l and and Crosby 1915). Apples and pears are the main economic hosts but the l a r vae have o c c a s i o n a l l y been found in peaches, a p r i c o t s , c h e r r i e s and var ious nu t s . In fes ted f r u i t gene ra l l y show the c h a r a c t e r i s t i c symptom of ent ry holes clogged w i th f r a s s . In unprotected o rchards , e s p e c i a l l y i n commercial p roduct ion areas and warmer c l ima t e s , l o s ses may reach 95% or g rea te r (Metca l f et aJL 1962). V i r t u a l l y a l l t r e e - f r u i t product ion i n B r i t i s h Columbia occurs i n the Okanagan and Similkameen V a l l e y s , w i t h a sma l l e r i ndus t r y i n the East Kootenay. The cod l i ng moth t y p i c a l l y undergoes two or three generat ions per year i n southern B r i t i s h Columbia. The mature l a r vae overwinter w i t h i n t h i n s i l k e n cases underneath loose bark or in the s o i l and pupate in the s p r i n g . Adu l t moths begin to emerge as e a r l y as the blossom per iod of app l e . The peak of adu l t emergence occurs three to four weeks l a t e r depen-d ing on weather c o n d i t i o n s . Mating a c t i v i t y o f moths i s reduced a t below 15°C, but prov ided tha t warm temperatures p r e v a i l , females begin to o v i -p o s i t on f r u i t or f o l i a g e three to f i v e days a f t e r emergence. The newly-hatched l a rvae may feed f o r a shor t t ime on f o l i a g e before en te r i ng the f r u i t , o f ten a t the ca l yx end. The l a rvae mature in approx imate ly three weeks and leave the f r u i t to pupate on tw i g s , branches, under bark or i n the s o i l . Peak emergence of adu l t s of the second brood occurs dur ing mid-- 2 -J u l y through mid-August depending on weather c ond i t i o n s . In years w i th very warm summers, a t h i r d f l i g h t o f moths may occur i n September, j u s t before normal apple ha rves t i ng dates (Madsen and Arrand 1971). As even r e l a t i v e l y low popu la t ions of the cod l i ng moth can cause se r ious damage, con t ro l measures are v i t a l . The f r u i t must be p ro tec ted by a r e s i dua l spray a t a t ime when the adu l t moths are p resent . In past y ea r s , compounds such as lead arsenate and DDT prov ided good c o n t r o l , but the development of r e s i s t an ce (Marsha l l 1959; Putman 1962) a long w i th un-de s i r a b l e e f f e c t s on the environment (Newsom 1967) c u r t a i l e d t h e i r use. Three organophosphate i n s e c t i c i d e s are p resen t l y recommended f o r cod l i ng moth c o n t r o l . Az inphos-methyl (Guthion) i s most w ide l y used and i s normal ly app l i ed s h o r t l y a f t e r the appearance of adu l t moths. Th is com-pound i s a broad-spectrum i n s e c t i c i d e which does not concent ra te i n food cha ins and prov ides e x c e l l e n t con t ro l i f used c o r r e c t l y . I t s r e s i dua l a c t i v i t y may be as long as two weeks on f o l i a g e , p rov id i ng extended con t ro l (Mar t in 1971). Furthermore, i t s t o x i c i t y to predatory mi tes i s low, a l l ow i ng i n t e g r a t i o n w i th b i o l o g i c a l mi te con t ro l (Downing and Arrand 1978). At the same t ime , az inphos-methyl i s a very t o x i c p e s t i c i d e , w i th an acute o ra l LDgg ( r a t s ) o f 16.4 mg/kg (Mar t in 1971). The use of t h i s i n s e c t i c i d e presents a hazard to the a p p l i c a t o r , who must wear a r e s p i r a t o r and p ro tec -t i v e c l o t h i n g . As the high t o x i c i t y and long pe r s i s t ence of az inphos-methyl prevent i t s use w i t h i n seven days of ha rves t , the compound i s not recommended f o r con t ro l o f a t h i r d cod l i ng moth brood (Anonymous 1980). Phosalone (Zolone) and phosmet (Imidan) are a l so broad-spectrum i n se c -t i c i d e s not b i o l o g i c a l l y concentrated (Mar t in 1971) and of low t o x i c i t y to predatory mites (Downing and Arrand 1978). Both are of lower t o x i c i t y and - 3 -pe r s i s t ence than az inphos-methyl and can be app l i ed up to one day before harvest on apples so ld i n Canada (Anonymous 1980). Contro l e f f e c t ed by these two compounds does not u s ua l l y reach tha t o f az inphos -methy l . A l l th ree organophpsphates have been observed to d i s r up t non- target spec i e s , i n c l ud i ng na tu ra l enemies of the pear p s y l l a , P s y l l a p y r i c o l a Foe r s te r (McMullen and Jong 1967; West igard 1979). A l t e r n a t i v e methods of cod l i ng moth con t ro l are h i gh l y d e s i r a b l e . The a v a i l a b i l i t y o f the s yn the t i c c od l i ng moth sex pheromone prov ides severa l po s s i b l e con t ro l techn iques . The " con fus ion" techn ique i nvo l ves r e l ease of the pheromone over a g iven area i n amounts s u f f i c i e n t to prevent males from l o c a t i n g females. M o f f i t t (1978) demonstrated good po t en t i a l f o r t h i s method. A second technique i nvo l ves mass- t rapp ing and removal o f males us ing sex pheromone t r a p s . Hagley (1978) suggested tha t t h i s was qu i t e f e a s i b l e , but Madsen and Car ty (1979) showed tha t the technique was e f f e c t i v e on l y i f c od l i ng moth popu la t ions were low and i f i s o l a t i o n p re -c luded r e i n f e s t a t i o n . In any case , the sex pheromone a l l ows accura te mon i to r ing of pest l e v e l s and more p r e c i s e a p p l i c a t i o n of chemical c on t r o l s (Myburgh et al_. 1974). The use of b i o l o g i c a l agents aga in s t the cod l i ng moth has rece ived cons ide rab le a t t e n t i o n . Cox (1932) reared l a rge numbers of Ascogaster  carpocapsae V ie reck (Hymenoptera: Braconidae) from f i e l d - c o l l e c t e d cod l i ng moth l a rvae i n New York. Russ and B rands ta t t e r (1978) repor ted progress i n the r ea r i ng of Ascogaster quadr identatus Wesm., another important p a r a s i t e o f the cod l i ng moth. Voegele e_t aJL (1978) showed a reduc t i on i n c od l i ng moth damage a f t e r r e l ease of the egg pa ra s i t e s Trichogramma spp. (Hymenop-t e r a : Tr ichogrammat idae) . In another form "of b i o l o g i c a l c o n t r o l , Solomon - 4 -e t aj_. (1976) showed tha t b i rds i n c e r t a i n Eng l i s h orchards took up to 95% o f the ove rw in te r i ng cod l i ng moth l a r v ae . M i c r ob i a l agents such as B a c i l l u s t h u r i n g i e n s i s and the entomopathogenic fungus Beauver ia bass iana have shown l i m i t e d success (Ferron and V incent 1978). E x c e l l e n t con t ro l has been obta ined us ing g ranu lo s i s v i r u s aga ins t the cod l i ng moth ( F i s c he r -Col br>ie 1978; D i c k l e r and Huber 1978) even though t h i s method has been shown to be somewhat i n c on s i s t e n t (Huber and D i c k l e r 1978). Probably the two most promis ing non-chemical con t ro l methods are the use of g r anu l o s i s v i r u s ( e s ) and the r e l ea se of s t e r i l i z e d adu l t c od l i ng moths. An i n t en s i v e eva l ua t i on of the s t e r i l e i n s e c t technique as a con t ro l measure aga in s t the cod l i ng moth was i n i t i a t e d in 1962 as a p ro j e c t o f the A g r i c u l t u r e Canada Research S t a t i o n a t Summerland, B.C. Th i s program expanded u n t i l i n 1976, 1977 and 1978 i t i nc luded the g rea te r par t of a l l apple and pear orchards i n the Similkameen V a l l e y . The r e s u l t s were most encourag ing. Desp i te high c o s t s , the economic f e a s i b i l i t y o f the program was inc reased by improved e f f i c i e n c y i n r ea r i ng and r e l ease techniques (Proverbs e t aj_. 1977). The adu l t moths are reared on a s yn the t i c d i e t a t the Summerland Research S t a t i o n and s t e r i l i z e d w i th 35 krad of gamma r a d i a t i o n immedia-t e l y p r i o r to r e l e a s e . For optimum c o n t r o l , a r a t i o of 40 s t e r i l e males to one na t i ve male i s d e s i r a b l e (Proverbs 1978). To ensure tha t t h i s r a t i o i s ma in ta ined , popu la t i on l e v e l s o f na t i ve and re leased s t e r i l e moths are cons tan t l y monitored w i th sex pheromone t r a p s . S t e r i l e moths can be i den -t i f i e d by the presence i n t e r n a l l y of ca l co o i l r ed , a dye p laced i n the l a r v a l d i e t (B r i n ton e t aj_. 1969). As the s t e r i l e i n s e c t technique i s gene ra l l y f e a s i b l e on ly when - 5 -app l i ed aga i n s t low pest popu l a t i on s , concerted e f f o r t s were made to reduce na t i v e c od l i ng moth popu la t ions in the Similkameen V a l l e y p r i o r to the r e l ea se of s t e r i l e moths. Measures taken inc luded removal o f abandoned host t r ees and i n t en s i v e spray ing of badly i n f e s t ed o r cha rds . During the course o f the program, i n s e c t i c i d e s were app l i ed to areas i n which w i l d popu la t ions of c od l i ng moths rose to damaging l e v e l s desp i t e s t e r i l e i n s e c t r e l ea se (Proverbs 1978). I t can be seen, t h e r e f o r e , tha t i n s e c t i c i d e s s t i l l have a s i g n i f i c a n t r o l e i n ensur ing the success o.f-..a s t e r i l e c od l i n g moth program. A l though az inphos-methyl i s cus tomar i l y used when sprays are deemed necessary , the compound i s p o t e n t i a l l y h i gh l y t o x i c to the a p p l i c a t o r , non- ta rget organisms and to adu l t c od l i ng moths. Because of t o x i c i t y to the s t e r i l e moths and the-person idi.spensing them, s t e r i l e i n s e c t r e l ease i s c u r t a i l e d i n sprayed orchards f o r three to seven days (M.D. Proverbs , personal communicat ion). Release of s t e r i l e cod l i ng moths must be resumed at or before ce s sa t i on of e f f e c t i v e r e s i dua l chemical c o n t r o l , o therwise p r o t e c t i on of the orchard i s incomplete . A l e s s t o x i c , .more , p e s t - s p e c i f i c i n s e c t i c i d e w i th good r e s i dua l a c t i v i t y would be p r e f e r ab l e to az inphos-methyl whether used a lone or i n con junc t i on w i th s t e r i l i t y - c o n t r o l . I f r e l ease of aduTt"moths was cont inuous , an i n s e c t i c i d e of lower t o x i c i t y to adu l t moths but e f f e c t i v e aga ins t immature "stages would d i s r up t s t e r i l i t y -con t ro l to a l e s s e r ex t en t . The i n s e c t growth r egu l a t o r d i f l ubenzu ron (D im i l i n ) may s a t i s f y these c r i t e r i a . When app l i ed a t very- low concen t ra t i ons (van Daalen et a]_. 1972), the compound has e f f e c t i v e l y c o n t r o l l e d many pest spec ies w i t h i n the major i n se c t o rde r s , p a r t i c u l a r l y D i p t e r a , Co leoptera and Lep idop te ra . In the - 6 -l a t t e r o rde r , the gypsy moth P o r t h e t r i a d i spa r (L . ) (Granet t and Dunbar 1975), the zebra c a t e r p i l l a r Ceramica p i eta (Ha r r i s ) (Tamaki and Turner 1974), the f o r e s t t en t c a t e r p i l l a r Malacosoma d i s s t r i a (Hbn.) (Retnakaran et al_. 1979), the Doug l a s - f i r tussock moth Orygia pseudotsugata (McDunnough) (Neisess e t al_. 1976) and other pests have been shown to be s u s c ep t i b l e to d i f l u benzu ron . Research conducted on Culex pi p i ens p i pi ens (D i p t e r a : Cu l i c i d ae ) suggests tha t r e s i s t an ce to the growth r egu l a t o r accumulates much more s l ow ly than to convent iona l i n s e c t i c i d e s (Brown et aj_. 1978). There are repor t s which suggest tha t the cod l i ng moth may be s e n s i t i v e to the compound (Anderson 1978; Audemard 1978; Cranham 1978; Wearing and Thomad 1978; West igard 1979) and the v e r i f i c a t i o n of t h i s i s the major aim of t h i s s tudy . I t appears tha t d i f l u ben zu ron , a stomach po i son , i n h i b i t s the c h i t i n synthetase enzyme invo lved i n the syn thes i s and depos i t i on of new c u t i c l e (Post and V incent 1973; Mayer e_t al_. 1980). E f f e c t s on i n sec t s are u sua l l y no t i c eab l e dur ing the moult i n t ha t s u s c ep t i b l e immatures are incapab le of shedding t h e i r exuviae or form t h i n and deformed c u t i c l e s which rupture e a s i l y . Ov i c i d a l q u a l i t i e s have been observed i n t e s t s on mosquitoes (Muira e t al_. 1976), b l a c k f l i e s (Lacey and Mu l l a 1977), armyworms (Ascher and Nemny 1976) and the cod l i ng moth (Anderson 1978; Wearing and Thomas 1978). Adu l t c h e m o s t e r i l i z a t i o n has been recorded f o r mosquitoes (Muira e t al_. 1976), b o l l weev i l s (Moore and Ta f t 1975; Johnson et aj_. 1978), s t ab l e f l i e s and horn f l i e s (Wright and Ha r r i s 1976). C l a r ke e t al_. (1977) showed feed ing de te r ren t p rope r t i e s aga ins t Locusta m i g r a t o r i a . The modes of a c t i on of d i f l ubenzu ron as an o v i c i d e , chemos te r i l an t and feed ing de te r ren t are not f u l l y understood. - 7 -Di f lubenzuron i s gene ra l l y formulated as a wet tab le powder. Th is may remain a c t i v e up to s i x months in s to red g ra i n (McGregor and Kramer 1 9 7 6 ) , three weeks on l e a f sur faces (Sahota and Shepard 1 9 7 5 ) , th ree weeks in water (Mu l la and Darwazeh 1 9 7 5 ) and has a h a l f - l i f e o f about two months in dry s o i l . D i f lubenzuron i s n o n - v o l a t i l e and qu i t e s t a b l e in extremes o f temperature and l i g h t . I t s water s o l u b i l i t y i s about 1 . 0 ppm at 2 5 ° C (Me tca l f e t al_. 1 9 7 5 ) . Research has been conducted i n to other fo rmu la t ions as we. l l . Ta f t and Hopkins ( 1 9 7 5 ) obta ined 98% s t e r i l i z a t i o n of adu l t b o l l weev i l s by app ly ing d i f l ubenzu ron i n a sprayab le b a i t o f i n v e r t sugar and molasses. L loyd e_tal_. ( 1 9 7 7 ) app l i ed d i f l ubenzu ron i n cot tonseed o i l aga ins t bo l l weev i l s , w i th e x c e l l e n t r e s u l t s . Other o i l f o rmu la t i ons have been i nves -t i g a t e d and hold promise (Johnson et a l . 