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Effects of certain insecticides on the biotic potential of Epitrix tuberis Gentner (Coleoptera: Chrysomelidae) Finlayson, Douglas Gordon 1950

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THE EFFECTS OF CERTAIN INSECTICIDES ON THE • BIOKO POTENTIAL GF B p i t r i x t u b e r i s Gentner (COLIOPTERA: CHRYSOMELIDA!) by-Douglas Gordon F i n l a y s o n A Thesis Submitted i n P a r t i a l F u l f i l l m e n t o f the Requirements f o r the Degree of MASTER OF ARTS i n the Department of ZOOLOGY The U n i v e r s i t y of B r i t i s h Columbia A p r i l , 1950 THE EFFECTS OF CERTAIN INSECTICIDES ON' THE BIOTIC POTENTIAL OF E p i t r i x t u b e r i s Gehtner .  (COLEOPTERA: CHRYSOMELIDAE) ABSTRACT I n v e s t i g a t i o n s on b i o l o g y and c o n t r o l o f the tub e r f l e a b e e t l e E p i t r i x t u b e r i s Gentner, were conducted a t M e r r i t t , B.C. i n 194#« Although some i n s e c t i c i d e s under examination were commercially e f f e c t i v e , t h e r e were i n d i c a t i o n s t h a t tuber damage was g r e a t e r than expected i n p r o p o r t i o n t o t h e c o n t r o l produced. The p o s s i b i l i t i e s o f a s u b - l e t h a l dosage and i t s e f f e c t on t h e p o t e n t i a l o f t h i s .species n e c e s s i t a t e d a d d i t i o n a l experiments i n the l a b o r a t o r y . C u l t u r e s were f e d on potato l e a v e s dipped i n s o l u t i o n s o f the f o l l o w i n g i n s e c t i c i d e s : 0.005$ D.D.T. 0.005$ Toxaphene 0.005$ D.D.T./O.3$ Calcium Arsenate 0.3$ Calcium Arsenate Since the e f f e c t s of i n s e c t i c i d e s on both m o r t a l i t y and o v i p o s i t i o n were under o b s e r v a t i o n t h e s e treatments were i n t r o d u c e d a f t e r t he female o f a mated p a i r o f b e e t l e s had o v i p o s i t e d f o r one day. One hundred percent m o r t a l i t y was produced by each i n s e c t i c i d e i n 4$ hours w i t h a marked decrease i n o v i p o s i t i o n below the normal. However, the f a c t t h a t o v i p o s i t i o n o c c u r r e d at a l l i s the suspected reason t h a t tuber damage was greater than expected from the control produced. This, accompanied by a mistimed ap p l i c a t i o n of the i n s e c t i c i d e could well account for a heavy l a r v a l i n f e s t a t i o n of potato tubers although achieving excellent control of the adults. Contact treatments were carr i e d out with the above i n s e c t i c i d e s and s i m i l a r r e s u l t s were obtained which further substantiated the supposition that o v i p o s i t i o n commenced before the a p p l i c a t i o n of the chemicals. TABLE OF CONTENTS Page INTRODUCTION , • 1 BIOLOGY OF S p i t r i x , tuper.is Gent., 4 D e s c r i p t i o n of Stages- 4 L i f e H i s t o r y - 7 Co p u l a t i o n , P r e - O v i p o s i t i o n , and O v i p o s i t i o n 10 S p r i n g Emergence 12 Sex R a t i o of Emergent B e e t l e s 13 Reproductive System 14 B i o t i c P o t e n t i a l ; 16 A l t e r n a t e Hosts and the E f f e c t on Ma t u r a t i o n and F e c u n d i t y 19 NATURAL CONTROL 21 FIELD EXPERIMENTS IN CHEMICAL 'CONTROL 23 Methods and Procedures 23 Experimental R e s u l t s 27 LABORATORY EXPERIMENTS IN CHEMICAL CONTROL 32 Methods and Procedures 32 Expe r i m e n t a l R e s u l t s 41 DISCUSSION OF RESULTS 47 CONCLUSIONS ' 50 ACKNOWLEDGMENTS 52 LITERATURE CITED 54 APPENDIX 60 APPENDIX Appendix "A" (Tables) Page Table I The Range and Average Du r a t i o n of V a r i o u s Stages of E p i t r i x t u b e r i s i n the I n s e c t a r y at S c o t t ' s B l u f f , Nebraska. ( A f t e r H i l l and Tate (1942)) 61 Table I I The L i f e P e r i o d of Mala and Female B e e t l e s E p i t r i x t u b e r i s Gent, at Room Temperature 62 < Table I I I P r e - O v i p o s i t i o n P e r i o d of Emergent and F i r s t Summer Generations at Room Temperature 63 Table IV Sex of Overwintered A d u l t B e e t l e s M e r r i t t , 1948 64 Table V Dust Schedule f o r 1948 and T e n t a t i v e Dates f o r C o n t r o l D u s t i n g i n Future Years 65 Table VI E f f e c t of D u s t i n g w i t h I n s e c t i c i d e s on Ad u l t P o p u l a t i o n s of E p i t r i x t u b e r i s Gent. M e r r i t t , B.C. 1948 66 Table VII L a r v a l , Pupal, and Pre-Adult Stages per H i l l of Potatoes Examined M e r r i t t , B.C. 1948 67 T a b l e V I I I Examination of Tubers Taken at Time of A n a l y s i s by F l o a t a t i o n Method, M e r r i t t , 1948 68 Table IX E f f e c t of I n s e c t i c i d e s A p p l i e d to Net t e d Gem Potatoes f o r C o n t r o l l i n g E p i t r i x t u b e r i s Gent, as Shown by Tubers dug a t M e r r i t t , B.C. September 1, 1948 69 - i n -Table X E f f e c t of I n s e c t i c i d e s A p p l i e d to Net t e d Gem Potatoes f o r C o n t r o l l i n g E p i t r i x  t u b e r i s Gent, as shov/n by Tubers dug a,t H e r r i t t , B.C. September 11, 1948 Table XI E f f e c t of I n s e c t i c i d e s a t V a r i o u s Percentages on E p i t r i x t u b e r i s by D i p p i n g Method Table XII O v i p o s i t i o n and lumber of Days of Egg-l a y i n g i n C o n t r o l C u l t u r e Table X I I I C a l c u l a t i o n of Reg r e s s i o n of M o r t a l i t y of E p i t r i x t u b e r i s Table XIV O v i p o s i t i o n and Number of Days of Egg-l a y i n g when Treated w i t h 0.005$ D.D.T. Table XV O v i p o s i t i o n and Number of Days of Egg-l a y i n g when Tre a t e d w i t h 0.005$ Toxaphene Table XVI O v i p o s i t i o n and Number of Days of Egg-l a y i n g when Treated w i t h 0.005$ D.D.T. and 0.3$ Calcium Arsenate Table XVII O v i p o s i t i o n and Number of Days of Egg-l a y i n g when Treated w i t h 0.3$ Ca l c i u m Arsenate Table XVHI O v i p o s i t i o n and Number of Days' of Egg-l a y i n g whenTreated with 5$ D.D..T. Dust Table XIX O v i p o s i t i o n and Number of Days of Egg-l a y i n g when Tre a t e d with 69.0$ Calcium Arsenate Dust - i v -Table XX O v i p o s i t i o n and Number of Days of Egg-l a y i n g when Treated w i t h 10% Toxaphene Dust 82 Table XXI I n s e c t i c i d e A p p l i c a t i o n to C u l t u r e s of the Tuber E l e a B e e t l e 83 Table XXII Normal and Reduced O v i p o s i t i o n B e f o r e , and A f t e r Treatments 84 Table XXIII The E f f e c t s of D.D.T., Calcium Arsenate, and Toxaphene as Eumigants 85 - V -Appendix "B" ( F i g u r e s ) Page F i g u r e 1 H i b e r n a t i o n Gage used f o r L i f e H i s t o r y Study 87 F i g u r e 2 Emergence Cage i n .Plot 6A 8  F i g u r e 3 Emergence Cage i n P l o t 6C 8  F i g u r e 4 R e a r i n g Cage f o r Observation of L a r v a l and Pupal Movements i n the S o i l 89 F i g u r e 5 R e c o n s t r u c t e d Diagram of the Male Reproductive System 90 F i g u r e 6 R e c o n s t r u c t e d Diagram of the Female Reproductive System 91 F i g u r e 7 Cage used f o r P a r a s i t e I n v e s t i g a t i o n s , M e r r i t t , 1948 92 F i g u r e 8 Cage used f o r P a r a s i t e I n v e s t i g a t i o n i n L a b o r a t o r y Experiments 93 F i g u r e 9 . Diagramatic R e p r e s e n t a t i o n of Potato P l o t s , M e r r i t t , 1948 94 F i g u r e 10. Potato F i e l d , M e r r i t t , 1948 95 F i g u r e 1 D o r s o - l a t e r a l View of F l o a t a t i o n Equipment 96 F i g u r e 12 D o r s a l View of F l o a t a t i o n Screens 96 F i g u r e 13 Cage used to Study O v i p o s i t i o n of B e e t l e s 97 F i g u r e 14 Equipment used f o r D u s t i n g i n I n s e c t i c i d e Study 97 F i g u r e 15 Apparatus f o r Measuring Small Areas Eaten from a Leaf 98 - v i -P i g u r e 16 Graph 1 E f f e c t of 30$ D.D.T.; 5.0$ D.D.T. and 10.0$ Toxaphene on A d u l t P o p u l a t i o n Compared to Un t r e a t e d P o p u l a t i o n 99 Pi g u r e 17 Graph 2 E f f e c t of D. D . T . / C r y o l i t e and 5.0$ Chlordane on Adult P o p u l a t i o n Compared to Untreated P o p u l a t i o n 99 Pi g u r e 18 Graph 3 E f f e c t of 3.0$ D.D.T.; 5.0$ D.D.T.; and D.D.T./Cryolite on l a r v a l and Pupal P o p u l a t i o n s as Compared w i t h U n t r e a t e d P o p u l a t i o n s 100 Pi g u r e 19 Graph 4 . E f f e c t of 5.0$ Chlordane and 10.0$ Toxaphene on L a r v a l and Pupal P o p u l a t i o n s as Compared with U n t r e a t e d . Pop u l a t i o n s 100 pi g u r e 20 Graph 5 M o r t a l i t y Curve f o r E p i t r i x  t u b e r i s Gentner Under C o n d i t i o n s of the Experiment . 101 Pi g u r e 21 Graph 6 R e g r e s s i o n L i n e of E p i t r i x t u b e r i s M o r t a l i t y Curve 101 pi g u r e 22 Graph 7 Normal M o r t a l i t y as Opposed to E f f e c t Produced when B e e t l e s T r e a t e d with 0.005$ D.D.T. 102 Pig u r e 23 Graph 8 M o r t a l i t y of the Tuber P l e a B e e t l e when Treated with 0.005$ Toxaphene Compared w i t h Normal Death Rate 102 - v i i F i g u r e 24 Graph 9 E f f e c t on M o r t a l i t y when • Treated w i t h 6.005% D.V.T,/0.3% Calcium Arsenate , 103 F i g u r e 25 Graph 10 M o r t a l i t y Caused by Treatment wi t h 0.3^ Calcium Arsenate 103 F i g u r e 26 Graph 11 E f f e c t on M o r t a l i t y of E p i t r i x t u b e r i s Treated w i t h 5.0% D.D.T. 104 F i g u r e 27 Graph 12 M o r t a l i t y of Tuber F l e a B e e t l e when Treated w i t h 69.0/^ Calcium Arsenate 104 F i g u r e 28 Graph 13 E f f e c t on M o r t a l i t y of E p i t r i x t u b e r i s T r e a t e d with 10.0% Toxaphene 105 -1-IN.TRQDU0TION The tuber f l e a b e e t l e , E p i t r i x t u b e r i s Gentner, has been known to cause c o n s i d e r a b l e damage to potatoes through-out the northwestern s t a t e s of the U n i t e d S t a t e s of America f o r the p a s t 20 y e a r s . Damage was a p p a r e n t l y r e c o g n i z e d by Johnson i n the G r e e l y d i s t r i c t of Colorado as l o n g ago as 1904. Since t h a t time there have been many r e p o r t s of i t s b i o l o g y and damage; Baker (1928), Hanson (1930), L a n d i s (1943), Webster, L a n d i s , ahd Getzendaner (1941), and Webster, Baker, and Hanson (1932) of the S t a t e of Washington; Bennet (1907), D a n i e l s (1933, 1937, and 1941), G i l l e t t e (1927), Hoerner and G i l l e t t e (1928), Johnson (1904), and Metzger (1938) of C o l -orado; Besse (1941) of Oregon; H i l l (1946), H i l l and Tate (1942), and Swenk and Tate (1940) of Nebraska; and Smith (1938) of Idaho have a l l made c o n t r i b u t i o n s to our knowledge of t h i s s p e c i e s . Many of these r e p o r t s were p u b l i s h e d as being the work of E p i t r i x cucumeris ( H a r r i s ) , and I t was not u n t i l 1944, t h a t Gentner's work separated the two s p e c i e s , E . cucumeris and E . t u b e r i s , and showed t h a t the c u l p r i t i n the n o r t h -western U n i t e d S t a t e s Is the l a t t e r s p e c i e s . In B r i t i s h Columbia, damage was f i r s t n o t i c e d i n the E r a s e r V a l l e y by Glendenning and E o u l t o n (1940). Although pres e n t f o r some y e a r s , i t was not u n t i l 1945 t h a t the tuber f l e a b e e t l e became of economic importance i n the I n t e r i o r of -2-B r i t i s h Columbia. S t u d i e s were i n i t i a t e d the f o l l o w i n g y e a r and have continued u n t i l the p r e s e n t . The experimental data presented here concern s t u d i e s made w h i l e the author was em-ployed by the Dominion F i e l d Crop I n s e c t L a b o r a t o r y , Kamloops, B. C. d u r i n g 1948 and 1949. Damage l o s s e s to the grower have been estimated sev-e r a l times. Hoerner and G i l l e t t e (1928) approximated the an-nual l o s s f o r Colorado a t #100,000; only f i v e y e ars l a t e r , D a n i e l s (1933) assessed the annual l o s s a t n e a r l y h a l f a m i l -l i o n d o l l a r s f o r that s t a t e . Damage by the a d u l t b e e t l e i s c o n f i n e d to the l e a v e s and i s of l i t t l e importance unless the b e e t l e s are presen t i n l a r g e numbers, when they are capable of k i l l i n g young p l a n t s by s t r i p p i n g the f o l i a g e . The main damage i s . i n f l i c t e d by the l a r v a e which feed on the tubers causing "pimples", "worm-t r a c k s " , and " s l i v e r s " . M a c M i l l a n and S c h a l l (1929) and S c h a l l (1934) p o i n t out the i n c r e a s e d chance of p a t h o l o g i c a l i n o c u l a t i o n s from these i n j u r i e s . Johannsen (1913) r e p o r t s the f l e a b e e t l e a c t i n g as a c a r r i e r f o r e a r l y b l i g h t and i n -c r e a s i n g the p r o b a b i l i t y of i n f e c t i o n by e a t i n g h o l e s i n the l e a v e s . In 1948 j o i n t I n v e s t i g a t i o n s were made i n the Kam-loops and M e r r i t t d i s t r i c t s by N e i l s o n and F i n l a y s o n r e s -p e c t i v e l y . The r e s u l t s o f these i n v e s t i g a t i o n s gave a p a r t i a l answer to c o n t r o l by i n s e c t i c i d e s , but i n d i c a t i o n s of complex -3-f a c t o r s were observed. These f a c t o r s appeared r e s u l t a n t r a t h e r than e x i s t i n g i . e . , the tuber damage was not p r o p o r t -i o n a l to the m o r t a l i t y caused by the a p p l i c a t i o n s of i n s e c t -i c i d e s . The l a r v a l and pupal p o p u l a t i o n s seemed g r e a t e r than was expected from the a d u l t p o p u l a t i o n p r e s e n t . Glendenning (Correspondence) r e p o r t e d s i m i l a r c o n d i t i o n s i n experiments at A g a s s i z , B.C. Suggested e x p l a n a t i o n s f o r t h i s c o n d i t i o n a r e : 1. The i n s e c t i c i d e s concerned e i t h e r r e t a r d , reduce, s t i m u l a t e , or i n h i b i t o v i p o s i t i o n . 2. The chemicals were not s u f f i c i e n t l y t o x i c to prevent females from d e p o s i t i n g t h e i r normal number of eggs b e f o r e death. 