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The effect of various chemicals as selective herbicides for British Sovereign strawberries (Fragaria… Freeman, Jack Allen 1950

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THE EFFECT OF VARIOUS CHEMICALS AS SELECTIVE HERBICIDES FOR BRITISH SOVEREIGN STRAWBERRIES (Fragaria c h i l o e n s i s ) .  by  Jack A l l e n Freeman, B.S.A.  A thesis submitted i n p a r t i a l f u l f i l m e n t of the requirements f o r the Degree of MASTER OF SCIENCE IN AGRICULTURE i n the Department of HORTICULTURE  THE UNIVERSITY OF BRITISH COLUMBIA A p r i l , 1950  ABSTRACT  Five experiments i n a l l were c a r r i e d out w i t h t h e object of studying t h e use of s e l e c t i v e h e r b i c i d e s on B r i t i s h Sovereign s t r a w b e r r i e s .  Before l a y i n g out a l a r g e  r e p l i c a t e d experiment i t was f e l t the* (a) the general response of strawberry p l a n t s t o v a r i o u s h e r b i c i d e s and (b) the e f f e c t o f these h e r b i c i d e s on both broad-leaved weeds and grasses should be determined.  Small p l o t s were l a i d out  on a three year o l d strawberry p l a n t a t i o n and subjected t o 3 4 d i f f e r e n t treatments (Experiment I ) . S i m i l a r treatments were a p p l i e d i n Experiments I I and I I I t o newly seeded and e s t a b l i s h e d grasses.  These treatments c o n s i s t e d o f  d i f f e r e n t concentrations and mixtures o f the f o l l o w i n g : 2,4-dichlorophenoxyaeetie aeid  (2,4-D)  Sodium s a l t o f t r i c h l o r o a c e t i c a c i d  (TCA)  Ammonium s a l t of i s o p r o p y l N-phenyl carbamate (IPC) 2 methyl-4-chlorophenoxyacetic a c i d Sodium pentaehlorophenate  (MCP)  (POP)  Ammonium s a l t of dinitro-O-secondary b u t y l phenol (DNOSBP) Potassium cyanate E m u l s i f i a b l e pentachlorophenol The e f f e c t s o f these treatments on the strawberry p l a n t s , grasses and broad-leaved weeds are reported and discussed.  2. In the f i n a l experiment 2,4-D  six treatments (£,4-D and  plus IPC) were l a i d out i n three r e p l i c a t e s on a  maiden B r i t i s h Sovereign strawberry plantation. of 1, 2, 3 and 4 pounds of 2,4-D 2,4-D  Treatments  per acre and 2 pounds of  plus 40 pounds of IPC per acre were compared with a  hand-weeded check.  I t was found from these experiments that  (1) the sprays should be applied when the weeds are small and succulent, especially i s t h i s true for annuals; and that under conditions of t h i s experiment pounds of 2,4-D  (2)  a mixture of 2  plus 40 pounds of IPC can be s a f e l y  recommended f o r the deweeding of B r i t i s h Sovereign strawberry plantations provided i t i s not used when the plants are i n blossom.  ACKNOWLEDGEMENTS  The author acknowledges with thanks, the assistance given by Dr. G.H. H a r r i s , Professor of the Department of Horticulture, University of B r i t i s h Columbia, and Dr. T.H. Anstey, H o r t i c u l t u r i s t , Dominion Experimental Farm, Agassiz, B.C., i n the planning and execution of the experimental work and manuscript.  The writer also wishes to  express h i s appreciation to Dr. A.F. Barss, Head of the Department of H o r t i c u l t u r e , University of B r i t i s h Columbia, f o r his encouragement of the completion of t h i s work; and to Mr. W.H. Hicks, Superintendent, Dominion Experimental Farm, Agassiz, B.C.,  f o r permission to carry on the f i e l d work at  the Experimental Farm.  TABLE OF CONTENTS Page INTRODUCTION  6  REVIEW OF LITERATURE ,  7  EXPERIMENT I  14  Object  14  Materials and Methods  14  Results  13  Discussion  18  Conclusions  20  EXPERIMENT I I  20  Object  20  Materials and Methods  20  Results  22  Discussion  25  Conclusions  ••  27  EXPERIMENT I I I  27  Object ,  27  Materials and Methods  27  Results Discussion Conclusions EXPERIMENT 17  •  28  •••  29 30 30  Objeot  30  Materials and Methods  30  Results  35  Page E f f e c t on Grasses  •  35  Effeot on Strawberry Plants  •  49  Discussion •  50  Conclusions  56  EXPERIMENT 7  58  Object  58  Materials and Methods  •  58  Results  61  Control of Various Weed Species  »  61  E f f e c t on Strawberry Plants  63  Condition of Strawberry Plants  65  Weed Control  65  •  Discussion  70  Weed Control  70  The E f f e c t on Strawberry Plants  74  Conclusions  ,  •  76  SUMMARY  78  Effeot on Strawberry Plants  •  E f f e c t on Grasses  79 79  LITERATURE CITED  82  APPENDIX  86  FIGURES: Figure 1 - General View Showing the Layout of plots i n the Greenhouse Figure 2 - Method of Spraying  33 34  Page Figure 3 - Mean Heights of Hog M i l l e t  37  Figure 4 - The E f f e c t of Pentaohlorophenol and Potassium Cyanate upon B r i t i s h Sovereign Strawberry Plants and Grass Seedlings  40  Figure 5 - The E f f e c t of 2,4-D and 2,4-D plus IPC upon Various Grasses  41  Figure 6 - Weight of Creeping Red Fescue Clippings  44  Figure 7 - Weight of Perennial Rye Grass Clippings  45  Figure 8 - Weight of Orchard Grass Clippings .  46  Figure 9 - Weight of Hog M i l l e t Clippings ....  47  Figure 10- General Layout of Experiment V and Method of Spraying  •  66  Figure 11- E f f e c t s of 2,4-D on Strawberry Plants  ,  67  TABLES: Table 1 -  Treatments Applied to Established B r i t i s h Sovereign Strawberry Plants (1949)  Table 2 -  Treatments Applied to Well E s t a b l i shed Grass and Weed P l o t s  Table 3 -  15  21  Height of Hog M i l l e t at 12 days Following the Treatments  36  Page Table 4 - Amount of Grass remaining one Month after Treatments were Applied (Weight of C l i p p i n g s ) . . . .  43  Table 5 - S e n s i t i v i t y of Some Monocotyledonous Plants to IPC  57  Table 6 - S o i l Analysis of Strawberry Plots Obtained by Spurway Tests  ••  60  Table 7 - E f f e c t of the Various Treatments upon the Broad-leaved Weeds and Grasses •  64  Table 8 - The Condition of the Strawberry Plants  68  Table 9 - E f f e c t of the Various Treatments upon the Weeds  69  6. THE EFFECT OF VARIOUS CHEMICALS AS SELECTIVE HERBICIDES FOR  BRITISH SOVEREIGN STRAWBERRIES (Fragaria c h i l o e n s i s ) .  INTRODUCTION  Information on the use of herbicides for weed control i n strawberries i s l i m i t e d , but grower i n t e r e s t has increased to the point where recommendations for safe usage are needed.  From the l i m i t e d investigations (6,13,17,19,23)  of the past three years i t has been shown that strawberry v a r i e t a l responses to 2,4-D  (this abbreviation w i l l be used  for 2,4-dichlorophenoxyacetic a c i d throughout the paper) are wide and, f o r that reason, i t i s imperative  that the  response of the B r i t i s h Sovereign strawberry to 2,4-D  be  determined since t h i s v a r i e t y i s used extensively i n commercial plantings i n the Fraser V a l l e y .  In addition a  number of new herbicides have made t h e i r appearance since 2,4-D  and i t i s possible that some of them may  have a place  for weed control i n strawberries. With the above points i n mind the following experiments were c a r r i e d out: 1.  An exploratory experiment with several herbicides  and a large range of concentrations to determine t h e i r e f f e c t  7. on B r i t i s h Sovereign strawberry plants. 2.  An exploratory experiment with several herbicides  and a large range of concentrations to determine t h e i r effect on well established grass and weeds. 3.  A follow up of experiments 1 and 2 conducted i n the  greenhouse under controlled conditions t o determine the effeot of various concentrations of the more promising herbicides on newly germinated grass seedlings. 4.  An experiment i n the greenhouse with various  combinations and concentrations of 2,4-D  and Isopropyl N-  phenylcarbamate (I.F.C.) to determine the most e f f e c t i v e combinations to be used i n deweeding of strawberries. 5.  An experiment to study the effeot of various  concentrations of 2,4-D  and 2,4-D  supplemented with I.P.C,  on both weeds and strawberry plants i n the f i e l d .  