1 9 7 8 ) , as d i f l ubenzuron so app l i ed might work.as a con tac t as we l l as a stomach po i son . The compound has been app l i ed aga in s t mosquitoes as a f l owab le concentrate and in a g ranu la r form as we l l as the wet tab le powder (Mu l la and Darwazeh 1 9 7 6 ) . The t o x i c i t y o f d i f l ubenzu ron to non- ta rget organisms appears to be r e l a t i v e l y low v i z . acute o ra l LDgg ( r a t s ) = 4 , 6 4 0 mg/kg, LC^Q ( b i r d s ) = 4 , 6 5 0 ppm and L C 5 Q i ( f i s h ) = 1 3 5 - 1 9 5 ppm (Anonymous 1 9 7 4 , 1 9 7 7 ) . I t appears to be non - tox i c to predatory mites (Wearing and Thomas 1 9 7 8 ; Bower and Kaldor 1 9 8 0 ) and na tura l enemies o f the pear p s y l l a (West igard 1 9 7 9 ) . L i t t l e hazard i s presented to Ap i s m e l l i f e r a L. (Anonymous 1 9 7 4 ) . There i s no apprec i ab l e accumulat ion of d i f l ubenzu ron i n b i o l o g i c a l food cha ins (Metca l f e t al_. 1 9 7 5 ) and MacGregor e_t al_. ( 1 9 7 9 ) observed no mutagenic p r o pe r t i e s . In many wel l -managed, s a n i t a r y orchards in the Similkameen Va l l e y no - 8 -i n s e c t i c i d e s were requ i r ed throughout the growing season as long as the cod l i ng moth was c o n t r o l l e d by the s t e r i l i t y program. Th is appears h igh l y advantageous to growers, but a se r ious d i f f i c u l t y may a r i s e as a r e s u l t . The r educ t i on ' i n number o f i n s e e t i c i d a l sprays. i n - B r i t i s h Columbia orchards because of s t e r i l i t y - c o n t r o l or i n t eg ra t ed con t ro l programs might r e s u l t i n h igher popu la t ions of apple pests not p r ev i ou s l y of economic s i g n i f i c a n c e (Madsen and Davis 1971). Th is was demonstrated by G lass and L ienk (1971) who conducted a study on a New York apple o r cha rd , ma in ta i n i ng i t f o r 10 years w i th no i n s e e t i c i d a l ' sp rays . Wi th in two yea r s , damage caused by the cod l i ng moth and apple maggot reduced the economic va lue of the crop to n i l . In a dd i t i o n to t h i s , popu la t ions of l e s s e r apple pests such as the plum cu r -c u l i o , the l e s s e r appleworm and severa l spec ies of l e a f r o l l e r s ( Lep idop te ra : T o r t r i c i d a e ) ' began to r i s e . In the i n t e r i o r o f B r i t i s h Columbia there appear to be f ou r major spec ies of l e a f r o l l e r s which a t t a ck app le . These i nc l ude the f r u i t - t r e e l e a f r o l l e r A rch ips a r g y r o sp i l u s (Wa lker ) , the European l e a f r o l l e r A rch ips  rosanus ( L . ) , the t h r e e - l i n e d l e a f r o l l e r Pandemis l i m i t a t a (Rob.) and the obi iquebanded l e a f r o l l e r Chor i s toneura rosaceana ( H a r r i s ) . These fou r spec ies are pests on pears , c h e r r i e s , a p r i c o t s and peaches as we l l (Madsen ejt al_. 1977; Madsen and Madsen 1980). Other app le - feed ing l e a f r o l l e r s are present i n B r i t i s h Columbia but not as s i g n i f i c a n t pests (Doganlar and Be i rne 1978, 1979). Adu l t l e a f r o l l e r s are s m a l l , be l l - shaped moths, the l a r vae of which feed on and r o l l up leaves o f va r i ous p l a n t s . Th i s f o l i a r symptom prov ides p ro t e c t i on aga ins t na tu ra l enemies, adverse environmental cond i t i ons and i n s e c t i c i d e s dur ing the l a r v a l and pupal s tages . D e f o l i a t i o n can be extremely severe , but i n commercial apple orchards f r u i t i n j u r y i s - 9 -much more important than f o l i a r damage. Larvae feed in buds and on young deve lop ing f r u i t l e t s , caus ing f lower abo r t i on and damage to the young f r u i t . The l a t t e r causes l a rge un s i gh t l y scars to develop as the f r u i t matures, which r e s u l t s i n downgrading (Chapman 1973). A- a r g y r o sp i l u s and A. rosanus are the most important l e a f r o l l e r pes t s , p a r t i c u l a r l y the former. While u sua l l y on ly marginal problems, t h e i r po t en t i a l s i g n i f i c a n c e i s c ons i de r ab l e , p a r t i c u l a r l y i n orchards where i n s e c t i c i d e use has been reduced by i n t eg ra t ed pes t management o r s t e r i l i t y - c o n t r o l f o r the cod l i ng moth (Madsen 1970; Madsen and Davis 1971). Both spec ies overw in te r i n egg masses and undergo a s i n g l e generat ion per year (Madsen 1970). A. a r gy r o sp i l u s and A. rosanus can be c o n t r o l l e d by pink or p e t a l - f a l l a p p l i c a t i o n s of az inphos -methy l , d i a z i non or t r i c h l o r f o n (Madsen et al_. 1977).. P r e sen t l y , growers are adv ised to spray .az inphos-methyl or d i a z i non a t p e t a l - f a l l , to reduce bee po i son ing (Anonymous 1980). P_. 1 im i t a t a and C. rosaceana were o r i g i n a l l y cons idered to be u n i v o l -t i n e in the Okanagan' V a l l e y (Venables 1924; Mayer and Be i rne 1974a,b) though P. 1 im i t a ta was recogn ized as b i v o l t i n e in Washington s t a t e (Mayer and Be i rne 1974b) and C_. rosaceana the same in New York s ta te (Chapman et a l . 1968). At the present t ime , both spec ies appear to be b i v o l t i n e i n the Okanagan and Similkameen V a l l e y s , ove rw in te r i ng as f i r s t - i n s t a r l a r v a e , and are i n c r ea s i ng i n numbers and economic s i g n i f i c a n c e (H.F . Madsen, per -sonal communication; R.D. McMul len, personal communication; Madsen and Madsen 1980).. During the 1979 growing season, which was p a r t i c u l a r l y hot and d r y , popu la t ions of P.' 1 im i t a t a and C_. rosaceana rose to se r i ous l e v e l s and a number o f growers were fo rced to spray aga in s t the second gene ra t i on . -10 -Azinphos-methyl was gene ra l l y s e l e c t e d . The problem was most se r ious on c he r r i e s because the second brood emerges j u s t p r i o r to normal cher ry harves-t i n g da tes . Sprays are not recommended a t t h i s t ime, but the presence of l a r vae and l a r v a l s i l k on the f r u i t neces s i t a t e s fumigat ion and/or c a r e f u l c l e an i ng , a t cons ide rab l e expense. I f the problem p e r s i s t s , a chemical spray of low t o x i c i t y to harves te rs which c o n t r o l l e d T e a f r o l l e r s e a r l y i n t h e i r l i f e c y c l e s would be a boon to cher ry growers (R.D. McMul len, personal communicat ion). I t can be seen tha t l e a f r o l l e r s a re s i g n i f i c a n t pests i n the Okanagan and Similkameen Va l l e y s and tha t the po t en t i a l of d i f l ubenzu ron as a con t ro l agent i s worthy of i n v e s t i g a t i o n . F i e l d t e s t s have suggested tha t l e a f -r o l l e r s are not h i gh l y s e n s i t i v e to d i f l ubenzu ron (Wearing and Thomas 1978), but these were f i e l d i n v e s t i g a t i o n s which d i d not eva lua te a l l l i f e stages to f i n d po s s i b l e areas of s u s c e p t i b i l i t y . S en s i t i v e l i f e stages should be cons idered when choosing the t ime , fo rmu la t i on and method of a p p l i c a t i o n of sp rays . A. a r g y r o sp i l u s and A. rosanus are d i f f i c u l t i n se c t s to study i n the l abo ra to r y because of a tendency to diapause every a l t e r n a t e gene ra t i on . There fo re , C_. rosaceana was s e l e c t ed as a r ep re sen ta t i ve t e s t spec ies of T o r t r i c i d a e . £• rosaceana i s a polyphagous i n s e c t which feeds on a long l i s t of unre la ted p l a n t s , but p re fe r s woody Rosaceae. I t i s na t i ve to and w ide ly d i s t r i b u t e d in temperate North Amer ica . C_. rosaceana appears to be u n i -v o l t i n e in co lde r Canadian a reas , b i v o l t i n e i n B r i t i s h Columbia and northern s t a t e s and t r i vol t i n e in Tennessee (Chapman et al_. 1968). I t i s one of the l a r g e s t and most fecund t o r t r i c i d s i n North America (Chapman and L ienk 1971). Th i s spec ies was recorded by Venables (1924) as the s i n g l e most important - 1 1 -l e a f r o l l e r i n the Okanagan V a l l e y p r i o r to 1918. I t s s i g n i f i c a n c e dec l i ned over the next 60 years u n t i l the present r i s e i n numbers. Cons ider ing the d i f f i c u l t i e s encountered i n the c l a s s i f i c a t i o n of the T o r t r i c i d a e (Chapman 1973), i t i s p o s s i b l e tha t severa l spec ies have been invo l ved w i t h i n the same nomenclature. Re i s s i g (1978) obta ined good con t ro l o f the obi iquebanded l e a f r o l l e r i n New York apple orchards w i th methyl para th ion and methomyl app l i ed a t p e t a l - f a l l and w i th az inphos -methy l , phosmet and methyl para th ion app l i ed in J u l y aga in s t the second gene ra t i on . In B r i t i s h Columbia, growers are adv ised to con t ro l the f i r s t (overw in te r ing) generat ion w i th the same measures used aga ins t the s i n g l e genera t ion l e a f r o l l e r s , and the second (summer) genera t ion w i th d i a z i non (Anonymous 1980). O r i en t a t i on d i s r u p t i o n of adu l t males us ing the s yn the t i c sex pheromone was i n s u f f i c i e n t to prov ide s a t i s f a c t o r y con t ro l (Re i s s i g et aj_. 1978) but the s yn the t i c pheromones have been improved ( H i l l and Roe lofs 1979) and have e x c e l l e n t po t en t i a l i n the mon i to r ing of popu la t ion l e v e l s of t h i s pes t . The i n t en t of t h i s study was to eva luate the e f f e c t i v ene s s of d i f l u -benzuron as a con t r o l agent f o r the cod l i ng moth. A second ob j e c t i v e was to determine the s e n s i t i v i t y o f C_. rosaceana to the growth r e gu l a t o r . In both cases , l abo ra t o r y s tud i e s on the s e n s i t i v i t y o f d i f f e r e n t l i f e stages preceded f i e l d t r i a l s i n Okanagan orchards through a t y p i c a l growing season. MATERIALS AND METHODS A. Rear ing Techniques Cod l ing moth eggs and adu l t s were supp l i ed by researchers a t the A g r i c u l t u r e Canada Research S t a t i o n , Summerland, B.C. V i r g i n adu l t c od l i ng moths were requ i r ed f o r c e r t a i n t e s t s so severa l broods were reared in immature apples of mixed c u l t i v a r s . The cu l t u r e s were mainta ined a t 25°C, 60% R.H. and 16-hour photoper iod . A f t e r feed ing in the app les , mature l a r vae crawled i n to and pupated w i t h i n corrugated wooden s t r i p s ( P l a t e I) where they were c o l l e c t e d and sexed. The sexed pupae were p laced i n sepa-r a t e cages to complete development to the adu l t s tage. Eggs were c o l l e c t e d from adu l t moths us ing a r o t a t i n g o v i p o s i t i o n cage l i n e d w i th wax paper ( P l a t e I I ) ( a f t e r Proverbs and Logan 1970). Egg masses of the obi iquebanded l e a f r o l l e r were c o l l e c t e d from Okanagan orchards by Dr. H.F. Madsen. A l abo ra to r y co lony was e s t ab l i s hed by i n i t i -a l l y r ea r i ng the l a r vae on an agar-based s yn the t i c d i e t composed of the f o l l ow i ng c on s t i t u en t s (modi f ied a f t e r Redfern 1964; B r in ton et aj_. 1969; Bucher and Bracken 1976; M.D. P roverbs , personal communicat ion): V i t am ins : Asco rb i c a c i d Vanderzant v i t am in mixture 10.0 g 2.5 g Agar c on s t i t u en t s : Agar 25.0 g 35.0 g 2.0 g 28.0 g 10.0 g 1.0 g 20.0 g 30.0 g 3.0 ml 30.0 ml 20.0 ml 550.0 ml Case in Cys te ine Wheat germ Wesson s a l t s W Cho l ine c h l o r i d e Methyl c e l l u l o s e Sucrose Soybean o i l 2 M K0H *Mold i n h i b i t o r D i s t i l l e d water - 13 -*Mold i n h i b i t o r : So rb i c a c i d 20.0 g 15.0 g 170.0 ml Methyl parahydroxybenzoate Ethy l a l coho l A f t e r mix ing the agar c o n s t i t u e n t s , the medium was heated to 90°C f o r 5 min and then coo led to 70°C, when the v i t am in mix tu re and a s co r b i c a c i d were added. F i ve to 10 ml of medium were p laced i n j e l l y cups (Redfern 1964) or whi te p l a s t i c cream con ta ine r s (Bucher and Bracken 1976). The con ta ine r s were covered w i th paper t owe l l i n g to reduce funga l spore contaminat ion and a l lowed to se t f o r 12-16 h to a l l ow excess water to evaporate . The conr t a i n e r s were then capped and r e f r i g e r a t e d at-4°C u n t i l r e qu i r e d . To compen-sa te f o r h igh m o r t a l i t y , two to fou r newly-emerged l a r vae were p laced i n each con ta ine r and r ea red a t cond i t i ons desc r ibed p r e v i o u s l y . Th i s r ea r i ng method gave a poor y i e l d of i n s e c t s as on l y 10-15% of the f i r s t - i n s t a r l a r vae su rv i ved to the adu l t s tage . In a dd i t i o n to t h i s , l a r v a l development l a s t e d fou r to s i x weeks wh i ch"necess i t a ted t r a n s f e r r i n g the l a r vae onto f r e sh medium two or three t imes . Consequent ly , a f t e r three generat ions on the s yn t he t i c d i e t , the l e a f r o l l e r s were reared e x c l u s i v e l y on broad beans ( V i c i a faba L.) ( P l a t e I I I ) . The p l an t s and a s soc i a t ed l e a f r o l l e r s were r a i s ed i n a greenhouse, under a 16-hour photoper iod but w i th v a r i a b l e tem-peratures (20-30°C) a n d r e l a t i v e humidi ty (70-95%). Al though d i f f i c u l t i e s encountered w i th t h i s r e a r i ng method l i m i t e d the a v a i l a b i l i t y of i n s e c t s , a l l t e s t s were conducted on f o l i a r - f e d l e a f r o l l e r s . Pupae were c o l l e c t e d from r o l l e d leaves and p laced in wax paper cages to complete development to the adu l t s tage ( P l a t e IV ) . Egg masses were c o l l e c t e d from the inner su r -faces of the cages. B. Tes t Compounds D i f lubenzuron ( D i m i l i n 25% W.P.; N-(4-ch loropheny l ) - N ' - ( 2 , 6 -- 1 4 -P l a t e I . Corrugated wooden s t r i p s used f o r c o l l e c t i o n o f c od l i n g moth l a r v ae . P l a t e I I . Ro ta t ing o v i p o s i t i o n cage used f o r c o l l e c t i o n of c od l i n g moth eggs. - 1 5 -P l a t e IV. Wax paper cage used f o r experiments on adu l t moths and f o r c o l l e c t i o n of l e a f r o l l e r eggs. -16 -d i f l u o r oben zoy l ) u rea; Thompson-Hayward Chemical Company) and the su r f a c t an t Tween 20 (po lyoxyethy lene (20) s o r b i t an monolaurate) were prepared a t va r i ous concen t ra t i ons in d i s t i l l e d water . The termino logy "par t s per m i l l i o n (ppm)" i s used to denote concen t ra t i on . , These va lues are equ i va l en t to micrograms of compound per m i l l i l i t r e of water . C. Tests on Eggs The contac t o v i c i d a l a c t i v i t y of d i f l ubenzu ron and/or Tween 20 was determined by app l y i ng the compound(s) to c od l i ng moth and l e a f r o l l e r eggs, u s ua l l y w i t h a f i n e "brush. ' The e f f e c t s on egg hatch were recorded d a i l y u n t i l emergence was-complete. Any hatched l a rvae were-removed to prevent cann iba l ism of eggs. The s e n s i t i v i t y of c od l i ng moth eggs a t va ry ing i n t e r -va l s a f t e r o v i p o s i t i o n w a s t e s t e d by observ ing the e f f e c t s o f -10 ppm d i f l u -benzuron on h a t c h a b i l i t y . Paper t owe l l i n g soaked in 10 ppm d i f l ubenzu ron was p laced on cod l i ng moth eggs f o r - d i f f e r e n t l e n g t h s o f t ime i n Order to determine the e f f e c t s o f d i f f e r e n t d ry ing ra tes on o v i c i d a l a c t i v i t y . The numbers of r e p l i c a t e s i n each study depended upon the a v a i l a b i l i t y of eggs, but each r e p l i c a t e u sua l l y cons i s t ed of 50 cod l i ng moth eggs or one l e a f -r o l l e r egg-mass, which conta ined ca . 