3. The i n s e c t i c i d e s were a p p l i e d too l a t e to prevent o v i p o s i t i o n . F u r t h e r i n v e s t i g a t i o n s on the e f f e c t s of i n s e c t i c i d e s on the p o p u l a t i o n s of the tuber f l e a b e e t l e were i n d i c a t e d and c o n t r o l l e d l a b o r a t o r y experiments were planned to a s c e r t a i n the reason or reasons f o r the r a t i o between a d u l t m o r t a l i t y and l a r v a l p o p u l a t i o n s which were found a f t e r the a d u l t s were supposedly k i l l e d o f f . -4-BXOLOGY" OJ' E p i t r i x t u b e r i s Gen t r i e r . DESCRIPTION Off THE STAGES A d u l t The f o l l o w i n g i s Gentner's o r i g i n a l d e s c r i p t i o n of E p i t r i x t u b e r i s (Gentner, 1944|. ~ "Elongate ovate, p i c e o u s , moderately s h i n i n g . Ant-ennae r u f o t e s t a c e o u s , outer f i v e j o i n t s d a r k e r . Head smooth, w i t h few punctures near each eye. Eyes not prominent, t h e i r combined width when viewed from the f r o n t l e s s than the i n t e r -o c u l a r d i s t a n c e . Pronotum l e s s than one-half wider than l o n g , narrowed somewhat a n t e r i o r l y , a n t e r i o r angles o b l i q u e l y t r u n -c a t e , s i d e s moderately a r c u a t e , d i s c convex, e s p e c i a l l y ant-e r i o r l y , punctures moderately coarse, c l o s e l y p l a c e d , u s u a l l y separated by l e s s than t h e i r diameters, somewhat f i n e r and s p a r s e r a n t e r i o r l y , t r a n s v e r s e a n t e - b a s a l impression s i n u a t e , deep, with many f a i r l y coarse punctures, l o n g i t u d i n a l impres-s i o n s at each end w e l l marked. E l y t r a s c a r c e l y wider a t base than pronotum, l a t e r a l margins somewhat s u b p a r a l l e l , humeri not prominent, umbones moderately d i s t i n c t , d i s c f e e b l y convex, s t r i a e f e e b l y impressed, punctures l a r g e , c l o s e l y p l a c e d , f i n e r toward apex, i n t e r v a l s v ery narrow. Legs r u f o t e s t a c e o u s , a n t e r i o r and middle femora fuscous, p o s t e r i o r femora p i c e o u s . Males: length,1.60-1.96 mm., width 0.84-1.08 -5-mm.; females: l e n g t h 1.80-2.Q4 mm., width 0.96-1.12 mm." •Egg The eggs are about 0.5 mm. l o n g and 0.2 mm. wide and are s c a r c e l y d i s c e r n a b l e i n t h e i r normal l o c a t i o n of incub-a t i o n , but can be seen q u i t e e a s i l y on a dark background. They are e l l i p t i c a l i n shape and when viewed w i t h a micros-cope the s u r f a c e appears p i t t e d or r e t i c u l a t e d . They are white to creamy white i n c o l o u r . The f o l l o w i n g data were obtained f o r t h i r t y eggs measured w i t h an o c u l a r micrometer: l e n g t h , maximum 0.53 mm., minimum 0.48 mm., mean 0.51 mm.; width, maximum 0.22 mm., minimum 0.19 mm., mean 0.20 mm. L a r v a When f i r s t hatched the l a r v a i s very d e l i c a t e and t h r e a d - l i k e i n appearance and i s approximately 1.0 mm. l o n g . I t i s white to'creamy c o l o u r e d and almost i m p o s s i b l e to l o c a t e i n the s o i l . The f u l l grown l a r v a averages 5.3 mm. i n l e n g t h and i s about 0.8 mm. wide, m a i n t a i n i n g i t s white, d e l i c a t e , t h r e a d l i k e appearance. The head i s s m a l l , sub-ovate, and bent downward. The e p i c r a n i a l p l a t e i s l i g h t brown w i t h darker brown margins. The three-segmented antennae are sma l l and i n c o n s p i c u o u s . The mouth p a r t s are w e l l developed; the mandibles, l a b i a l -6-and m a x i l l a r y p a l p i "being most prominent. The mandibles are r e d d i s h brown a t t h e i r bases and almost b l a c k a p i c a l l y . The head has a few h a i r s s c a t t e r e d on the v e r t e x . The thorax i s w e l l d i f f e r e n t i a t e d i n t o three segments, and the s h o r t simple l e g s terminate i n a s i n g l e t a r s a l seg-ment without a claw. The tan l e g s and the brown eoxosternum are the only p a r t s of the thorax which d e v i a t e from the uniform creamy white c o l o u r i n g . There are a few h a i r s evenly d i s t r i b u t e d on the thorax. The ten-segmented abdomen i s almost g l a b r o u s . The a n a l s h i e l d i s l i g h t brown t e r m i n a t i n g i n brown, v e r t i c a l l y curved, a n a l f o r k s . The 10th abdominal segment i s r e t r a c t i l e with a locomotary organ p r e s e n t . Pupa When f i r s t transformed the pupa i s u n i f o r m l y white i n c o l o u r approximately 2.5 mm. l o n g and 1.5 mm. wide a c r o s s t h e mesothorax, the widest p a r t . The head i s r e f l e x e d and the antennae extending caudad are p a r t l y concealed beneath the pro and mesolegs. The metalegs are almost concealed beneath the d e v e l o p i n g wings. There are sparse h a i r s on the v e r t e x , pronotum and abdomen. The abdomen terminates i n a p a i r o f curved appendages. As the t r a n s f o r m a t i o n approaches com-p l e t i o n the mandibles and compound eyes become darker and the body g e n e r a l l y becomes s l i g h t l y grey. . The a d u l t does 1 - - 7 -not "become b l a c k u n t i l approximately two hours a f t e r emer-gence from the s o i l . L I F E HISTORY Sin c e no attempt was made i n t h i s i n v e s t i g a t i o n to com-p l e t e a d e t a i l e d study of the l i f e h i s t o r y of the tuber f l e a b e e t l e the technique and the f i n d i n g s of H i l l and Tate (1942), are quoted. M In g e n e r a l the r e a r i n g technique was s i m i l a r to t h a t employed by Jdhannsen (1921), Hoerner and G i l l e t t e (1928), and Anderson and Walker (1934). Instead of l a n t e r n globes, however, the cages were made of 30 mesh copper s c r e e n wire supported by a l i g h t metal frame. For o b t a i n i n g d a t a on o v i p o s i t i o n the cages were p l a c e d on dark blue b l o t t i n g paper i n c o n t a c t w i t h moist sand i n f l o w e r p o t s . M o i s t u r e was s u p p l i e d through c a p i l l a r y a c t i o n by p l a c i n g each pot i n a s h a l l o w pan of water. I n d i v i d u a l eggs were p l a c e d i n s a l v e boxes, about 45 mm. i n diameter and 20 mm. i n h e i g h t , the bottoms of which contained sand covered w i t h b l o t t i n g paper. M o i s t u r e was added i f needed but f r e q u e n t l y i t was d i f f i c u l t to prevent the accumulation of excess m o i s t u r e . As the eggs hatched the l a r v a e were t r a n s f e r r e d to s m a l l p i e c e s of potato tuber and p l a c e d i n s a l v e boxes. M o i s t u r e was p r o v i d e d by l i n i n g the bottom of the c o n t a i n e r w i t h blot-t i n g paper and then adding water as-needed. As the l a r v a e -8-reached m a t u r i t y an environment f a v o r a b l e f o r pu p a t i o n was obtained by p a r t i a l l y f i l l i n g the box w i t h f i n e s o i l . Newly formed pupae were removed and p l a c e d i n s l i g h t l y mois-tened s o i l i n another s a l v e box f o r the d u r a t i o n of the pupal p e r i o d . " Table I shows the range and average d u r a t i o n of the i n -c u b a t i o n , l a r v a l and pupal p e r i o d s determined by H i l l and Tate (1942). No mention of the a d u l t l i f e p e r i o d was made by H i l l and Tate (1942-:). In t h i s i n v e s t i g a t i o n the range of the a d u l t l i f e , from the date c o p u l a t i o n was f i r s t observed u n t i l death, was 6 to 106 days w i t h a mean of 56.6*5.9 days. S i n c e both sexes appeared to have a l o n g span of l i f e . a l l b eetles, were sexed and the mean l i f e p e r i o d f o r the male and female b e e t l e s estimated, as shown i n Table I I . Except i n cage f o u r , d i s s e c t i o n showed, that the female b e e t l e s had eggs i n t h e i r o v a r i e s , and the males o u t l i v e d the females. No f e m a l e . o v i p o s i t e d a f t e r the death of the. male. T h i s r a i s e s the q u e s t i o n : Is i t necessary i n t h i s s p e c i e s f o r continued i n t e r m i t t e n t c o p u l a t i o n to s t i m u l a t e the r e p r o d u c t i v e organs of the female f o r the development of ova, or was t h i s a c o i n c i d e n c e ? Although no. d e t a i l e d study was made of the i n d i v i d u a l stages of the l i f e , c y c l e , the p e r i o d from egg to a d u l t , emergence was observed f o r both the f i r s t and second gener-a t i o n s . The p e r i o d estimated (42 days) l i e s \vell w i t h i n the - 9 -range o f H i l l and Tate (1942). No cages were used f o r the obs e r v a t i o n s made on the f i r s t g n e r a t i o n , hut f o r the second g e n e r a t i o n cages ( f i g u r e 1) prepared by N e i l s o n i n 1948 were used. These cages 2^ f e e t square and 2a f e e t h i g h were cov-ered w i t h l u m i t e and were p l a c e d over potato p l a n t s f r e e from f l e a b e e t l e s . B e e t l e s were put i n one cage on J u l y 21, 1949, and i n t o another on August 4. On August 15, the cages were removed and the potato p l a n t s cut o f f about one i n c h above the ground. Emergence cages ( f i g u r e s 2 and 3 ) ( a f t e r Glenden-ning) were p l a c e d above the cut stub of the potato p l a n t s . E g g - l a y i n g f o r t h i s g e n e r a t i o n commenced J u l y 24, 1949. A d u l t s emerged from the f i r s t cage on September 1, and on September 11 from the second cage. The maximum number of days f o r the t o t a l l i f e c y c l e from egg to a d u l t was 39 days f o r cage I and 38 days f o r cage I I . The f i r s t date of emergence f o r the f i r s t g e n e r a t i o n i n the M e r r i t t d i s t r i c t i n 1948 was J u l y 20 and no second gen-e r a t i o n was recorded th e r e , which may be due to the f l o o d s and the u n u s u a l l y heavy r a i n s t hat y e a r . In the Kamloops area the f i r s t g e n e r a t i o n of 1949 began emergence on J u l y 19 and the second g e n e r a t i o n on September 1. Temperature and s o i l moisture a f f e c t the l e n g t h of the v a r i o u s stages and the number of i n d i v i d u a l s . H i l l and Tate (194;g) showed t h a t a d e c r e a s i n g temperature i n c r e a s e d the p e r i o d necessary to reach the a d u l t s t a g e . D a n i e l s (1933) -10-found that f l e a "beetles t h r i v e b e s t i n heavy moist s o i l s and t h a t the numbers of immature stages from i r r i g a t e d and non-i r r i g a t e d p l o t s v a r i e d from 543 and 553 l a r v a e and pupae f o r normal and heavy i r r i g a t i o n , to 115 l a r v a e and pupae f o r no i r r i g a t i o n . An attempt was made to study the immature stages of the l i f e h i s t o r y which take p l a c e below the s o i l s u r f a c e i n a r e a r i n g cage f o r s o i l i n s e c t s ( f i g u r e 4) adapted from the mod-i f i c a t i o n of the Comstock cage by Lohrenz (1911). However, the s i z e of the l a r v a e i n r e l a t i o n to the r o o t s of the potato plant made i t i m p o s s i b l e to f o l l o w t h e i r movements. A more r e f i n e d method w i l l have to be d e v i s e d i f t h i s study i s c o n t i n u e d . COPULATION, PRE-OVIPOSITION, AND OVIPOSITION The a d u l t f l e a b e e t l e s were observed to copulate twenty-f o u r hours a f t e r emergence. The p e r i o d of c o p u l a t i o n v a r i e s but the a c t was repeated p e r i o d i c a l l y u n t i l the f i f t y - f o u r t h day of o v i p o s i t i o n over a range of a t l e a s t s i x t y days. H i l l (1946), who a l s o observed t h i s , s t a t e s , " I t seems l i k e l y , t h e r e f o r e , that o v i p o s i t i o n i s s t i m u l a t e d by repeated cop-u l a t i o n and t h a t frequency of mating i s i n f l u e n c e d i n some ways by the q u a l i t y of f o o d . " Whether they had f e d or not b e f o r e c o p u l a t i o n i n my cages was not d e f i n i t e l y e s t a b l i s h e d but i t was assumed, s i n c e there were s m a l l h o l e s t y p i c a l of f l e a b e e t l e damage i n the potato l e a v e s . -11-A. knowledge of the p r e - o v i p o s i t i o n p e r i o d i s necessary, f o r i f the a d u l t s can he c o n t r o l l e d b e f o r e o v i p o s i t i o n com-mences then the damage to tubers w i l l be reduced c o n s i d -e r a b l y . The p r e - o v i p o s i t i o n p e r i o d was determined f o r both the emergent g e n e r a t i o n and f i r s t summer g e n e r a t i o n i n 1949, and i s shown i n Table I I I . The o v i p o s i t i o n p e r i o d f o r the c o n t r o l c u l t u r e had a wide range. Although the number of females under o b s e r v a t -i o n was not l a r g e the average number of days of o v i p o s i t i o n was comparable w i t h that determined by H i l l (1946) who found i t to be 44.7 days. In my i n v e s t i g a t i o n the average o v i -p o s i t i o n p e r i o d was 37.5 days w i t h a minimum of 12 days and a maximum of 54 days as shown i n Tables X I I and XXII. The eggs are l a i d s i n g l y w i t h no uniform number being d e p o s i t e d d a i l y . The maximum number of eggs l a i d i n one day was 17. The t o t a l number of eggs l a i d by females v a r i e d c o n s i d e r -a b l y , r a n g i n g from 28 to 203 w i t h a mean of 86.9 eggs. Hoerner and G i l l e t t e (1928).. found that the eggs are d e p o s i t e d a t a depth of one-half to two inches i n moist s o i l . They r e p o r t a female l a y i n g 28 eggs i n 24 hours and a maximum of 245 eggs f o r one female. H i l l (1946) found the number of eggs d e p o s i t e d per female v a r i e d from 161 to 215, averaging 187 eggs. - 1 2 -SPRING EMERGENCE Since early control of t h i s species i s necessary i t s f i r s t appearance on or about the potatoes must be known. Prom previous investigations i n the i n t e r i o r of B r i t i s h Columbia the indicated a r r i v a l or emergence was the l a s t week of May and the f i r s t week of June. In 1 9 4 8 a survey of the areas surrounding the potato plots was made i n both the Nicola Val l e y and Kamloops d i s t r i c t s , and again f o r the Kamloops d i s t r i c t i n 1 9 4 9 . This survey consisted of sweeping weeds in the ditches and potato p l o t s , crops adjacent to the potato plots, and vegetation i n general within a h a l f mile radius of the f i e l d under observation. Neilson and Pinlayson ( 1 9 4 8 ) , recorded the emergence of E p i t r i x tuberis i n 1 9 4 8 as followsf M e r r l t t , B. C., May 2 8 , 1 9 4 8 and Eayleigh, B. C , June 1 , 1 9 4 8 . In 1 9 4 9 further studies were made in the Eiamloops d i s t r i c t and the f i r s t record was made at Westsyde on May 30. Other areas investigated i n t h i s general d i s t r i c t showed dates up to and including June 3 , at Mission P l a t s . Since this extension occurs i t i s necessary that the growers become f a m i l i a r with the signs i n d i c a t i v e of the presence of f l e a beetles and apply i n s e c t i c i d e s so that mortality i s caused i n the six-day pre-oviposition period. -13-SEX RATIO OF EMERGENT BEETLES In 1948 a l l b e e t l e s c o l l e c t e d from May 30 to June 13 were preserved f o r s e x i n g a t a l a t e r date to determine the r a t i o of males and females pres e n t i n the e a r l y stages of emergence from h i b e r n a t i o n . There i s no ready means of sep-a r a t i n g males from females by e x t e r n a l c h a r a c t e r s so an examination