REVIEW OF LITERATURE  Strawberry weed control has long been a laborious and expensive process where mild winters, such as experienced i n the Fraser Valley, promote the germination and growth of grasses and weeds throughout the winter months.  Annual  broad-leaved weeds and grasses are the most troublesome i n the f i r s t - y e a r bed, while the f r u i t i n g bed often becomes infested with perennial weeds and grasses.  Growers estimate  8. that costs of c u l t i v a t i o n , hoeing, and hand weeding run up to $100 and more per acre per season.(18) Various methods and suggestions have appeared from time to time i n the l i t e r a t u r e f o r easing t h i s problem. However, as mentioned i n the introduction, information on the use of herbicides for weed oontrol i n strawberries i s l i m i t e d . Bush (2) describes a method using t a r - o i l f o r c o n t r o l l i n g weeds i n strawberry beds.  T a r - o i l at &% i n water  i s applied between the rows i n autumn, taking eare to avoid the strawberry crowns. turned, leaving a clean  When the weeds die the s o i l i s l i g h t l y bed.  Elder, E l w e l l and Romans (8) state that there i s some evidence that most strawberry v a r i e t i e s are f a i r l y resistant to 2,4-D.  They state i t may  be used throughout the  growing season the f i r s t year plants are set, but on older beds i t should be used only a f t e r the harvest season.  Some  d i s t o r t i o n of leaves and runners w i l l be seen, but the plants usually recover and continue normal growth.  Applications  three to four days a f t e r thorough shallow c u l t i v a t i o n s are most e f f e c t i v e . The suggested rate i s one pound (aoid equivalent) per acre, with applications not c l o s e r than four weeks unless heavy r a i n should f a l l i n the meantime. The D i v i s i o n of H o r t i c u l t u r e , Dominion Experimental Farm Service, (23) reports that a sodium s a l t , an amine s a l t and a butyl ester of 2,4-D  each at the rates of  one-half,  one and two pounds aoid equivalent per acre were applied to  9.  the f o l i a g e of several v a r i e t i e s of strawberry plants. Included  i n the t e s t were the v a r i e t i e s : Ambrosia. Big Joe,  Crimson Clow. Daybreak. Fairpeake,  Gandy, Massey, Maytime,  Premier, Red Star, Redwing and a seedling 0-374.  The  one-  h a l f pound rate caused s l i g h t curvature and twisting of the p e t i o l e s of a l l the v a r i e t i e s .  Moderate d i s t o r t i o n of a l l  the v a r i e t i e s resulted from the two pound r a t e .  Application  of the amine resulted i n i n j u r y similar to that caused by the sodium salt..  The degree of d i s t o r t i o n , however, was  greater and ranged from s l i g h t to considerable.  The  ester  was the most injurious and caused d i s t o r t i o n ranging i n degree from s l i g h t to severe. s u s c e p t i b i l i t y to the 8,4-D  V a r i e t a l differences i n  were evident.  The v a r i e t y  Fairpeake appeared to be the most r e s i s t a n t to the 2,4-D. Reports (21) from four looations indicate that f r u i t i n g plants of three v a r i e t i e s are tolerant of  2,4-D  applications up to one pound, acid equivalent, per acre. Higher dosages caused severe d i s t o r t i o n of leaves but did not k i l l the plants nor reduce the production of runner plants.  No differences between amine s a l t , sodium s a l t and  ester formulations were reported.  Seedling plants, however,  showed a great v a r i a t i o n i n tolerance. weeds was  Control of annual  s a t i s f a c t o r y , i n a l l cases, but one pound d i d  not control perennial weeds. Carder (3) reporting on the control of dandelions i n strawberries by 2,4-D  states that rates of 8,16,  ounces, acid equivalent, per acre of butyl ester of  and  32  2,4-D  10. were applied at three growth stages of Dakota strawberry, viz.,  just previous to flowering, at time of flowering, and  i n l a t e summer a f t e r harvest*  The strawberry plants showed  no i n j u r y from 8 and 16 ounce rates but exhibited c u r l i n g of leaves from the 32 ounce spraying at time of flowering.  Most  complete k i l l of the dandelions was effected by t r e a t i n g before the strawberry plants were i n f u l l flower.  Spraying  at t h i s time eliminated the dandelions 55, 70 and 80 per cent with the 8, 16 and 32 ounce rates r e s p e c t i v e l y . Many o l d established dandelions had only t h e i r tops k i l l e d and l a t e r f u l l y recovered. Nylund (17) studying the use of 2,4-D f o r weed control i n Arrowhead strawberries found that the isopropyl ester at one pound per acre and the sodium s a l t at one and two pounds per acre, s a t i s f a c t o r i l y controlled weeds.  broad-leaved  Some d i s t o r t i o n of the leaves and runners of the  strawberry plants was noticeable.  Leaf counts and runner  plant counts indicated no detrimental e f f e c t of the 2,4-D on either l e a f production or on runner plant formation. According to Carlson (4) spraying against broadleaved weeds with 2,4-D at 1,000 parts per m i l l i o n was successful without damage to the strawberry plants at any time i n the f i r s t required —  season of planting —  i n which no crop i s  and a f t e r harvest i n the second year.  Carlson and Moulton (5) i n v e s t i g a t i n g the use of the ammonium s a l t of trichloroacetate, the sodium s a l t of  11. triehloroacetate, ammonium thiocyanate and herbieide "PB , M  i n the eradication of grasses, and the e f f e c t of these chemicals on strawberry and raspberry plants found that both the ammonium and sodium salts of triehloroacetate (TCA) gave slow but e f f e c t i v e control of couch grass, Agropyron repens. and Kentucky bluegrass, Poa pratensls. under greenhouse conditions, i f applied at the rates of 150 -£00 pounds per acre i n the case of well established grass and of 40 - 80 pounds per acre i n the case of young growth.  After a gradual  colour change the leaves became chlorotlc and withered 4 weeks a f t e r treatment.  Ammonium thiocyanate proved l e s s  e f f e c t i v e than the two s a l t s of TCA, and PB". W  The l a t t e r  k i l l e d broad-leaved weeds without i n j u r i n g the grasses.  The  strawberries were k i l l e d by the TCA s a l t s when applied at h e r b i c i d a l strength. A preliminary report by S l i f e and B a l l (19) states that TCA was applied to the Premier variety of strawberry, at the rates of 10, 20, 30, 40, and 50 pounds, acid equivalent, per acre.  In a l l plots, plants were severely burned and  on a l a t e r date, there was no evidence of recovery. Otis (18) states that good r e s u l t s were obtained with a mixture of water and Diesel o i l f o r t i f i e d with Dow General Weed K i l l e r (a concentrate of Dinitro-o-secondarybutylphenol).  Proportions used were 1 quart of Dow General,  30 gallons of Diesel o i l , and 100 gallons of water. The material was sprayed so as t o thoroughly wet the vegetation.  12. On small weeds 125 t o 150 gallons per acre are usually sufficient.  The oil-dinitro-water mix k i l l s hack top growth  but does not injure crowns or root systems of perennials. Hence strawberries treated even a f t e r growth was well started were only temporarily "burned" back.  By the same token, of  course, annual weeds and grasses are eradicated, but e s t a b l i s h ed perennial weeds are not. Much work, the p r i n c i p l e s of which may prove o f value i n the weed control of strawberries, has been done, by Hitchcock and Zimmerman (12) on the a c t i v a t i o n of 2,4-D by various adjuvants.  They found that mixtures of 2,4-D and  certain adjuvants (Benolor 3C, ammonium thiocyanate, ammonium sulphamate, Hammond's Weed K i l l e r , d i a l l y l maleate, sodium bicarbonate, and sodium chloride) were more e f f e c t i v e herbicides than any o f the i n d i v i d u a l components used at the same conoentration.  