50-600 eggs. The o v i c i d a l a c t i v i t y o f d i f lubenzuron/Tween 20 app l i ed to pear f o l i a g e and apples was a l s o assessed . The f o l i a g e , immature Golden De l i c i o u s apples and mature Spartan apples were dipped in d i f lubenzuron/Tween 20 s o l u t i on s and a l lowed to d ry . Female c od l i ng moths were a l lowed to o v i p o s i t on the t r ea t ed subs t ra tes f o r four to s i x days and the e f f e c t s on egg hatch r e -corded a f t e r l a r v a l ec los io r i was complete. To assess the r e s i dua l a c t i v i t y of d i f l ubenzu ron on f r u i t , immature Golden De l i c i o u s apples were dipped i n a s o l u t i o n . conta in ing 100 ppm"dif lubenzuron + 500 ppm Tween 20 and s to red i n cages f o r 10 days a t 25°C, .60% R.H. and 16-hour photoper iod . At the end of t h i s t ime, female cod l i ng moths were in t roduced and a l lowed to o v i p o s i t . To s imu la te the e f f e c t s o f r a i n or heavy dew on the e f f i c a c y of d i f l u ben zu ron , pear f o l i a g e which had been dipped in 100 ppm d i f l ubenzu ron + 500 ppm Tween 20 was sprayed to r un - o f f w i th d i s t i l l e d water on a d a i l y b a s i s . D* Tests on Larvae As young cod l i ng moth l a rvae have been observed to feed on apple f o l i -age p r i o r to en te r i ng t h e - f r u i t , the . t o x i c i t y o f d i f l ubenzu ron to f i r s t -i n s t a r l a r vae was assessed . Young apple p lan ts c a . 15 cm high were sprayed to r un - o f f w i th d i f lubenzuron/Tween 20 s o l u t i o n s and a l lowed to d ry . F i r s t -i n s t a r codl ing moth. la rvae were p laced in c l i p - c age s which we re -a f f i x ed to the f o l i a g e ( P l a t e V ) . A f t e r the l a r vae had fed on the f o l i a g e f o r one or two days ( P l a t e V I ) , they were t r an s f e r r ed onto app le s . The number of l a r -vae which s u c c e s s f u l l y entered the apples and su rv i ved to the 4 t h - i n s t a r stage was compared with- the success and development of untreated l a r v ae . F i r s t - i n s t a r l e a f r o l l e r l a r vae were p laced on t r ea ted pear f o l i a g e which had been dipped in d i f lubenzuron/Tween 20 s o l u t i o n s . Larva l s u r v i -va l was assessed over two weeks. F i r s t s 2nd- , 3 r d - , 4 t h - and 6 t h - i n s t a r l e a f r o l l e r l a r vae were 'p laced on t r ea ted apple f o l i a g e and t h e i r a b i l i t y to moult determined. E• Tests on Adu l t s One- to t h ree -day -o l d v i r g i n adu l t c od l i ng moths and l e a f r o l l e r s were dipped in or fed s o l u t i o n s of d i f l ubenzu ron and/or Tween 20. Four males and females were p laced in wax paper cages and a l lowed to d r i nk water or t reatment s o l u t i o n s from soaked co t ton w i c k s . Adu l t l o nge v i t y , f e cund i t y and egg v i a b i 1 i t y were assessed . P la te V. C l i p - c age used fo r t e s t s on f i r s t - i n s t a r c od l i n g moth l a r v ae . P l a t e V I . Apple f o l i a g e showing feed ing i n j u r y by c od l i n g moth f i r s t -i n s t a r l a r v a e . -19 -F. F i e l d -Tests i ) Cod l ing Moth A l l f i e l d t e s t s were conducted a t the A g r i c u l t u r e Canada Research S t a t i o n , Summerland. The e f f e c t i v ene s s of severa l d i f l ubenzuron fo rmu la -t i o n s was • 'evaluated aga in s t t ha t o f az inphos -methy l , which was app l i e d a t recommended r a t e s . The f i v e treatments which were eva lua ted inc luded 1) unsprayed check, 2) 47 ppm d i f l ubenzu ron , 3) 47 ppm d i f l ubenzu ron + 500 ppm Tween 20, 4) 187 ppm d i f l ubenzu ron and 5) 187 ppm az inphos-methy l . The c od l i n g moth t e s t s were-conducted i n an orchard of mixed c u l t i v a r s and an orchard of Golden D e l i c i o u s . Both orchards r e c e i v e d a s p r a y of d i a z i non on May 14, 1980 f o r con t ro l o f the San Jose s c a l e , Quadraspidaotus pe rn i c i o sus (Comstock). In the Golden De l i c i o u s o r cha rd , a balanced incom-p l e t e b lock des ign (Hicks T973) was s e l e c t e d , • w i th f i v e .b locks, , f i v e t reatments and f o u r " r e p l i c a t e s per treatment ( F i g . l a ) . Each r e p l i c a t e con-s i s t e d of th ree ad jacent t rees of the same e u l t i v a r , separated f rom-other r e p l i c a t e s by a t l e a s t one "bu f f e r " t r e e . In the mixed-cu l . t i va r o r cha rd , the check' t reatment was omit ted and i t s va lue i n f e r r e d by examinat ion -[oft bu f f e r t r e e s . • The remaining four treatments each"conta ined one r e p l i c a t e o f each e u l t i v a r (Mc i n t o sh , ' Spa r t an , D e l i c i o u s , Newtown and Rome), arranged i n a complete ly randomized des ign ( F i g . l b ) . Sprays were app l i ed a t * 21> 2 • kg/cm. us ing a convent iona l handgun sp raye r . Spray dates were se l e c t ed to co i n c i de w i t h t h e ' p e r i o d o f maximum f-1 i gh t a c t i v i t y which was determined w i th the use of Zoecon sex pheromone t raps (Myburgh et ajk 1974). Treatments were app l i ed a g a i n s t t h e f i r s t brood on May 28, 1980 (11 days a f t e r peak p e t a l - f a l l o f Mcintosh) and aga in s t the second brood on August 7, 1980. E f f e c t i v ene s s of the t reatments was assessed on the bas i s of percent c od l i ng -20 -F i g . 1. Schematic r ep r e sen t a t i on . o f the cod l i ng moth f i e l d - t e s t orchard, (0=buffer, •=check, »=47 ppm d i f l u ben zu ron , A=47 ppm d i f l u b e n -zuron + 500 ppm Tween 20, •=187 ppm d i f l ubenzu ron , H=187 ppm az inphos -methy l ) . a) Golden De l i c i o u s o rchard . (J) BLOCK: 1 • o B o • o • o • • o B o • o • o • • o B o • o • o • o o o o o o o o o • o • o a o • o • • o • o B o • o • • o • o IS o • o • o o o o o o o o o a o • o • o • o • B o • o • o • o • a o • o • o • o • o o o o o o o o o • o • o • o • o B • o • o • o • o SI • o • o • o • o a  2 3 4 5 b) Mixed c u l t i v a r o r cha rd . • o • o B O • o B O A o • o B o • o • • o • o B O • o B o A o • o B o • o • • o • o B O A o B o A o • o B o • o • o o o o O ' O o o O o o o o o O o o o o o o o o O O o o 0 o o o o o o o o o o A o • o B O • o • o A o • o A o B o • • o • o B O • o • o A o • o A o B o • A o • o B O • o • o A o • o A o B o • \ - 21 -moth damaged f r u i t a t ha rves t . i i ) ' M i tes Using methods desc r ibed by Downing and Arrand (1978), phytophagous and predaceous mites were c o l l e c t e d from f o l i a g e throughout the summer i n both cod l i ng moth t e s t o r chards . On'the va r ious -samp l ing da tes , 50. leaves were c o l l e c t e d a t random f r o m f i v e t rees in each t reatment . The leaves were brushed and the t o t a l numbers of predatory and pest m i t e s e o u n t e d . Wi th in each t reatment , the same f i v e t rees were used throughout the summer f o r mi te co l l e c t i o n s . i i i ) • Leaf r o l l e r s ' . The treatments t e s t ed "aga i n s t l e a f r o l l e r s inc luded 1) cheek, 2) 94 ppm d i f l u ben zu ron , 3) 94 ppm d i f l ubenzu ron + 500 ppm Tween 20, 4) 375 ppm d i f l u -benzuron and 5) 375ppm az inphos-methy l . The 'o rchard se l e c ted f o r t h i s study had rece ived few sprays in recent years and conta ined a mix ture of c u l t i v a r s . Because of the wide host range of l e a f r o l l e r s (Madsen and Madsen 1980), d i f f e r i n g s u s c e p t i b i l i t y between c u l t i v a r s was not a n t i c i p a t e d and no attempt was made to i s o l a t e the c u l t i v a r s . As i n the cod l i ng moth t r i a l s , each r e p l i c a t e cons i s t ed of th ree adjacent t r e e s , buf fe red from other r e p l i -c a t e s . The f i v e treatments were arranged in a randomized b lock des ign w i th f i v e b locks and f i v e r e p l i c a t e s per t reatment . ( F i g . 2 ) . As 15-20 l e a f r o l l e r l a r vae were found per 100 l e a f c l u s t e r s , the i n f e s t a t i o n exceeded the econo-mic t h re sho ld of 10 la rvae/100 c l u s t e r s (Madsen e t al_. 1977). A s i n g l e spray was app l i ed on A p r i l 26, 1980 a t the pink bud stage of Mc in tosh . At t h i s t ime, l e a f r o l l e r s were predominate ly a t the f i r s t - or 2nd - i n s t a r s tage . E f f e c t i v enes s of t reatments was assessed on the bas i s of percent l e a f r o l l e r damaged f r u i t a t ha rves t . ^22-F ig . 2. Schematic representation of the l e a f r o l l e r f i e l d - t e s t orchard. (-=dead or missing t ree, 0=buffer t ree, •=check, «=94 ppm dif lubenzuron, *=94 ppm diflubenzuron + 500 ppm Tween 20, •=375 ppm dif lubenzuron, B=375 ppm azinphos-methyl). • -\ \ • • 0 a • • 0 \ • \ 0 a ,'o A A A j - - • 0 0 \ \ \ \ \ IB 0 0 0 0 0 - • • a m 0 A \ t A / 0 0 ;o • • • 1 ° B - 0 a o • f 0 / 0 1 A A - 0 0 0 B B 0 • 1 1 0 A - • • • 0 0 0 • • 0 -1 0 0 0 0 0 0 • • 0 • • • 0 / •>«• 1 • - - a a 0 - - - • 0 -1 O 0 • o a 0 • 0 A 0 -0 • f • / 0 • • 0 0 0 • • 0 A A 0 Block 1 / Block 2 Block 3 Block 4 o m 0 A O • 0 0 B O • . 0 0 0 « . 0 A 0 * 0 0 B 0 B 0 0 Block 5 0 » O A 0 4 0 0 f f l O « 0 0 - 23 -G. S t a t i s t i c a l Ana l y s i s M u l t i p l e comparison procedures are used e x t en s i v e l y and o f ten i n c o r -r e c t l y i n s t a t i s t i c a l a na l y s i s of da t a . Such t e s t s should on ly be performed when an experiment conta ins a l a rge number of q u a l i t a t i v e t reatments ( L i t t l e 1978). Regress ion a na l y s i s i s the appropr i a te method f o r determin ing s t a t i s t i c a l s i g n i f i c a n c e of severa l l e v e l s o f a q u a n t i t a t i v e f a c t o r . When a r eg res s i on i s s i g n i f i c a n t , a l l t reatments are s i g n i f i c a n t l y d i f f e r e n t i n t h e i r e f f e c t s , i n c l ud i ng in te rmed ia te ones not used in the experiment (Chew 1976). F a c t o r i a l a n a l y s i s o f va r i ance t e s t s the e f f e c t s of two or more f a c -t o r s s imu l taneous l y , i n c l ud i ng i n t e r a c t i o n e f f e c t s of the f a c t o r s on each o the r . When treatments are q u a l i t a t i v e i n na tu re , the ana l y s i s of va r i ance w i th p a r t i t i o n e d degrees of freedom prov ides a powerful t e s t of much g rea te r r e l i a b i l i t y than m u l t i p l e comparison procedures (Chew 1976, 1980). Experiments i n vo l v i n g q u a n t i t a t i v e treatments were tes ted us ing r e -g re s s i on a na l y s i s and the method of orthogonal po lynomia ls ( L i t t l e and H i l l s 1978). Q u a l i t a t i v e treatments were analyzed us ing i n d i v i d u a l degree of . f r e edom . con t r a s t s . and . f a c t o r i a l a n a l y s i s was conducted when two f a c t o r s were t e s t e d . s imu l t a n eou s l y . ( L i 1964). The ana lyses of va r i ance of the above t e s t s were conducted a t the 5% s i g n i f i c a n c e l e v e l . The term "h i gh l y s i g n i -f i c a n t " i nd i c a t ed s i g n i f i c a n c e at the 1% l e v e l . P r ob i t ana lyses i n vo l v i n g g raph i ca l p l o t s and maximum l i k e l i h o o d t e s t s (F inney 1962) were used to determine LD^Q va lues f o r c od l i ng moth eggs, f i r s t - i n s t a r l a r vae and 2nd-i n s t a r l a r v ae . To c o r r e c t f o r na tura l m o r t a l i t y , Abbo t t ' s formula was app l i ed to the data p r i o r to p r ob i t a na l y s i s (Abbott 1925). The data ob-ta ined were condensed and tabu la ted i n the Resu l t s s e c t i o n . The raw data and s t a t i s t i c a l ana lyses were p laced in corresponding t ab l e s i n the Appendix. -24-RESULTS I . Laboratory S tud ies A. Cod l ing Moth i ) Ov i c i de Tests Table I shows the contac t o v i c i d a l a c t i v i t y o f d i f l ubenzuron app l i ed t o p i c a l l y w i t h a f i n e brush to eggs o f d i f f e r e n t ages. When d i f l ubenzuron was app l i ed to 3-day-o ld eggs, egg hatch was on ly s l i g h t l y i n h i b i t e d a t one ppm but was seve re l y reduced a t 100 ppm. Younger eggs (0-60 hours a f t e r o v i p o s i t i o n ) showed increased s e n s i t i v i t y to d i f l ubenzu ron . A l though a r e -duc t ion i n egg hatch was apparent a t 0.1 ppm, 100 ppm d i f l ubenzu ron produced over 95% suppress ion o f egg hatch . A f t e r c o r r e c t i n g f o r na tu ra l m o r t a l i t y (Abbott 1925) g raph i ca l p l o t s and maximum l i k e l i h o o d t e s t s were performed to determine L D ^ va lues f o r young and o l d eggs (Table I I ) . The LD va lues obta ined suggested grea te r s e n s i t i v i t y o f younger eggs to d i f l u benzu ron . I f such i s the case , the LD va lue f o r cod l i ng moth eggs would vary cons i de r -ab ly depending on the t im ing of t reatment . As embryonic development in the cod l i ng moth co lony was normal ly com-p l e t ed w i t h i n seven days, the s e n s i t i v i t y o f 0- to 132-h-o ld eggs to 10 ppm d i f l ubenzu ron was determined (Table I l i a ) . Th i s concen t ra t i on was chosen because i t produced in te rmed ia te ye t s i g n i f i c a n t egg m o r t a l i t y . Regress ion a na l y s i s showed a h igh l y s i g n i f i c a n t e f f e c t of egg age on s e n s i t i v i t y to d i f l u ben zu r on . Younger eggs were much more s e n s i t i v e , e s p e c i a l l y up to 60 h post o v i p o s i t i o n . When the t ime between o v i p o s i t i o n and treatment was reduced s t i l l f u r t h e r , i t was ev ident tha t eggs were more s e n s i t i v e to d i f l ubenzu ron when t r ea t ed immediately a f t e r o v i p o s i t i o n (Table 11 l b ) . -25 -Table I . Percent hatch and con t ro l of c od l i ng moth eggs t r ea ted t o p i c a l l y w i t h va ry ing concent ra t i ons of d i f l u ben zu ron . Egg age D i f lubenzuron % hatch (days a f t e r cone. o v i p o s i t i o n ) (ppm) (mean i S .E . ) % con t ro l 3 - d a y - o l d 2 0 78.5 ± 1.7 -1.0 69.0 ± 2.6 13.2 10.0 47.5 ± 5.1 40.3 100.0 18.5 ± 1.5 76.7 ( L inea r reg ress ion h igh l y s i g n i f i c a n t , quad ra t i c r eg res s i on s i g n i f i c a n t ) 2 i - d a y - o l d 0 68.7 ± 2.5 -0.01 70.4 - 2.4 0 0.1 50.0 ± 2.5 28.1 1.0 39.3 ± 2.0 43.5 10.0 , 8 . 