of the g e n i t a l i a i s necessary. The b e e t l e s were p l a c e d i n a warm 10% potassium hydroxide s o l u t i o n f o r ten minutes to s o f t e n the c h i t i n s u f f i c i e n t l y to f a c i l i t a t e r a p i d examination. M i n u t i n p i n s i n s e r t e d i n match s t i c k s were used to d i s s e c t the b e e t l e s and the r e s u l t s obtained are shown i n Table IV. Table IV shows l i t t l e v a r i a t i o n between the number of males and females pres e n t and seems to i n d i c a t e a 1:1 sex r a t i o . T h i s was s u b s t a n t i a t e d i n 1949 d u r i n g the c o l l e c t i o n of mating p a i r s of tuber f l e a b e e t l e s when no d i f f i c u l t y was encountered i n f i n d i n g them i n c o p u l a t i o n ; three days a f t e r the f i r s t r e c o r d of emergence from h i b e r n a t i o n 45 p a i r s were caught at Westsyde, B . C . Th i s r a t i o was f u r t h e r substant-i a t e d by the f i r s t emergence of the f i r s t summer g e n e r a t i o n on J u l y 18, 1949, from a c u l t u r e under o b s e r v a t i o n f o r the presence of p a r a s i t e s . On the f o l l o w i n g day 162 b e e t l e s were c o l l e c t e d , a l l i n c o p u l a t i o n , g i v i n g a 1:1 r a t i o . -14-REPRODUCTIVE SYSTEM Study of the r e p r o d u c t i v e system of the male and female f l e a b e e t l e s was i n i t i a t e d to determine, i f p o s s i b l e , the anatomy of the p a r t s and the a b s o l u t e p o t e n t i a l , but was ham-pered by the minute s i z e , about 1 mm., of the i n s e c t s abdomens. S e v e r a l procedures were employed i n an e f f o r t to o b t a i n the a b s o l u t e p o t e n t i a l because m i c r o - d i s s e c t i o n and s t a i n i n g proved u n s a t i s f a c t o r y on account of the s i z e of the b e e t l e . The exact s e p a r a t i o n of the o v a r i o l e s proved im-p o s s i b l e by o r d i n a r y methods of d i s s e c t i o n and the minute-ness of the p a r t s . Preserved specimens were too b r i t t l e to a l l o w f l e x i n g of the o v a r i o l e s and counting the d e v e l o p i n g ova was t h e r e f o r e hampered. Imbedding i n c e l l o d i n and par-a f f i n f o r s e c t i o n i n g r e s u l t e d i n s i m i l a r c o n d i t i o n s . The c h i t i n o u s body w a l l and t i s s u e t o r e b a d l y . F u r t h e r r e f i n e d methods, not p o s s i b l e a t t h i s time, are necessary b e f o r e the a b s o l u t e p o t e n t i a l of t h i s s p e c i e s w i l l be r e v e a l e d anatom-i c a l l y . The g e n e r a l anatomy of the r e p r o d u c t i v e system, although i t was not an easy task, proved more g r a t i f y i n g and was done w i t h sharpened minuten p i n s . The e l y t r a and meta wings were removed, the abdomen severed from the thorax, and the t e r g a l s e l e r i t e s removed from the abdomen. A f t e r the removal of the t e r g i t e s , the s t e r n i t e s were severed from the muscles which -15-e n c i r c l e the organs. The organs were dehydrated and s t a i n e d i n a 1.0^ s o l u t i o n of a c i d f u c h s i n i n 70% e t h e y l a l c o h o l , f u r t h e r dehydrated and taken to toluene where they were s t i l l f u r t h e r teased a p a r t then mounted i n balsam. Since the p a r t s were so f r a g i l e many d i s s e c t i o n s were necessary to o b t a i n a composite p i c t u r e . The terminology of the r e p r o d u c t i v e system, as used here, i s t h a t of Snodgrass (1935) f o r the male and that of Henneguy (1904) and Weber (1933) f o r the female. Male Reproductive System and G e n i t a l Armature ( F i g u r e 5) The o v a l , h i g h l y convoluted, t u b u l a r t e s t e s l i e on the meson from the 1 s t . to the 3rd. segments. They p a r t i a l l y o v e r l a p and are a p p a r e n t l y f u s e d . From each t e s t i s a vas deferens passes backward w i t h an enlargement immediately behind the t e s t e s , the v e s i c u l a e seminales, c o n t i n u i n g caudad to u n i t e i n the ductus e j a c u l a t o r i u s . The duct enters a l a r g e muscular mass, the aedeagus, which i s s i t u a t e d i n a concave c h i t i n o u s s t r u c t u r e , the par-ameres. The parameres are e n c i r c l e d by a U-shaped s c l e r o t i c annulus p r o v i d e d w i t h a v e n t r a l apodeme which g i v e i t a "Y" shape. The whole mass occupies the 7th sternum. -16-ffemale Reproductive System and G e n i t a l Armature ( F i g u r e 6) The o v a r i e s , each a p p a r e n t l y composed of s i x o v a r i o l e s , l i e on each s i d e of the a l i m e n t a r y c a n a l . The o v a r i o l e s are a c r o t r o p h i c and u n i t e p o s t e r i o r l y to form a s l i g h t en-largement, the egg-calyces, from which the p a i r e d o v i d u c t s o r i g i n a t e . The o v i d u c t s then u n i t e forming the common o v i -d uct. The seminal r e c e p t i c l e l i e s to the l e f t o f , and le a d s to j u s t "below, the j u n c t i o n of the p a i r e d o v i d u c t s . The seminal r e c e p t i c l e terminates i n a gland. There was no e v i d -ence of a "bursa c o p u l a t r i x . The v a g i n a passes p o s t e r i o r l y t e r m i n a t i n g between the o v i p o s i t o r . The o v i p o s i t o r c o n s i s t s of two segments which are tendenous a n t e r i o r l y and s c l e r o t i z e d a t the t i p s . The t i p s hear sense organs of two types, one be i n g s e t i f o r m . The two b a s a l p o r t i o n s of the o v i p o s i t o r are attac h e d by muscles. A c h i t i n o u s rod, a r i s i n g near the o r i g i n of the common o v i d u c t , i s at t a c h e d on the mesal l i n e to the 6 t h s t e r n i t e . C o n t r a c t i o n of muscles a t t a c h e d to t h i s rod ap-p a r e n t l y f u n c t i o n to e j e c t the whole e g g - l a y i n g apparatus. BIOTIC POTENTIAL Chapman (1931) d e f i n e s " b i o t i c p o t e n t i a l " as"the i n -herent p r o p e r t y of an organism to reproduce; i . e . , to i n --In-crease i n numbers". He a l s o s t a t e s that "the b i o t i c - pot-e n t i a l of the s p e c i e s i s a q u a n t i t a t i v e e x p r e s s i o n of the dynamic power of the s p e c i e s which i s p i t t e d a g a i n s t the r e s i s t a n c e of the environment i n which i t l i v e s i n i t s s t r u g g l e f o r e x i s t e n c e . " Thus on one s i d e of the equation i s the b i o t i c p o t e n t i a l , the product of the average number of young of each r e p r o d u c t i o n , the number of r e p r o d u c t i o n s i n a g i v e n p e r i o d of time, and the sex r a t i o , l e s s the number not r e a c h i n g m a t u r i t y or r e p r o d u c t i v e stage due to c o n d i t i o n s of i t s environment. On the o p p o s i t e s i d e of the equation t h e o r e t i c a l l y i s the more or l e s s b a l a n c e d p o p u l a t i o n of the s p e c i e s w i t h s l i g h t f l u c t u a t i o n s about a mean. I f a f a c t o r of the s p e c i e s ' environment i s a l t e r e d then these f l u c t u a t i o n s can increa.se or decrease t o a. degree dependent on the magnitude and importance of tha,t -c o n d i t i o n . This f l u c t u a t i o n can a f f e c t e i t h e r the p o p u l a t i o n as a whole or i s o l a t e d p o r t i o n s of the p o p u l a t i o n . F o r example, i n c r e a s e d p a r a s i t i s m can reduce a p o p u l a t i o n to the extent t h a t c y c l i c f l u c t u a t i o n s are produced from the par-•, a s i t e - h o s t r e l a t i o n s h i p , thus c a u s i n g outbreaks. L o t k a (1925) uses the t e r m • q u a s i - e q u i l i b r i u m f o r such systems because there i s a c o n t i n u a l d i s s i p a t i o n or d e g r a d a t i o n of energy i n v o l v e d i n m a i n t a i n i n g the s t a t i o n a r y s t a t e . O u t r i g h t (1930) concluded t h a t when the p o t e n t i a l of a s p e c i e s i s - 1 8 -h i g h then r e c u r r e n t i n f e s t a t i o n s are p r o b a b l e . To c o n t r o l an i n s e c t pest he s t a t e s , "The chances t h a t a c o n t r o l of from 94 to 98 percent e f f e c t i v e n e s s w i l l f a i l where the i n s e c t concerned has a low p o t e n t i a l are p r a c t i c a l l y neg- , l i g i b l e while i n the case of those w i t h h i g h p o t e n t i a l s such a c o n t r o l amounts to l i t t l e i f the environmental r e s i s t a n c e i s low." In c a l c u l a t i n g the approximate b i o t i c p o t e n t i a l of a s p e c i e s H e r r i c k (1926), to t e s t the c a l c u l a t i o n s of |Huxley. (1858), found t h a t a s i n g l e stem, mother of the common cab-bage aphid, B r e v i c o r y n e b r a s s i c a e L i n ne, c o u l d g i v e r i s e on-an average to 41 young. Assuming no m o r t a l i t y f o r the twelve generations between March 31 and August 15 the number l i v i n g at that time would be 564 x 10 progeny. Huxley (1858), i n h i s c a l c u l a t i o n s of weight based on f i g u r e s taken from Tougard o r i g i n a l l y , estimated that the aphids produced at- the end of the t e n t h g e n e r a t i o n would outweigh 500,000,000 men. "To say a t l e a s t more than the whole p o p u l a t i o n of C h i n a l " Even h i s weight c a l c u l a t i o n s were on l y p a r t i a l i n as much as two more generations per season c o u l d have been c o n s i d e r e d . Nov/ the average number of f l e a b e e t l e eggs per female under the c o n d i t i o n s of my experiment i s c o n s i d e r a b l y , lower than the average number per female as determined by H i l l (1946); i . e., 87 to 187. Chapman (1931) i n t r o d u c e d the f o l l o w i n g formula f o r c a l c u l a t i n g the b i o t i c p o t e n t i a l . -19-B i o t i c p o t e n t i a l r I^Z where P = Average r e p r o d u c t i o n r a t e per g e n e r a t i o n Z " Sex r a t i o n = Number of g e n e r a t i o n s per year s u b s t i t u t i n g B.P. B ( 8 7 ) 2 x 0.5 - 3784 Thus the b i o t i c p o t e n t i a l f o r E p i t r i x t u b e r i s under the experimental c o n d i t i o n s i B 3784. T h e o r e t i c a l l y i f one p a i r of b e e t l e s i s p r e s e n t ori a potato p l a n t i n the s p r i n g and the female l a i d her compliment of eggs under t h a t p l a n t , i f a l l reached m a t u r i t y and the females l a i d t h e i r f u l l com-pliment of eggs under the same p l a n t and a l l reached mat-u r i t y , approximately 3800 a d u l t b e e t l e s would be p r e s e n t on one p l a n t by mid-September. ALTERNATE HOSTS AND THE EFFECTS ON MATURATION AMD FECUNDITY In the 1948 i n v e s t i g a t i o n N e i l s o n and F i n l a y s q n found the f o l l o w i n g p l a n t s to be eaten by the tuber f l e a b e e t l e : A l f a l f a , Medicago s a t i v a ; Dandelion, Taraxacum o f f i c i n a l e ; Wild Mustard, B r a s s i c a a r v e n s i s ; Green Tansy Mustard, Sisymbrium incisum; Tomato, L y c o p e r s i c o n esculentum; Radish, Raphanus s a t i v u s ; Horse radish., Amoracia r u s t i c a n n a ; Lamb's Quarters, Chenopodium album; Beets, Beta v u l g a r i s ; Spinach, Spinacca o l e r a c e a ; H o l l y Hock, A l t h a c e a r o s e a Red C u r r a n t , Ribes rubruin; Peppers, Capsicum annuum; L e t t u c e , L a c t u c a s a t i v a ; Beans, Phaseolus v u l g a r i s . Whether or not v o l u n t a r y f e e d i n g on these p l a n t s i s continued a f t e r the potato p l a n t s were a v a i l a b l e was not i n v e s t i g a t e d . Uo con t i n u e d i n v e s t i g a t i o n was ma.de to determine whether or not a l l h o s t p l a n t s a f f e c t e d maturation, but no eggs c o u l d be found i n b e e t l e s taken from dandelion i n e a r l y June; y e t b e e t l e s taken from potato p l a n t s d u r i n g t h e same p e r i o d and under s i m i l a r c o n d i t i o n s , c o n t a i n e d mature eggs i n t h e i r o v a r i e s . In both i n s t a n c e s c o p u l a t i o n had a l r e a d y taken p l a c e . That p l a n t s other than p o t a t o , t h a t are eaten by f l e a b e e t l e s d e f i n i t e l y a f f e c t m a t u r a t i o n of eggs, i s claimed by H i l l (1946) who s t a t e s : 1 . "The type of food p l a n t consumed by caged f l e a b e e t l e s markedly i n f l u e n c e d o v i p o s i t i o n and l e n g t h of a d u l t l i f e . Potato f o l i a g e was the most s a t i s f a c t o r y food, egg p r o d u c t i o n b e i n g h i g h e s t and m o r t a l i t y lowest on such a d i e t . -20 a-E g g . v i a b i l i t y was u n a f f e c t e d by type of food: 97.27$ of 1392 eggs under o b s e r v a t i o n on potatoes hatched. There was some i n d i c a t i o n t h a t the frequency of c o p u l a t i o n was i n f l u e n c e d by the q u a l i t y of f o o d consumed by the b e e t l e s . Although these i n s e c t s w i l l f e e d on v a r i o u s p l a n t s , the experimental r e s u l t s i n d i c a t e t h a t of these o n l y potato adequately meets a l l the requirements f o r optimum l o n g e v i t y , r e p r o d u c t i v i t y , and l a r v a l development." -21-NATURAL. CONTROL. P a r a s i t e s have "been r e p o r t e d on a l l i e d s p e c i e s of f l e a b e e t l e s , hut up to the present no r e c o r d s of p a r a s i t e s of E p i t r i x t u b e r i s have been l o c a t e d i n l i t e r a t u r e . Records of p a r a s i t i s m on a l l i e d s p e c i e s are the following.: C h i t t e n d e n (1899) r e p o r t s a hymenopterous p a r a s i t e of the f a m i l y Braconidae a t t a c k i n g E p i t r i x cucumeris ( H a r r i s ) and E p i t r i x p a r v u l a Pab. Forbes (1900) r e p o r t s a hymenopterous p a r a s i t e , prob-a b l y one of the Braconidae, on E p i t r i x cucumeris ( H a r r i s ) Cameron (1914) records P e r i l i t u s e p i t r i c i s V i e r e c k as p a r a s i t i c , o n the f l e a b e e t l e s . Hanson (1933) r e p o r t s t h a t the nematode Howerdula  benigna was l o c a t e d i n a number of l a r v a e of E p i t r i x cucum5-e r i s i n s i d e the abdomen both i n the a n t e r i o r and p o s t e r i o r segments. He a l s o r e p o r t s a s p e c i e s of Entomophthora causing death to a d u l t f l e a b e e t l e s each year, but not epidemic among them. Peter s o n (1933) r e p o r t s a new b r a c o n i d p a r a s i t e Mic-ronatus v i t t a t a e Mues. of a d u l t f l e a b e e t l e s ; I n v e s t i g a t i o n s of p a r a s i t i s m were made l o c a l l y i n 1948 and 1949. In 1948 a l l l a r v a e and pupae recovered i n the August 7 f l o a t a t i o n a n a l y s i s were