Adjuvants which funotioned as aotivators  of 2,4-D included wetting agents, s o l u b i l i z e r s , e m u l s i f i e r s , penetrants, hormones other than 2,4-D and toxicants commonly used as contact herbicides. Mixtures containing l e t h a l and sub-lethal concentrations of contact herbicides increased the a c t i v i t y of the hormone-like preparations with respeot to the induction of hormone-curvature responses, i n i t i a l injury to f o l i a g e , and k i l l i n g of the entire plant.  The  h e r b i c i d a l a c t i v i t y of these mixtures increased with increasing concentrations of the contact weed k i l l e r up to the point where the mixture was no more e f f e c t i v e than the  13. contact weed k i l l e r used alone at the same concentration as i n the mixture.  R e l a t i v e l y high concentrations of contact  herbicides (1$ to 30%) were required to prevent 2,4-D from inducing additive e f f e c t s .  They conclude that i t i s believed  that more e f f e c t i v e general-purpose herbicides than those used to date are l i k e l y to contain more than one hormone, at least one toxicant, and additional adjuvants which are e f f e c t i v e as wetting agents, s o l u b i l i z e r s , penetrants, emulsifiers, and s t i c k e r s . A description i s given by Hance (10) of a method used i n the Hawaiian Islands t o supplement the h e r b i c i d a l e f f e c t of 2,4-D and at the same time reduce i t s i n j u r i o u s effect on sugar-oane.  I t has been found that i n c e r t a i n  cases the amount of 2,4-D applied may be reduced t o a concentration harmless to germinating sugar-oane — pounds per acre —  say two  while at the same time maintaining f o r  three months or longer i t s f u l l pre-emergence h e r b i c i d a l e f f e c t on the f i e l d , provided that 2,4-D i s supplemented with about f i v e times i t s weight of H.S.P.A. activator (pentachlorophenol, or sodium pentachlorophenate).  Some  similar method might prove of value i n the weed control of strawberries.  14. EXPERIMENT I  Object: To determine the e f f e c t of various concentrations of several d i f f e r e n t herbicides and combinations of herbicides on B r i t i s h Sovereign strawberry plants. Materials and Methods: Plots one square yard i n area of established B r i t i s h Sovereign strawberry plants were sprayed with the various treatments as shown i n table 1. a knapsack sprayer.  A l l sprays were applied with  General notes were taken p e r i o d i c a l l y  following the applications and the e f f e c t of the sprays upon the strawberry plants noted.  15. Table 1  -  Treatments Applied to Established Sovereign Strawberry Plants.  Treat: No.  Material  Rates per acre  British  (1949)  Volumes gals/aore  Date sprayed  Temp  150  May 23 v  72°  25,40,80,100 & 200 pounds 1000 ppm  150  May 23  72°  2.4-D  1000 ppm  150  May 25  73°  4.  IPC  5,10,20,30,40,50, 60,70 & 80 lb».  150  May 25  73°  5.  IPC plus 2,4-D  5,10,20,30,40,50 60,70 & 80 l b s . 1000 ppm  150  May 25  73°  6.  MCP  1 & 2 lbs.  150  June 7  71°  7.  PCP  24 l b s .  150  June 8  75°  8.  DNOSBP  2qt/100 gal H 0  75  June 8  75<>  9.  Untreated  1*.  TCA  25,40,80,100 & 200 pounds  2.  TCA plua 2,4-D  5.  2  Legend: TCA 2,4-D IPC MCP PCP DNOSBP-  Sodium salt o f Trichloroacetic a c i d 2,4-Diohlorophenoxyacetic acid Ammonium s a l t of Isopropyl N-phenol carbamate 2 methyl-4-chlorophenoxyacetic acid Sodium pentachlorophenate Ammonium s a l t of dinitro-0-secondary butyl phenol  16 RESULTS  On May 24 (one day following spraying with TCA and TCA plus 2,4-B) TCA at 25 pounds per acre caused marginal browning of the strawberry leaves and t h i s browning increased d i r e c t l y with increased concentration of TCA u n t i l a t 100 and 200 pounds per acre the leaves were completely browned. Treatment 2 (TCA plus 2,4-D) gave similar r e s u l t s . On June 17 (twenty-five days following spraying with TCA and TCA plus 2,4-D) new leaves appeared from a l l plants treated with TCA and TCA plus 2,4-D.  The plants sprayed with  2,4-D a t 1000 ppm showed s l i g h t curvature and twisting of petioles and c u r l i n g of leaves.  Treatment 4 (IPC) regardless  of concentration appeared to have no effect upon the strawberry p l a n t s .  Treatment 5 (IPC plus 2,4-D) affected the  plants the same as described above for 2,4-D alone.  Treatment  6 (MCP) caused s l i g h t c u r l i n g of the leaves and twisting of petioles.  Treatment 7 (PCP) caused s l i g h t browning to leaves  and blossoms and also caused considerable damage to the f r u i t . Treatment 8 (DNOSBP) caused p a r t i a l browning of the leaves. A f i n a l survey was made on August 1 of a l l p l o t s and complete notes taken.  Following are a few b r i e f extracts  taken from these notes: Treatment 1 (TCA) The majority of the plants i n TCA treated p l o t s were dead.  The odd plant i n p l o t s treated with 25, 40 and 80  17. pounds of TCA showed a few small green leaves breaking from the crown, but i n p l o t s treated with 100 and 200 pounds per acre a l l plants were completely dead. Treatment 2 (TCA plus 2.4-D) The r e s u l t s from these treatments were the same as described above f o r TCA only the plants were i n a worse condition. Treatment 5 (2.4-D) The plants i n these plots appeared to be developing normally a l l d i s t o r t i o n s of p e t i o l e s and leaves had disappeared. Treatment 4 (IPC) A l l IPC treated plants appeared to be developing normally and were as vigorous as the untreated plants. Treatment 5 (IPC plus 2.4-D) Plants under t h i s treatment also appeared to be developing normally though not quite as vigorously as those plants treated with IPC alone. Treatment 6 (MCP) Plants treated with MCP at 1 and 2 pounds per acre appeared to be recovering, but leaves were rather small.  The  plants as a whole appeared siok. Treatment 7 (POP) Plants were recovering, but the leaves appeared smaller than normal.  Also no f r u i t was obtained from these  plants a f t e r spraying since as mentioned previously t h i s treatment dried up the blossoms and f r u i t .  18. Treatment 8 (DNOSBP) Plants treated with DNOSBP had recovered  though i n  general the plants were smaller than those treated with IPC.  DISCUSSION  The  results with TCA i n t h i s experiment are i n agree  ment with those obtained by Carlson and Moulton, (5) who report that strawberries were k i l l e d by the TCA s a l t s when applied at h e r b i c i d a l strength.  The F i f t h Annual North  Central Weed Control Conference Research Report (21) states that TCA, at a rate as.low as 10 pounds, a c i d equivalent, per acre caused severe i n j u r y t o strawberry plants.  Thus i n  l i g h t of these reports and the r e s u l t s obtained i n t h i s experiment i t appears that TCA i s worthless as a weedicide for  strawberries. On the other hand, IPC apparently did not have any  effect upon the strawberry plants.  Lachman (14) found that  IPC was valuable as a selective herbicide i n that i t e f f e c t i v e l y k i l l s grasses with l i t t l e or no harm to broadleaved plants. Thus IPC should prove useful as a control f o r grasses i n strawberry plantings. From the r e s u l t s of t h i s experiment i t i s also seen that 2,4-D at 1000 ppm and IPC plus 2,4-D apparently did not have any l a s t i n g detrimental e f f e c t s upon the strawberry plants.  The F i f t h Annual North Central Weed Control  19. Conference Research Report (21) states that reports from four locations indicate that f r u i t i n g plants of three v a r i e t i e s of strawberries are tolerant to 2,4-D applications up to one pound, aoid equivalent, per acre.  Higher dosages caused  severe d i s t o r t i o n of leaves but did not k i l l the plants nor reduce the production of runner plants.  No differences  between amine s a l t , sodium s a l t and ester formulations were reported.  Carder (3) reported that strawberry plants showed  no i n j u r y from 8 and 16 ounce rates of 2,4-D, but exhibited c u r l i n g of leaves from 32 ounce spraying. Davidson (6) 16 ounce concentrations formative  According t o  of 2,4-D caused s l i g h t  e f f e c t s on the new strawberry f o l i a g e (variety  Premier), which emerged immediately affeer treatments.  