9 ± 2.1 87.2 • 100.0 4.9 t 1.1 92.9 (L inear r eg ress i on h i gh l y s i g n i f i c a n t ) co r r e c t ed a f t e r Abbott (1925). 50 e g g s / r e p l i c a t e , four r e p l i c a t e s / t r e a t m e n t . 50 e g g s / r e p l i c a t e , n ine r e p l i c a t e s / t r e a tmen t . -26-Table I I . Maximum l i k e l i h o o d t e s t s on the t o x i c e f f e c t s of d i f l ubenzu ron to eggs of the cod l i ng moth. Parameter 3-day-o ld eggs 2^-day-old eggs No. eggs/treatment 200 450 Check m o r t a l i t y ± S .E . 21.5 ± 1 . 7 3 1 . 3 * 2 . 5 P r ob i t l i n e s lope ± S .E . 0.95 ± 0.11 0.82 ± 0.05 L D 5 Q (ppm) 17.2 1.1 95% conf idence l i m i t s 12.1 - 24.6 0.4 - 3.2 Heterogene i ty f a c t o r (X 2 ) 0.32 16.1 -27-Table I I I . Percent hatch of c od l i ng moth eggs t rea ted t o p i c a l l y w i th 10 ppm d i f l ubenzu ron a t va ry ing t imes from o v i p o s i t i o n . Egg age % hatch (hours a f t e r o v i p o s i t i o n ) (mean - S .E . ) a ) 1 0 - 36 15.6 i 2.9 36 - 60 18.0 - 2.3 60 - 84 41.3 ± 3.7 84 - 108 39.8 t 3.5 108 - 132 61.1 - 4.9 ( L i nea r - r eg r e s s i on h i gh l y s i g n i f i c a n t ) b ) 2 0 - 12 5.0 - 2.9 12 - 24 40.0 i 4.1 24 - 36 32.5 - 9.5 36 - 48 60.0 t 9.1 ( L inea r r eg ress i on s i g n i f i c a n t ) 50 e g g s / r e p l i c a t e , n ine r e p l i c a t e s / t r e a tmen t . 10 e g g s / r e p l i c a t e , fou r r e p l i c a t e s / t r e a tmen t . -28-In the prev ious t e s t s , d i f l ubenzu ron s o l u t i o n s remained in contac t w i th the eggs f o r upwards of four hours before d r y i n g . When d ry ing was acce l e ra ted w i th a fan in p r e l im i na r y t e s t s , h a t c h a b i l i t y i n c r ea sed . For t h i s reason, t e s t s were performed to determine the i n f l u ence of d ry ing r a te s on the o v i c i d a l a c t i v i t y o f d i f l u ben zu ron . As i nd i c a t ed i n Table IVa d i f l ubenzu ron was more e f f e c t i v e as an o v i c i d e when kept i n s o l u t i o n on the egg su r faces f o r longer per iods of t ime. In t h i s t e s t , the t ime in s o l u t i o n was manipulated by b l o t t i n g the eggs dry w i th paper t o w e l l i n g . However, w i th t h i s method i t was f e l t tha t l e s s : d i f l ubenzu ron res idue would be l e f t on the eggs than i f they d r i ed norma l l y . Consequent ly, the t e s t was repeated,except i n t h i s ins tance t ime i n s o l u t i o n was enforced by p l a c i ng d i f1ubenzuron-soaked paper t owe l l i n g i n contac t w i th the eggs f o r va ry ing i n t e r v a l s and then a l l ow ing the eggs to d r y . (Tab l e IVb) . Aga in , egg hatch was s i g n i f i c a n t l y reduced as time in s o l u t i o n i n c r eased . The su r f a c t an t Tween 20 was used i n l abo ra to r y s tud i e s to reduce the sur face tens ion of t e s t s o l u t i o n s and improve d i s t r i b u t i o n and r e t en t i o n on var ious su r f a ce s . The presence of Tween 20 apparen t l y enhanced the o v i c i d a l a c t i o n of d i f l ubenzu ron s o l u t i o n s app l i ed d i r e c t l y to 3-day-o ld and 1 to 2 day -o ld eggs (Table V ) . Mature apples dipped in d i f lubenzuron/Tween 20 s o l u t i o n s showed s i g n i -f i c a n t o v i c i d a l a c t i v i t y , but not e f f e c t i v e con t ro l (Table V i a ) . These apples were extremely waxy, however, and s o l u t i o n s tended to bead up and drop o f f even when Tween 20 was added. When immature apples were used, which were much l e s s waxy, the r e s i dua l o v i c i d a l a c t i on of d i f l ubenzu ron was e x c e l l e n t , p a r t i c u l a r l y when Tween 20 was inc luded (Table V Ib ) . Th i s r e s i dua l a c t i v i t y was unreduced 10 days a f t e r a p p l i c a t i o n . Res idual con t ro l -29 -Table IV. Percent hatch of c od l i ng moth eggs placed i n contac t w i t h 10 ppm d i f l ubenzu ron s o l u t i o n s f o r va ry ing per iods of t ime. Time i n s o l u t i o n (hours) % hatch (mean - S .E . ) a ) 1 0.25 77.5 i 1.3 0.5 69.5 - 1.3 1.0 71.5 t 1.5 2.0 61.5 t 1.3 4 .0 40.5 - 3.1 (Log 1 inear r eg res s i on h i gh l y s i g n i f i c a n t , l og quadra t i c and log cub ic reg ress ions s i g n i f i c a n t ) b ) 2 0.25 76.0 ± 3.6 0.5 64.2 - 2.8 1.0 60.2 ± 2.6 2.0 58.4 t 1.8 4.0 36.7 - 7.6 (Log l i n e a r r eg res s i on h i gh l y s i g n i f i c a n t , l og quadra t i c and log cub ic reg ress ions s i g n i f i c a n t ) 50 e g g s / r e p l i c a t e , four r e p l i c a t e s / t r e a tmen t , eggs b l o t t ed d ry . 50 e g g s / r e p l i c a t e , n ine r e p l i c a t e s / t r e a tmen t , eggs d r i ed normal ly a f t e r contac t w i t h soaked paper t o w e l l i n g . Table V. Percent hatch of cod l i ng moth eggs t r ea ted w i th d i f l ubenzu ron s o l u t i o n s in the presence (+) and absence (-) of Tween 20. 500 ppm 1 ppm 10 ppm % ha£ch Treatment Tween 20 d i f l ubenzuron d i f l ubenzu ron (mean - S .E . ) a ) 1 B + - 82.0 + 1.8 E - - + 40.5 + 3.0 • F..' + Contrasts : (B+E) versus (F) (B) versus (E) -+ 17.0 - h i gh l y s i g n i f i c a n t , h i gh l y s i g n i f i c a n t . + 2.1 b ) 2 A - - 76.0 + 1.6 B + - 76.4 + 1.8 C - + 68.9 + 2.5 D + + 63.3 + 2.5 E - - + 40.0 + 3.0 F + - + 32.7 + 2.9 F a c t o r i a l ANOVA: e f f e c t s of e f f e c t s of d i f l ubenzu ron - h i g h l y Tween 20 - s i g n i f i c a n t . s i g n i f i c a n t . 50 e gg s / r e p l i c a t e , four r ep l i c a t e s / t r e a tmen t , eggs 3 days o l d a t t ime of t rea tment . 50 e gg s / r e p l i c a t e , nine r ep l i c a t e s / t r e a tmen t , eggs 1-2 days o ld a t t ime of t reatment . Table V I . Hatchab i1 i t y o f cod l i ng moth eggs ov i po s i t ed on apples which had been dipped i n di f lubenzuron/Tween 20 s o l u t i o n s . Treatment 500 ppm Tween 20. 100 ppm d i f l ubenzuron % hatch (mean - S.E, a) A B C Cont ras t s : + + 81.0 ± 1.7 75;3 - 2.1 73.0 - 1.5' (A) v s . (B+C) - s i g n i f i c a n t . (B) v s . (C) - not ' s i g n i f i c a n t . b) ' + + + 67.3 - 1.8 40.2 - 2.1 21.2 t 1.5 19.5 t 1.2 Cont ras t s : (A) v s . (B+C+D) - h i gh l y s i g n i f i c a n t . (B) v s . (C+D) - h i gh l y s i g n i f i c a n t . - - . . . ,(C) v s . (D) - not s i g n i f i c a n t . 1 s i x mature Spartan apples per t reatment . •12 immature Golden De l i c i ous apples per t reatment . t he apples i n t h i s treatment were t rea ted 10 days e a r l i e r than the o t h e r s . -32 -of eggs was a l s o good on pear f o l i a g e (Table V i l a ) but was even be t te r i f the leaves were l e f t on twigs p laced i n water (Table V l l b ) , as these leaves remained t u r g i d and hea l thy much l onger . The rewet t ing t reatment , which s imu la ted r a i n or heavy dew, decreased the r e s i dua l o v i c i d a l a c t i v i t y o f d i f l ubenzu ron (Table V11b), but apparen t l y not s i g n i f i c a n t l y . 1 1 ) L a r v i c i d e Tests . F i r s t - i n s t a r l a r vae showed high m o r t a l i t y when fed agar medium con-t a i n i n g d i f l ubenzu ron / (Tab l e V i l l a ) . Second- ins ta r l a rvae appeared even more su s cep t i b l e (Table V11 l b ) . M o r t a l i t y occurred dur ing the moult; a f -f ec ted l a r vae were unable to shed t h e i r exuv iae or formed t h i n c u t i c l e s which ruptured e a s i l y . P r ob i t a n a l y s i s was conducted to determine LD^Q va lues f o r both i n s t a r s (Table I X ) . The 2nd - i n s t a r l a r vae appeared more s e n s i t i v e than the f i r s t - i n s t a r l a r v ae . F i r s t - i n s t a r l a r vae which had been fed d i f l ubenzu ron - t r ea t ed apple f o l i a g e f o r 1-2 days were p laced on app les . The var ious treatments had no s i g n i f i c a n t e f f e c t on the a b i l i t y of the l a rvae to penetrate the apples (Table Xa) . However, both d i f l ubenzu ron concen t ra t i on and time of feed ing were found to be s i g n i f i c a n t f a c t o r s i n the subsequent s u r v i v a l of l a r vae (Table Xa) . Su r v i va l was assessed on ly to the 4 t h - i n s t a r because of r ap i d d e t e r i o r a t i o n of app les . While most l a rvae s u c c e s s f u l l y entered app les , the ma j o r i t y of those which fed on 500 ppm d i f l ubenzu ron - t r ea t ed f o l i a g e d i d not moult s u c c e s s f u l l y i n t o 2 nd - i n s t a r s . They d ied c a . 8 mm i n s i d e the app l e s , l eav ing a smal l b lemish ( " s t i n g " ) . Newly emerged l a rvae which were p laced on sprayed apples w i thout p r i o r feed ing on d i f l ubenzu ron - t r ea t ed f o l i a g e s u c c e s s f u l l y entered and fed on the f r u i t w i th no apparent inc rease in m o r t a l i t y (Table Xb). Table V I I . H a t c h ab i l i t y of cod l i ng moth eggs o v i po s i t ed on pear f o l i a g e which had been dipped in di f lubenzuron/Tween 20 s o l u t i o n s . Treatment 500 ppm Tween 20 100 ppm d i f l ubenzuron % hatch (mean - S .E . ) a) b) ' A B A B C + - 79.9 - 2.2 +• + 36.1 - 3.3 Cont ras t : (A) v s . (B) - h i gh l y s i g n i f i c a n t . 94.3 - 2.2 + + Cont ras t s : + + + 48.1 - 9.5 26.7 - ' 4 . 5 40.1 ± 7.6 (A) vs . (B+C+D) - h i gh l y s i g n i f i c a n t . (B) vs . (C+D) - not s i g n i f i c a n t . (C) v s . (D) - not s i g n i f i c a n t . 1 s i x l eaves/ t rea tment , leaves not sus ta ined by water. 2 n i n e l eaves/ t rea tment , leaves at tached to twigs placed in water . 3 t h e f o l i a g e i n t h i s treatment was rewetted d a i l y w i th d i s t i l l e d water. Table V I I I . M o r t a l i t y -Of a) f i r s t - and b) 2nd - i n s t a r cod l i ng moth l a r vae feed ing on agar medium con ta i n i ng va r ious concen-t r a t i o n s o f ; d i f l u b e n z u r o n . D i f lubenzuron % m o r t a l i t y cone. (ppm) (mean ± S .E . ) a ) 2 0 15.0 + 5.0 io' 45.0 + 9.6 50 50.0 + 5.8 100 70.0 (L inear r eg res s i on s i g n i f i c a n t ) + 5.8 b ) 3 0 20.0 + 8.2 10 65.0 + 9.6 50 85.0 + 5.0 100 95.0 (L inear r eg ress i on s i g n i f i c a n t , quadra t i c r eg res s i on s i g n i f i c a n t ) + 5.0 ^modif ied from Anderson (1978). 2 f i v e f i r s t - i n s t a r l a r vae per r e p l i c a t e ( j e l l y cup) , 4 r e p l i c a t e s / t rea tment , m o r t a l i t y assessed a f t e r 14 days. f i v e 2nd - i n s t a r l a r vae per r e p l i c a t e ( j e l l y cup) , 4 r e p l i c a t e s / t reatment , m o r t a l i t y assessed a f t e r 10 days. -35 -Table IX. Maximum l i k e l i h o o d t e s t s on the t o x i c e f f e c t s o f d i f l ubenzu ron to l a r vae of the cod l i ng moth. Parameter l s t - i n s t a r l a rvae 2nd - i n s t a r l a r vae No. l a rvae/ t rea tment 20 20 Check m o r t a l i t y - S .E . 15.0 ± 5.0 20.0 - 8.2 P r ob i t l i n e s lope ± S .E . 0.69 - 0.48 1.28 ± 0.53 L D 5 Q (ppm) 48.2 8.13 95% conf idence l i m i t s 1 3 . 6 - 1 7 1 . 0 2 . 2 - 3 0 . 0 Heterogene i ty f a c t o r C* 2) 1.10 0.38 Table X. Penet rat ion of apples and su r v i v a l to 4 t h - i n s t a r by c od l i n g moth f i r s t - i n s t a r l a r vae , a f t e r feed ing on apple f o l i a g e sprayed w i th d i f l ubenzuron/Tween 20. D i f lubenzuron 500 ppm days % ente r ing apples % su r v i v a l to 4 t h - i n s t a r cone. Tween 20 feeding (mean ± S .E . ) (mean ± S .E . ) (ppm) 0 - 1 87.5 ± 4.8 65.0 - 5.0 2 80.0 ± 4.1 65.0 ± 6.5 0 + 1 85.0 t 2.9 70.0 t 4.1 2 87.5 ± 4.8 65.0 ± 2.9 10 + 1 85.0 t 2.9 . 65.0 ± 5.0 2 82.5 ± 4.8 60.0 ± 4.1 100 + 1 85.0 ± 5.0 70.0 ± 4.1 2 70.0 ± 7.1 52.5 - 2.5 500 + 1 85.0 ± 2.9 27.5 ± 4.8 2 77.5 ± 4.8 15.0 ± 6.5 F a c t o r i a l ANOVA (on % ente r ing app l e s ) : no s i g n i f i c a n t d i f f e r en ce s between t rea tments . (on su r v i v a l to 4 t h - i n s t a r ) : e f f e c t of d i f l ubenzu ron - h i gh l y s i g n i f i c a n t . e f f e c t o f t ime feed ing - s i g n i f i c a n t . b ) 2 0 + 0 75.0 60.0 500 + 0 80.0 60.0 ' ten l a r vae and a p p l e s / r e p l i c a t e , four r ep l i c a t e s / t r e a tmen t . 