p l a c e d i n s t e r i l i z e d s o i l i n a wooden cage ( f i g u r e 7 ) . D i c e d potatoes were -22-added f o r the l a r v a e to feed on. The l a r v a e and pupae con-t i n u e d development to the a d u l t stage but no p a r a s i t e s were observed. In 1949 the cages employed ( f i g u r e 8) were b a t t e r y j a r s so f i t t e d w i t h l u m i t e that a box l i d allowed a d d i t i o n or -removal of food substances from the cage. As i n 1948 l a r v a e and pupae were o b t a i n e d by f l o a t a t i o n a n a l y s i s and p l a c e d i n s t e r i l i z e d s o i l w i t h p i e c e s of potato f o r the l a r v a e to feed on. On J u l y 18, 1949, the f i r s t a d u l t b e e t l e s began to emerge. From t h a t date u n t i l August 20 potato l e a v e s were added d a i l y f o r the b e e t l e s to feed on; water was added when necessary by s q u i r t i n g i t through the l u m i t e s c r e e n i n g from an eye-dropper, thus d i s t r i b u t i n g i t about the cages. In these experiments a l s o no p a r a s i t e s were o b t a i n e d . FIELD EXPERIMENTS Of CHEMICAL CONTROL METHODS -AND PROCEDURE 1 * P l o t Arrangement Twenty-four p l o t s , 4 r e p l i c a t i o n s of each of 6 t r e a t -ments, were arranged somewhat on the p a t t e r n of a Random--i z e d B l o c k ( f i g u r e 9 ) . The i n d i v i d u a l p l o t s were s e l e c t e d i n such a way th a t i n f e s t a t i o n from any d i r e c t i o n would a f f e c t as many of the treatments as p o s s i b l e . The s i z e o f -the i n d i v i d u a l p l o t s v a r i e d because of the shape of the f i e l d used ( f i g u r e 10). The u t i l i z a t i o n of th r e e s i d e s of the f i e l d was necessary f o r maximum i n f e s t a t i o n . In r e p l i c a t i o n A the p l o t s were approximately o n e - s i x t e e n t h of an acre i n area; i n r e p l i c a t i o n s B, C, and D the p l o t s were about one-tw e n t i e t h of an acre i n area. 2. Types of I n s e c t i c i d e s and A p p l i c a t i o n In f i e l d experiments at M e r r i t t , B. C , the i n s e c t i c i d e s used were: Treatment 1 3.0$ D.D.T. (2,2* b i s . p a r a c h l o r o p h e n y l 1 , 1 , 1 , - t r i c h l o ro e thane) Treatment 2 5.0$ D.D.T. -24-Treatment 4 Treatment 5 Treatment 6 Treatment 3 D . D . T . / C r y o l i t e (Sodium f l u o a l u m i n a t e ) -r a t i o 6 l b s . of 50.0% D.D.T. to 25 l b s . of Sodium f l u o a l u m i n a t e p l u s a t a l c c a r r i e r . 10.0%' Toxaphene, a c h l o r i n a t e d camphene. 5.0% Chlordane (1,2,4,5,6,7,8,8,-Octoch-l o r o 4,7-methano 3a, 4,7,7a -tetrahydroindane) Untreated check The above i n s e c t i c i d e s were a p p l i e d as dusts between the hours of 4.00 a.m. and 8.00 a.m. by means of a Niagara hand d u s t e r . A t t h i s time of day there i s l i t t l e or no breeze and the dew on the f o l i a g e a c t s as a w e t t i n g agent hence the dusts adhere to the f o l i a g e b e t t e r and are e f -f e c t i v e l o n g e r . S i x a p p l i c a t i o n s of dust were a p p l i e d , the f i r s t two a t the r a t e of 20 l b s . per a c r e , the l a s t four a t 30 l b s . per a c r e . The f i r s t a p p l i c a t i o n i n 1948 was made on June 8 when approximately 75% of the potatoes were up and/or 2 or 3 b e e t l e s were found on the potato p l a n t s i n ten sweeps of a 14 i n c h i n s e c t n e t . The remaining a p p l i c a t i o n s were made ac-c o r d i n g to the a d u l t p o p u l a t i o n on the f o l i a g e which was det-ermined by sweeping i n the same way. The schedule of dust-i n g i s shown i n Table V. -25-3. Determination of P o p u l a t i o n s E f f e c t s of the i n s e c t i c i d e s on the p o p u l a t i o n were obtained i n two ways: (1) A d u l t p o p u l a t i o n counts and (2) L a r v a l and Pupal p o p u l a t i o n counts. A d u l t p o p u l a t i o n s were determined by three c o l l e c t -ions per p l o t , each c o l l e c t i o n c o n s i s t i n g of 10 sweeps w i t h a 14-inch i n s e c t net, each sweep c o n t a c t i n g 3 to 4 p l a n t s . One c o l l e c t i o n was taken from the c e n t r e row and one from each of the marginal rows. These counts were made f o r a l l s e r i e s w i t h i n twenty-four hours b e f o r e dust a p p l i c a t i o n and again f o r the t r e a t e d s e r i e s w i t h i n f o r t y - e i g h t hours a f t e r a p p l y i n g the i n s e c t i c i d e s . A f t e r dust a p p l i c a t i o n s 2-6 i n c l u s i v e , l a r v a l and pupal p o p u l a t i o n counts were made by the F l o a t a t i o n Method of A n a l y s i s which depends upon the f a c t t h a t l a r v a e and pupae f l o a t i n water. Although t h i s method i s by no means ac c u r a t e f o r p o p u l a t i o n s of t h i s s i z e , i t give s the r e l a t i o n of the number of l a r v a e and pupae of one s e r i e s compared to another s e r i e s . In t h i s a n a l y s i s one h i l l o f potatoes per p l o t c o n s t i t u t e d a sample. Each sample con-s i s t e d o f the s o i l from the area approximately twelve inches square by e i g h t inches deep w i t h the potato p l a n t stem as the ce n t r e of the sample. -26-4. F l o a t a t i o n Method of A n a l y s i s The s o i l samples were d i v i d e d approximately i n t o h a l v e s . Each p o r t i o n was put i n t o a bucket h a l f f u l l of water and thoroughly mixed. The l i q u i d was then poured o f f through an apparatus ( f i g u r e s 11 and 12) made by N e i l s o n i n 1948, i t s e l f a m o d i f i c a t i o n of that employed by S h i r c k (1930) and D a n i e l s (1933) but us i n g three t r a y s i n s t e a d of f o u r . The t r a y s were made of copper s c r e e n i n g , the top one of 10-mesh and the two bottom ones of 20-mesh s c r e e n . The screens were g e n t l y washed w i t h c l e a n water to remove excess s o i l , and a l l pupae and l a r v a e except minute ones t h a t passed through the scree n , were recovered and counted. 5. A p p r a i s a l of I n s e c t Damage to Tubers The tubers of untreated v i n e s and of v i n e s t r e a t e d w i t h i n s e c t i c i d e s were examined f o r l a r v a l damage. This examination was completed i n three phases: (a) Examination of the tubers from each sample taken when l a r v a l and pupal p o p u l a t i o n counts were made by f l o a t a t i o n (b) O v e r a l l a p p r a i s a l on September 1, 1948, of tubers from three h i l l s of each p l o t dug a t random from two rows, one on each s i d e of the centre row (c) O v e r a l l a p p r a i s a l of tubers from s i x h i l l s of each p l o t dug a t random September 11, 1948, from -27-the c e n t r e row. Th i s a p p r a i s a l i n c l u d e d the number of tubers not i n f e s t e d , those s l i g h t l y i n f e s t e d , and those h e a v i l y i n -f e s t e d . The examination of the tubers was done by removing a s i n g l e t h i c k n e s s of the p e e l w i t h an o r d i n a r y potato p e e l e r , and then c o u n t i n g the i n d i v i d u a l "pimples", "worm t r a c k s " , and " s l i v e r s " d e f i n e d as f o l l o w s : -"Piinples" are l e s i o n s on the s u r f a c e of the po t a t o , u s u a l l y i n a c i r c u l a r area about 7 mm. i n diameter-. '•Worm tracks" 1 are l e s i o n s caused by l a r v a e t u n n e l i n g a l o n g j u s t under the epidermis. " S l i v e r s ' * are l e s i o n s caused by angular burrowing i n t o the potato to i r r e g u l a r depths g e n e r a l l y not more than 10 mm. EXPERIMENTAL RESULTS 1. P o p u l a t i o n Counts- M e r r i t t , 1948 (a) A d u l t p o p u l a t i o n s (Table VI and Graphs I and 1 2 ) Prom the s p r i n g emergence i n e a r l y June to June 18 there was a gradual i n c r e a s e i n the average numbers of a d u l t s per p l o t . This occurred even i n the t r e a t e d p l o t s but to a l e s s e r extent than i n the unt r e a t e d . Prom June 18 to J u l y 1, there was a d e c l i n e i n the a d u l t p o p u l a t i o n f o r a l l s e r i e s . When p o p u l a t i o n counts were made on J u l y -28-19 the average number of "beetles per p l o t a g a i n i n d i c a t e d an i n c r e a s i n g p o p u l a t i o n . The peak was reached on August 8 i n a l l s e r i e s except t h a t one t r e a t e d w i t h 10.0% toxaphene. On August 31, when the l a s t count of a d u l t s was made, there was a s l i g h t decrease i n the p o p u l a t i o n s of a l l s e r i e s except again i n the case of 10.0% toxaphene. There was a v a r i a t i o n of 4.7 to 10.6 times the number of b e e t l e s on the u n t r e a t e d s e r i e s as compared wi t h the t r e a t e d s e r i e s . The g r e a t e s t d i f f e r e n c e was from treatment w i t h 5.0% D.D.T. wh i l e the l e a s t d i f f e r e n c e was from treatment w i t h 10.0% toxaphene. (b) L a r v a l and pupal p o p u l a t i o n s (Table V I I and Graphs 5, & 4). The f i r s t a n a l y s i s of the h i l l s of potatoes on June 26 showed l i t t l e , i f any, d i f f e r e n c e between the v a r i o u s t r e a t e d s e r i e s . However, a comparison showed d i f f e r e n c e s of 3.6 to 18.2 times more l a r v a e and pupae prese n t on the un-t r e a t e d p l o t s . The peak of p o p u l a t i o n s was e s t a b l i s h e d ".. between J u l y 3 and J u l y 24 but the v a r i a t i o n i n d i f f e r e n c e s a l t e r n a t e d from a n a l y s i s to a n a l y s i s . An o v e r a l l t o t a l f o r l a r v a e and pupae f o r the analyses gave an i n d i c a t i o n of the d i f f e r e n c e between t r e a t e d and untreated p l o t s . The v a r -i a t i o n i n numbers of pupae and l a r v a e found i n the a n a l y s i s of the t r e a t e d p l o t s was s l i g h t . The u n t r e a t e d p l o t s had from 4.2 to 5.7 times g r e a t e r p o p u l a t i o n than was found i n the t r e a t e d s e r i e s . F i v e p e r c e n t D.D.T. had the s m a l l e s t -29-l a r v a l and pupal p o p u l a t i o n and 10.0$ toxaphene the l a r g e s t . 2. A p p r a i s a l of damage to tu b e r s - H e r r i t t , 1948 (a) From examination of tubers taken a t l a r v a l and  pupal p o p u l a t i o n counts (Table V I I I ) Although no g r a d i n g of damage was made i n t h i s p r e l i m i n a r y examination the d i f f e r e n t i a t i o n o f marked and unmarked tubers showed a s i m i l a r trend to the percent o f unmarked potatoes c a l c u l a t e d i n the l a t t e r examinations. In order of d e c r e a s i n g percentage the s e r i e s showed the f o l l o w i n g : 1. 10.0$ Toxaphene j2. 3.0$ D.D.T. 3. 5.0$ D.D.T. 4. 5.0$ Chlordane 5. D. D . T . / C r y o l i t e 6. Untreated. (b) From examination of tubers dug September 1, 1948  (Table IX) There were some changes i n the order of the t r e a t e d p l o t s f o r unmarked p o t a t o e s . However, they a l l showed the e f f e c t of a p p l i c a t i o n o f i n s e c t i c i d e s , i . e . , there was a p r o p o r t i o n a t e l y g r e a t e r percent of tubers unmarked than where no treatment was a p p l i e d . The order of h i g h e s t to lowest percentage of unmarked tubers was as f o l l o w s : 1. 10.0$ Toxaphene 2. 5.0$ Chlordane j 3 . D.D.T./Cry-o l i t e 4. 5.0% D.D.T. 5. 3.0% D.D.T. d. Unt r e a t e d . In examining the potatoes dug at t h i s p e r i o d a d i f -f e r e n t i a t i o n was made so th a t marketable.tubers would be considered w i t h those which were not i n f e s t e d . Tubers w i t h not more than f i v e blemishes were i n c l u d e d w i t h those completely unmarked and the order of t r e a t e d p l o t s v a r i e d from the unmarked tuber a p p r a i s a l . The d e c r e a s i n g v a l u e s were as f o l l o w s : 1. 10.0% Toxaphene 2. 5.0%" Ohiordane 3. 3.0% D.D.T. 4. 5.0% D.D.T. 5. D . D • T . / C r y o l i t e U n t r e a t e d . (e) From examination of tubers dug September 11, 1948 (Table X) In the f i n a l a p p r a i s a l of damage t o tubers by the tuber f l e a b e e t l e two c l a s s e s of tubers were c o n s i d e r e d ; those which were unblemished and those having l e s s than f i v e marks. Potatoes o f the l a t t e r c o n d i t i o n when i n t e r -mingled w i t h unmarked potatoes v/ould pass i n s p e c t i o n and not be "graded down." In summarizing the rank of p l o t s f o r unmarked tubers the p o s i t i o n s remained the same as those f o r marketable potatoes i n the September 1 examination. The r e l a t i o n s h i p i n t h i s a p p r a i s a l was as. f o l l o w s : (1) 10.0% Toxaphene (2). 