Nylund  (17) states that l e a f counts and runner plant counts indicated no detrimental e f f e c t of 2,4-D on either l e a f production or on runner plant formation  (variety Arrowhead).  S l i f e and  B a l l (19) report that Premier strawberry was sprayed with 0.50, 0.75,  1.0, 2.0, and 3.0 pounds per acre of the amine  preparation of 2,4-D.  The twisting and durling e f f e c t was  s l i g h t on the 0.50 and 0.75 pound a p p l i c a t i o n , but rather severe on the 1, 2 and 3 pound r a t e s .  Within one month from  application, a l l plots appeared normal and showed no apparent effects of treatment.  According to K l e i n (13) the premier  strawberry tolerated a weed-killing spray of 1,400 ppm of 2,4-D i n July and August; two applications were made, three weeks apart.  I t i s apparent from the r e s u l t s of t h i s  experiment and of those quoted that 2,4-D and 2,4-D plus IPC  20. hold promise as s e l e c t i v e weedicides f o r B r i t i s h Sovereign strawberries. From the r e s u l t s of t h i s experiment i t i s e a s i l y seen that PCP, MCP and DNOSBP are a l l too injurious to a c t i v e l y growing strawberry plants*  I t i s possible that  these chemicals may prove useful as weedicides i f applied after harvest or when the plants are dormant*  CONCLUSIONS  Of the various chemicals tested i n t h i s exploratory experiment i t appears that 2,4-D and 2,4-D supplemented with IPC o f f e r the greatest promise as s e l e c t i v e herbicides f o r B r i t i s h Sovereign strawberries during the growing period. Furnher experimentation i s d e f i n i t e l y warranted i n order that complete information as to most e f f e c t i v e concentrations and combinations of these chemicals can be determined.  EXPERIMENT I I  Object: To determine the e f f e c t of various concentrations of several d i f f e r e n t herbicides and combinations of herbicides on well established grass and weeds. Materials and Methods: Plots one yard square were l a i d out on a weed  21. Table 2  -  Treatments Applied to Well Established Grass and Weed P l o t s .  Treat; No.  Material  Rates per acre  (1949)  Volumes gals/acre  Date sprayed  Temp: P  150  May 26  71°  150  May 26  71°  150  May 26  71°  150  May 26  71°  1.  TCA  25,40,80,100 & 200 l b s .  2.  TCA plus 2,4-D  40 & 100 l b s .  3.  IPC  10,30,50 & 80 lbs.  4.  IPC plus 2,4-D  10,50 & 80 l b s .  5.  MCP  1 & 2 lbs.  150  June 7  71°  6.  PCP  24 l b s .  150  June 8  75°  7.  DNOSBP  2 qt/100 g a l H„0  75  June 8  75°  8.  Untreated  1000 ppm  1000 ppm  Legend: TCA 2,4-D IPC MCP PCP DNOSBP-  Sodium salt of T r i c h l o r o a c e t i c acid 2,4-Dichlorophenoxyacetic acid Ammonium s a l t of Isopropyl N-phenol carbamate 2 methyl-4-chlorophenoxyacetic acid Sodium pentachlorophenate Ammonium s a l t of dinitro-0-secondary butyl phenol  22. infested piece of t u r f .  Grasses present were couch grass,  Agropyron repens, Kentucky hluegrass, Poa pratensis, and a scattering of other miscellaneous grasses.  These plots  provided a more extreme grass and weed condition than would normally be encountered i n a strawberry plantation.  The  potential h e r b i c i d a l value of these sprays could be best determined under such conditions. The plots were treated as shown i n table 2.  Heavy rains followed within 12 hours a f t e r  applications of treatments 1, 2, 3 and 4. applied with a knapsack sprayer.  A l l sprays were  General notes were taken  p e r i o d i c a l l y following the applications and the e f f e c t of the sprays upon the grass and weed growth recorded.  RESULTS  Extraots from the general notes taken on June 1 are as follows: Treatment 1  (TCA) - at 25 pounds per acre - no apparent  effect.  - at 40 pounds per acre - s l i g h t browning of the grass. - at 80 pounds per acre - browning of the grass s l i g h t l y more than 40 pounds. - at 100 pounds per acre - appeared the same as the 80 pound treatment. - at 200 pounds per acre - appeared to be h i t t i n g  23. dandelion, plantain, etc., more severely than the lower concentrations.  The grass was only s l i g h t l y  browner than i n the p l o t s of lower concentrations. Treatment 2 (TCA plus 2.4-D) - at 40 pounds per acre plus 2,4-D - browning of grass and marginal browning of broad-leaved weeds. Some c u r l i n g of plantain leaves. - at 100 pounds per acre plus 2,4-D - There appeared to be less browning of the grass f o l i a g e as compared t o 50 pounds per acre plus 2,4-D. Treatment 5 (IPC) - no apparent e f f e c t from any of the concentrations on the grass or the weeds. Treatment 4 (IPC plus 2.4-D) - a l l concentrations show s l i g h t 2,4-D effect on broad-leaved weeds, but no effect apparent on the grass. Further notes were taken on June 17, extracts of which follow: Treatment 1 (TCA) - at 40 pounds per acre grass s l i g h t l y burned and as the concentration increases burning of grass increases u n t i l at 200 pounds per acre some of the grass i s d e f i n i t e l y dead. Treatment 2 (TCA plus 2.4-D) - at 40 pounds per acre plus 2,4-D - plantain dying, dandelion showing e f f e c t s , grass browning.  24. - at 100 pounds per acre plus 2,4-D 1000 ppm as above but damage more severe. Treatment 5 (IPC) - no apparent effect from any of the concentrations on the grass or weeds. Treatment 4 (IPC plus 2.4-D) - only 2,4-D e f f e c t on broad-leaved weeds apparent. Treatment 5 (MCP) - l i t t l e e f f e c t on the grass. Treatment 6 (PCP) - grass showed browning. Treatment 7 (DNOSBP) - grass showed some browning. An extract from notes taken on June SO follows: Treatments 5 & 4 (IPC & IPC plus 2.4-D) - a l l p l o t s at t h i s time were showing the following e f f e c t s : grass stunted and browned; broad-leaved weeds showed t y p i c a l 2,4-D damage. A f i n a l survey was made o f a l l the p l o t s on August 1. and b r i e f extracts follow: Treatment 1 (TCA) - i n a l l plots treated with TCA above 25 pounds per acre a l l grasses appeared dead.  The broad-leaved  weeds, however, spread r a p i d l y . Treatment 2 (TCA plus 2.4-D) - This treatment i n addition, to k i l l i n g the grass  25. also controlled the broad-leaved weeds to a degree —  plantain appeared to be completely  eradicated, whereas the well established  dandelion  and yellow cress showed recovery. Treatments 3 & 4 (IPC & IPC pins 2.4-D) - In a l l p l o t s , grasses were p a r t i a l l y k i l l e d and stunted.  Broad-leaved weeds were growing i n a l l  p l o t s , but to a l e s s e r extent i n p l o t s treated with IPC plus 2,4-D. Treatments 5. 6 & 7 (MCP. PCP & DNOSBP) - Plots treated with these chemicals a l l showed p a r t i a l and stunting of the grass.  DISCUSSION  From the above r e s u l t s i t i s apparent that TCA w i l l e f f e c t i v e l y control well established couch grass, Kentucky bluegrass and other grasses i f applied at 40 pounds per acre. TCA plus 2,4-D appears promising as a weedicide for land infested with both perennial grasses and broad-leaved weeds. Carlson and Moulton (5) report that both ammonium and sodium s a l t s of trichloroacetate (TCA)  gave slow but  e f f e c t i v e control of couch grass and Kentucky bluegrass under greenhouse conditions, i f applied a t the rates of 150 - 200 pounds per acre i n the case of well established grass and 40 80 pounds per acre i n the case of young growth.  26. Barrons (1) obtained good k i l l s of couch grass from as l i t t l e as 40 pounds per acre. In t h i s experiment  IPC required approximately a  month before effect upon the grass was apparent.  However, as  seen from the results IPG f i n a l l y gave a f a i r l y e f f e c t i v e control of the grasses present though not as absolute a control as was obtained from TCA.  