2 2 0 l a r vae and app les/ t rea tment . Newly-emerged l a rvae were p laced on sprayed apples w i thout f o l i a r f eed i ng . -37-1 i 1 ) Tox ic and chemos te r i l an t t e s t s on adu i t s The t o x i c and chemos te r i l an t p rope r t i e s were i n i t i a l l y assessed by d ipp ing the adu l t s i n s o l u t i on s con ta i n i ng va ry ing concent ra t i ons of d i f l u -benzuron (Table X I ) . Longev i ty was not s i g n i f i c a n t l y reduced by the t r e a t -ments, a l though males l i v e d longer than females . Egg v i a b i l i t y was a l s o una f f e c ted . S ince the number of eggs l a i d could be a f f e c t ed by l ongev i t y of females , f e cund i t y was assessed and analyzed in terms of eggs/cage and eggs/female/day. In both i n s t ance s , r eg res s i on ana l y s i s showed s i g n i f i c a n t reduc t i on i n f e cund i t y due to d i f l ubenzu ron t reatments . When these t e s t s were repeated w i th Tween 20 /d i f l ubenzuron m ix tu res , f e cund i t y was not r e -duced (Table X I I ) . The treatments had no e f f e c t on adu l t l o ngev i t y or f e cund i t y , but egg hatch was s i g n i f i c a n t l y reduced a t 100 ppm d i f l ubenzuron as compared to 10 ppm. Adu l t moths fed d i f l ubenzuron s o l u t i o n s showed no r ea c t i on i n terms of l ongev i t y or f e cund i t y , but egg v i a b i l i t y was s i g n i -f i c a n t l y reduced (Table X I I I ) . B. Obiiquebanded Lea f r o l1e r i ) Ov i c i de Tests The egg masses of the obi iquebanded l e a f r o l l e r showed a c o n s i s t e n t l y poor hatch even i n the checks (Table X IV) . Mold was one reason f o r t h i s , and i t i s po s s i b l e tha t poor f e r t i l i z a t i o n was a l s o r e spon s i b l e . Th is compl icated i n v e s t i g a t i o n s on the s u s c e p t i b i l i t y o f egg masses to d i f l u b e n -zuron . I t was apparent , however, tha t s u s c e p t i b i l i t y to d i f l ubenzu ron was low s i n ce even 1,000 ppm d i f l ubenzu ron had no de tec tab l e i n h i b i t o r y i n f l u ence on egg hatch. Regress ion a na l y s i s showed no e f f e c t , even when egg masses which showed no hatch were excluded from a n a l y s i s . Desp i te the presence of a conspicuous depos i t o f d i f l ubenzu ron on the egg masses, the l a r vae which Table X I . Longev i ty , f e cund i t y and egg v i a b i l i t y of adu l t c od l i ng moths dipped i n d i f lubenzuron s o l u t i o n s . D i f lubenzuron Male Female Fecundi ty* Fecundi ty* % hatch cone. l ongev i t y l ongev i t y (ppm) 1 (days) (days) (eggs/cage) Ceggs/J/day) 0 15.2 ± 1 . 3 9.7 ± 1.6 521.3 ±117 . 7 14.6 ± 1 . 9 65.9 ± 8 . 8 10 8.9 ± 1.5 9.1 - 1 . 9 248.3 ± 56.3 7.0 ± 0 . 8 69.4 ± 9 . 1 100 9.2 ± 1 . 3 6.8 ± 1 . 5 194.7 ± 13.9 7.4 ± 1 . 0 65.9 ± 9 . 1 * L i near r eg ress i on s s i gni f i cant fou r males and females/cage, three cages/t reatment. Table X I I . Longev i ty , f ecund i t y and egg v i a b i l i t y of adu l t c od l i n g moths dipped i n di f lubenzuron/Tween 20 s o l u t i o n s . D i f lubenzuron 500 ppm Male Female Fecund i ty Fecund i ty % hatch* cone. Tween 20 l ongev i t y l ongev i t y (PPm) 1 (days) (days) (eggs/cage) (eggs/g/day) (A) 0 12.0 + 1.1 9.3 ± 1 .3 550.1 t 1.8 14.6 ± 4.2 75.6 + 6.5 (B) 10 8.6 + 1.2 9.2 i 1 .0 418.7 ± 47.9 11.3 ± 2.9 84.6 + 2.7 (C) 100 9.3 + 1.5 9.8 ± 0 .8 546.3 ± 53.2 13.8 - 3.5 75.3 + 2.5 (D) 100 + 7.8 + 1.0 10.1 i 1 .1 374.3 ± 156.2 11.2 t 4.7 64.4 + 6.0 *Cont ras t s : % hatch of (B) s i g n i f i c a n t l y g rea te r than (C+D). four males and females/cage, three cages/t reatment. Table X I I I . Longev i ty , f e cund i t y and egg v i a b i l i t y of a du l t c od l i ng moths fed d i f l ubenzuron s o l u t i o n s . D i f lubenzuron Male Female Fecundi ty Fecund i ty % h a t c h * c o n e , l ongev i t y l ongev i t y (.ppm)1 (days) (days) (eggs/cage) (eggs/g/day) 0 12.0 ± 0.9 10.1 ± 0.7 514.7 ± 35.5 13.2 ± 2.0 81.4 ± 3.0 10 11.8 ±0 .8 11.5 - 1.0 563.3 ± 129.1 12.1 ±2 . 3 79.9 ± 3.1 100 11.6 ±0 .9 11.7 ± 1.0 603.0 ± 27.6 12.9 ± 0.6 61.6 ±7 .3 ' : * L inear regress ion s i g n i f i c a n t four males and females/cage, three cages/treatment. - 4 1 -Table XIV. Percent hatch of l e a f r o l l e r egg masses t o p i c a l l y t r ea ted w i th va ry ing concent ra t i ons of d i f l u ben zu ron . D i f lubenzuron % hatch 1 % hatch^ cone. (ppm) (mean - S .E . ) (mean ± S .E . ) 0 22.9 ± 14.0 57.2 + 1.0 • 1, 37.9 - 17.5 63.1 + 15.0 10 33.9 - 16.5 42.4 + 18.3 100 62.1 ± 15.8 77.6 + 3.8 1,000 36.0 - 15.2 60.0 + 7.1 reg ress ions not s i g n i f i c a n t a l l egg masses inc luded i n the c a l c u l a t i o n s ; f i v e masses/treatment. those egg masses which showed no hatch were excluded from the c a l c u l a t i o n s . -42 -emerged were apparent ly hea l thy and e xh i b i t e d no subsequent i l l e f f e c t s . i i ) L a r v i c i d e Tests When f i r s t - i n s t a r l e a f r o l l e r l a rvae were reared on pear f o l i a g e tha t had been dipped i n va ry ing concent ra t ions of d i f l ubenzu ron and/or Tween 20, l a r v i c i d a l e f f e c t s were apparent (Table XV). Desp i te high l a r v a l m o r t a l i t y i n the check t reatment , f a c t o r i a l a n a l y s i s of var iance found s i g n i f i c a n t i n t e r a c t i o n of d i f l ubenzuron w i th Tween 20. The e f f e c t s of d i f l ubenzu ron a lone were not s i g n i f i c a n t , i n d i c a t i n g the importance of the su r f a c t an t i n enhancing the a c t i on of d i f l ubenzu ron . The m o u l t - i n h i b i t i n g p rope r t i e s of d i f lubenzuron/Tween 20 were assessed on the l a r v a l i n s t a r s (Table XVI ) . A l -though the l i m i t e d a v a i l a b i l i t y o f i n sec t s prec luded s t a t i s t i c a l a n a l y s i s , l a r v a l s u s c e p t i b i l i t y was apparent . D i f f e rences i n 5 s e n s i t i v i t y between i n -s t a r s cou ld not be determined. i i i ) Tox i c and chemos te r i l an t t e s t s on adu l t s Adu l t l e a f r o l l e r moths dipped i n 100 ppm d i f l ubenzu ron showed a s i g n i -f i c a n t reduc t i on in l o ngev i t y when compared to those dipped in 0 ppm d i f l u -benzuron (Table XV I I ) . No reduc t i on was observed in f e cund i t y or egg v i a b i 1 i t y . I I . F i e l d Tests A. L ea f r o l 1 e r t e s t The seasonal abundance o f four l e a f r o l l e r spec ies i n the t e s t orchard i s shown i n F i g . 3. The two-generat ion l e a f r o l l e r s , p a r t i c u l a r l y C_. rosaceana, were the most abundant t o r t r i c i d s , as i nd i c a t ed by the catches of sex pheromone t r a p s . Trapping was c u r t a i l e d in mid-August, consequent ly the captured moths were l i k e l y f i r s t - g e n e r a t i o n adu l t s (see Madsen and Madsen 1980). Table XVIII shows the percent of harvested apples e x h i b i t i n g - 43 -Table XV. Percent s u r v i v a l of f i r s t - i n s t a r l e a f r o l l e r l a r vae feed ing on pear f o l i a g e which had been dipped in d i f lubenzuron/Tween 20 s o l u t i o n s . D i f l ubenzuron 500 ppm % s u r v i v a l 1 cone. Tween 20 (ppm) (mean ± S .E . ) 0 - 44.5 ± 1 1.1 0 + 88.9 ± 1 1.1 10 - 66.7 ± i 1.1 10 + 55.5 ± " 1.1 100 - 55.5 ± " 1.1 100 + 11.1 ± " 1.1 F a c t o r i a l ANOVA: d i f l ubenzu ron X Tween 20 i n t e r a c t i o n - s i g n i f i c a n t . three l a r v a e / l e a f , three l eaves / t rea tment , s u r v i v a l assessed a f t e r 14 days o f f e ed i ng . Table XVI. Mou l t ing success of f i v e l e a f r o l l e r l a r v a l i n s t a r s p laced on appl f o l i a g e sprayed w i th di f lubenzuron/Tween 20 s o l u t i o n s . * d i f l e T u r o n T ^ 2 0 l s t i n s t - ^ i n s t a r 3rd i n s t a r 4th i n s t a r 6th i n s t a r one l a r v a / p l a n t , f i v e p l an t s / t rea tment . i -Pi I Table "XVII. Longev i ty , f ecund i t y and egg v i a b i l i t y of a du l t l e a f r o l l e r moths dipped i n di f lubenzuron/Tween 20 s o l u t i o n s . 100 ppm 500 ppm Male Female Fecundi ty Fecund i ty % hatch l ongev i t y* l ongev i t y* d i f l ubenzu ron 1 Tween 20 (days) (days) (eggs/cage) (eggs/^/day) + 5.8 t 0.6 6.2 t 0.7 1040.8 ± 87.7 42.5 - 4.7 49.6 ± 3.5 + + 4.3 ± 0.6 5.2 - 0.6 850.2 ± 82.0 42.1 ± 6.9 52.1 - 6.4 * Cont ras t : s i g n i f i c a n t reduc t i on i n l ongev i t y at 100 ppm d i f l u ben zu r on . fou r males and females/cage, four cages/t reatment. 3. Seasonal abundance of four l e a f r o l l e r spec ies i n the t e s t orchard dur ing summer, 1980. A A C rosaceana A • f\ limitata • • • •• rosanus Table XV I I I . Percent of harvested apples showing l e a f r o l l e r damage. Treatment 94 ppm 375 ppm 375 ppm 500 ppm % damage d i f lubenzuron d i f l ubenzuron az inphos-methyl Tween 20 (mean - S .E . ) A - - - ' - 15.8 ± 1.4 B + - - - 12.1 - 0.9 C + - - + • 10.2 ± 0.8 D ' +• - - . 7;9 ± 0.9 E - - + - 1.9 ± 0.3 Con t ras t s : (A) v s . (B+C+D+E) - h i gh l y s i g n i f i c a n t . (B) v s . (C) - not s i g n i f i c a n t . (B) v s . (D) - s i g n i f i c a n t . (D) vs . (E) - ^ s i g n i f i c a n t . -48-l e a f r o l l e r damage i n the t e s t o r cha rd . The high number of adu l t s present i s r e f l e c t e d i n a high damage r a t e in the check t reatment , where 15.8% f r u i t damage occu r red . At recommended ra tes (375 ppm) az inphos-methyl was the , most e f f e c t i v e treatment t e s t e d , as on ly 1.9% i n j u r y r e s u l t e d . At compar-ab le r a t e s , d i f l ubenzu ron reduced the i n f e s t a t i o n , but cons ide rab l y l e s s than az inphos -methy l . The lower- d i f l ubenzu ron concen t ra t i on was l e s s e f f e c -t i v e and percent damage was not s i g n i f i c a n t l y reduced by the add i t i o n of Tween 20. B > Cod l ing Moth Tests F i g . 4 shows the seasonal abundance of the cod l i ng moth in orchards at the Summerland Research S t a t i o n dur ing the summer of 1980. Two broods were observed to emerge, the f i r s t i n l a t e May to e a r l y June and the second in e a r l y August. Large numbers o f f i r s t - g e n e r a t i o n moths emerged in mid-May, approx imate ly a t the p e t a l - f a l l s tage . F r u i t would not have developed s u f f i c i e n t l y a t t h i s stage to prov ide food f o r young l a r v a e . I t i s po s s i b l e tha t the m i ld w in te r and hot sp r i ng of 1979-1980 induced premature emergence of the f i r s t brood. Poor s u r v i v a l of t h i s f i r s t generat ion may have been the major reason f o r the low subsequent i n f e s t a t i o n s . Cod l ing moth damage to harvested apples from the m i x ed - c u l t i v a r orchard i s shown i n Table XIX. A check treatment was not i n c l uded , but examinat ion of bu f f e r t rees gave an approximate va lue of 2.0% damage. Whi le low, t h i s i s s t i l l above the economic th resho ld of c a . 0.5-1.0%. The Rome t rees set very few f r u i t , so were not inc luded in the a n a l y s i s . D i f lubenzuron appeared to g ive be t t e r con t ro l than az inphos-methyl when app l i ed a t recommended ra tes (187 ppm), but the two treatments were not s i g n i f i c a n t l y d i f f e r e n t . The presence of Tween 20 s i g n i f i c a n t l y enhanced the a c t i on of 47 ppm d i f l u b e n -F i g . 4. Seasonal abundance of the cod l i ng moth in*Summerland orchards dur ing summer, 1980. Spray.dates are i nd i c a t ed by ar rows. Table XIX. Percent of harvested apples o f mixed c u l t i v a r s showing cod l i ng moth damage. Treatment 1 47 ppm 187 ppm 187 ppm 500 ppm % damage d i f l ubenzuron d i f l ubenzuron az inphos-methyl Tween 20 (mean - S .E . ) A + - - 2.0 + 0.7 B + - + 0.8 + 0.1 C - + • - 0.4 + 0.1 D — Cont ras t s : (A) (A) .(C) vs . v s . vs . (B) (C) (D) + - s i g n i f i c a n t . - s i g n i f i c a n t . - not s i g n i f i c a n t . 0.7 + 0.2 est imated check i n f e s t a t i o n = 2.0%. zu ron . The higher d i f l ubenzuron concen t ra t i on gave s i g n i f i c a n t l y be t t e r con t ro l than the lower d i f l ubenzuron concen t r a t i on . Table XX shows the cod l i ng moth damage to harvested Golden De l i c i o u s app le s . The i n f e s t a t i o n i n the check treatment was s i g n i f i c a n t l y g rea te r than the average of the other four t rea tments , but no f u r t h e r d i f f e r en ce s between treatments were found. C. Mi tes The use of c od l i ng moth con t ro l measures which do not d i s r up t predaceous mites i s c r i t i c a l i n apple pest management. Two f a c t o r s which are c r i t i c a l i n determin ing European red mite i n f e s t a t i o n s are the numbers of red mites per l e a f (economic th resho ld c a . 15-30) and numbers of red mites per phyto-s e i i d mite (economic th resho ld c a . 10:1) (Downing and Arrand 1978). Both th resho lds should be exceeded before proceeding w i th a c a r i c i d a l sp rays . As shown in F i g . 5, none of the treatments used aga ins t the cod l i ng moth r e s u l -ted i n dangerous l e v e l s of red m i t e s . The most common predator was the phy t o se i i d Typhlodromus occ i den ta l i s N e s b i t t , but other phy t o se i i d spec ies and the s t igmae id Z e t z e l l i a mal i (Ewing) were present as w e l l . M i c roscop i c examinat ion found no ev idence o f t o x i c i t y to these p reda to r s . Whi le r u s t mites were present throughout the season, they were not abundant and never exceeded 10 mites per l e a f . The McDaniel sp ide r mite (Tetranychus mcdan ie l i McGregor) and the two-spotted sp ide r mite (J_. u r t i c a e (Koch)) were seldom observed. Table XX. Percent of harvested Golden De l i c i ous apples showing cod l i ng moth damage. Treatment 47 ppm 187 ppm 187 ppm 500 ppm % damage d i f l ubenzuron d i f l ubenzuron az inphos-methyl Tween 20 (mean ±*S.E.) '.A ' - - - 2.1 + 0.2 B + - - 0.8 + 0.1 C + - + 0.8 + 0.1 D - + - 0.5 + 0.1 E Cont ras t s : (A) (B) (B) (D) v s . v s . vs . v s . + (B+C+D+E) - s i g n i f i c a n t . (C) - not s i g n i f i c a n t . (D) - not s i g n i f i c a n t . (E) - not s i g n i f i c a n t . 0.4 + 0.1 -53 -F i g . 5. European red mite numbers, per l e a f and per phy t o s e i i d , : i n the cod l i ng moth f i e l d t e s t orchards dur ing summer, 19,80. Spray dates are i nd i c a t ed by arrows. 10 J DISCUSSION During the l a s t two decades, apple i n s e c t cont ro l s t r a t e g i e s have evolved away from a t o t a l r e l i a n c e on i n s e c t i c i d e s (Hoyt and Burts 1974). By - i n co rpo ra t i ng b i o l o g i c a l and c u l t u r a l c on t r o l s wherever f e a s i b l e , a long w i th ca re fu l a p p l i c a t i o n of more s e l e c t i v e p e s t i c i d e s , chemical con t ro l measures can be s i g n i f i c a n t l y reduced. Pheromone t raps and other mon i to r ing techniques can be used to determine numbers of pest i n sec t s and dates of peak a c t i v i t y . Th is con t r i bu te s to a r educ t i on i n chemical sprays by a l -lowing g rea te r e f f i c i e n c y and accuracy in a p p l i c a t i o n of p e s t i c i d e s (Myburgh et al_. 