5.0% Chlordane' (3) 3.0%: D.D.T. (4) 5..0% D.D.T.. (5) D . D . T . / C r y o l i t e (6) Untreated; When the percentage of marketable tubers per t r e a t -ment was c a l c u l a t e d f o r t h i s a n a l y s i s , the p o s i t i o n of the t r e a t e d p l o t s remained f i x e d . The d i f f e r e n c e i n tuber dam' age between the a p p l i c a t i o n of D . D . T . / C r y o l i t e and the un-t r e a t e d p l o t s was not s i g n i f i c a n t i n e i t h e r appraisal.. -32-LABORATORY EXPERIMENIS IN CHEMICAL CONTROL METHODS AND PROCEDURES 1. C o l l e c t i o n of Mated A d u l t s and P r e p a r a t i o n of C u l t u r e s Por the study of the p r e - o v i p o s i t i o n p e r i o d a care-f u l check of the potato f i e l d s was necessary so t h a t the i n i t i a l presence of the b e e t l e c o u l d he determined. I t i s i n t h i s p e r i o d t h a t the most e f f e c t i v e c o n t r o l can he a c h i e v e d . D a i l y o b s e r v a t i o n s were made and the f i r s t r e c o r d of the b e e t l e ' s presence on potatoes i n the Kamloops a r e a f o r 1949,was May 30. On May 31 a d d i t i o n a l b e e t l e s had i n c r e a s e d the numbers present and c o p u l a t i o n was observed. Since there are no e x t e r n a l c h a r a c t e r i s t i c s f o r d i f f e r e n t -i a t i n g male and female b e e t l e s , the only way to make a b s o l -u t e l y c e r t a i n of having a p a i r of b e e t l e s i n a cage i s to c o l l e c t them i n c o p u l a t i o n . This not only assures a p a i r of b e e t l e s , but a l s o that they have mated, wit h a h i g h prob-a b i l i t y of caging a f e r t i l i z e d female. The s i z e and r a p i d movements of the b e e t l e s made these c o l l e c t i o n s a major undertaking. A v e r y e x t e n s i v e survey of the potato f o l i a g e a t extremely c l o s e range was ne c e s s a r y . The e a s i e s t method found f o r c a p t u r i n g mating f l e a b e e t l e s was to use a small b o t t l e 30 mm. i n diameter and 40 mm. l o n g . Although l a r g e r b o t t l e s f a c i l i t a t e the procedure, the l a r g e r s i z e prevents one from c a r r y i n g many b o t t l e s w h i l e s c r u t i n i z -i n g the f o l i a g e . When a c o p u l a t i n g p a i r of b e e t l e s v/as observed, the open mouth of the b o t t l e was brought w i t h i n approximately 1.5 inches of them by a slow d e l i b e r a t e movement. I f and when t h i s was accomplished, simultaneous r a p i d movements of the f r e e hand to the opposite s i d e of the l e a f , and the open b o t t l e towards them r e s u l t e d i n a s u c c e s s f u l c a p t u r e . A s m a l l potato l e a f was added to each b o t t l e so that food was p r e s e n t u n t i l the f o l l o w i n g day when the b e e t l e s were removed. Suf-f i c i e n t mated b e e t l e s were c o l l e c t e d per day to complete any one phase of the experiment. The b e e t l e s were p l a c e d i n cages, one mated p a i r per cage. These cages ( f i g u r e 13) were m o d i f i c a t i o n s of the type used by Johannsen (1921), Hoerner and G i l l e t t e (1928), And-erson and Walker (1934), and H i l l and Tate (1942). Instead of l a n t e r n globes, however, a q u a r t e r p i n t c a r t o n was mod-i f i e d by c u t t i n g a h o l e , approximately 50 mm. i n diameter, i n the bottom of the c a r t o n . Across t h i s h o l e a d i s c of l u m i t e of 30-mesh was s e a l e d f o r the b e e t l e to o v i p o s i t through. A p e t r i d i s h 10 cm. i n diameter was used f o r the top and bottom of the cage. The bottom p e t r i d i s h was p a r t -i a l l y f i l l e d w i t h s t e r i l i z e d sandy c l a y s o i l and moistened w i t h water when necessary. A c i r c u l a r p i e c e of green b l o t --34-t i n g paper approximately 60 mm. i n diameter, a l l o w i n g the c o n t a i n e r to f i t snugly a g a i n s t i t , was p l a c e d on the moist-ened 3 o i l to f a c i l i t a t e the egg count. The top p e t r i d i s h was used as a l i d f o r the c o n t a i n e r so that f r e s h food c o u l d he added d a i l y without d i f f i c u l t y . The cage was s m a l l and compact, a l l o w i n g q u i c k and r e l a t i v e l y easy h a n d l i n g of l a r g e numbers of b e e t l e s . The cages were thoroughly checked each day f o r eggs and t h i s proved a major t a s k . Instead of o v i p o s i t i n g through the mesh a t the bottom of the cage, th e b e e t l e s d e p o s i t e d eggs through the l u m i t e , on the l u m i t e , on the square of potato l e a f , on the w a l l s of the c o n t a i n e r , and on the i n s i d e s u r -f a c e of the l i d . Because of t h i s , a thorough examination of the whole cage and contents was necessary. However, the eggs of the tuber f l e a b e e t l e are r e l a t i v e l y l a r g e i n comparison w i t h the s i z e of the female and t h i s h e l p e d c o n s i d e r a b l y as the eggs could be seen on dark s u r f a c e s without the a i d of a microscope but on l i g h t c o l o r e d s u r f a c e s they c o u l d be l o c a t e d only by e x t e n s i v e s e a r c h w i t h a b i n o c u l a r microscope. A l l eggs were removed d a i l y w i t h a f i n e camel h a i r brush. Each day f o u r square cm. of potato l e a f were added to each cage. The l e a f - s q u a r e s were cut w i t h a template p r e -pared from a p i e c e of wood j u s t l e s s than 2 cm. square, then by g l u e i n g on f o u r "pieces of r a z o r blade, a c u t t i n g box w i t h an a r e a of 4 sq. cm. was obtained. To each l e a f - s q u a r e a small drop of water was added. During the p e r i o d of egg -35-counts b e e t l e s were observed to d r i n k t h i s water. 2. A p p l i c a t i o n of I n s e c t i c i d e s I n s e c t i c i d e s were a p p l i e d i n three ways namely: (a) D i p p i n g method i n which three ways of e f f e c t i n g m o r t a l i t y were pre s e n t ; (b) D u s t i n g method i n which only c o n t a c t w i t h the i n s e c t i c i d e was c o n s i d e r e d ; (c) Fumigation. (a) D i p p i n g method Squares were cut from f r e s h potato l e a v e s and weighed on a c h a i n balance. A f t e r the i n i t i a l weight was determined the squares were s t r u n g on a f i n e s t e e l wire and dipped i n the d e s i r e d s o l u t i o n of i n s e c t i c i d e and then allowed to d r i p f o r approximately two minutes. The l e a f - s q u a r e s were then reweighed to o b t a i n the d e p o s i t of i n s e c t i c i d e per square centimeter. (b) D u s t i n g Method A m o d i f i c a t i o n of B u l g e r ' s (1932) apparatus was used employing a dust tower ( f i g u r e 14). T h i s c o n s i s t e d of a p l a s t i c c y l i n d e r 50 cm. h i g h and 30 cyim. i n diameter. The base of the tower was p l a c e d on a board 35 cm. square and approximately 1 cm. t h i c k . Through a h o l e d r i l l e d i n the -36-centre of the hoard a sma l l g l a s s f u n n e l was i n s e r t e d , and a rubber tube was f i t t e d to the stem of the f u n n e l . The i n s e c t i c i d e was p l a c e d i n the f u n n e l and a quick p u f f of a i r was blown i n t o the tube from the mouth to d i s t r i b u t e the d u s t . The dust was allowed to s e t t l e f o r a s h o r t p e r i o d u n t i l the l a r g e p a r t i c l e s descended and the c y l i n d e r was then t r a n s f e r r e d to another board c o n t a i n i n g the m a t e r i a l to be dusted. The m a t e r i a l used i n t h i s p o r t i o n of the experiment was green b l o t t i n g paper cut i n t o p i e c e s of 4 s. ^ . sq. cm. each. The dust was allowed to s e t t l e t i l l a f i n e f i l m coated the s u r f a c e of the b l o t t i n g paper. By weighing the> squares on a c h a i n balance before and a f t e r the dust ap-p l i c a t i o n , t h e amount of dust per s q . cm. was ob t a i n e d . Although t h i s procedure was to t e s t the e f f e c t o f co n t a c t w i t h the i n s e c t i c i d e s i t i s p o s s i b l e that s l i g h t f u m i g a t i o n e f f e c t s were p r e s e n t . In no case were the i n s e c t i c i d e s a p p l i e d d i r e c t l y to the b e e t l e s . (c) Fumigation Although no s p e c i f i c experiments were completed i n t h i s type of i n v e s t i g a t i o n i t was thought a d v i s a b l e to see i f any p r o p e r t i e s of f u m i g a t i o n were prese n t i n the i n s e c t -i c i d e s used. C u l t u r e s were s e t up with the i n s e c t i c i d e s d i r e c t l y below the cage and s e a l e d to the bottom of the c o n t a i n e r , but i n no way a c c e s s i b l e to the b e e t l e s . Since -37-the set-up of the cages was u n s a t i s f a c t o r y f o r complete egg-counts no attempt was made to record the o v i p o s i t i o n d a t a . 3• I n s e c t i c i d e s under i n v e s t i g a t i o n As a r e s u l t of f i e l d experiments c e r t a i n i n s e c t i c i d e s were omitted from the l a b o r a t o r y i n v e s t i g a t i o n . Those chem-i c a l s a p p l i e d by the d i p p i n g method are as f o l l o w s ; 1. D.D.T. (50$ wettable powder) 2. Toxaphene (45$ Wettable powder) 3. Calcium Arsenate (69.0$ d i l u t e d w i t h water) 4. D.D.T./Calcium Arsenate (50$ wettable powder / 69.0 Calcium Arsenate) Although none of the above i n s e c t i c i d e s i s s o l u b l e i n water, t h i s medium was used f o r r e d u c i n g the percentage of the i n s e c t i c i d e s . T h i s e l i m i n a t e d another v a r i a b l e , i . e . , s o l v e n t f o r the i n s e c t i c i d e s , which n e c e s s i t a t e d another s e r i e s of c u l t u r e s . An a d d i t i o n a l s e r i e s would have been i m p o s s i b l e to examine f o r eggs because of the time i n v o l v e d . Contact i n s e c t i c i d e and f u m i g a t i o n i n v e s t i g a t i o n s were completed w i t h the f o l l o w i n g types and percentage o f i n s e c t -i c i d e s : 1. 5.0$ D.D.T. dust as used i n f i e l d c o n t r o l experr iment. 2. 10.0$ Toxaphene dust as used i n f i e l d c o n t r o l experiments. -38-3. Calcium Arsenate (69.0%) C u l t u r e s were prepared w i t h p a i r s of b e e t l e s c o l l e c t e d from the emergent ge n e r a t i o n and t r e a t e d w i t h i n s e c t i c i d e s from the 5.0% to 0.5% l e v e l by the d i p p i n g method. This i n v e s t i g a t i o n was to observe the e f f e c t s of the i n s e c t i c i d e s on o v i p o s i t i o n and m o r t a l i t y and to e s t a b l i s h a percentage l e v e l f o r the chemicals. The c u l t u r e s prepared were as f o l -lows : A. C o n t r o l C u l t u r e 20 cages- 1 p r . b e e t l e s per cage B^,.5.0% Toxaphene 5 cages- 1 p r . b e e t l e s per cage ~S>2 3.5% Toxaphene 5 cages- 1 p r . b e e t l e s per cage 2.0% Toxaphene 5 cages- 1 p r . b e e t l e s per cage B 4 1.0% Toxaphene 5 cages- 1 p r . b e e t l e s per cage B 5 0.5% Toxaphene 5 cages- 1 p r . b e e t l e s per cage In the t r e a t e d cages 100% m o r t a l i t y was produced i n twenty-four hours without o v i p o s i t i o n i n any cage. Prom these r e s u l t s i t was necessary to reduce the percentage l e v e l and to appraoch a s u b l e t h a l dose i f p o s s i b l e . - S i n c e toxaphene was so e f f e c t i v e a t the l e v e l s used the f o l l o w i n g c u l t u r e s of D.D.T. and c a l c i u m a r senate were prepared. C 0.5% D i D i T . 5 cages- 1 p r . b e e t l e s per cage D 0.5% C a l c i u m Arsenate- 5 cages- 1 p r . b e e t l e s per cage In c u l t u r e "C" 3 eggs were l a i d but 100% m o r t a l i t y had been obtained whereas i n c u l t u r e "D" 20 eggs were l a i d and no m o r t a l i t y o c c u r r e d . Fo f u r t h e r o v i p o s i t i o n o c c u r r e d i n "Dtt • --39-but w i t h i n 72 hours there was 100$ m o r t a l i t y . In the twenty cages used as a c o n t r o l c u l t u r e o v i p o s i t i o n was i n pr o g r e s s i n f i f t e e n cages a f t e r 8 days. From the i n f o r m a t i o n obtained a d d i t i o n a l c u l t u r e s were prepared a t reduced l e v e l s . The r e s u l t s are shown i n Table XI. A d d i t i o n a l r e d u c t i o n of the pe r c e n t l e v e l of the i n -s e c t i c i d e s was continued and the l e v e l f i n a l l y used f o r the c u l t u r e s was: 0.005$ D.D.T.; 0.005$ Toxaphene; 0.3$ Cal c i u m Arsenate; 0.005$ D.D.T./0.3$ Calcium A r s e n a t e . Although t h i s was not a s u b - l e t h a l l e v e l both o v i p o s i t i o n and m o r t a l i t y oc-curre d . In t h i s p o r t i o n of i n v e s t i g a t i o n the b e e t l e s used were from the 1 s t . summer g e n e r a t i o n of a d u l t s which s t a r t e d to emerge J u l y 18, 1949. A l l p a i r s of b e e t l e s were c o l l e c t e d J u l y 19. Ten cages, each w i t h one p a i r of b e e t l e s , were used f o r each treatment. The treatments were: A, C o n t r o l ; B. 0.005$ D.D.T.; C. 0.005$ Toxaphene; D. 0.005$ D.D.T./ 0.3$ Calcium Arsenate; E . 0.3$ Calcium A r s e n a t e . Three a d d i t i o n a l treatments were designed to i n v e s t i g a t e the e f f e c t s of con-t a c t i n s e c t i c i d e s namely: F. 5.0$ D.D.T; G. 69.0$ Calcium Arsenate; H. 10.0$ Toxaphene. The i n s e c t i c i d e s were a p p l i e d s i x days a f t e r the b e e t l e s were taken i n c o p u l a t i o n because the pre-ovipo3ition p e r i o d determined from the s p r i n g emergent b e e t l e s was 6.05 days. Since o v i p o s i t i o n as w e l l as l e t h a l e f f e c t s were being i n v e s t i g a t e d , the p e r i o d c o n s i d e r e d most a p p r o p r i a t e f o r the -40-a p p l i c a t i o n was when o v i p o s i t i o n commenced. M o r t a l i t y was c a l c u l a t e d by the method i n t r o d u c e d by Abbot (1925) i n which the formula ( x-y)x 100 equals the percentage m o r t a l i t y x . caused by the treatment; where "x w i s the number l i v i n g i n the check and "y" i s the number l i v i n g i n the t r e a t e d p l o t . Abbot (1925) s t a t e s , " When the a c t u a l count of the l i v i n g and dead i n s e c t s i n both the t r e a t e d and untreated p l o t s i s a v a i l a b l e , i t i s obvious that the i n s e c t s which d i e from n a t u r a l causes must be c o n s i d e r e d . " 4. Method of measuring s m a l l l e a f - a r e a s To approximate the amount of i n s e c t i c i d e i n g e s t e d by the b e e t l e s an instrument f o r measuring s m a l l areas was needed. The apparatus used by Bulger (1935), i n which a p h o t e l e c t r i c c e l l i s used, s t i m u l a t e d the e r e c t i o n of the apparatus shown i n f i g u r e 15. In t h i s r e l a t i v e l y simple d e v i c e the s t r e s s was p l a c e d on three p o i n t s ? 1. C o n t r o l of the l i g h t i n t e n s i t y , accomplished by the use of a s m a l l transformer so that the v o l t a g e c o u l d be i n c r e a s e d or de-creased as necessary. By c o n t r o l l i n g the i n t e n s i t y , con-t o r t i o n of the image was reduced to a minimum. 2. A movable l i g h t f o r a l t e r i n g the r a t i o of the d i s t a n c e between o b j e c t to l i g h t and o b j e c t to image. 3. A g r i d paper dependent upon the s i z e o f the h o l e s to be measured. From the amount of l e a f eaten a reasonably a c c u r a t e ,-41-approximation of the i n s e c t i c i d e i n g e s t e d can he made. EXPERIMENTAL RESULTS 1. C o n t r o l (Tahles X I I ; X I I I . XXI. and XXII and Graphs 5 & 6) M o r t a l i t y i n the u n t r e a t e d cages produced a sigmoid curve i n which the death r a t e was r e l a t i v e l y low f o r the p e r i o d up to 40 days. Prom then to 70 days approximately 60$ of the b e e t l e s d i e d . A f t e r t h i s p e r i o d of h i g h e r death r a t e , m o r t a l i t y decreased and the remaining 20$ of the b e e t l e s d i e d d u r i n g the next 36 days. Thus, approximately 20$ d i e d i n each of the f i r s t and l a s t 40 days and the remaining 60$ d i e d i n the i n t e r v e n i n g 30 day p e r i o d . The number of eggs d e p o s i t e d t h e . f i r s t day of o v i -p o s i t i o n ranged from 1-13, t o t a l l i n g 26. The number of days of o v i p o s i t i o n v a r i e d from 13-54. The number of eggs de-p o s i t e d per female was from 28 to 203 t o t a l l i n g 782 w i t h a mean of 86.9 eggs. There was an i n c r e a s e i n t o t a l d a i l y o v i -p o s i t i o n from the f i r s t to the second day of 21 eggs. Kb measurements were made on the l e a f areas eaten s i n c e no i n s e c t i c i d e was i n v o l v e d and the l e a f consumption was not under o b s e r v a t i o n i n t h i s i n v e s t i g a t i o n . 