Broad-leaved weeds were  apparently not harmed except i n those p l o t s to which  2,4-D  had been added. Lachman (14) found that IPC was valuable as a selective herbicide i n that i t e f f e c t i v e l y k i l l s grasses with l i t t l e or no harm to broad-leaved plants. M i t c h e l l and Marth (16) report that when IPC  was  applied at r e l a t i v e l y high rates (50 and 100 pounds per acre) to potted s o i l i n which crab grass had become established and had developed leaves extending about 1 - 2  cm. above the  surface of the s o i l , the plants f a i l e d to grow further and died within a period of two weeks following treatment. In l i g h t of the r e s u l t s obtained i n Experiment would appear that a suitable combination of IPC and  1 it  2,4-D  should o f f e r promise as a weed-killer i n plantations of a c t i v e l y growing B r i t i s h Sovereign strawberries where weeds and grasses are p l e n t i f u l . PCP, MCP and DNOSBP gave no better control of grasses than did IPC under conditions of t h i s Since the results of Experiment  experiment.  1 show they cause considerable  27.  harm t o a c t i v e l y growing B r i t i s h Sovereign p l a n t s i t can be concluded that they o f f e r l i t t l e promise as weedicides f o r strawberries during the growing p e r i o d .  CONCLUSIONS  Of the various h e r b i c i d e s t e s t e d i n t h i s exploratory experiment i t appears t h a t IPC plus 2,4-D o f f e r s the greatest promise as a s e l e c t i v e weedicide f o r B r i t i s h Sovereign  strawberries during the growing p e r i o d i n p l a n t a -  t i o n s where both broad-leaved weeds and grasses are p l e n t i f u l .  EXPERIMENT I I I  Object: To determine t h e e f f e c t o f various  concentrations  of t h e more promising h e r b i c i d e s (as p r e v i o u s l y determined from Experiments I and I I ) on newly germinated grass seedlings. M a t e r i a l s and Methods: P l o t s one square foot i n area were l a i d out i n f l a t s i n the greenhouse and sown t o p e r e n n i a l r y e grass on June 8.  The f o l l o w i n g treatments were a p p l i e d on June 20  at which time the grass was 2^ inches  tall.  28  Treatment No.  Material  Bate/acre  1.  PCP  10 l b s .  2.  IPC  10,40 & 80 l b s . (as a spray)  3.  IPC  40 & 80 l b s . (as a dust with sand)  4.  IPC plus 2,4-D  40 l b s .  5.  1000 ppm  Untreated  Note: PCP - Sodium pentachlorophenate IPC - Ammonium salt o f Isopropyl N-phenol carbamate General notes were taken p e r i o d i c a l l y following treatments and the effect of the sprays upon the grass recorded.  RESULTS  A f i n a l survey of the f l a t s was made on July 18. and cpmplete notes taken.  Extracts from these notes follow:  Treatment 1 (PCP) - p a r t i a l k i l l and stunting of the grass.  89.  Treatment 8 (IPC) - at 10 pounds per acre - p a r t i a l k i l l and stunting of the grass. - at 40 pounds per acre - p a r t i a l k i l l and stunting. - at 80 pounds per acre - complete k i l l . Treatment 5 (IPC dust) - at both 40 and 80 pounds per acre - oomplete k i l l . Treatment 4 (IPC plus 2.4-D) - p a r t i a l k i l l and stunting.  DISCUSSION  From an examination  of the above r e s u l t s i t i s seen  that 40 pounds of IPC i n sand gave complete k i l l of the perennial rye grass whereas only p a r t i a l k i l l and stunting was obtained from 40 pounds of IPC i n water; to the greater residual e f f e c t of dust.  t h i s may be due  There was l i t t l e  difference i n effect upon the grass between IPC (spray) at 10 pounds, 40 pounds or 40 pounds per acre plus 2,4-D. But IPC at 80 pounds per acre gave complete k i l l .  Thus i t would  appear that the higher concentrations are required when IPC i s applied as a spray.  M i t c h e l l and Marth (16) found that  IPC i s inactivated i n the presence of moist, f e r t i l e  soil.  PGP at 10 pounds per acre gave only p a r t i a l k i l l and stunting.  Therefore, i t appears to be no better than IPC  at 10 pounds per acre f o r k i l l i n g perennial rye grass seedlings  30. and further from Experiment  1 i t was shown that PCP was  detrimental to the strawberry plants at higher concentrations. IPC would appear, therefore, to be the most promising herbicide f o r the control of grasses i n strawberries.  CONCLUSIONS  Further experimentation i s required to determine the most e f f e c t i v e combination o f IPC and 2,4-D for use as a selective herbicide f o r B r i t i s h Sovereign strawberries.  EXPERIMENT IV  Object: To study the e f f e c t s of various combinations and concentrations of 2,4-D and IPC and other promising herbicides on several kinds of newly germinated grass seedlings and B r i t i s h Sovereign strawberry plants i n the greenhouse.  Materials and Methods: Grass Seedlings Three randomized blocks were l a i d out on the greenhouse benches.  Each block consisted of 23 f l a t s so that one  f l a t constituted a p l o t .  Each f l a t was 4 inches deep and  1 foot wide by l£ feet long.  One blck of f l a t s was f i l l e d  31. with composted s o i l while the f l a t s of the other two blocks were f i l l e d with garden s o i l (sandy loam).  On August 18,  1949,  the 69 f l a t s were sown with the following grasses: creeping red  fescue (Festuoa rubra; perennial rye (Lolium perenne);  orchard (Dactylis glomerata) and hog m i l l e t (Panicum miliaceumi. Thus each f l a t contained the four species of grass seed sown so that each specie was i n a separate band 4& inches wide across the f l a t .  Therefore, the e f f e c t of the various t r e a t -  ments upon each specie of grass could be e a s i l y studied. Strawberry Plants On August 18, 1949,  sixty-nine uniform, young,  B r i t i s h Sovereign strawberry plants were l i f t e d from the f i e l d and planted i n oomposted s o i l contained i n t i n pots 7 inches i n diameter and 8 inches deep, with bottom drainage. The pots were then arranged i n three randomized blocks on the greenhouse benohes so that one pot constituted a plot (see figure 1 f o r general l a y o u t ) . Treatments: Both the grass seedlings and the strawberry plants were given the following treatments: Treatment Ho.  Material and Rates  1  ^ l b . 2,4-D  per acre.  2-6  & l b . 2,4-D plus 10,20,40, 60 and 80 l b s . IPC per acre.  7  1 l b . 2,4-D  per acre.  32. 8-12  1 l b . 2,4-D plus 10,20,40 60 & 80 l b s . IPC per acre.  13  2 l b s . 2,4-D per acre.  14-18  2 l b s . 2,4-D plus 10,20,40, 60 & 80 l b s . IPC per acre. 75 g a l . per acre of emulsifiable Pentachlorophenol.  19 20  150 g a l . per acre of emulslfiable Pentachlorophenol.  21  1$ aero oyanate  22 23  Z% aero cyanate Untreated  Note: 2,4-D —  Sodium s a l t of 2,4-Diehlorophenoxyaeetic a c i d . (Dow-Deweed).  IPC  Ammonium s a l t of Isopropyl N-phenol carbamate.  —  Aero-cyanate —  91$ potassium cyanate prepared by American Cyanamide Co.  Emulslfiable pentachlorophenol — oil-in-water. emulsion of pentachlorophenol prepared by Monsanto Chemical Co. On August 30 a l l treatments were applied with a hand sprayer of one-pint capacity. Cardboard  shields were  held along the sides of each area being sprayed to avoid d r i f t of the mixture (See f i g u r e 2.) General notes, measurements and photographs were taken p e r i o d i c a l l y following the applications and the effect of the sprays upon the various species of grasses and strawberry plants noted.  33.  Figure 1 - General View Showing the Layout of the P l o t s i n the Greenhouse.  34.  Figure 2 - Method of Spraying Greenhouse P l o t s . Note the Cardboard Shields held along the sides of each area being sprayed to avoid d r i f t of the mixture.  35. RESULTS  Twelve days following application of the treatments the height of the Hog M i l l e t was recorded.  These were the  only measurements made at t h i s time since the Hog M i l l e t appeared to he representative of the e f f e c t s of the treatments on a l l the grasses.  These measurements are shown i n table 3  and figure 3. On October 30, (two months a f t e r sprays had been applied) the grasses remaining were harvested (by c l i p p i n g at the s o i l l e v e l ) and weighed*  The c l i p p i n g r e s u l t s are  presented i n table 4 and i n figures 6, 7, 8 and 9. A complete s t a t i s t i c a l analysis of the r e s u l t s was made. However, only minimum s i g n i f i c a n t differences at the •05 l e v e l w i l l be shown here, but the complete a n a l y s i s w i l l be found i n the appendix. The treatment heights (from table 3) are l i s t e d below i n descending order and entered alongside each i s the amount of the difference from the previous value (M.S.D. 1.08). Treatment  Mean Height (cms)  23 - Untreated  Difference from pre v. value.  