1974). S t e r i l e i n s e c t r e l ease and the pheromone confus ion method show promise and may make va luab le c on t r i b u t i o n s to f u tu r e apple pest manage-ment (Hoyt and Burts 1974). I t seems l i k e l y , however, tha t p e s t i c i d e s w i l l remain the major recourse of the pest manager i n the fo reseeab le f u t u r e . Organophosphate i n s e c t i c i d e s such as az inphos-methyl are used e f f e c -t i v e l y f o r con t ro l o f apple pe s t s . Th is i s due in par t to the r e s i s t an ce of many b e n e f i c i a l a r th ropods , no tab ly predaceous m i t e s , to the compounds (Hoyt 1969). Un t i l t h i s r e s i s t an ce deve lops , a p e s t i c i d e may be extremely nonse l e c t i v e and e l im i n a t e na tu ra l enemies of a number of pe s t s . The c a r -bamate i n s e c t i c i d e s , f o r example, are not as s e l e c t i v e as the organophos-phates (Downing and Arrand 1978), probably s i nce the l a t t e r have been i n use f o r much longer pe r i ods . However, concur rent r e s i s t an ce to organophosphates has a l s o been observed w i th a number o f l e s s e r apple pests i n c l ud i ng l e a f -r o l l e r s , l ea fhoppers , aphids and l e a f miners (C ro f t 1979). There fo re , i t i s po s s i b l e tha t r e s i s t an ce may develop in major pests such as the cod l i ng moth, p a r t i c u l a r l y i n areas w i t h i n the Un i ted S ta tes where growers may have been -55 -us ing organophosphorous compounds f o r over 20 years (C ro f t 1979). I t i s po s s i b l e tha t d i f f e r e n t groups of chemica ls may be requ i red f o r con t ro l of app le pests i n the near f u t u r e . Such a change in con t ro l measures might r e s u l t i n a d i s r u p t i o n of b e n e f i c i a l ar thropods because of broad-spectrum e f f e c t s . U n t i l r e s i s t a n t s t r a i n s of these spec ies deve lop, apple pest management would be much l e s s e f f i c i e n t than i t i s a t p resent . The carbamates and p a r t i c u l a r l y the s yn the t i c py re th ro ids are l i k e l y cand idates f o r apple pest con t ro l (Hoyt et al_. 1978). The py re th ro ids are of low mammalian t o x i c i t y and are h i gh l y t o x i c to many pest spec ies (C ro f t and Hoyt 1978). However, the problem of n o n s p e c i f i c i t y , p a r t i c u l a r l y aga ins t predaceous m i t e s , has a l ready been observed (Hoyt e_t al_. 1978; Wong and Chapman 1979). As desc r ibed i n the I n t r oduc t i on , f i e l d s tud ies have shown tha t d i f l u -benzuron has cons i de rab l e po t en t i a l i n the i n t eg ra ted con t ro l of orchard pests (Cranham 1978; Wearing and Thomas 1978; West igard 1979). The compound has a low mammalian t o x i c i t y (Anonymous 1974) and would pose l e s s hazards to the a p p l i c a t o r than most r e g i s t e r e d compounds. In a d d i t i o n , the compound i s more s e l e c t i v e than many convent iona l i n s e c t i c i d e s . Because d i f l ubenzu ron i s non-systemic i n p l an t s (Bu l l and I v i e 1978) and ac ts p r i m a r i l y as a stomach poison (Post and V incent 1973), i t i s t o x i c to p l an t - f eed i ng spec ies but not d i r e c t l y t o x i c to many predatory and p a r a s i t i c ar thropods (Anony-mous 1974). Predatory mites are of p a r t i c u l a r importance in apple p ro tec -t i o n and s tud ies i n New Zealand (Wearing and Thomas 1978), A u s t r a l i a (Bower and Kaldor 1980) and the U.S. (West igard 1979) suggest tha t d i f l ubenzu ron i s non- tox i c to predaceous m i t e s . As d i f l ubenzu ron i s a l s o of low t o x i c i t y to honeybees (Anonymous 1974), use of the compound i n apple pest management would l i k e l y have few adverse s i d e - e f f e c t s aga ins t b ene f i c i a l o rgan i sms. -As ment ioned, a number o f f i e l d s tud i e s have i nd i c a t ed tha t d i f l u b e n -zuron e f f e c t i v e l y c on t r o l s the cod l i ng moth. However, these t e s t s d i d not e s t a b l i s h which l i f e stages were most s e n s i t i v e . When choosing the da te , f o rmu la t i on and method of a p p l i c a t i o n of sp rays , s e n s i t i v e l i f e stages should be cons i de red . The cu r ren t s tud i e s i n d i c a t e tha t the eggs and young l a r vae of the cod l i ng moth are the on ly stages s u s cep t i b l e to d i f l u ben zu r on . Adu l t moths showed no marked adverse e f f e c t s when dipped i n or ' f ed d i f l u -benzuron s o l u t i o n s , a l though margina l reduc t ions i n f e cund i t y and egg v i a -b i l i t y were observed. S ince the treatments were l i k e l y more severe than sprays which moths would encounter i n an orchard s i t u a t i o n , con t ro l o f the adu l t moths seems most u n l i k e l y . The apparent immunity o f adu l t s puts d i f l ubenzu ron a t a d isadvantage when compared to customary i n s e c t i c i d e s . Az inphos -methy l , f o r example, i s t o x i c to eggs (Wel ls and Guyer 1962), l a r vae (Gratwick et al_. 1965) and adu l t s ( M o f f i t t and White 1972) o f the c od l i n g moth. T o x i c i t y of d i f l ubenzu ron to eggs and l a rvae o f . t h e cod l i ng moth must t he re f o r e be extremely h igh i n order to match the e f f i c a c y of convent iona l compounds. The eggs appear very s e n s i t i v e , e s p e c i a l l y when t rea ted t o p i c a l l y s h o r t l y a f t e r o v i p o s i t i o n . One hundred ppm d i f l ubenzu ron prov ided 95% con-t r o l o f 0- to 2 5 - d a y - o l d eggs, and younger eggs were even more s e n s i t i v e . The r e s i dua l o v i c i d a l a c t i v i t y of d i f l ubenzu ron was extremely good when i t d r i ed on f r u i t and f o l i a g e and 'did not no t i c eab l y d im in i sh 10 days a f t e r a p p l i c a t i o n . When t rea ted f o l i a g e was sprayed w i th water on a d a i l y b a s i s , the o v i c i d a l a c t i o n was apparent l y reduced, but not to a s i g n i f i c a n t e x t en t . Consequent ly , extended con t ro l o f eggs would be expected because of the pe r s i s t ence of d i f l ubenzu ron on f r u i t and f o l i a g e . The use of Tween 20 was e s s en t i a l i n l abo ra to r y t e s t s f o r improving r e t en t i o n and d i s t r i b u t i o n of t e s t s o l u t i o n s on sub s t r a t e s . In the absence of the s u r f a c t an t , s o l u t i o n s tended to bead up and drop o f f , p a r t i c u l a r l y on waxy mature app le s . Immature, apples and f o l i a g e showed be t t e r r e t en t i o n of aqueous s o l u t i o n s , p a r t i c u l a r l y when Tween 20 was added. When eva luated in f i e l d t e s t s , however, the su r f a c t an t d id not appear to improve the i n see -t i c i d a l a c t i on o f d i f l u ben zu ron . While one cod l i ng moth f i e l d t e s t (mixed c u l t i v a r orchard) d id suggest such an improvement, v a r i a b l e and low i n f e s -t a t i o n l e v e l s cas t doubt on t h i s . Furthermore, i n the h e a v i l y - i n f e s t e d l e a f r o l l e r o r cha rd , no s i g n i f i c a n t enhancement was observed. There may be many reasons why Tween 20 d id not perform we l l i n the f i e l d , but the r e s u l t emphasizes the importance of f i e l d t e s t i n g as a f o l l ow-up to l abo ra to r y s t u d i e s . The mode of a c t i o n of d i f l ubenzu ron as an o v i c i d e i s not we l l under-s tood . Younger c od l i n g moth eggs were more s e n s i t i v e to the compound than o l de r eggs; t h i s was a l so noted f o r Spodoptera 1 i t t o r a l i s (Noctuidae) by Ascher ejt aJL (1980). At the same t ime, s e n s i t i v i t y was g rea te r i f the d i f l ubenzu ron remained i n s o l u t i o n on cod l i ng moth eggs as opposed to d ry ing r a p i d l y . The presence of Tween 20 in the t e s t s o l u t i o n s a l so increased s e n s i t i v i t y . I t i s po s s i b l e tha t d i f l ubenzu ron must enter the eggs wh i l e i n s o l u t i o n , s ince the compound i s not v o l a t i l e (Metca l f e_t aj_. 1975). Entry may take p lace through the aeropy les and/or c ho r i on , i n which case the r e -duced su r face tens ion e f f e c t ed by Tween 20 might f a c i l i t a t e d i f l ubenzu ron uptake. However, i t must be remembered tha t the r e s i dua l o v i c i d a l a c t i o n of d i f l ubenzu ron was high when the compound had d r i ed on f r u i t and f o l i a g e . Eggs would con tac t d i f l ubenzu ron a t o v i p o s i t i o n and would c e r t a i n l y be moist w i t h sec re t i ons from the accessory g lands , which cement the eggs to o v i p o s i -t i o n s i t e s . Th is mois ture might be s u f f i c i e n t to mob i l i z e the d i f l ubenzu ron aga i n s t the h i gh l y s u s cep t i b l e young eggs. Ascher et_ al_. (1980) observed tha t a l i q u i d fo rmu la t i on of d i f l ubenzu ron was about ten t imes more a c t i v e aga ins t S_. l i t t o r a l i s eggs than was the wet tab le powder f o rmu l a t i on . Eggs ° f Lobes ia botrana ( T o r t r i c i d a e ) were more s e n s i t i v e to d i f l ubenzu ron a t h igher temperatures (Ascher e_t aj_. 1978). I t i s p o s s i b l e , t h e r e f o r e , tha t under c e r t a i n cond i t i ons cod l i ng moth eggs may be even more s e n s i t i v e to d i f l ubenzu ron than revea led in the cu r ren t s tudy , s ince a l l t e s t s were per-formed a t room temperature ( c a . 25°C) w i t h a wet tab le powder f o rmu l a t i on . Most d i f l ubenzu ron - t r ea t ed cod l i ng moth eggs developed to the po in t of e c l o s i o n (the "b lackhead" stage) but the l a rvae were unable to break the chor ion and emerge. I f the chor ions were opened and the l a r vae a ided to emerge, they remained l e t h a r g i c , d id not f eed , and i n v a r i a b l y d i e d . The i r c u t i c l e s appeared much more d e l i c a t e than those of hea l thy l a r v a e , r up tu r i ng e a s i l y and causing- d e s i c c a t i o n . S ince t h i s c ond i t i o n represents c l a s s i c symptoms of d i f l ubenzu ron po i son i ng , i t appears tha t the compound i n h i b i t s c h i t i n syn thes i s i n the pharate c u t i c l e o f deve lop ing embryos p a r t i c u l a r l y i f absorbed dur ing e a r l y embryogenesis. Laboratory t e s t s showed tha t d i f l ubenzu ron was a l s o t o x i c to young cod l i ng moth l a r v a e . I f s u f f i c i e n t d i f l ubenzu ron was i nges ted , f i r s t - and 2nd - i n s t a r l a r vae proved incapab le o f mou l t ing to subsequent i n s t a r s . S ince no t o x i c e f f e c t s were observed except dur ing the moul t , f r u i t en t ry may occur before death , l a v i ng a small b lemish . As f i r s t - i n s t a r l a r vae fed r e a d i l y on d i f l ubenzu ron - t r ea t ed f o l i a g e , i t appears l i k e l y tha t s i g n i f i c a n t -59-. l a r v a l m o r t a l i t y would occur i n the f i e l d . In f i e l d t e s t s a t Summerland, d i f l ubenzu ron appeared equal to az inphos-methyl i n suppress ing cod l i ng moth damage. Un fo r tuna te l y , the c od l i n g moth i n f e s t a t i o n was low i n the t e s t orchards and d i f f e r en ce s between treatments were d i f f i c u l t to de t e c t . In a h e a v i l y - i n f e s t e d o r cha rd , d i f l ubenzu ron was not as e f f e c t i v e as az inphos-methyl f o r cod l i ng moth con t ro l (Bower and Kaldor 1980). However, i n t h i s study sprays were not synchronized w i th peak adu l t a c t i v i t y . As demonstrated i n the cu r ren t s tudy , f r e s h l y o v i -pos i t ed eggs are the most s e n s i t i v e stage so ca r e f u l t im ing i s e s s en t i a l in the use o f d i f l u ben zu r on . Sprays should be app l i ed s h o r t l y a f t e r emergence of adu l t moths. Other f i e l d t e s t s (Wearing and Thomas 1978; Cranham 1978; West igard 1979) have r e su l t e d i n e x c e l l e n t c o n t r o l . Egg masses of the obi iquebanded l e a f r o l l e r d i d not appear s e n s i t i v e to d i f l ubenzu ron even a t 1,000 ppm. These masses are covered w i th a g e l a -t inous cement - l i ke s e c r e t i o n from the accessory glands and t h i s substance may prevent access to the eggs. Th is i n s e n s i t i v i t y i s puz z l i ng in view of the f a c t tha t S_. l i t t o r a l i s eggs are l a i d in masses but are s t i l l suscep-t i b l e to d i f l ubenzu ron (Ascher e t aJL 1980). L e a f r o l l e r adu l t s showed a s l i g h t r educ t i on in l ongev i t y when dipped in 100 ppm d i f l ubenzu ron s o l u t i o n s , but no other adverse e f f e c t s . I t appears tha t f i r s t - i n s t a r l e a f r o l l e r l a r vae are s e n s i t i v e to d i f l ubenzu ron when i t i s ingested from f o l i a g e . Other i n -s t a r s may be s u s c ep t i b l e as w e l l , but t h i s cou ld not be c o n c l u s i v e l y demon-s t r a t e d . The l abo ra to r y s t u d i e s , t h e r e f o r e , d i d not i n d i c a t e good po t en t i a l f o r d i f l ubenzu ron as a con t ro l agent f o r l e a f r o l l e r s . F i e l d t e s t s aga ins t l e a f r o l l e r s r e f l e c t e d the l abo ra t o r y f i n d i n g s . While d i f l ubenzu ron d id s i g -n i f i c a n t l y reduce l e a f r o l l e r damage, az inphos-methyl gave c a . four times -60 -be t t e r c on t r o l . t h an d i f l ubenzu ron . • Increases in numbers of app le pests might come about i n the f u tu re because of 1) a reduc t i on i n cod l i ng moth and other sprays due to s t e r i l i t y -con t ro l or i n teg ra ted pest management or 2) the use of n on - s pe c i f i c p e s t i -c ides which d i s r up t predatory and p a r a s i t i c a r th ropods . I t appears l i k e l y tha t d i f l ubenzu ron would not cause t h i s l a t t e r phenomenon and the re fo re i s a s u i t a b l e cand idate f o r i n v e s t i g a t i o n regard ing con t ro l o f apple pe s t s . L e a f r o l l e r s are not e f f e c t i v e l y c o n t r o l l e d by d i f l u ben zu r on , but the com-pound has cons ide rab le po t en t i a l f o r c od l i ng moth c o n t r o l . S ince d i f l u b e n -zuron i s e f f e c t i v e aga ins t immature stages but not adu l t moths, i t s use i n con junc t ion w i th s t e r i l i t y - c o n t r o l would be l e s s d i s r u p t i v e than convent iona l compounds. West igard (1979) showed tha t d i f l ubenzu ron was l e s s t o x i c to na tu ra l enemies of the pear p s y l l a than were az inphos-methyl and phosmet. I t might be of va lue to t e s t o ther pome f r u i t , p e s t s f o r s e n s i t i v i t y to d i f l u -benzuron, g iven the l i k e l i h o o d tha t use o f the growth r egu l a t o r would not g r e a t l y d i s r u p t b e n e f i c i a l organisms. -61-LITERATURE CITED Abbot t , W.S. 1925. A method f o r computing the e f f e c t i v ene s s of an i n s e c -t i c i d e . J . Econ. Ent . 