2. Treatment w i t h 0.005$ D.D.T. by d i p p i n g method (Tables XIV.  XXI. and XXII and Graph 7) -42-The r a p i d i n c r e a s e i n m o r t a l i t y "brought about by the i n t r o d u c t i o n of 0.24 micrograms of D.D.T. per sq. cm. lea v e s l i t t l e to be d e s i r e d i n the e f f e c t i v e n e s s of the i n s e c t i c i d e . One hundred percent m o r t a l i t y was produced a t the end of 48 hours a f t e r i n t r o d u c t i o n of the t r e a t e d l e a f squares. O v i p o s i t i o n the day previous to the a p p l i c a t i o n of the i n s e c t i c i d e to the food ranged from 1-17 eggs w i t h a t o t a l of 40 eggs, d e p o s i t e d . In no case was there i n c r e a s e d o v i -p o s i t i o n i n the 24 hours a f t e r the i n s e c t i c i d e was i n t r o d u c e d . The number of eggs per female f o r t h i s p e r i o d v a r i e d from 1-7 t o t a l l i n g 11 eggs. The number of eggs per female ranged from 2-24 t o t a l l i n g 51 w i t h a mean of 6.4 eggs. The average amount o f l e a f eaten per cage was 3.4 sq. mm. 3. Treatment w i t h 0.005% toxaphene by d i p p i n g method (Tables  xyv/XXI-r^and XXIIand Graph 8.]) When l e a f - s q u a r e s t r e a t e d w i t h 0.005% toxaphene were added to the cages a marked i n c r e a s e i n m o r t a l i t y o c c u r r e d i n the 24 hours f o l l o w i n g . A t the end of 48 hours 100% mort-a l i t y had been produced. The r a t e of i n s e c t i c i d e per sq. cm. was 0.18 micrograms. The number of eggs l a i d per female p r e v i o u s to treatment although s m a l l e r than that of the D.D.T. s e r i e s s t i l l has an impressive t o t a l . I t was from 2-13 t o t a l l i n g 30 eggs. In t h i s c u l t u r e two females l a i d as many or more eggs a f t e r treatment, but i n ge n e r a l i t was l e s s . The number of eggs -43-per female ranged from 3-15 t o t a l l i n g 44 w i t h a mean of 5.5 eggs per female o v i p o s i t i n g . The amount of f o l i a g e consumed i n these cages v a r i e d , hut the o v e r a l l average was 0.5 sq. mm. of potato l e a f per cage. 4. Treatment w i t h 0.005$ D.D.T./Q.3$ c a l c i u m arsenate by d i p -p i n g method (Tables XVI,XXIand XXIIand Graph 9) M o r t a l i t y caused by the i n t r o d u c t i o n of the combined i n s e c t i c i d e s D.D.T. and c a l c i u m a r s e n a t e , was 100$ a t the end of 48 hours a f t e r a p p l i c a t i o n . Ho attempt was made to determine the s y n e r g i s t i c e f f e c t s . The amount of i n s e c t i c i d e s added to the l e a v e s was 0.19 micrograms per 3q.cm. of l e a f . The. range i n o v i p o s i t i o n f o r the day be f o r e treatment was 1-3 eggs. In a l l cases but one, the females l a i d as many or more eggs i n the 24 hours a f t e r treatment w i t h the i n s e c t i c i d e . The t o t a l number of eggs l a i d a f t e r treatment was 9; one more than b e f o r e treatment. The average number of eggs l a i d per female was 3.2 eggs. The amount of l e a f eaten per cage v a r i e d c o n s i d e r a b l y but the average amount per cage was 0.4 sq. mm. 5. Treatment w i t h 0.3$ c a l c i u m arsenate by d i p p i n g method (Tables X V I I , X X E ,and XXII and Graph 10) -44-Th e amount of i n s e c t i c i d e added i n t h i s c u l t u r e was 1.4 micrograms per sq. cm. of potato l e a f . The e f f e c t on mort-a l i t y of t h i s i n s e c t i c i d e , a lthough not as gre a t as the others a d m i n i s t e r e d by t h i s method, produced a 100% k i l l i n 96 hours. The range i n the number of eggs l a i d per female b e f o r e , and f o r 24 hours a f t e r treatment, was 1.-3 and 1-5. The t o t a l number of eggs l a i d b e f o r e treatment was 25, while the number l a i d a f t e r treatment was 22. The average number o f eggs l a i d per female was 4.7 eggs. In only one i n s t a n c e was there an i n c r e a s e i n the egg l a y i n g from the p r e - t r e a t -ment p e r i o d to post-treatment p e r i o d . The mean amount of potato f o l i a g e eaten per cage was. 1.6 sq. mm. 6. Treatment w i t h 5.0% D.D.T. by d u s t i n g method (Tables  XVll\t,XXI,and XXIIand Graph 11) ' The m o r t a l i t y induced by a p p l i c a t i o n of 5% D.D.T. dust was 100% a f t e r 96 hours of exposure. This m o r t a l i t y was. caused by the a p p l i c a t i o n of 12.0 micrograms of D.D.T. per sq. cm. of green b l o t t i n g paper. The b e e t l e s came i n t o c o n t a c t w i t h i t by movements about the cage. O v i p o s i t i o n p r e v i o u s to the i n t r o d u c t i o n of the t r e a t e d squares of b l o t t i n g paper ranged from 1-14 eggs per female w i t h a t o t a l of 35 eggs. The t o t a l number of eggs l a i d -45-a f t e r treatment was 1 egg. The average number of eggs per female f o r the o v i p o s i t i n g p e r i o d was 7.2 eggs. 7. Treatment w i t h 69.0% c a l c i u m arsenate by d u s t i n g method (Tables XIX, XXI, ahdlXXII and Graph 12) E i g h t y - t h r e e micrograms of c a l d i u m arsenate were a p p l i e d to each sq. cm. of b l o t t i n g paper added to the cages; t h i s caused 100% m o r t a l i t y i n 48 hours. O v i p o s i t i o n p r i o r to treatment ranged from. 1-16 eggs., per female w i t h a t o t a l of 21 eggs. Three eggs were, l a i d i n the 24-hour p e r i o d a f t e r treatment and 1 egg i n the 24-48 hour p e r i o d a f t e r a p p l i c a t i o n of the i n s e c t i c i d e . The t o t a l o v i p o s i t i o n f o r the c u l t u r e was 25 eggs w i t h a mean of 6.2 eggs per female. 8. Treatment w i t h 10.0% toxaphene by d u s t i n g "method (Tables  XX. XXI. and XXII and Graph 15) The a p p l i c a t i o n of 10.0% toxaphene at the r a t e of 10.0 micrograms per sq. cm. of b l o t t i n g paper caused 95.Q/& -m o r t a l i t y i n 96 hours. The remaining 5.0% (one b e e t l e ) l i v e d f o r 41 days. I t was assumed that t h i s b e e t l e d i d not come i n c o n t a c t w i t h the i n s e c t i c i d e . O v i p o s i t i o n pre-treatment ranged from 1-7 eggs per female, t o t a l l i n g 31 eggs. The post-treatment o v i p o s i t i o n v a r i e d from 1-11, t o t a l l i n g 14 eggs. The over a l l o v i p o s i --46-t i o n f o r t h i s c u l t u r e was 44 w i t h a mean of 6.3 eggs per female. 9• E f f e c t s of f u m i g a t i o n with D.D.T., c a l c i u m arsenate and  toxaphene, (Table XXI11) In t h i s p r e l i m i n a r y i n v e s t i g a t i o n no e f f o r t was made to study o v i p o s i t i o n s i n c e the cages used d i d not a l l o w s a t -i s f a c t o r y egg counts. The m o r t a l i t y produced by the v o l a t i l i z a t i o n of the i n s e c t i c i d e s i s shown i n Table XX111. Tox-aphene produced 100$ m o r t a l i t y i n 72 hours by f u m i g a t i o n , t h i s was f o l l o w e d by D.D.T..and D.D.T./calcium arsenate i n 96 hours and 120 hours r e s p e c t i v e l y . C a l c i u m arsenate ap-p a r e n t l y has l i t t l e or no fumigatory power. DISCUSSION OF RESULTS In the i n v e s t i g a t i o n of i n s e c t i c i d e s a t M e r r i t t , B.C., i n the summer of 1948, although the experiments were completed under adverse weather c o n d i t i o n s , the r e s u l t s i n d i c a t e d the r e l a t i v e e f f e c t i v e n e s s of the i n s e c t i c i d e s . F o l l o w i n g the three methods of examination, the t a b u l a t e d d a t a suggested that c e r t a i n i n s e c t i c i d e s warranted f u r t h e r i n v e s t i g a t i o n b efore c o n c l u s i o n s c o u l d be drawn. The i n s e c t i c i d e s under o b s e r v a t i o n : 3.0% D.D.T., 5.0% D.D.T. D . D . T . / C r y o l i t e , 10.0% Toxaphene, and 5.0% Chlordane showed v a r y i n g t o x i c i t y . The chemcials i n d i c a t i n g c o n t r o l of l a r v a l damage were 3.0^ D.D.T., 5.0% D.D.T., 10.0% Toxaphene, and 5.0% -Chlordane. Of these 5.0% Chlordane and 3.0% D.D.T. were r e j e c t e d from f u r t h e r experiments. F i v e percent Chlordane was excluded because the co s t of d u s t i n g was too gre a t to show p r o f i t a b l e r e s u l t s f o r the tonnage ha r v e s t e d i n t h i s a r e a . Three percent D.D.T. was ex^uded because 5.0% D.D.T. app a r e n t l y c o n t r o l l e d p o p u l a t i o n s b e t t e r w i t h l i t t l e d i f -f e r ence i n tuber damage. I t was assumed t h a t i f the second ge n e r a t i o n had been p r e s e n t i n 1948 the damage to the tubers i n the p l o t s t r e a t e d w i t h 3.0% D.D.T. would have been com-par a b l e to the p l o t s t r e a t e d with' D . D . ^ C r y o l i t e . The chemical toxaphene seemingly d i d not s a t i s f a c t -o r i l y c o n t r o l the a d u l t b e e t l e p o p u l a t i o n but i n d i c a t e d good p o s s i b i l i t i e s from an examination of the tu b e r s . The per--48-centage of marketable t u b e r s , i n both the e a r l y and l a t e ap-p r a i s a l s , p l a c e d toxaphene as the most e f f e c t i v e ; y e t i t was the l e a s t e f f e c t i v e when p o p u l a t i o n s t u d i e s were c a r r i e d out. D.D.T. at the f i v e p ercent l e v e l , i n d i c a t e d e f f e c t i v e c o n t r o l of the p o p u l a t i o n s . The examination of the tubers from these p l o t s i m p l i e d that p r o p o r t i o n a t e l y g r e a t e r damage was i n f l i c t e d than the a d u l t p o p u l a t i o n s p r e s e n t warranted. C o n t r a s t i n g l y toxaphene, a p p a r e n t l y w i t h l a r g e r a d u l t pop-u l a t i o n s present, had l e s s tuber damage. Because of t h i s c o n d i t i o n the, assumption was made that the number of s o i l samples examined f o r l a r v a e and pupae were not s u f f i c i e n t to e s t a b l i s h t h e i r numbers. Time d i d not permit more rep-l i c a t i o n which might have gi v e n the e x p l a n a t i o n f o r the ap-parent anomaly. The problem of determining the reason f o r the seemingly l a r g e l a r v a l p o p u l a t i o n s w i t h c o n t r a s t i n g l y s m a l l ' a d u l t p o p u l a t i o n s s t i l l remained. In the l a b o r a t o r y s t u d i e s of the e f f e c t s of the i n -s e c t i c i d e , two aspects, of the b i o l o g y were c o n s i d e r e d ; "ihese were m o r t a l i t y and the e f f e c t s on o v i p o s i t i o n . Time did. not permit the study of egg v i a b i l i t y and development o f the s t a g e s . The comparison between un t r e a t e d and t r e a t e d c u l t u r e s i n d i c a t e d a v a r y i n g e f f e c t on o v i p o s i t i o n . F i v e percent D.D.T. a p p l i e d as a dust showed the h i g h e s t m o r t a l i t y and lowest egg p r o d u c t i o n i n the 24 hour post-treatment p e r i o d . Tables ;..XL1, XIV to XX i n c l u s i v e , and XXII show the r e l a t i v e m o r t a l i t y and -49-o v i p o s i t i o n a f t e r treatment. S i n c e o v i p o s i t i o n occurred a f t e r the i n t r o d u c t i o n o f the i n s e c t i c i d e s , the n e c e s s i t y f o r c o r r e c t t i m i n g of dust a p p l i c a t i o n s must he c o n s i d e r e d . The l i f e - h i s t o r y s t u d i e s i n d i c a t e that the most e f f e c t i v e a p p l i c a t i o n s w i l l he the l s t , ; . 2nd, 4th and 5th as shown i n Table V. I f these t r e a t -ments are so a p p l i e d that m o r t a l i t y i s produced w i t h i n the p r e - o v i p o s i t i o n p e r i o d then the r e s u l t a n t damage to the tubers should be reduced c o n s i d e r a b l y . The assumption was made t h a t i n 1948, f a u l t y t i m i n g occurred i n the f i r s t a p p l i c a t i o n and as a r e s u l t o v i p o s i t i o n was i n progress b e f o r e the dust was a p p l i e d . Because of t h i s , g r e a t e r damage r e s u l t e d than would be expected from the m o r t a l i t y produced. C O N C L U S I O N S JfL. A d u l t f l e a b e e t l e s can l i v e on a v a r i e t y of v e g e t a t i o n , but migrate to potato p l a n t s when they are a v a i l a b l e . 2. The examination of b e e t l e s from the emergent g e n e r a t i o n i n d i c a t e s a 1:1 sex r a t i o . 3. The number of eggs l a i d per female under the c o n d i t i o n s of the experiment ranged from 28 to 203 w i t h a mean of 86.9 egg3. 4. Two generations of b e e t l e s u s u a l l y occur a n n u a l l y i n the Kamloops a r e a . 5. In general the males o u t l i v e the female al t h o u g h over-l a p p i n g of the a d u l t l i f e p e r i o d s f o r the sexes, o c c u r s . 6. C o p u l a t i o n occurs i n t e r m i t t e n t l y over i r r e g u l a r p e r i o d s of the o v i p o s i t i o n stage of the female, and p o s s i b l y a c t s as a st i m u l u s to the development of ova. 7. Bb i n d i c a t i o n s of p a r a s i t i s m were found. 8. F i v e percent D.D.T. dust i n f i e l d experiments i n d i c a t e d b e t t e r c o n t r o l o f the p o p u l a t i o n than the other i n s e c t i c i d e s used. 9. Ten percent toxaphene dust treatments showed l e a s t damage to the t u b e r s . 