14.3  2 - &lb. 2,4-D + 101b. IPC  12.7  1.6  1 - is l b . 2,4-D  12.3  0.4  8 - 1 l b . 2,4-D + 101b. IPC  11.7  0.6  Table 3  -  36,  The Height of Hog M i l l e t at Twelve Days following the Treatments.  Treatment No.  (1949)  Treatments (per acre)  Mean Height (cms)  1.  £  l b . 2,4-D  2.  l b . 2,4-D  + 10 l b s .  IPC  12.7  3.  £ £  l b . 2,4-D  20 l b s .  IPC  11.3  4.  £  l b . 2,4-D  * 40 l b s .  IPC  10.7  5.  £  2,4-D  + 60 l b s .  IPC  10.0  6.  £  l b . 2,4-D  + 80 l b s .  IPC  8.3  7.  l  l b . 2,4-D  8.  l l b . 2,4-D  + 10 l b s .  IPC  11.7  9.  l l b . 2,4-D  + 20 l b s .  IPC  10.3  10.  l l b . 2,4-D  40 l b s .  IPC  9.0  11.  I  l b . 2,4-D  60 l b s .  IPB  8.0  12.  I  l b . 2,4-D  80 l b s .  IPC  7.7  13.  2 l b . 2,4*D  14.  2 l b . 2,4-D  15.  2 l b . 2,4-D  4  16.  12.3  -  11.3  9.0 10 l b s .  IPC  11.7  20 l b s .  IPC  8.3  2 l b . 2,4-D  + 40 l b s .  IPC  7.7  17.  2 l b . 2,4-D  + 60 l b s .  IPC  7.3  18.  2 l b . 2,4-D  + 80 l b s .  IPC  5.7  19.  75 g a l . Pentachlorophenol  0.3  20.  150 g a l . Pentachlorophenol  1*7  21.  1 <fo aero cyanate  3.0  22.  2 $ aero cyanate  3.7  23.  Untreated ~" M.S.D. » 1.08 cms. ^ f o r treatments (.05 l e v e l )  14.3  37.  s •  1 •  «  n  IPC i n pounds per acre Figure 3 - E f f e c t of Applications of Various Amounts of 2,4-D  and Mixtures of 2,4-D  and IPC on  the Height of Hog M i l l e t (Panicum miliaceum) as at September 11,  1949.  38. 14  mm  3 7 4 9 5 10 13 6  -  -  15  -  11  -  12 16 17 18 22 21 20 19  -  -  l b . IPC  11.7  0 0  20  l b . IPC  11.3  0.4  11.3  0.0  l b . IPC  10.7  0.6  20  l b . IPC  10.3  0.4  60  l b . IPC  10.0  0.3  40  l b . IPC  9.0  1.0  9.0  0.0  2,4-D  k lb.  2,4-D  lb.  2,4-D  * lb.  2,4-D  +  40  2,4-D  *  2,4-D  •  1  - l lb. - * lb. - l lb. - 2 lb. mm  10  ID.  2  +  2,4-D 2,4-D  #  *  lb.  2,4-D  •  80  l b . IPC  8.3  0.7  2  lb.  2,4-D  +  20  l b . IPC  8.3  0.0  1  lb.  2,4-D  60  l b . IPC  8.0  0.3  1  lb.  2,4-D  +  80  l b . IPC  7.7  0.3  2  lb.  2,4-D  *  40  l b . IPC  7.7  0.0  2  lb.  2,4-D  60  l b . IPC  7.3  0.4  2  lb.  2,4-D  80  l b . IPC  5.7  1.6  25 %  aero oyanate  3.7  2.0  1? I  aero cyanate  3.0  0.7  g a l . Pentaehlorophenol  1.7  1.3  7 5 g a l . Pentachlorophenol  0.3  1.4  150  Now any difference or cumulative difference greater than 1 . 0 8 the M.S.D. proves a s i g n i f i c a n t decrease i n height (repression of growth) over treatments higher up on the l i s t . On t h i s basis, treatment 1 9 i s s i g n i f i c a n t l y better than any of the treatments.  I t follows that treatments 2 0 , 2 1 , and 2 2  i n that order are s i g n i f i c a n t l y better than any of the remaining treatments.  However, these treatments severely  damaged the strawberry plants (see figure 4) and thus are  39.  of no value as selective herbicides f o r a c t i v e l y growing  strawberry plants. The remaining treatments (2,4-D and 2,4-D • IPC) caused no apparent damage t o the strawberry plants and thus can be considered. Now i f the above l i s t i s studied along with figure 3 i t w i l l be noted that treatment 18 i s s i g n i f i c a n t l y better than any other of the remaining t r e a t ments.  There i s no s i g n i f i c a n t difference between treatments  17, 16, 12, 11, 15 or are  6.  However, treatments, 17, 16 and 12  a l l s i g n i f i c a n t l y better than treatment 13 (see f i g u r e 5).  There i s no s i g n i f i c a n t difference between treatment 13 or 5. But treatment 13 i s s i g n i f i c a n t l y better than treatment 9. There i s no s i g n i f i c a n t difference between treatments 9, 4 and 7.  Treatment 9 i s s i g n i f i c a n t l y better than treatment 14.  There i s no s i g n i f i c a n t difference between treatments 7, 3, 14, 8 and 1.  Treatments 7 and 3 are s i g n i f i c a n t l y better than  treatment 2.  F i n a l l y , treatment 2 i s s i g n i f i c a n t l y better  than treatment 23. It i s also noted from the above l i s t and figure 3 that the addition of only 10 pounds IPC to 2,4-D has a reverse effect i.e.,  i n a l l cases 10 pounds of IPC caused an increase  i n the height of the m i l l e t over those treated with 2,4-D alone.  Almost 20 pounds o f IPC i s required to increase the  effeot of 2,4-D.  With each a d d i t i o n a l increase i n IPC the  growth i s further repressed.  40.  Figure 4 - The E f f e c t o f Pentaehlorophenol and Potassium Cyanate upon B r i t i s h Sovereign Strawberry Plants and Grass Seedlings as a t Sept. 6, 1949. The numbers r e f e r t o treatments as f o l l o w s : No, 21 - 1% Aero Cyanate No. 23 - Untreated No. 19 - 75 g a l . per acre of e m u l s i f i a b l e pentaehlorophenol.  41  Figure 5 - The E f f e c t of 2,4-D  and 2,4-D  plus IPC upon  the various Grasses as at Sept. 11,  1949.  The Numbers r e f e r to treatments as f o l l o w s : No. 23 - Untreated No. 13 - 2 l b s . 2,4-D  per acre  No. 1 8 - 2  p l u s 80 l b s . IPC per acre.  l b s . 2,4-D  42. A l l plots were harvested two months a f t e r  treatments  were applied. The clippings from each specie of grass i n each plot were weighed and the weights recorded.  The r e s u l t s are  summarized i n table 4 and figures 6, 7, 8 and 9. Creeping red fescue (Festuea rubra) An examination of table 4 and figure 6 shows that an a p p l i c a t i o n of k pound 2,4-D per acre caused a s i g n i f i c a n t increase i n weight of clippings over the untreated p l o t . There i s no s i g n i f i c a n t difference between treatment 7 (1 pound 2,4-D) and the unsprayed p l o t .  However, 2 pounds 2,4-D  per acre did cause a s i g n i f i c a n t reduction i n the grass as oompared to the untreated p l o t . reduced the amount of grass.  The addition of IPC further  In general t h i s reduction i n  grass increases with an increase i n IPC. However, i t w i l l be noted especially f o r the mixtures containing i pound 2,4-D and 2 pounds 2,4-D that there i s only a slight difference between the mixture containing 40, 60 and 80 pounds of IPC per acre. Perennial rye grass (Lolium perenne) An examination of table 4 and figure 7 shows that both £ pound 2,4-D and 1 pound 2,4-D per acre very s i g n i f i cantly increased the amount of grass i n comparison with the unsprayed p l o t s .  No s i g n i f i c a n t difference was found  between the p l o t s sprayed with 2 pounds 2,4-D per acre and the unsprayed p l o t s .  In general the amount of grass present  43. , Table 4 - The amount of grass remaining one month a f t e r treatments were applied (weight of e l i p p i n g s ) .  Grasses  Creeping Perennial Orchard Hog red fescue rye grass millet (Festuca rubra)(Lolium perenne) (Daetylis (Pan!cum glomerata) miliaceum)  Treatments 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22 •  23.  M.S.D. (.05 l e v e l ) (gms)  Mean weight i n grams 10.1 5.3 2.5 2.2 1.5 1.5 8.8 4.0 5.8 3.8 2.7 1.7 6.2 5.0 3.7 1.8 1.7 8.7 3.8 8.0 9.0 9.2  26.7 13.7 3.8 4.7 4.0 4.0 26.8 10.7 15.7 7.7 4.7 4.3 15.5 14.2 12.5 5.7 6.8 3.8 28.7 13.0 11.7 18.4 15.7  13.8 12.3 5.0 2.8 1.7 1.7 10.5 6.3 6.8 2.8 2.3 1.7 6.7 6.5 6.2 2.3 2.2 1.5 5.7 1.7 10.0 18.0 12.7  34.7 48.7 43.8 45.7 51.7 55.3 36.8 45.7 34.0 41.7 26.5 39.5 36.2 29.7 29.0 30.0 33.7 23.5 1.5 9.2 12.3 14.3 44.5  0.5  3.7  2.8  6.9  2•2  44  O  io  IO  l/o  *<>  "  6  IPC i n pounds per acre Figure 6 - E f f e c t of Applications of,Various Amounts of 2,4-D  and Mixtures of 2,4-D  and IPC on the  weight of Clippings from Creeping Red Fescue (Festuca rubra) as at Sept. 30, {M.S.D. at .05 l e v e l » 0.5)  1949.  45  o  'o  zo  Y&  vo  IPC i n pounds per acre Figure 7 - E f f e c t of Applications of Various Amounts of and Mixtures of 2,4-D  2,4-D  and IPC on the weight of  Clippings from Perennial Rye Grass (Lolium perenne) as at Sept. 30,  1949.  (M.S.D. at .05 l e v e l =  3.7)  46.  