18; 265-267. Anderson, D.W. 1978. The e f f e c t s of d i f l ubenzu ron on the cod l i ng moth, Laspeyres ia pomonella L., r e l a t ed to use in s t e r i l i t y - c o n t r o l programs. B. Sc . 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P redat ion of ove rw in te r i ng l a rvae of c od l i n g moth (Cydia pomonella L.) by b i r d s . J . App l . E c o l . 1_3: 341-352. T a f t , H.M. and A.R. Hopkins. 1975. Bo l l weev i l s : f i e l d popu la t i on c o n t r o l l e d by - s t e r i l i z i n g emerging overwintered females w i th a TH-6040 sprayab le b a i t . J . Econ. Ent. 68: 551-554. Tamaki, G. and J . E . Turner . 1974. The zebra c a t e r p i l l a r on sugarbeets: con t ro l w i t h two phenyl urea compounds. J . Econ. Ent . 67: 697-699. van Daalen, J . J . , J . Me l t z e r , R. Mulder and K. We l l i nga . 1972. A s e l e c t i v e i n s e c t i c i d e w i th a novel mode of a c t i o n . Naturwissen. 59_: 312-313. Venab les , E.P. 1924. Leaf r o l l e r s a t t a c k i ng orchard t rees in the Okanagan V a l l e y . P roc . Ent . Soc. B.C. 21_: 22-26. Voege le , J . , D. Martouret and R. Goujet . 1978. P r e l im ina r y experiments us ing Trichogramma spp. aga ins t the cod l i ng moth i n apple o r cha rds , i n the P a r i s i a n r eg i on . M i t t . B i o l . Bundesanst. Land- F o r s t w i r t s c h . B e r l . Dahlem 180: 88-90. Wearing, C H . and W.P. Thomas. 1978. Integrated con t ro l o f app le pests i n New Zea land. 13. S e l e c t i v e t insect con t ro l us ing d i f l ubenzu ron and B a c i l l u s t h u r i n g i e n s i s . P roc . 31st N.Z. Weed and Pest Contro l Conf: We l l s , A . L . and G. Guyer. 1962. E f f e c t s of chemica ls on European corn borer eggs. J . Econ. Ent . 5_5: 631-633. Wes t iga rd , P.H. 1979. Cod l ing moth: con t ro l on pears w i th d i f l ubenzu ron and e f f e c t s on nontarget pest and b e n e f i c i a l s pec i e s . J . Econ. Ent . 72: 552-554. Wong, S.W. and R.B. Chapman. 1979. T o x i c i t y of s yn the t i c py re th ro id i n s e c -t i c i d e s to predaceous phy t o se i i d mites and t h e i r prey. Aus t . J . A g r i c . Res. 30: 497-501. Wr ight , J . E . and R.L. H a r r i s . 1976. Ov i c i da l a c t i v i t y o f Thompson-Hayward TH 6040 i n the s t ab l e f l y and horn f l y a f t e r sur face con tac t by a d u l t s . J . Econ. Ent. 69: 365-367. - 68 -APPENDIX Table Percent hatch of 3 -day-o ld cod l i ng moth eggs t o p i c a l l y t r ea ted l a . w i th d i f l ubenzu ron s o l u t i o n s . 50 eggs per r e p l i c a t e . Rep l i c a t e 0 ppm 1 ppm 10 ppm 100 ppm 1 84 70 46 20 2 76 76 62 16 3 78 66 38 16 4 80 64 44 22 X 79.5 69.0 47. 5 18.5 Ana l y s i s of va r i ance Source DF S_S MS Tota l 15 9169. 8 Treatment 3 8708. 8 2902.9 75.56* L inea r r eg res s i on 1 7214. 1 7214.1 187.78* Quadrat ic r eg res s i on 1 1387. 4 1387.4 36.11* Dev ia t i ons 1 no. 0 110.0 2.86 E r ro r 12 461. 0 38.4 Table . Percent hatch of 0- to 2 j - d a y - o l d cod l i ng moth eggs t o p i c a l l y l b . t r ea ted w i th d i f l ubenzu ron s o l u t i o n s . 50 eggs per r e p l i c a t e . Rep l i c a t e 0 ppm 0;.01 ppm 0, .1 ppm 1. ,0 ppm 10 .0 ppm 100 ppm 1 78 64 54 38 8 12 2 58 78 50 46 0 4 3 64 56 52 42 0 6 4 72 78 40 44 18 4 5 '58 76 44 46 14 2 6 72 72 66 34 12 6 7 68 68 52 36 8 0 8 70 74 46 40 6 4 9 78 68 46 28 14 6 X 68.7 70.4 50.0 39.3 8.9 . 4.9 Ana l y s i s o f va r i ance (exc lud ing 0 ppm from ana l y s i s ) Source DF SS MS F Tota l 44 29280.1 Treatment 4 27788.1 V6947; 2 186.37 * l og L inea r r eg ress i on 1 26694.4 26694. 4 716.11 * l og Quadrat ic r eg res s i on 1 103.1 103. 1 2.77 log Cubic r eg res s i on 1 250.0 250. 0 6.71 * l og Dev ia t ions 1 738.3 738. 3 19.80 * Er ro r 40 1491.1 37. 3 -69 -Table Percent hatch of cod l i ng moth eggs t o p i c a l l y t rea ted w i th 10 ppm I l i a . d i f l ubenzu ron a t d i f f e r e n t lengths of t ime from o v i p o s i t i o n . 50 eggs per r e p l i c a t e . Rep l i c a t e 0 - 36 h 36 - 60 h 60 - 84 h 84 - 108 h 108 - 132 1 12 32 52 48 46 2 26 14 36 30 70 3 32 18 64 34 56 4 8 18 40 36 58 5 10 22 42 64 62 6 22 18 28 40 72 7 10 20 44 40 64 8 12 8 36 32 66 9 8 12 30 34 56 X 15.6 18.0 41.3 39.8 61.1 Ana l y s i s of ' var iance Source DF SS MS_ F_ Tota l 44 16108.0 Treatment 4 12682.6 3170.7 37.03* L inea r r eg res s i on • 1 11925.0 11925.0 139.26* Quadrat ic r eg ress ion 1 146.8 146.8 1.71 Cubic r eg ress i on 1 5.4 5.4 0.06 Dev ia t i ons 1 1349.3 1349.3 15.76* E r ro r 40 3425.4 85.6 Table Percent hatch of young c od l i n g moth eggs t o p i c a l l y t r ea ted w i th 111 b. 10 ppm d i f l ubenzu ron a t d i f f e r e n t lengths of t ime from o v i p o s i t i o n . 10 eggs per r e p l i c a t e ) l i c a t e 0 - 12 h 12 - 24 h 24 - 36 h 36 - 48 h 1 0 40 20 40 2 . 10 50 60 80 3 0 30 20 50 4 10 40 30 70 X 5.0 40.0 32.5 60.0 Ana l y s i s of va r i ance Source DF_ SS MS F Tota l 15 8969 .8 Treatment 3 6218 .8 2072.9 9.75* L inea r r eg res s i on 1 4961 .3 4961.3 23.31* Quadrat i c r eg res s i on 11 56 .3 56.3 0.26 Dev ia t i ons 1 1201 .2 1201.2 5.65* E r ro r 12 2551 .0 212.6 -70 -Table . Percent hatch of 3-day-o ld cod l i ng moth eggs p laced i n contac t w i th IVa. 10 ppm d i f l ubenzu ron s o l u t i o n f o r va ry ing per iods of t ime , d i f l u -benzuron app l i ed w i th a f i n e brush. 50 eggs per r e p l i c a t e . Rep l i c a t e 0.25 h 0. ,5 h 1.0 h 2.0 h 4.0 h 1 74 70 74 62 32 2 80 72 74 64 46 3 78 66 70 62 44 4 78 70 68 58 40 X 77.5 69.5 71.5 61.5 40.5 Ana l y s i s of va r i ance Source DF SS MS F Tota l 19 3503.6 Treatment 4 3308.8 827.2 63.68* l og L i nea r r eg res s i on 1 2689.6 2689.6 207.05* log Quadrat ic r eg res s i on 1 412.6 412.6 31.76* log Cubic r eg ress i on 1 176.4 176.4 13.58* Tori Dev ia t i ons 1 30.2 30.2 2.33 E r ro r 15 194.8 13.0 Table Percent hatch of 0- to 2£-day-o ld cod l i ng moth eggs placed in con-IVb. t a c t w i th 10 ppm d i f l ubenzu ron s o l u t i o n f o r va ry ing per iods of t ime , d i f l ubenzu ron app l i ed in soaked paper t o w e l l i n g . 50 eggs per r e p l i c a t e . i c a t e 0.25 h 0.5 h 1.0 h 2.0 h 4.0 h 1 80 64 60 64 34 2 72 70 62 60 54 3 62 62 58 58 34 4 58 74 68 52 36 5 74 70 66 58 48 6 88 58 56 60 30 7 76.. 52 52 64 38 8 86 54 48 62 22 9- 88 74 72 48 34 X 76.0 64.2 . 60.2 58.4 36.7 A Ana l y s i s of va r i ance Source DF Tota l 44 Treatment 4 log L inea r r eg ress i on 1 l og Quadrat i c r eg res s i on 1 log Cubic r eg ress i on 1 l og Dev ia t i ons 1 E r ro r 40 s_s MS F_ 8469 .3 7457 .5 1864 .4 73.69* 6417 .8 6417 .8 253.67* 203 .2 203 .2 8.03* 694 .4 694 .4 27.45* 35 .7 35 .7 1.41 1011 .8 25 .3 - 71 -Table Percent hatch of 3-day-o ld cod l i ng moth eggs t r ea ted t o p i c a l l y Va. w i th 10 ppm d i f l ubenzu ron in the presence and absence of 500 ppm Tween 20. 50 eggs per r e p l i c a t e . Rep l i c a t e (A) 500 ppm Tw20 (B) 10 ppm d i f (C) 10 d i f + 500 Tw20 1 84 • 48 16 2 80 34 12 3 78 42 18 4 86 38 22 X 82.0 40.5 17.0 Ana l y s i s of va r i ance Source DF SS MS f_ Tota l 11 8865.0 Treatment 2 8666.0 4333.0 196.06* (A+B) v s . (C) 1 5221.5 5221.5 236.27* (A) vs . (B) 1 3444.5 3444.5 155.86* E r r o r 9 199.0 22.1 Table Percent hatch of 1- to 2-day-o ld c od l i ng moth eggs t r ea ted t o p i -Vb. c a l l y w i th d i f l ubenzu ron s o l u t i o n s in the presence and absence of 500 ppm Tween 20. 50 eggs per r e p l i c a t e . Rep l i c a t e 0 ppm d i f 0 ppm+Tw 1 ppm 1 ppm+Tw 10 ppm 10 ppm+Tw 1 68 80 80 78 38 42 2 74 68 64 68 50 28 3 82 82 76 70 48 40 4 74 70 66 60 52 38 5 82 84 56 60 46 16 6 76 74 72 54 32 42 7 76 78 70 58 36 I 34 8 72 74 62 64 28 28 9 80 78 74 58 30 26 X 76.0 76.4 68.9 63.3 40.0 32.7 Anal ys is^o; l : v a r i ance Source DF SS MS F Tota l 53 18469 .3 Treatment 5 15862 .2 3172.4 58.42* D i f lubenzuron 2 15480 .4 7740.2 142.55* Tween 20 1 232 .2 232.2 4.28* D i f X Tw20 i n t e r a c t i o n 2 149 .6 74.8 1.38 E r r o r 48 2607 .1 54.3 -72 -Table r. Hatchab i l i t y o f c od l i ng moth eggs o v i po s i t ed on mature Spartan V i a . apples which had been dipped in d i f l ubenzu ron s o l u t i o n s i n the presence and absence of Tween 20. One apple = one r e p l i c a t e . Treatment Rep. eggs hatched t o t a l eggs percent hatch X 0 ppm d i f 1 63 78 80.8 + 2 114 144 79.2 0 ppm Tw20 3 71 90 78.9 81.0 (A) 4 141 172 82.0 5 58 76 76.3 6 86 97 88.7 -100 ppm d i f 1 79 107 73.8 + 2 82 109 75.2 0 ppm Tw20 3 68 83 81.9 75.3 (B) 4 95 118 80.5 5 97 137 70.8 6 57 82 69.5 100 ppm d i f 1 86 121 71 .1 + 2 80 114 70.2 500 ppm Tw20 3 72 103 69.9 73.0 (C) 4 86 111 77.5 5 116 163 71.2 6 71 91 78.0 Ana l y s i s o f va r i ance Source DF_ MS F To ta l 17 664.2 Treatment 2 203.6 101.8 3.32 (A) vs . (B+C). 1 186.7 186.7 6.08* (B) vs . (C) 1 16.0 16.0 0.52 E r r o r 15 460.6 30.7 - 73 -Table H a t c h a b i l i t y o f c od l i ng moth eggs ov i po s i t ed on immature Golden VIb. De l i c i o u s apples which had been dipped i n d i f l ubenzu ron s o l u t i o n s i n the presence and absence of Tween 20. The apples i n the f ou r t h treatment were t r ea ted 10 days e a r l i e r than the o t he r s . One apple = one r e p l i c a t e . Treatment Rep. eqqs hatched t o t a l eggs percent 0 ppm d i f 1 85 120 70.8 + 2 43 70 61.4 0 ppm Tw20 3 61 84 72.6 (A) 4 86 151 56.9 5 48 64 75.0 6 82 135 60.7 7 82 110 74.6 8 82 135 60.7 v 9 79 113 69.9 TO. 79 122 64.7 11 48 71 67.6 12 89 123 72.4 100 ppm d i f 1 42 86 48.8 + 2 37 92 40.2 0 ppm Tw20 3 36 77 46.7 (B) 4 24 68 35.3 5 44 96 45.8 6 23 44 52.3 7 38 95 40.0 8 43 129 33.3 9 32 121 26.4 10 42 124 33.9 11 24 58 41 .4 12 29 75 38.7 100 ppm d i f 1 23 102 22.6 + 2 26 143 18.2 500 ppm Tw20 3 14 106 13.2 (C) 4 25 93 26.9 5 47 212 22.2 6 21 93 22.6 7 31 99 31.3 8 12 71 16.9 9 25?. 113 22.1 10 19 135 14.1 11 20 "'95 21.0 12 12 51 23.5 67.3 40.2 21.2 -74-Table V lb (concluded) Treatment Rep. eggs hatched 100 ppm d i f 1 13 + 2 12 500 ppm Tw20 3 16 4 19 ( a f t e r 10 5 37 days) 6 27 7 18 (D) 8 13 9 10 10 14 11 22 12 13 Ana l y s i s o f va r i ance Source DF Tota l 47 Treatment 3 (A) vs . (B+C+D) 1 (B) v s . (C+D) 1 (C) v s . (D) 1 E r ro r 44 t o t a l eggs percent hatch X 74 17.6' 49 24.5 63 25.4 74 25.7 168 22.0 122 22.1 19.5 123 14.6 78 16.7 56 17.9 89 15.7 161 13.7 72 18.1 SS MS F 19297.6 17810.6 5936.9 175.68* 14639.0 14639.0 433.18* 3150.9 3150.9 93.24* 17.5 17.5 0.52 1487.0 33.8 Table H a t c h a b i l i t y of c od l i ng moth eggs o v i po s i t ed on pear f o l i a g e V i l a . which had been dipped in dif1ubenzuron/Tween 20 s o l u t i o n s . One l e a f = one r e p l i c a t e , leaves not p laced i n water . Treatment Rep. eggs hatched t o t a l eggs percent 0 ppm d i f 1 155 200 77.5 + 2 63 84 75.0 500 ppm Tw20 3 86 107 80.4 4 26 29 89.7 5 58 77 75.3 6 45 55 81.8 100 ppm d i f 1 10 23 43.5 + 2 25 105 23.8 500 ppm Tw20 3 20 61 32.8 4 27 59 45.8 5 32 98 32.6 6 18 47 38.3 X 79.9 36.1 -75 -Table V i l a (conc luded). Ana l y s i s o f va r i ance Source . DF SS. MS F Tota l 11 6238.7 Treatment 1 5755.3 5755.3 119.08* E r ro r 10 483.4 48.3 Table V l l b . H a t c h a b i l i t y o f c od l i n g moth eggs o v i po s i t e d on pear f o l i a g e which had been dipped in d i f lubenzuron/Tween 20 s o l u t i o n s . The f o l i a g e in the f ou r t h treatment was rewetted d a i l y w i t h d i s t i l l e d water . One l e a f = one r e p l i c a t e , w i th the leaves at tached to twigs which were p laced in v i a l s o f water . Treatment Rep. eggs hatched t o t a l eggs percent 0 ppm d i f • 1 29 29 100.0 + 2 35 36 97.2 0 ppm Tw20 3 36 36 100.0 (A) 4 22 22 100.0 5 34 41 82.9 6 40 41 97.6 7 33 39 84.6 8 27 28 96.4 9 36 40 90.0 100 ppm d i f 1 22 22 100.0 • • • • + 2 44 52 84.6 0 ppm Tw20 3 16 25 64.0 (B) ; 4 3 16 18.8 5 12 34 35.3 6 12 45 26.7 7 6 14 42.9 8 7 21 33.3 9 3 11 27.3 100 ppm d i f 1 4 21 19.1 •+• 2 20 40 50.0 500 ppm Tw20 3 9 21 42.9 (C) 4 3 13 23.1 5 9 29 31.0 6 2 30 6.7 7 5 16 31.3 8 5 29 17.2 9 6 31 19.4 X 94.3 48.1 26.7 Table v i ' l b ( c o n c " l u d e d ) -76-Treatment Rep. eggs hatched t o t a l eggs percent hatch X 100 ppm d i f 1 10 14 71.4 + 2 11 22 50.0: 500 ppm Tw20 3 , 23 33 69.7 4 7 25 28.0 (rewetted) 5 3 31 9.7 40 6 5 17 29.4 (D) 7 10 17 58.8 8 7 29 24.1 9 2 10 20.0 Ana l y s i s of va r i ance Source DF SS MS_ f_ Tota l 35 35656.5 Treatment 3 23257.8 7752.6 20.01.* (A) v s . (B+C+D) 1 21168.0 21168.0 54.63* (B) v s . (C+D) 1 1296.5 1296.5 3.35 (C) v s . (D) 1 808.0 808.0 2.09 E r r o r 32 12398.7 387.5 Table Cod l ing moth f i r s t - i n s t a r l a r vae en te r i ng apples and s u r v i v i n g Xb. to 4 t h - i n s t a r . Apples were dipped in dif1ubenzuron/Tween 20 s o l u t i o n s . 