10. Highest m o r t a l i t y and c o r r e s p o n d i n g l y the lowest o v i -p o s i t i o n was a t t r i b u t e d to the e f f e c t s of 5.0$ D.D.T. dust, i n l a b o r a t o r y c u l t u r e s . -51-11. No evidence of s t i m u l a t i o n or r e t a r d a t i o n of o v i p o s i t i o n was i n d i c a t e d by any of the i n s e c t i c i d e s used, and i t was as-sumed that the d i f f e r e n c e s shown i n the 1948 i n v e s t i g a t i o n s arose from f a u l t y t i m i n g i n the a p p l i c a t i o n o f the chemicals coupled w i t h weather c o n d i t i o n s t h a t were adverse f o r e f -f e c t i v e c o n t r o l . - 52 -ACKNOWLEDGEMENTS The w r i t e r wishes t o express h i s a p p r e c i a t i o n to the D i v i s i o n o f Entomology, Dominion Department of A g r i c u l t u r e , f o r p e r m i s s i o n to use the m a t e r i a l comprising t h i s paper and t o thank Dr. R.H. Handford, Entomologist i n Charge o f the Dominion F i e l d Crop I n s e c t Laboratory, Kamloops, B.C., f o r h i s a d v i c e and c r i t i c i s m s . In a d d i t i o n I am indebted t o Dr. W.A. Clemens, Head of the Department of Zoology at t h e U n i v e r s i t y o f B r i t i s h Columbia; P r o f e s s o r G.J. Spencer, Entomologist, without whose suggestions and encouragement p o r t i o n s o f t h i s i n v e s t i g a t i o n would be incomplete; and Mr. C.L. N e i l s o n , Entomologist a t the Dominion F i e l d Crop I n s e c t Laboratory, Kamloops, B.C., f o r a s s i s t a n c e i n the p r e p a r a t i o n and ex e c u t i o n o f t h e experiments and who photographed the m a j o r i t y o f the i l l u s t r a t i o n s . I a l s o wish to thank Mr. J.D. Gregson, Entomologist i n Charge of the Dominion L i v e s t o c k L a b o r a t o r y at Kamloops, B.C., f o r t h e use of l a b o r a t o r y space and equipment; Mr. H. C o l l e t t o f M e r r i t t , B.C. and Mr. R. Dodding, Lower N i c o l a , B.C. a t whose ranches the 194& experiments were completed; Dr. P.A. L a r k i n , Dr. K. Graham, and Dr. W.S. Hoar f o r v a l u a b l e a d v i c e on s t a t i s t i c a l procedures; Miss M. Skeene and Mr. R. B a i l e y o f Kamloops f o r a s s i s t a n c e i n l a b o r a t o r y i n v e s t i g a t i o n s ; Miss I . P i l l e r o f Kamloops who so k i n d l y typed t h i s m a t e r i a l ; -53-Dr. Ian McT. Cowan, Dr. P. Ford, Dr. J.R. Adams, and c e r t a i n c i t i z e n s o f the Kamloops and M e r r i t t d i s t r i c t s who have c o n t r i b u t e d t o t h i s i n v e s t i g a t i o n . I furthermore wish to thank the Department of Veterans A f f a i r s who gave me the o p p o r t u n i t y to complete my U n i v e r s i t y t r a i n i n g t o t h i s l e v e l . F i n a l l y , to my w i f e Ruth, I wish to express my profound a p p r e c i a t i o n f o r the manner i n which she has c o n t r i b u t e d , not o n l y t o t h i s p r o j e c t , but a l s o t o my u n i v e r s i t y advance-ment. I f i t had not been f o r her u n f a i l i n g encouragement and many s a c r i f i c e s t h i s p rogress c o u l d not have been accomplished. -54-LITERATUKB CITED (# References s t a r r e d w i t h an a s t e r i s k were w r i t t e n con-c e r n i n g E ^ cucumeris (H.) hut are i n r e a l i t y about E ^ t u b e r i s Gent.; a u t h o r i t y Gentner (1944).) Abbo t, W. S. 1925. A method of computing the e f f e c t i v e n e s s of an i n s e c t i c i d e . Jour. Econ. Ent., 18: pp. 265-267. Anderson, L.D. and H.G. Walker. 1934. The l i f e h i s t o r y and c o n t r o l of the potato f l e a b e e t l e E p i t r i x cucumeris ( H a r r i s ) . Jour. Econ. Ent., 27: pp. 102-106. #Baker, Win.W. 1928. Potato f l e a b e e t l e . W. Wash. S t a . B u i . 10-V, n.s. Oct., p.12. #Bennet, E.R. 1907. The Colorado potato i n d u s t r y . C o l o . S t a . B u i . 117, Jan., pp. 15-17. #Besse, R.S. 1941. Oregon's A g r i c u l t u r a l Research Aids N a t i o n a l Defence. B i e n n i a l Report, Ore. S t a . B u i . 401 D e c , pp. 58-59. Bulger, J.W. 1932. - A d d i t i o n s to our knowledge on the t o x i c i t y of stomach poisons to i n s e c t s . Jour. Econ. Ent., 25: p. 261. -55-Bulger, J.VT. 1935. A p h o t o e l e c t r i c method f o r measuring sma l l l e a f areas. Jour. Econ. Ent., 28: p. 76. Cameron, A.E. 1914. C o n t r o l of the potato f l e a b e e t l e . Rept. H.J. Agr. C o l . Exp. S t a . , 1914: pp. 375-381. Chapman, Royal„ H. 1931. Animal E c o l o g y . 464 pp. McGraw-Hill Book -Company, Hew York and London. Chittenden, 3P.H. 1899. Some i n s e c t s i n j u r i o u s to garden and o r c h a r d c r o p s . U.S.D.A. l?iv. E n t . B u i . 19, n.s. 99 pp. O u t r i g h t , C R . 1930. A s i g n i f i c a n t f e a t u r e of b i o t i c p o t e n t i a l as r e l a t e d to i n s e c t c o n t r o l . Ann. E n t . Soc. Am., 23: pp. 145-148. #Daniels, L.B. 1933. Potato f l e a b e e t l e c o n t r o l . C o l o . S t a . B u i . 400, May, 34 pp. 1937. C o n t r o l l i n g Colorado potato p e s t s . C o l o . S t a . B u i . 437, Oct., pp. 15-21. 1941. Colorado potato p e s t s . C o l o . S t a . B u i . 465, Mar., pp. 15-22. Eorbes, S.A. 1900. The potato f l e a b e e t l e . Rept. 111. S t a . Entom. 21: p. 117. -56- ' F o u l t o n , H.G. and R. Glendenning. 1940. Annual Report, Dominion E n t o m o l o g i c a l L a b o r a t o r y , Aggasiz, B.C. (Unpublished). 1946. The tuber f l e a b e e t l e i n B r i t i s h Columbia and i t s c o n t r o l . D i v . of E n t . P r o c e s s e d P u b l . , 48, Ottawa, Canada. * Gentner, L.G. 1944. The b l a c k f l e a b e e t l e of the genus E p i t r i x commonly i d e n t i f i e d as cucumeris ( H a r r i s ) ( C o l e o p t e r a : Chrysomelidae). E n t . Soc. Wash. P r o c , 46 (6) : pp. 137-149. # G i l l e t t e , C P . 1927. Potato f l e a b e e t l e , 40th Ann. Rept. C o l o . Agr. Expt; S t a . f o r the year 1927, p. 31. #Hanson, Ar t h u r J. 1930. Potato f l e a b e e t l e . W. Wash. S t a . B u i . 18-Wn.s., Oct., pp. 11 * 1 2 . 1933. The potato f l e a b e e t l e s E p i t r i x cucumeris ( H a r r i s ) and E p i t r i x s u b c r i n a t a Le Conte. Wash. Agr. Exp. Sta. B u i . 280, 27 pp. Henneguy, P. 1904. Les I n s e c t e s . 804 pp. Masson et C , E d i t e u r s , P a r i s . H e r r i c k , G.W. 1926. The ponderable substance of aphids (Homop.) E n t . Hews, 37: pp. 207-210. -57-H i l l , Roscoe.E. 1946. I n f l u e n c e of .'food p l a n t s on f e c u n d i t y , l a r v a l development,.. and abundance of the tuber f l e a b e e t l e i n Nebraska. Nebr. Agr. Exp. S t a . Res. B u i . 143, 16 pp. # H i l l , Roscoe E. and Douglas -H. Tate. 1942. L i f e h i s t o r y and h a b i t s of the potato f l e a b e e t l e i n Western Nebraska, E p i t r i x cucumeris ( H a r r i s ) . Jour. Econ. E n t . V o l . 35: pp. 879-884. 1944. Potato f l e a b e e t l e and c o n t r o l in-Western Nebraska. Nebr. Agr. Exp. S t a . B u i . 361. #Hoerner, J.L. and C P . G i l l e t t e . 1928. The potato f l e a b e e t l e . C o l o . S t a . Bui.. 337, , 16 pp. Huxley, T.H. 1858. On the agamic r e p r o d u c t i o n and morphology- ' , . of aphids. Trans. Linn. S o c. London,22: pp. 193-236. ffJohnson, S. A r t h u r . -1904. P a l l h a n d l i n g of potatoes to l e s s e n i n j u r y from i n s e c t s and f u n g i . C o l o . Press B u i . 23, 3 Pp. Johannsen, O.A. 1913. Potato f l e a b e e t l e E p i t r i x cucumeris ( H a r r i s ) , the f l e a b e e t l e and e a r l y b l i g h t . Maine Agr. Exp. S t a . B u i . 211. -58-Jo harms en, O.A. 1921. Eggs of the potato f l e a b e e t l e E p r i t i x cucumeris ( H a r r i s ) . Jour. Econ. E n t . 14: pp. 511-512. $Landis, B.J. 1943. Potato f l e a b e e t l e s and t h e i r c o n t r o l i n E a s t e r n Washington. V. c i r . 9, Wash. St a . , Apr., 4 pp. Lohrenz, H.W. 1911. A m o d i f i c a t i o n to Comstock s o i l i n s e c t r e a r i n g cage. Jour. Econ. E n t . 4: pp. 162-170. Lot k a , A.J. 1925. Elements of P h y s i c a l B i o l o g y . 460 pp. W i l l i a m s and W i l k i n s Co., B a l t i m o r e . MacMillan, H.G. and L.A. S c h a a l . 1929. A p a t h o l o g i c a l f e a t u r e of f l e a b e e t l e i n j u r y , o f potato tt i b e r s . Jour. Agr. Res. 39: pp. 807-815. #Metzger, C H . 1938. Growing b e t t e r potatoes i n C o l o r a d o . C o l o . S t a . B u i . 446, June, pp. 80-82. U e i l s o n , C I . and D.G. P i n l a y s o n . 1948. Annual Report. Dominion P i e l d Crops I n s e c t Laboratory, Kamloops, B.C. (Unpublished). Peterson, A. 1933. R e a r i n g notes on a new B r a c o n i d p a r a s i t e Micronatus v i t t a t a e Hues. of a d u l t f l e a b e e t l e s . A Manual of E n t o m o l o g i c a l Equipment and Methods. Edwards Bros., Inc. AnnArbor, Mich. Schaal, L.A. 1934. R e l a t i o n of the potato f l e a b e e t l e to common scab i n f e c t i o n of potatoes, E p i t r i x cucumeris ( H a r r i s ) . Jour. Agf. Res. 49: p. 251. S h i r c k , P.H. 1930. A s o i l - w a s h i n g device f o r use i n wireworm i n v e s t i g a t i o n s . Jour. Econ. E n t . 23: pp. 991-994. //Smith, L a u r e l G. 1938. T i n y i n s e c t menaces potatoes -- f l e a b e e t l e i s s p r e a d i n g i n Northwest. Ida. Farmer, 56; p. 622. Snodgrass, R.E. 1935. P r i n c i p l e s of I n s e c t Morphology. McGraw-Hill Book Co., New York and London. #Swenk, Myron H. and Douglas H. Tate. 1940. The potato f l e a b e e t l e and the potato p s y l l i d i n Nebraska. Neb. S t a . B u i . 327, pp. 1-9. Weber, H. 1933. Lehrbuch der Entomologie. 726 pp. V e r l a g Von Gustav E i s h e r In Jena. #Webster, R.L., V.W. Baker and Arthur J . Hansen. 1932. Potato f l e a b e e t l e s i n Washington. Wash. Agr. Exp. S t a . B u i . 261, pp. 1-20. #Webster, R.L., B. J . L a n d i s , and C.W. Getzendaner. 1941. B i o l o g y and c o n t r o l of the potato f l e a b e e t l e s i n E a s t e r n Washington. Wash. S t a . B u i . 410, pp. 48-49. -60-APPEEDIX  Appendix "A" (Tables) -61-Table I. The Range and Average D u r a t i o n of V a r i o u s Stages o f E p i t r i x t u h e r i s i n the I n s e c t a r y a t S c o t t ' s B l u f f , Nebraska. ( A f t e r H i l l and Tate (1942)) P e r i o d Generation Year Range i n Average Temperature days number .(1) I n c u b a t i o n L a r v a l Pupal T o t a l F i r s t Second F i r s t Second F i r s t Second F i r s t Second 1940 1941 1940 1940 1941 1940 1940 1941 1940 1940 1941 1940 3-11 3-14 3- 20 13- 29 14- 23 15- 43 4- 10 3-9. 5- 22 27-50 27-46 30-85 of days 5.5 6.2 5.9 18.45 17.7 22.76 5.8 6.29 11.16 72. 7.. F 69.4 F .68.3 F 73.1 F 70.8 F 65.7 F 75.4 F 72.2 F 61.6 F 73.7 F 70.8 F 65.2 F (1) This r e p r e s e n t s the average, mean d a i l y temperature f o r the i n t e r v a l from the time the f i r s t i n d i v i d u a l appeared i n a g i v e n stage u n t i l the l a s t i n d i v i d u a l of the group had been transformed to the succeeding stage. The same procedure was a p p l i e d to a l l stages o f . b o t h g e n e r a t i o n s . -62-Table II-. The L i f e P e r i o d of Male and Female B e e t l e s E p i t r i x t u b e r i s Gent, a t Room Temperature C u l t u r e "A" Number of days observed Cage No. Male Pemali 1 58 57 2 93 60 3 97 19 4 24 39 5 67 60 6 57 6 7 106 43 8 57 55 9 95 ' 43 10 56 43 Mean 70.9 * 25.3 42.5 + 17.8 .,63-Table III.. P r e - o v i p o s i t i o n P e r i o d of Emergent and F i r s t Summer Generations at Ro.om Temperature Number of P r e - o v i p o s i t i o n females p e r i o d observed Emergent g e n e r a t i o n 4 5 days 12 6 days 3 7 days 1 8 days Mean 6.05 + .46 days Summer ge n e r a t i o n 5 5 days 45 6 days 6 7 days 4 8 days Mean 6.06 '± .35 days -64-Table IV. Sex e f Overwintered A d u l t B e e t l e s , M e r r i t t , 1948 Date caught T o t a l : Both, sexes Male Female May 30 5 0 5 May 31 15 8 7 June 2 1 0 1 June 3 7 6 1 June 4 5 4 1 June 5 3 1 2 June 8 9 5 4 June 12 • 9 A 5 June 13 62 32 30 T o t a l 116 60 56 -65-Table V. Dust Schedule f o r 1948 and T e n t a t i v e Dates f o r C o n t r o l D u s t i n g i n Future Years A p p l i c a t i o n Date Approximate Rate of number a p p l i e d date f o r dust 1948 f u t u r e c o n t r o l per a c r e 1 June 8 June 3- 5 20 l b s . 2 June 18 June 13-15 20 l b s . 3 J u l y 1 J u l y 1 30 l b s . 4 J u l y 19 J u l y 18 30 l b s . 5 Aug. 8 J u l y 28 30 l b s . 6 Aug. 31 Aug. 10 30 l b s . # 7 Aug. 24 30 l b s . # A p p l i c a t i o n 7 was not made i n 1948 because there was only one g e n e r a t i o n of b e e t l e s i n the M e r r i t t a r e a t h a t y e a r . 3: r 3' i 3 3 L a S s s ^ £ bbLL h bbLb i lbhb k hh'"'" OOOO o o w o o -lhb s H B 3 233 '3 J OO c. o o o o J i;: L a Laa3 O OOOO O OOOO O O C O O b b b b b b b b b b I b b b b B fe &ssL £ s&u 8 Baa B " O O C OOOO C. OOOO- C OOOO o o o o 5 r B s i " t B B fe B B ' -asa & a c o o o b b . B B - O O • o' o O O O O OOOO b b b ; b b i b •S.3< B B 3 'B '" ; ' s B B s B B fe B B s B B s blbb • B B B l ; Cr. 0- O O <D -J (O o ui it) oi r„ OS £ BB»is 5 P S ° § B B e B B a B B C O O O O O OOOO o W O O o O OOOO o O O O O b OOOO O OOOO fe OOOO. b b b b b b OOOO s . l i c a t i o t III, =•3-151 8 Fill BE s a°°a s f Kt I I B I BE Bt 5 p ; s u*l ' f. est ' , Pa . •£? . I -67-T ' b l e Vi;i l a r v a l , P u p a l , +3 J u n e 26 l - r e - A a m t ' S t a y e a p e r i : i l l o f D a t e ahd F l o a t a t i o n A n a l y s i s r i t t , s.C. l j * f e t l o t nut, and'. . t r e a t W e n Im I HI I MI I Ml f :Ht I M! 1 A 1 0 •0 1,. 2 0" 3 2 0 "0 • 5 ' (j . 0 0 o. s 10 • •3W):-S DDT . '.B' 3 0 0 1 j •j •'. . t>. 0 '• j 0 7 o:. -' 0 0' ' 0 . 4 7 ' S- 1 1. y • 1' • P 0 - 1 1.. 0 '•' 0- - • 2 • 0' 0 -1 3 5 -'. D 0 d1 • 0 . •; o • 1 o. 10 11-' .0 3 o 0 10 0 10 2 a . A v e r s e 0.2 0.7.0. 7 0 . 6.5 3.5 <\ J .5 •')• 9 .7 „ .0 5.4 11.7 a ' A 1 0 0 0 • 3 0 ' 0 1 0 0 2 -o . l 0 0 6 • a 0 1 a 1 ' 2 • 0 •4 0 .0 1 1 i ' 2 0 • 7 10 :j .6;S DDT : c. 0 0 0 4 3 •'ti •0 .' 3 0 '0- 0 •'• 0 l 1 0 5 7 D 0 0 , u 5 19 ' 0 :2 •'• 7. o o ; '0' 0 0 o • . 7 26 Aver-aye 0.2 0.2 .0 2.2 6.7 1.7 3.7 J • o o.O 0.7 0.2 j 7 0.7 0.0 5 . 2 12.2 : 3 A 9 1 0 0 0. 0 3 • 3 o o J . 0- 1 0 3 6 : - ..'ii 1 0 0 0 1 0 12 3 : 0 o 16 0-. 0 3 0 13 4 23 D D T / C r y - • G-- .a 0 0 0 0 0 2 0 0 2 2 2 ' ,0 •ti 0 2 o l i t e D 2 '0 0 ;.: 3 20 u 3 1 : • J 0 -2 -. • I 2 3 1 10 26 •We r a g e J.7 U .2 0. 0 0.7 5.2 0.0 b . o 1.7 0.0 0.5 3 -0 0.7 0 7 1.7 0.2 7.5 1 4 . 0 4 A 0 2 .0 1 7 0 . 1 • 3 • .0 0 ' 0 o '•• 1 :. 2 3 22 ' B 2 0 0 1 0 0 • 4, • 5 •' 0 J 2 • i 1. • 7 3 I O . O ; T O X - •G 1 ' 2 0 . o. 1 : J i : •2 . 0 ;: 1 5 1 •j l 1 3 12 a t ) h e n e D 0 0 11 lb 0 2 6 . 0 • 0 .0, . 0. a 0 0 13 21 A v e r s e j .7 1.2 0 3.2 5.7 .0.0 2.0 5:. 5 o . o : 0.2 0 .2 2 1.7 0.2 6.2 16.0 D • A 3 0 u 1 1 0 •4 10 • j 0 9 0 3 0 0 11 2u y . u i C r . l o r -B • j 1 0 0 2 0 ' 2 o 0 1 5 1 0 4 .0 . 3 12 G 0' 0 0 1 1 0 4 4 o . 6 1 ' 0 3 0 " .5 - 1 4 • J a n e - . 3 Q._ u 0 2 1 . 0 4 5 • 0 0- 3 0 0 0 0 6 9 •'• A v e r a g e 0.7 0 . 2 0 Q 1 .0 1 . 2 0.0 3 . 5 .4.7 0.0 0.2 ' 5.7 0 . 5 0 7 .1.7 6 . 2 13.7 6 A 11 2 o ; c .-• ;., .0 . 9 '3 0 ' 4 24 0 Q 4 0 26 46 - B % 2 0 1 £>•'• J 25 25 o • 9 35 1 1 5 o '•• 35 107 U n t r e a t e d C- 2; a 0 3 6 0 0 6 0 2 1 0 0 0 0 7 12 D 7 . 3 0 6 52 0 15 40 o; S 26 7 5 14 2 , • 41 1 3 5 ,iverij'.e o . 2 1.7 u . 'J 3.0 1 7 . 2 J . ; 2 . ; U o 0.0 6.7 21.7 2.0 1.5 5.7 J.j 2 7 . 75*3 -68-Table V l l l Bxani «ti->n of Tubers Taken ut xime of Analysis by .'loatatifin Uetnod, . e r n t t , 1946 VI ot c Date and reau:ta of tuber examination nur'.oer tt July 21 Auguat 7 August 23 Total and i Number Hun. tier . Nun.ber Number Humber Number fT umber Una ber Percent u examined marked examined marked exantned marked •examined marked treatment marked 1 A 14 3 8 1 19 10 41 23 E 12 0 8 3 e 4 28 7 3.0j DDT C 5 1 26 5 i j 41 3 D 22 18 10 s 41 31 Average 13.2 7.0 13. |J 5.0 11 .5 5.5 37.7 17.5 53.4 a A 7 3 7 3 16 8 3U 14 b.0,« DDT B 4 2 11 6 1J 1 25 12 C 7 3 8 5 t 5 23 11 D 5 " 5 7 2 10 26 15 Average A 6.7 3.2 8.2 3.5 11.2 6.2 26.0 K 13.0 50.0 3 A 6 4 11 4 10 3 27 - | 11 a 6 5 8 6 8 6 22 17 DDT/Cry- c 10 10 12 4 5 ' 2b 17 olite D 20. 18 9 4 11 5 40 27 Average 10.5 3.2 10.0 4.5 8.7 4.2 29 .2 16.-J ' 33.7 . 