O  '0  2c  fa  To  *>"  IPC i n pounds per acre Figure 8 - E f f e c t of Applications of Various Amounts of 2,4-D and Mixtures of 2,4-D and IPC on the weight of Clippings from Orohard Grass (Dactylis glomerata) as at Sept. 30, 1949. (M.S.D.c at .05 l e v e l -  2.8)  47.  IPC i n pounds per acre Figure 9 - E f f e c t of Applications of Various Amounts of 2,4-D  and Mixtures of 2,4-D  and IPC on the  weight of Clippings from Hog M i l l e t (Panicum miliaceum), as at Sept. 30,  1949.  M.S.D. at .05 l e v e l =  6.9)  48. was d i r e c t l y related to the concentration of IPC*  However,  as with the fescue there i s l i t t l e difference between the plots sprayed with mixtures containing 40, 60 or.80 pounds of IPC. Orchard grass (Dactylis glomerata) An examination of table 4 and figure 8, shows that § pound 2,4-D increased the amount of grass s l i g h t l y as compared t o the unsprayed p l o t .  There i s no s i g n i f i c a n t  difference between treatment 7 (1 pound 2,4-D) and the unsprayed p l o t s .  However, 2 pound 2,4-D per acre gave a  s i g n i f i c a n t reduction i n the amount of grass present as compared t o the unsprayed p l o t s .  As i n the above two grasses  the addition of IPC oaused a decrease i n the amount of grass present.  I t i s also noted that there i s no s i g n i f i c a n t  difference between the treatments containing £ pound 2,4-D plus 40, 60 or 80 pounds IPC; 1 pound 2,4-D plus 40, 60 or 80 pounds IPC; or 2 pounds 2,4-D plus 40, 60, or 80 pounds IPC. Hog m i l l e t (Panioum miliaoeum) On examination of table 4 and figure 9 i t w i l l be noted that the i ,  1 and 2 pounds 2,4-D per acre a l l oaused a  s i g n i f i c a n t reduction i n the m i l l e t as compared to the unsprayed p l o t s .  However, there i s no s i g n i f i c a n t difference  between the three concentrations of 2,4-D.  Again as pointed  out previously r e : figure 3 (height of m i l l e t ) the treatments containing -§• pound and 1 pound of 2,4-D plus 10 pounds IPC  49. per acre caused an increase i n the weight of clippings as compared to the untreated p l o t s , however, t h i s increase i s not s i g n i f i c a n t l y greater than the unsprayed p l o t s .  It i s  also noted that plots treated with a mixture of h pound 2,4-D plus IPC tend to increase t n weight of clippings with concentration of IPC, t h i s r e s u l t i s i n d i r e c t reverse t o that obtained by the same mixtures with the other grasses. The resuits of p l o t s treated with 1 pound 2,4-D per acre plus IPC have no d e f i n i t e trend and with the exception of 60 pounds IPC no mixture i s better than the 1 pound of 2,4-D alone.  The treatments containing 2 pounds 2,4-D a l l gave a  s i g n i f i c a n t reduction i n weight of c l i p p i n g s .  There i s no  s i g n i f i c a n t difference between 2 pounds 2,4-D alone and 2 pounds 2,4-D plus 10, 20, 40 and 60 pounds IPC per acre. There i s , however, a s i g n i f i c a n t difference between 2 pounds 2,4-D alone and 2 pounds 2,4-D plus 80 pounds IPC per acre. E f f e c t on Strawberry Plants The treatments consisting of 2,4-D or of 2,4-D plus IPC caused no apparent detrimental effects t o the strawberry plants.  However, treatments 19 and 20 (Pentaehlorophenol)  caused excess burning and f i n a l l y death to the plants. Treatments 21 and 22 (Aero cyanate) caused marginal burning of the leaves and f i n a l l y complete browning, but the crowns were not k i l l e d as i n the pentaehlorophenol treatments.  See  figure 4 showing the e f f e c t s of treatments 19, 21 and 23 on the strawberry plants and grasses.  50. DISCUSSION it  This experiment was designed to study the various combinations and concentrations of 2,4-D, IPC and other promising herbicides on several kinds of newly germinated gravs  seedlings and B r i t i s h Sovereign strawberry plants i n  the greenhouse. An examination of f i g u r e 3 and table 3 om the e f f e c t s of 2,4-D  and various mixtures of 2,4-D  and IPC on  the height of Hog M i l l e t twelve days a f t e r the a p p l i c a t i o n of the treatments shows that 2,4-D  alone caused a s i g n i f i c a n t  decrease i n height and that t h i s stunting increased with Increase i n the concentration of 2,4-D.  At t h i s time a l l  the grasses present (Creeping red fescue, Perennial rye grass Orchard grass) appeared to respond i n the same manner. M i t c h e l l and Earth (15) obtained somewhat similar results.  They found that the growth of well-established  creeping bentgrass was depressed by spraying with a water mixture of 2,4-D  at rates equivalent to £, l£, 2 i and 3 pound  of the acid per acre.  Plants sprayed at rates equivalent to  £ and l£ pounds per acre recovered during a period of  3-4  months following treatment. Further from table 3 and figure 3 i t i s noted that the addition of only 10 pounds of IPC i n a l l oases caused an increase i n the height of the grass over those treated with 2,4-D  alone.  I t would appear at t h i s point that 10 pounds of  IPC had a s l i g h t i n a c t i v a t i n g effect upon the 2,4-D.  51. However,  even t h i s mixture resulted i n a s i g n i f i c a n t suppression of growth of the grass as compared to the untreated p l o t s . Almost 20 pounds of IPC are required before t h i s i n a c t i v a t i n g effect i s overcome and the mixture of 2,4-D and IPC i s made more e f f e c t i v e than the 2,4-D alone.  With each a d d i t i o n a l  increase i n IPC stunting i s further increased.  The mixture  containing 2 pounds 2,4-D and 80 pounds of IPC per acre was s i g n i f i c a n t l y better than any of the other 2,4-D and 2,4-D plus IPC mixtures.  I t i s i n t e r e s t i n g to note that there i s  no s i g n i f i c a n t difference between treatments 6, 11, 12, 15, 16 and 17 ( i . e . h pound 2,4-D plus 60 pounds IPC, 1 pound 2,4-D plus 60 pounds IPC, 1 pound 2,4-D plus 80 pounds IPC, 2 pounds 2,4-D plus 20 pounds IPC, 2 pounds 2,4-D plus 40 pounds IPC, and 2 pounds 2,4-D plus 60 pounds IPC) and these treatments are second best.  There appears to be a tendency  towards d e f i n i t e optimum combinations of 2,4-D and IPC. From these r e s u l t s and using the above combinations the following generality appears f e a s i b l e : beginning with % pound 2,4-D plus 80 pounds IPC we may say that as the IPC i s reduced by 20 pounds i t i s necessary to double the amount of 2,4-D to obtain the same effects i . e . , X pound 2,4-D plus 60 pounds IPC or 2 pounds 2,4-D plus 40 pounds IPC gives the same e f f e c t s as h pound 2,4-D plus 80 pounds IPC.  Therefore,  i t would appear that both chemicals have a supplementing value for one another i n the depressing of grass growth.  Such a  relationship i s of value f o r i t means that the h e r b i o i d a l  52.  effect of 2,4-D can be supplemented with IPC and at the same time reduce the i n j u r i o u s effeot of 2,4-D on crop plants. On examination of table 4 and figures 6, 7, 8 and 9, on the weight of clippings of the various grasses one month after treatments were applied i t i s r e a d i l y seen that the various grasses responded somewhat d i f f e r e n t l y from one another.  An a p p l i c a t i o n of £ pound of 2,4-D per acre to  Creeping red fescue caused a s i g n i f i c a n t increase i n weight of clippings over the unsprayed p l o t .  I t took 2 pounds of  2,4-D to s i g n i f i c a n t l y decrease the weight.  Both the £ pound  2,4-D and the 1 pound 2,4-D per acre to perennial rye grass caused very s i g n i f i c a n t increases i n weight of clippings over the unsprayed p l o t .  The 2 pounds 2,4-D was not s i g n i f i c a n t l y  d i f f e r e n t from the unsprayed p l o t whereas i n the orchard grass there was no s i g n i f i c a n t differences i n weight of clippings between the p l o t s sprayed with £ pound 2,4-D or 1 pound 2,4-D and the unsprayed p l o t .  But 2 pounds of 2,4-D  reduced the weight of clippings s i g n i f i c a n t l y .  In the case  of the m i l l e t i t i s noted that the § pound, 1 pound and 2 pounds of 2,4-D per acre a l l caused a s i g n i f i c a n t reduction i n the c l i p p i n g weight of m i l l e t as compared t o the unsprayed plots.  