20 l a r vae and apples per treatment Treatment no. en te r i ng . no. t o 4 t h - i n s t a r 0 ppm d i f + 15 12 500 ppm Tw20 500 ppm d i f + 500 ppm Tw20 16 12 Table Xa, Cod l ing moth f i r s t - i n s t a r l a r vae en te r ing apples and s u r v i v i n g to 4 t h - i n s t a r , a f t e r feed ing on apple f o l i a g e which had been sprayed w i th d i f lubenzuron/Tween 20 s o l u t i o n s . Ten l a r vae and apples per r e p l i c a t e . Treatment Rep. no. en te r i ng apples and feed ing to 4 t h - i n s t a r a f t e r 1 day of feed ing on f o l i a g e no. en te r i ng a feed ing to 4th 2 days of feed 0 ppm d i f 1 9 en te red , 6 to 4 t h - i n s t a r 8 en te red , < + 2 8,6 9,7 0 ppm Tw20 3 10,8 7,5 4 8,6 8,6 0 ppm d i f 1 8,7 8,7 + 2 9,8 8,6 500 ppm Tw20 3 9,6 10,6 4 8,7 9,7 10 ppm d i f 1 8,7 9,7 + 2 9,7 9,6 500 ppm Tw20 3 8,5 8,6 4 9,7 7,5 100 ppm d i f 1 10,7 8,5 + 2 8,8 5,5 500 ppmTw20 3 8,6 7,6 4 8,7 8,5 500 ppm d i f 1 9,2 7,1 + 2 8,2 9,2 500 ppm Tw20 3 8,3 7,0 4 9,4 8,3 Ana l y s i s of va r i ance (on s u r v i v a l to 4 t h - i n s t a r ) . Source DF SS MS f_ Tota l 39 143.9 Treatment 9 128.4 14.3 27.50* D i f lubenzuron (A) 4 119.2 29.8 57.31* Days feed ing (B) 1 6.4 6.4 12.31* (A) X (B) i n t e r a c t i o n 4 2.8 0.7 1.36 E r r o r 30 15.5 0.52 -78-Table M o r t a l i t y of f i r s t - i n s t a r cod l i ng moth l a r vae p laced on agar V i l l a . medium con ta in ing d i f f e r e n t concent ra t ions of d i f l u ben zu ron . F i ve l a rvae per r e p l i c a t e , m o r t a l i t y assessed a f t e r 14 days of feed ing ( a f t e r Anderson 1978). Rep l i c a t e 0 ppm d i f 10 ppm d i f 50 ppm d i f 100 ppm d i f 1 1 3 3 3 2 0 1 3 4 3 1 3 2 3 4 1 2 2 4 X 15% 45% 50% 70% Ana l y s i s of va r i ance Source P£ SS MS F_ Tota l 15 8400 Treatment 3 6200 2067 20.67* L inear r eg re s s i on 1 4879 4879 48.79* Quadrat ic r eg res s i on 1 172 172 1 .72 Dev ia t i ons 1 1149 1149 11.49* E r r o r 12 1200 100 Table M o r t a l i t y of 2nd - i n s t a r c od l i ng moth l a r vae p laced on agar medium V H I b . con ta i n i ng d i f f e r e n t concen t ra t i ons of d i f l u ben zu r on . F i ve l a r vae per r e p l i c a t e , m o r t a l i t y assessed a f t e r 10 days of feed ing ( a f t e r Anderson 1978). Rep l i c a t e 0 ppm d i f 10 ppm d i f 50 ppm d i f 100 ppm d i f 1 1 3 4 5 2 0 4 5 5 3 1 4 4 5 4 2 2 4 4 X 20% 65% 85% 955? t Ana l y s i s o f va r i ance Source DF SS MS F Tota l 15. 15775 Treatment 3 13275 4425 21.24* L inea r r eg res s i on 1 9316 9316 44.72* Quadrat ic r eg ress i on 1 2117 2117 10.16* Dev ia t i ons 1 1842 1842 8.84* E r ro r 12 2500 208 i -7-9-Table Longev i t y , f e cund i t y and egg v i a b i l i t y of adu l t cod l i ng moths X I . dipped i n d i f l ubenzu ron s o l u t i o n s . Four males and fou r females per cage. eggs t o t a l percent Treatment Cage Sex Longev i ty (days) hatched eggs hatch X pm d i f 1 M 14 , 16, 18, 19 463 677 68.4 F 4 , 1 3 , 15, 19 2 M 15 , 15, 17, 18 467 586 79.7 65.9 F 8 , 13, 13, 14 3 M 8 , io, 16, 17 154 311 49.5 F 1 , 3, 4 , 9 ppm d i f 1 M 3 , 14, 15, 16 187 340 55.0 F 2 , 3, 13, 16 2 M 3 , 5, 7, 8 223 259 86.1 69.4 F 3 , 9, 14, 20 3 M 1 , 9, 12, 14 98 146 67.1 F 1 , 3, 11, 14 ppm d i f 1 M 3 , 3, 11, 14 81 167 48.5 F 2 , 2, 5, 12 2 M 8 , 9, 11, 17 149 211 70.6 65.9 F 1 , 1, 9, 13 3 M 3 , 7, 12, 13 162 206 78.6 F 2 , 9, 12, 14 Ana l y s i s o f var iance ( f e cund i t y ) Source DF SS MS f_ Tota l 8 280910.3 Treatment 2 188135.1 94067.6 6.08* L inea r r eg ress i on 1 90539.5 90539.5 5.86 Dev ia t i ons 1 97600.0 97600.0 6.31* E r ro r 6 92775.2 15462.5 Ana l y s i s o f var iance (percent hatch) Source DF SS MS f_ To ta l 8 1484.9 Treatment 2 22.2 11. 1 0.05 L inea r r eg re s s i on 1 3.6 3. 6 0.01 Dev ia t i ons 1 18.3 18. 3 0.08 E r r o r 6 1462.7 243. 8 -80 -Table XI , ( conc luded) ; Ana l y s i s o f va r i ance (sex X concen t r a t i on , e f f e c t s on l ongev i t y ) Source DF SS MS F_ Tota l 71 2318 .4 Concent ra t ion (2) . 289 .5 144 .8 3. 89 L inea r r eg res s i on 1 172 .2 172 .2 4. 62 Dev ia t ions 1 117 .4 117 .4 3. 15 Cages/concent ra t ion 6 223 .4 37 .2 Sex 1 156 .1 156 .1 7. 02* Sex X l i n e a r cone. 1 0 .3 0 .3 0. 01 Sex X dev i a t i on s cone. 1 100 .9 100 .9 4. 54 Sex X t o t a l cone. (2) 101 .2 50 .6 2. 28 Sex X cage/concent ra t ion 6 133 .3 22 .2 Insec t s / sex and cage 54 1414 .7 26 .2 Table Longev i t y , f e cund i t y and egg v i a b i l i t y of adu l t c od l i ng moths X I I . dipped in d i f lubenzuron/Tween 20 s o l u t i o n s . Four males and four females per cage. eggs t o t a l percent Treatment Cage Sex Longev i ty (days) hatched eggs hatch X 0 ppm d i f 1 M 8, 12, 15, 17 360 547 65.8 + F 6, 11, 13, 17 0 ppm Tw20 2 M 7, 11. 13, 16 403 553 72.9 (A) F 5, 6, 12, 14 3 M 5, 11» 14, 15 486 552 88.0 F 2, 6, 8, 12 10 ppm d i f 1 M 5, 6, 8, 14 388 461 84.2 + F 5, 7, 12, 16 0 ppm Tw20 2 M 6, 8, 8, 13 378 472 80.1 (B) F 7, 8, 11, 12 3 M 2, 6, 12, 15 . 289 323 89.5 F 4, 8, 9, 11 100 ppm d i f 1 M 9, 11, 12, 13 381 539 70.7 + F 7, 8, 9, 14 0/ ppm' Tw20 2 M 5, 7, 8, 13 347 458 . 75.8 ( 0 F 6, 8, 9, 12 3 M 7, 10, 11» 16 509 642 79.3 F 8, 10, 13, 14 100 ppm d i f 1 M 2, 5, 6, 12 380 499 76.2 + F 4, 9, 10, 11 500 ppm Tw20 2 M 5, 8, 12, 14 36 64 56.2 (D) F 3, 9, 13, 16 3 M 5, 7, 8, 9 341 560 60.9 F 9, 10, 12, 15 - 8 1 -Table 'XII (concluded) Ana l y s i s o f va r i ance ( f e cund i t y ) Source DF SS MS Tota l 11 249428.0 Treatment 3 72298.1 24099.4 1.09 (A) v s . (B+C+D) 1 24440.1 24440.1 1.10 (B) v s . (C+D) 1 3472.2 3472.2 0.16 (C) v s . (D) 1 44376.0 44376.0 2.00 E r ro r 8 177129.9 22141.2 Ana l y s i s of va r i ance (percent hatch) Source DF SS MS f_ Tota l 11 1146.9 Treatment 3 604.6 201.5 2.97 (A) v s . (B+C+D) 1 2.2 2.2 0.03 (B) v s . (C+D) 1 420.5 420.5 6.20* (C) v s . (D) 1 181.5 181.5 2.68 E r r o r 8 542.3 67.8 Ana l y s i s o f va r i ance (sex X t reatment , e f f e c t s on l ongev i t y ) Source DF SS MS F Tota l 95 1321.9 Treatment (3) 56.4 18.8 1 .46 (A) v s . (B+C+D) 1 36.1 36.1 2.81 (B) v s . (C+D) 1 5.1 5.1 0.40 (C) vs . (D) 1 15.2 15.2 1.18 Cages/treatment 8 102.8 12.9 Sex 1 0.0 0.0 0.00 Sex X treatment 3 80.4 26.8 6.34* Sex X cage/treatment 8 1014.6 : 14.1 ' Insec t s / sex and cage 72 33.9 4.2 - 82 -Table Longev i t y , f e cund i t y and egg v i a b i l i t y o f adu l t c od l i ng moths X I I I . fed d i f l ubenzu ron s o l u t i o n s on cot ton w i c k s . Four males and four females per cage. eggs t o t a l percent Treatment Cage Sex Longev i ty (days) hatched eggs hatch X 0 ppm d i f 100 ppm d i f 1 1 M 9, 14, 16, 16 493 567 86.9 F 8, 9, 10, 10 2 M 7, 9, 12, 15 427 530 80.6 F 5, 8, 9, 13 3 M 8, 11, 12, 15 343 447 76.7 F 10, 12, 13, 14 1 M 9, 12, 14, 16 496 626 79.2 F 8, 10, 11, 14 2 M 8, 10, 11, 14 236 , 315 74.9 F 7, 9, 9, 17 3 M 8, 10, 14, 16 641 749 85.6 F 9, 13, 14, 17 1 M 8, 10, 12, 14 453 647 70.0 F 7, 9, 16, 16 2 M 8, 10, 14, 15 375 552 67.9 F 9, 9, 12, 17 3 M 7, 11, 14, 16 287 610 47.0 F 9, 10, 12, 14 81.4 79.9 61 .6 Ana l y s i s of va r i ance ( f e cund i t y ) Source DF_ SS MS F_ Tota l 8 123952 .0 Treatment 2 11734 .9 5867 .5 0 31 L inear r eg ress i on 1 9129 .2 9129 .2 0 .49 Dev ia t i ons 1 2615 .2 2615 .2 0 02 E r r o r ,6 112217 .1 18702 .8 Ana l y s i s of va r i ance ( f ecund i t y ) Source DF SS MS F_ Tota l 8 1176.2 Treatment 2 737.8 368.9 5.05 L inea r r eg re s s i on 1 738.7 738.7 10.12* Dev ia t i ons 1 0.2 0.2 0.002 E r ro r 6 438.4 73.1 - 83 -Table x 111 (concluded) Ana l y s i s o f va r i ance (sex X concen t r a t i on , e f f e c t s on l ongev i t y ) Source DF SS MS_ f_ To ta l 71 663.8 Concent ra t ion (2) 5.9 2.9 0.48 L inear r eg ress i on 1 1.6 1.6 • 0.27 Dev ia t i ons 1 4.3 - - 4.2 0.69 Cages/concent ra t ion 6 36.9 6.2 Sex 1 9.4 9.4 1.37 Sex X l i n e a r cone. 1 14.1 14.1 2.05 Sex X dev i a t i on s cone. 1 0.9 0.9 0.14 Sex X t o t a l cone. (2) 13.4 6.7 0.97 Sex X cage/treatment 6 557.0 10.3 Insec ts /sex and cage 54 41.3 6.9 Table H a t c h a b i l i t y o f 0- to 3-day-o ld l e a f r o l l e r egg masses t o p i c a l l y X i v . t r ea ted w i th d i f l ubenzu ron s o l u t i o n s . One egg mass = one r e p l i c a t e . Treatment Rep. eggs hatched t o t a l eggs percent hatch X 0 ppm 1 0 142 0.0 2 0 54 0.0 3 290 498 58.2 22.9 4 216 385 56.1 5 0 125 0.0 1.0 ppm 1 376 520 72.3 2 444 533 83.3 3 0 148 0.0 37.9 4 54 160 33.7 5 0 116 0.0 10 ppm 1 301 456 66.0 2 0 48 0.0 3 460 567 81.1 33.9 4 36 295 12.2 5 42 414 10.1 100 ppm 1 469 550 85.3 2 442 550 80.4 3 397 512 77.5 62.1 4 0 308 0.0 5 329 490 67.1 1,000 ppm 1 0 385 0.0 2 288 502 57.4 3 0 561 0.0 36.0 4 93 189 49.2 5 314 427 73.5 -84-Table XIV (concluded) Ana l y s i s o f va r i ance (exc lud ing 0 ppm) Source DF SS MS f_ To ta l 19 18958. .8 Treatment 3 2601. .2 876. .1 0, .86 log L inear reg ress ion 1 130. .0 130. .0 0, .13 log Quadrat ic r eg ress i on 1 605. .0 605. .0 0, .59 log Dev ia t ions 1 1866. .2 1866. .2 1. .83 E r r o r 16 16357. .6 1022. .4 Ind i v i dua l degree of freedom con t r a s t : 0 ppm vs . o ther t reatments -F va lue = 1.50 Table Su r v i v a l o f f i r s t - i n s t a r l e a f r o l l e r l a rvae p laced on pear f o l i a g e XV. which had been dipped i n d i f lubenzuron/Tween 20 s o l u t i o n s . Three l a rvae per l e a f , one l e a f = one r e p l i c a t e . Treatment Rep. Su r v i va l a f t e r 1 week Su rv i va l a f t e r 2 weeks 0 ppm d i f 1 1 2nd i n s t a r 1 3rd + 2 2 2nd 2 3rd 0 ppm Tw20 3 1 3rd 1 4th 0 ppm d i f 1 3 2nd 2 3 r d , 1 4th + 2 2 2nd 1 3 rd , 1 4th 500 ppm Tw20 3 3 2nd 2 4th 10 ppm. d i f 1 3 2nd 2 3 r d , 1 4th 2 2 2nd 2 3rd 0- ppm Tw20 3 2 2nd 1 4th 10 ppm d i f 1 3 2nd 2 3rd + - 2 2 2nd 1 4th 500 ppm Tw20 3 2 2nd 1 3 rd , 1 4th 100 ppm d i f 1 3. 2nd . . . . 2 3rd + 2 2 2nd 1 4th 0 ppm Tw20 3 2 2nd- ... . 1 3 rd , 1 4th 100 ppm d i f 1 i a l l dead a l l dead + 2 1 2nd fl- 2nd 500 ppm Tw20 3 a l l dead a i l dead -85 -Table XV (concluded) Ana l y s i s o f va r i ance (on s u r v i v a l a f t e r 2 weeks) Source DF SS. MS Tota l 17 12.44 Treatment 5 7.14 1.43 ••. 3.24* D i f lubenzuron (A) 1 2 2.77 1.38 , 3.14* Tween 20 (B) . 1 0.22 0.22 0.50 (A) X (B) i n t e r a c t i o n 2 4.12 2.06 4.66* E r r o r 12 : 5.30 , 0.44 Table ; Mou l t ing success of f i v e l e a f r o l l e r l a r v a l i n s t a r s p laced on XVI . apple f o l i a g e which had been sprayed w i th d i f lubenzuron/Tween 20 s o l u t i o n s . One l a r va per p l a n t , f i v e p lan ts per t reatment . Treatment : 1st i n s t a r 2nd i n s t a r 3rd i n s t a r 4th i n s t a r 6th i n s t a r 0 ppm d i f + 5 3 3 5 4 0 ppm Tw20 0 ppm d i f • + • 3 : 4 4 3 5 500 ppm Tw20 100 ppm d i f + 2 1 2 4 3 500 ppm Tw20 -86-Table XV I I . Treatment 0 ppm d i f Longev i t y , f e cund i t y and egg v i a b i l i t y of adu l t l e a f r o l l e r moths dipped i n d i f l ubenzuron s o l u t i o n s . Four males and fou r females per cage. eggs t o t a l percent Cage Sex Longev i ty (days) hatched • eggs hatch X 1 2 3 4 M F M F M F M F 8, 8 7, 9 7, 10 9, 9 8, 8 9, 10 7, 8 6, 9 585 417 402 674 1214 986 820 1143 48.2 42.3 49.0 59.0 49.6 ppm d i f 1 M 2, 2, 6, 8 411 726 56 .6 F 1, 6, 8, 9 2 M 1, 3, .. 6, 7 599 1088 55 .1 F 3, 4, 5, 6 52.1 3 M 2, 3, 5, 8 256 760 33 .7 F 2 , 3 , 6, 6 4 M 2, 3, 3, 8 522 827 63 .1 F 5, 6, 6, 8 Ana l y s i s o f var iance ( f e cund i t y ) Source DF SS MS F Tota l 7 245428.0 Treatment 1 72580.5 72580. 5 2.52 E r r o r 6 172847.5 28807. 9 Ana l y s i s of va r i ance (percent hatch) Source DF SS MS F Tota l 7 642.9 Treatment 1 20.5 20.5 0.20 E r ro r 6 622.4 103.7 Ana l y s i s o f va r i ance (sex X t reatment , e f f e c t s on l ongev i t y ) Source DF SS MS I F Tota l 63 409.0 D i f lubenzuron 1 25.0 25.0 24.04* Cages/cone. 6 6.2 1.0 Sex 1 6.2 6.2 4.17 Sex X treatment 1 1.0 1.0 0.67 Sex X cage/treatment 6 9.0 1.5 Insec t s / sex and cage 48 361 .5 7.5 - 87 -Table < Percent of harvested apples showing l e a f r o l l e r damage. XV I I I . subp lo t (of three t r ees ) per treatment and b l o c k . ' One Treatment Tree Block 1 Block 2 Block 3 Block 4 Block 5 X 0 ppm d i f + 0 ppm Tw20 (A) 1 2 3 16.0 19.0 24.7 15.7 15.4 16.1 12.0 8.4 6.6 12.1 26.6 15 .2 ' 13.5 15.0 20.6 15.8 94 ppm d i f + 0 ppm Tw20 (B) 1 2 3 15.9 10.3 13.8 10.7 11.6 20.5 9.0 12.7 14.5 13.3 9.9 7.9 7.3 12.8 11.7 12.1 94 ppm d i f 1 10.9 21.7 5.8 11.1 8.8 + 2 10.0 10.9 3.9 6.4 10.1 500 ppm Tw20 3 11.5 8.9 6.1 11.1 15.3 (C) 10.2 375 ppm d i f 1 7.4 7.6 13.5 9.5 5.0 + 2 3.4 9.8 10.6 12.3 5.1 0 ppm Tw20 3 6.3 3.4 9.8 11.1 4.0 (D) 375 ppm azinphos-methyl (E) 1 2 3 1.2 2.7 1.1 0.4 0.7 2.7 2.6 1.9 2.2 1.6 1.0 0.6 3.7 4 .0 2.2 7.9 1.9 Ana l y s i s o f va r i ance Source Df_ SS MS F Tota l 74 2608.8 Treatment 4 1606.1 401 .5 38.23* (A) v s . (B+C+D+E) 1 715.5 715 .5 68.14* (B) vs . (C) 1 24.1 24 .1 2.30 (B) vs . (D) 1 132.7 132 .7 12.64* (D) vs . (E) 1 271.2 271 .2 25.83* B locks 4 60.1 15 .0 1 .43 B locks X Treatment 16 418.4 26 .2 2.50* E r ro r 50 524.2 Table Percent of harvested apples showing cod l i ng moth damage. XIX. One subp lo t (of three t r ees ) of each e u l t i v a r was present each treatment Treatment Tree Mcintosh 47 ppm d i f 1 0.3 + ' 2 0.0 0 ppm Tw20 3 0.5 (A) 47 ppm d i f 1 0.7 + 2 0.7 500 ppm Tw20 3 0.5 (B) 187 ppm d i f 1 0.2 + 2 0.4 0 ppm Tw20 3 0.4 (C) 187 ppm 1 0.8 azi.nphos- 2 0.2 methyl 3 0.2 (D) Ana l y s i s o f va r i ance Source DF To ta l 47 C e l l s 15 Treatment 3 (A) v s . (B) 1 (A) v s . (C) 1 (C) v s . (D) 1 C u l t i v a r 3 Treatment X C u l t i v a r 9 Wi th in c e l l s ( e r r o r ) 32= Spartan De l i c i o u s Newtown X 0.5 0.2 1.2 4.0 0.6 1.6 0.0 5.6 0.0 2.0 1.1 1 .7 0.0 • 0.7 0.9 1 .0 0.8 0.0 0.6 1.4 0.4 0.2 0.7 0.4 2.3 0.0 1.1 0.7 0.8 0.5 0.7 SS MS F 83.95 36.28 17.15 8.17 14.88 0.57 5.93 13.20 47.67 5.72 •8.'17;. 14.88 0i57. 1.47 1.49 3.84* 5.48* 9.99* 0.38 1.32 0.99 -89-Percent of harvested Golden De l i c i o u s apples showing cod l i ng moth damage. Subplots ( three t r ees ) were arranged in a balanced incomplete b lock des ign w i th four treatments randomized w i t h i n each b lock . Treatment Tree Block 1 Block 2 Block 3 Block 4 Block 5 X 0 ppm d i f 1 2.8 1.4 3.6 2.2 + 2 _ 2.3 1.9 2.4 2.1 2.1 0 ppm Tw20 3 _ . 1.4 1.8 2.5 1.2 (A) 47 ppm d i f 1 0.0 1 .3 1.3 0.4 -+ 2 1.1 0.6 0.5 1.2 - 0.8 0 ppm Tw20 3 0.7 1.1 0.7 1.1 -(B) 47 ppm d i f 1 0.9 1.1 _ 0.8 0.6 + 2 0.0 1.2 - 1.1 1.4 0.8 500 ppm Tw20 3 0.8 0.5 - 1.0 0.6 (c5 187 ppm d i f 1 0.0 _ 0.6 0.0 0.7 + 2 0.5 - 1.0 1.1 0.8 0.5 0 ppm Tw20 3 0.0 - 0.2 0.4 0.8 (D) 187 ppm 1 0.0 0.7 0.5 - 0.6 az inphos - 2 0.0 0.7 0.6 - 0.0 0.4 methyl 3 0.0 0.8 1.2 - 0.3 (E) Ana l y s i s of va r i ance Source DF SS MS F_ Tota l 59 34.21 C e l l s 19 27.13 Treatments (4) 22.47 Treat (adjusted) 4 17.89 4.47 20.52* B locks (4) 6.84 B locks (adjusted) 4 2.26 0.57 3.20* (A) v s . (B+C+D+E) 1 2.70 2.70 12.40* (B) v s . (C) 1 0.0004 0.0004 0.002 (B) v s . (D) T 0.43 0.43 1.96 . (D) v s . (E) 1 0.008 0.008 0.04 Exp. e r r o r 11 2.40 0.22 Trees w i t h i n c e l l s 40 7.08 0.18 Table XX. 

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