4 A 11 4 16 7 34 12 B 6 3 9 4 lo 12 27 12-XQ,Q% Tox- C 15 7 7 1 9 2 31 9 aphene D 11 15 8 2 32 15 Average 10.7 4.7 11.7 4.5 6.0 3.0 28.5 12.2 57.2 5 A 6 i 3 16 12 29 17 8 6 4 3 6 e 2 23 12 a.O^ Cnl- C 10 3 20 13 20 11 50 37 ordane D 14 12 11 6 18 9 43 27 Average 11.0 5.2 11.7 7.0 15. 5 a .5 38.2 20.7 45.8 6 A 7 7 10 10 9 8 26 25 B 7 7 6 a 14 14 23 29 Untreated C 10 5 14 14 21 21 15 40 D 6 e 7 7 14 14 29 29 Average 8.0 6.7 3.7 9.7 14.5 14.2 32.2 30.7 -4.7 -69-Ta"ble IX E f f e c t of I n s e c t i c i d e s A p p l i e d to Netted Gem Potatoes f o r c o n t r o l l i n g E p i t r i x t u b e r i s , Gent, as shown by tubers dug a t M e r r i t t , B.C. September 1 1948 P l o t Number tubers Number Number Percent Percent Number examined u n i n f e s t e d 1-5 marks u n i n f e s t e d 0-5 marl 1. -A 41 16 19 39.0 85.4 B 31 14 17 45.0 100.0 C 43 22 19 51.2. 95.3 D 20 7 7 35i0 70.0 P l o t Average 45.2 91.7 2. A 30 14 17 46.7 70.0 B 38 22 12 . 57.9 89.5 C 25 16 8 64*0 96.0 D 25 8 9 32.0 68.0 P l o t Average 50.8 81.4 3.. A 47 18 20 38.3 80.9 B 31 17 14 54.8 100.0 C 38 20 12 52 i 6 84.2 D 24 8 9 33.3 70.8 P l o t Average 50.9 80.7 4. A 29 16 10 55.2 ' 89.6 B 36 24 11 66.7 97.2 C 24 15 9 62.5 100.0 D 26 16 10 61.6 100.0 P l o t Average 61.8 98.2 -70-Table IX E f f e c t o f I n s e c t i c i d e s A p p l i e d to Netted Gem Potatoes f o r c o n t r o l l i n g E p i t r i x t u b e r i s Gent, as shown by tubers dug at M e r r i t t , B . C . September 1 1948 P l o t Number tubers Number Number Pe r c e n t P e r c e n t Number examined u n i n f ested 1-5 marks u n i n f ested 0-5marls; 5. A 33 20 11 60.6 93.6 B 35 18 15 51.4 94.3 e 42 25 17 59.5 100.0 D 23 11 7 47.8 78.3 P l o t Average 55.6 95.4 6. A 28 0 1 0.0 21.4 B 32 2 7 6.3 28.1 C 29 4 11 13*0 51.7 D 27 0 5 0.0 18.5 P l o t Average 5.2 28.5 -71-Table X E f f e c t o f I n s e c t i c i d e s A p p l i e d to Netted Gem Potatoes f o r C o n t r o l l i n g E p i t r i x t u b e r i s Gent, as shown by tubers dug at M e r r i t t , B . C . September 11, 1948. P l o t Number tubers Number Number w i t h P e r c e n t Percent Number examined u n i n f e s t e d 1-4 marks u n i n f e s t - 0-4 ed marks 1 A 66 57 8 86.3 98.5 B 53 45 7 84;9 98.1 C 53 36 11 67.9 88.7 D 56 18 12 32.1 53.6 P l o t Average 67.8 84.5 2 A 50 23 14 46.0 74.0 B 68 44 14 64.7 85 i3 C 63 33 14 52.4 74.6 D 61 39 14 63.9 86.9 P l o t Average 57.2 80.2 3 A 75 27 . 20 36.0 62.7 B 63 33 17 52*4: 63.5 C 93 35 34 37.6 74.0 D 67 17 23 25i4 59.7 P l o t Average 37.8 65.0 4 A 83 66 13 79.5 95.2 B 54 46 7 85.2 98.1 G 52 34 15 65.4 94.2 D 52: 45 3 86.7 91.9 P l o t Average 79.2 94.8 72< Table X E f f e c t of I n s e c t i c i d e s A p p l i e d to Netted Gem Potatoes f o r C o n t r o l l i n g E p i t r i x t u b e r i s Gent, as shown by tubers dug at M e r r i t t , B.C. September 11, 1948. P l o t Number tubers Number Number w i t h Percent Percen 1 Number examined u n i n f e s t e d 1-4 marks i i n i h - 0-4 f e s t e d marks 5A 65 64 1 98.5 100.0 B 66 63 3 95.4 100.0 C 78 40 26 51; 2 84;6 D 61 28 15 45.9 70.5 P l o t Average 72*7 88.8 6A 82 70 8 85.4 95.1 B 64 12 14 18.7 40.6 C 43 19 20 44.2 90.7 D 58 1 6 1.7 12.6 P l o t Average 37.5 59.6 i Table X I. E f f e c t of I n s e c t i c i d e s at V a r i o u s Percentages on E p i t r i x t u b e r i s by D i p p i n g Method S e r i e s and number i n s e c t i c i d e used of cages A. 0.25$ Toxaphene 5 B. 0.25$ D.D.T. 5 C. 0.1$ D.D.T. # 5 D. 0.5$ Calcium Arsenate 5 E. 0.3$ D.D.T./ 0.3$ Calcium Arsenate 5 T o t a l M o r t a l i t y Time o v i p o s i t i o n i n t e r v a l 0 0 100$ 100$ 100$ 100$ 24 hours 24 hours 48 hours 24 hours 100$ 24 hours # Two b e e t l e s from t h i s c u l t u r e were p a r t l y p a r a l y s e d a t the end of 24 hours. Ho a d d i t i o n a l t r e a t e d l e a f squares were added, but f r e s h potato l e a v e s were s u p p l i e d to see i f rec o v e r y was p o s s i b l e ; however, both b e e t l e s d i e d i n the f o l l o w i n g 24 hours. Table XII Oviposition and : Cage Number of days a f t e r oviposition Number commenced that death occurred. Male Female l a 53 52 2a 88 55 3a 92 14 4a 19 54 5a 62. 55 6a 52 0 7a 101 38 8a 52 50 9a 90 38 10a 51 38 r of days of Egg-laying In Control Cultures her of days Number of Eggs l a i d female F i r s t day of Tot a l oviposited oviposition Oviposition 52 13 203 54 1 81 12 6 42 13 3 40 54 3 146 0 0 0 37 4 78 42 13 57 37 1 103 37 1 28 - 7 5 -T a b l e X l l l C a l c u l a t i o n o f R e g r e s s i o n o f M o r t a l i t y o f E p i t r i x t u b e r i s D e v i a t i o n f r o m m e a n S q u a r e o f m e a n P r o d u c t o f X Y X y x 2 y 2 d e v i a t i o n x y 6 1.2787 -48.7 1.3083 2371.69 1.716 -63.71 19, . 0.9542: -35.7 0.9838 1274.49 0.964 -35.12 24 0.7582 -30.7 0.7878 942.49 0.770 -24.18 39 0.6040 -15.7 0.6336 246.49 0.401 - 9.95 43 0.2695 -11.7 0.2991 136;89 0.089 - 3.50 54- 0.1761 - - 0.7 0.2057 .49 0.042 - 0.14 57 0 . 0 2.3 0.0296 5.29 0 . 0 0 1 .07 58 - 0.2684 3.3 - 0.2388 10.89 0.057 - 0.79 60 - 0.4776 5;3 - 0.4481 28.09 0.201 - 2.37 67 - 0.7021 12.3 - 0.6725 151.29 0.451 - 8.27 93 - 0.7545 38.3 - 0.7245 1466.89 0.524 -27.75 95 - ,0.9545 40.3 - 0.9249 1624.09 0.855 -37.27 97 - 1.2790 42.3 - 1.2494 1789.29 1.560 - 52.85 712 - 0.3845 0 . 0 0 . 0 10048.37 7.631 -265.83 y s - 0.0296 x = Sk.l Y S x y S x 2 (X - x ) A - 2 6 5 . 8 3 (X - 5^.7) Y « * -•0.0296 + 10048.37 Y = I'M? - 0.0264X r ta S x y ' l f s x 2 S y ^ = - 2 6 5 . 8 3 276.8 - 0 . 9 6 R e g r e s s i o n C o e f f i c i e n t O.96 Table XIV O v i p o s i t i o n and number of d Gage Number of days a f t e r i n s e c t i c i d e Number a p p l i c a t i o n that death o c c u r r e d Male Female l b 2. 1 2b 1 1 3b 1 1 4b 2 1 5b - - 2 1 6b 2 0 7b 1 1 8b 2 2 9b 2 2 10b 1 1 . of E g g - l a y i n g when t r e a t e d w i t h 0.005% DDT Number of days Number of eggs l a i d female F i r s t day of A f t e r o v i p o s i t e d o v i p o s i t i o n treatment 2 17 7 1 5 0 2 4 1 1 i l 1 2 6 1 0 0 0 2 3 1 1 3 0 1 2 0 0 >0 0 Table XV O v i p o s i t i o n and Number of Days of E g g - l a y i n g when t r e a t e d w i t h 0.005$ Toxaphene Cage Number of days a f t e r i n s e c t i c i d e Number of days Number of Eggs l a i d female Number a p p l i c a t i o n t h a t death o c c u r r e d E i r s t day of A f t e r Male Eemale o v i p o s i t e d o v i p o s i t i o n treatment I c 2 1 0 0 0 2c 1 2 3 2 2 3e 1 1 1 4 0 4c 1 1 0 0 0 5c 2 0 0 0 0 6c 1 1 2 5 10 7c 2 1 2 3 1 8c 1 1 2 13 1 9c 1 0 1 3 0 10c 1 1 0 0 0 Table Z&L O v i p o s i t i o n and Number of Days of E g g ^ l a y i n g when t r e a t e d w i t h 0.005% DDT/0.3% Calcium Arsenate Cage Number o f days a f t e r i n s e c t i c i d e Number of days Number of Eggs l a i d Number a p p l i c a t i o n that death occurred female F i r s t day of T o t a l a f t Hale Female o v i p o s i t e d o v i p o s i t i o n treatment Id 1 0 0 0 0 2d 1 1 2 2 3 3d 2 2 3 1 1 4d 1 1 0 0 0 5d 1 1 0 0 0 6d 2 2 1 0 2 7d 1 1 0 0 0 8d 2 1 2 3 3 9d 1 1 1 1 0 lOd 1 1 0 0 0 Table XVII O v i p o s i t i o n and Number of Days of E g g - l a y i n g when t r e a t e d w i t h 0.3$ Calcium Arsenate Cage Number of days a f t e r i n s e c t i c i d e Number o f days Number of eggs l a i d Number a p p l i c a t i o n t h a t death occurred female F i r s t day of T o t a l a f t i Male Female o v i p o s i t e d o v i p o s i t i o n treatment l e 2 1 2 5 2 2e 1 1 1 3 3 3e 2 1 1 1 0 4e . 1 2 3 2 1 5e 1 1 2 3 2 6e 1 1 1 5 0 7e 2 1 1 3 0 8e 2 2 2 3 3 9e 4 2 2 ' 1 5 lOe 1 2 3 2 6 f Table XV111 , O v i p o s i t i o n and Number of : Gage Number of days a f t e r i n s e c t i c i d e Number a p p l i c a t i o n that death occurred Male Female I f 1 1 2f 1 1 3f 1 1 4f 2 1 5f 4 1 6f 1 1 7f 1 1 8f 1 1 9f 1 1 l O f 1 1 ,ys of I g g - l a y i n g when t r e a t e d w i t h 5% DDT dust Number of days Number of eggs l a i d female F i r s t day of T o t a l a f t e r o v i p o s i t e d o v i p o s i t i o n treatment 0 0 0 0 • 0 0 1 8 0 1 1 0 0 0 0 0 0 0 2: 14 1 1 5 0 0 0 0 1 7 0 Table XIX O v i p o s i t i o n and Number of Days of E g g - l a y i n g when t r e a t e d w i t h 69.0%' Calcium J Arsenate Dust Gage Number of days a f t e r i n s e c t i c i d e Number of days Number of Eggs l a i d Number a p p l i c a t i o n t h a t death occurred female F i r s t day of T o t a l a f t e r Male' Female o v i p o s i t e d o v i p o s i t i o n treatr l g 1 0 0 0 0 2g* 3'g 2 0 1 1 0 4g 1 1 1 3 0 5g 2 0 0 0 0 6g 1 1 0 0 0 ?g 1 2 x 3 16 3 8g 1 1 0 0 0 9g 2 2 1 1 1 10g 1 1 0 0 0 A One b e e t l e escaped from t h i s cage on the f i r s t day of o v i p o s i t i o n so the cage was e l i m i n a t e d f o r the remainder of the experiment. T a b l e XX O v i p o s i t i o n and Number o f Days Gage Number o f days a f t e r I n s e c t i c i d e number a p p l i c a t i o n t h a t d e a t h o c c u r r e d Male Female l h 5 2 2h 1 2 3h 2 1 4h 2 1 5h 41 1 6h 2, 1 7h 1 1 8h 1 1 9h 5 2 l O h 1 2 o f E g g - l a y i n g when t r e a t e d w i t h 10% Toxaphene Dust Number o f days Number o f eggs l a i d female F i r s t day o f T o t a l a f t e r o v i p o s i t e d o v i p o s i t i o n treatment 1 3 0 1 6 0 0 0 0 1 5 0 1 1 0 a 7 2 0 0 0 2 5 1 2 4 11 0 0 0 Table XXL Insecticide Application to Cultures Series Insecticide applied Method Amount of of pure insect-application i c i d e per sq. cm. of surface N i l 0.24 micro gm. 0.18 micro gm. Control Culture 0.005$ DDT N i l Dipping A B C 0.005$ Toxaphene Dipping D 0.005$ DDT/0.3$ Galciurn Arsenate Dipping 1 0.3$ Arsenate, Calcium Dipping F 5.0$ DDT Dusting G 69.0$ Calcium Arsenate Dusting H 10.0$ Toxaphene Dusting 0.19 micro gm. 1.4 micro gm. 12.0 micro gm. 83.0 micro gm. 10.0 micro gm. of the Tuber Flea Beetle Material to Average amount which insect- of l e a f eaten i c i d e applied per cage N i l Not measured 4 sq. cm. Potato l e a f 3.4 sq. mm. 4 sq. cm. Potato l e a f 0.5 sq. mum. 4 sq. cm. Potato le a f 0.4 sq. mm. 4 sq. cm. Potato l e a f 1.6 sq. mm. 4 sq. em. Green B l o t t i n g N.A. paper 4 sq. cm. Green B l o t t i n g N.A. paper 4 sq. cm. Green B l o t t i n g N.A. paper Table XXII Normal and Reduced Oviposition Before and After Treatments Series Insecticide applied Method of application Control, 0.005% DDT Ingestion 0.005% Tox-aphene Ingestion 0.005% DDT/ Ingestion 0.3% Calcium Arsenate B 0.3$ Calcium Arsenate Ingestion ]? 5.0%^ DDT Contact G 69^0% Calcium Arsenate Contact H 10% toxaphene Contact Number of Eggs l a i d 1st. day of 0*24 hrs. after 24T48 hrs. Total o v i p o s i t i o n treatment after number 26 40 30 7 25 35 21 31 47 11 13 8 20 1 3 14 treatment oviposited 19 0 1 1 2 0 1 0 782 51 44 16 47 36 25 44 —So-Table XXIII. The E f f e c t s of D.D.T., Calcium Arsenate, and Toxaphene as Funiigants I n s e c t i c i d e Number of Percentage m o r t a l i t y i n 24-hour b e e t l e s i n t e r v a l s per cage 24 h r s . 48 h r s . 72 h r s . 96 h r s . 120 hrs, 10.0$ Toxaphene 10 70$ 90$ 100$ 5.0$ D.D.T. 10 40$ 70$ 90$ 100 ot 5.0$ D.D.T./ 69.0$ Cal c i u m Arsenate 10 30$ 55$ 80$ 90$ 100$ 69.0$ Cal c i u m Arsenate 10 0$ 0$ 0$ 10$ 20$ Appendix "B" (Figures) FIGURE 1. H i b e r n a t i o n Cage used f o r L i f e H i s t o r y Study. - 8 7 -FIGURE 2. Emergence Cage i n Plot 6 A. FIGURE 3. Emergence Cage i n Plot 6 C -88-FIGURE 4, Rearing Cage f o r Observation of L a r v a l and Pupal Movements i n the S o i l , 89 FIGURE 5 . R e c o n s t r u c t e d Diagram, of the Male Reproductive System. (A) Testes (B) V e s i c u l a e Seminales (C) Vas Deferens (D) Parameres (E) S c l e r o t i c Annulus. FIGURE 6. A. R e c o n s t r u c t e d Diagram of the Female Reproductive System. (A) Ovary. (B) Egg C a l y x (C) Common Oviduct (D) Vagina (E) O v i p o s i t o r (F) Spermatheca (G) Gland (H) C h i t i n o u s Rod. x B. R e t r a c t e d E g g - l a y i n g Apparatus. C. E j e c t e d E g g - l a y i n g Apparatus. -91-FIGURE 7. Cage used for Parasite Investigations, Merritt, 1948. FIGURE ;8. Cage used f o r P a r a s i t e I n v e s t i g a t i o n s i n L a b o r a t o r y E x p e r i -ments . FIGURE !9. Diagramatic R e p r e s e n t a t i o n of Potato P l o t s M e r r i t t , 1948. POTATOES o> > fo IP 10 o in > Ci n O I I ALFALFA FIGURE 10. P o t a t o F i e l d , M e r r i t t , 1948. 95-FIGURE 11, Dorso-lateraJL View of Floatation Equipment, FIGURE 12; Dorsal View of Floatation Screens. -96 FIGURE. 13. Cage used to Study O v i p o s i t i o n of B e e t l e s . FIGURE 14. Equipment used f o r D u s t i n g i n I n s e c t i c i d e Study. - 9 7 -FIGURE 15. Apparatus f o r Measuring Small Areas Eaten from a L e a f . -98-FIGURE. 16 (Graph 1) E f f e c t of 3.0%'D.D;T.; 5.0% D.D.T.; and 10.0% Toxaphene on A d u l t P o p u l a t i o n Compared to Untreated P o p u l a t i o n . FIGURE 17 (Graph 2.) E f f e c t of D . D . T . / C r y o l i t e and 5.0% Chlordane on A d u l t P o p u l a t i o n Compared to Untreated P o p u l a t i o n . -99 i i i 1 1 — J U N E 8 J U N E 18 J U L Y I J U L Y 19 A U G . 8 A U G . 31 D A T E O F C O L L E C T I O N PIGURE 18 (Graph 3.) E f f e c t of 3 * 0 $ D . D . T . ; 5 . 0 $ D . D i T . ; and D . D . T . / C r y o l i t e on L a r v a l and Pupal P o p u l a t i o n s as Compared w i t h Untreated P o p u l a t i o n s . PIGURE 19 (Graph 4.) E f f e c t of 5.0$ Chlordane: and Pupal P o p u l a t i o n s as Compared 10.0$ Toxaphene on L a r v a l and w i t h Untreated P o p u l a t i o n s . -100-J U N E 2 t -JULY 5 J U L Y M A U G . 7 A U G . ti D A T E O F E X A M I N A T I O N FIGURE 20 (Graph 5.) M o r t a l i t y Curve f o r E p i t r i x t u b e r i a Gentner Under Conditions of the Experiment. FIGURE 21 (Graph 6.) R e g r e s s i o n L i n e f o r E p i t r i x t u b e r i s M o r t a l i t y Curve. 101-FIGURE 22 (Graph 7.) Normal M o r t a l i t y as Opposed to E f f e c t Produced when B e e t l e s T r e a t e d w i t h 0.005% D;D.T. FIGURE 23 (Graph 8) M o r t a l i t y of the Tuber F l e a B e e t l e when Treated w i t h 0.005% Toxaphene Compared w i t h Normal Death Rate. -102-GRAPH 7 E F F E C T O N M O R T A L I T Y O F E . T U B E R I S T R E A T E D W I T H 0 . 0 0 5 % D.D.T. NUMBER OF DAYS NUMBER OF DAYS FIGURE 24 (Graph 9.) E f f e c t on M o r t a l i t y when Treated w i t h 0.005$ D;D.T./ 0.3$ Calcium A r s e n a t e . FIGURE 25 (Graph 10.) M o r t a l i t y Caused by Treatment w i t h 0.3$ Cal c i u m Arsenate. 1 0 3 -NUMBER OF DAYS FIGURE. 26 (Graph 11.) E f f e c t on M o r t a l i t y of E p i t r i x t u b e r i s Treated w i t h 5*0% D.D.T. FIGURE 27 (Graph 12.) M o r t a l i t y of Tuber F l e a B e e t l e when Treated w i t h 69.0% Galcium A r s e n a t e . -104-1 FIGURE 28 (Graph 13.) E f f e c t on M o r t a l i t y of E p i t r i x t u b e r i s Treated w i t h 10.0% Toxaphene. 105-N U M B E R O F D A Y S 

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