The increases i n growth over the unsprayed plots, as  noted i n creeping red fescue and perennial rye grass when lesser amounts of 2,4-D are used, may be due i n part to the elimination of weed competition i n the sprayed p l o t s .  53. M i t c h e l l and Marth (15) sprayed a water mixture containing 0.1$ 2,4-D and 0.5% Carbowax 1500 at rates equivalent to £, 1&, 2£ and 3 pounds of acid per acre on potted s o i l i n which Kentucky blue-grass, redtop, and creeping red  fescue grass seeds had been planted.  The treatments  reduced the number of redtop seedlings that appeared by 28, 83, 83, and 95$ respectively.  A s l i g h t l y greater number of fescue  seedlings emerged from the s o i l sprayed at rates equivalent to £ and l£ pounds of a c i d per acre, while the heavier a p p l i c a tions reduced emergence by 10 and 17%, i n comparison with the unsprayed s o i l .  Fourteen per cent more bluegrass seedlings  appeared i n the s o i l sprayed a t a rate equivalent to £ of a pound per acre than emerged i n the unsprayed s o i l .  The  heavier applications reduced the emergence of bluegrass by as much as 32% below that of the untreated  soil.  In general the addition of IPC to the p l o t s containing the perennial grasses reduced the weight o f c l i p p i n g s and t h i s reduction increased with concentration of IPC.  From  figures 6, 7, 8 and 9 i t i s seen that the curves tend to l e v e l out from 40 pounds of IPC on.  Thus 40 pounds of IPC i n the  mix appears to be the most p r a c t i c a l ;  i t depresses the  growth of grass almost as completely as do the higher concentrations of 60 and 80 pounds per acre.  Also, i t must be  mentioned at t h i s point that concentrations of IPC over 40 pounds per acre at the usual rates of a p p l i c a t i o n tend to precipitate and clog the spray nozzle.  Lachman (14) also had  54. the same trouble he states that the s o l u b i l i t y of IPC i s only about 250 p.p.m. and i s only attained a f t e r vigorous or s t i r r i n g . Carbowax 1500,  shaking  He has found that IPC i s r e a d i l y soluble i n ethyl alcohol, isopropyl alcohol, acetone,  and  g l a c i a l acetic acid and as cosolvents thSse oompounds are helpful i n a t t a i n i n g the maximum concentration i n a shorter time.  However, i n concentrations greater than 250 p.p.m. the  IPC i s precipitated upon the a d d i t i o n of water to the IPC and solvent.  Doxey (7) studying the e f f e c t of IPC on mitosis  i n rye and onion found that 200 p.p.m. solution c l o s e l y approached saturation. The chemical companies have recognised t h i s problem and are developing more soluble forms of IPC. From table 4 and f i g u r e 9 i t i s seen that the response  of annual hog m i l l e t to 2,4-D  and mixture of  2,4-D  and IPC i s quite d i f f e r e n t from that obtained i n the perennial grasses.  As mentioned e a r l i e r , even the l e s s e r  concentrations of 2,4-D  alone s i g n i f i c a n t l y depressed  growth i n comparison with the unsprayed p l o t .  the  There was  no  s i g n i f i c a n t difference between the three concentrations of 2,4-D. Again, i n the case of £ pound 2,4-D  and 1 pound  2,4-D  the a d d i t i o n of 10 pounds IPC appears to inactivate the 2,4-D. The m i l l e t appeared to more or l e s s recover from the mixtures of 2,4-D  and IPC, e s p e c i a l l y was t h i s true with the l e s s e r  amounts of 2,4-D. In general though, as the concentration of the 2,4-D growth.  was increased the greater was the depression of The 2,4-D  at the concentration of 2 pounds per acre  55. i s only made s l i g h t l y more e f f e c t i v e with the addition of IPC. Although these plots are s i g n i f i c a n t l y d i f f e r e n t from the unsprayed p l o t s , the r e s u l t s are not too s a t i s f a c t o r y since the control i s only about 50% as compared to 80 and 90% cont r o l obtained with the perennial grasses. Differences i n the s e n s i t i v i t y of grasses to IPC were also noted by M i t c h e l l and Marth (16) who found that when crabgrass and bluegrass seeds were planted i n s o i l containing known amounts of IPC that emergence of bluegrass seedlings was greatly reduced i n s o i l that contained as l i t t l e as 3.4 mg. of IPC per pound of s o i l , while the emergence percentage f o r crab grass ( D i g i t a r i a sanguinalis) increased with the a d d i t i o n of IPC to the s o i l .  Although the emergence  percentage of p a r t i a l l y dormant crab grass was apparently stimulated by IPC i n t h i s experiment, the subsequent growth of the plants was greatly i n h i b i t e d . M i t c h e l l and Marth (16) studied the s e n s i t i v i t y of several other monocotyledonous plants and have constructed a table showing the s e n s i t i v i t y of these plants to IPC. table has been reproduced here (see table 5).  This  An  examination of table 5 shows that rye grass, red top, and orchard grass are a l l very sensitive to IPC while m i l l e t i s only s l i g h t l y s e n s i t i v e .  Thus these r e s u l t s atie confirmed  by those obtained by the writer. Th<y further add that the effeot of IPC when applied at the rates of 30-60 pounds per acre on the growth of less  56. sensitive species (sorghum, Sudan grass) was prolonged so that plants grew above the surface of the s o i l f o r a distance of 1-3 cm. and then f a i l e d to develop f u r t h e r .  Microscopic  examination revealed that these plants remained a l i v e but stunted a f t e r appearing above the surface.  These stunted  plants f a i l e d t o produce seeds. As an Experiment 1, 2,4-D and 2,4-D plus IPC apparently did not cause any detrimental e f f e o t s t o the strawberry plants.  Such was not the case with  and potassium cyanate.  Pentaehlorophenol  pentaehlorophenol caused excess  burning and death while cyanate caused considerable marginal browning of the leaves though i t did not appear to harm the strawberry crown.  Therefore though these chemicals gave  excellent control of the grass they are, however, of no use as weedicides for strawberries during the growing season.  CONCLUSIONS  The r e s u l t s of t h i s experiment which was l a i d out i n the greenhouse using mixtures of three l e v e l s of 2,4-D and f i v e l e v e l s of IPC, two l e v e l s PCP and two l e v e l s of cyanate on four species of grass and B r i t i s h Sovereign strawberries shows that: 1.  There i s considerable difference i n s e n s i t i v i t y between  the different species of grass to 2,4-D and IPC.  57.  Table 5 - S e n s i t i v i t y of some Monoootyledonous Plants to IPC when Applied to the S o i l at a Rate Equivalent t o 5 pounds per acre, (after M i t c h e l l and Marth)  Plant  Emergence Index  Plant  Emergence Index  Fescue  0  Bermuda grass  130  Amber sorghum  99  Ryegrass  0  Sudan grass  88  Red top  0  Millet  86  Timothy  0  Bluegrass  4  Orchard grass  0  Barley  0  Quack grass  0  values represent r e l a t i v e emergence from seeds planted i n treated s o i l calculated on the basis that emergence i n comparable untreated s o i l equalled 100 per cent.  58. 2.  A mixture of 2 pounds of 2,4-D  and 40 pounds of IPC per  acre gives very s a t i s f a c t o r y control of perennial rye grass, Creeping red fescue, and orchard grass ( a l l perennial grasses) but not of the annual hog m i l l e t . 3.  Mixtures of 2 pounds of 2,4-D  and up to 80 pounds of IPC  per acre apparently did not cause any detrimental e f f e c t s to the B r i t i s h Sovereign strawberry plants. 4.  Pentachlorophenate and potassium cyanate are not suitable  herbicides f o r strawberries during the growing season. pentachlorophenate  The  caused extreme burning and f i n a l l y death.  The cyanate, however, only caused marginal to severe browning, but apparently did not i n j u r e the crown and, therefore, may be of value as an a f t e r harvest or dormant spray.  EXPERIMENT 7  Object;To-study the e f f e c t of various concentrations of 2,4-D  and 2,4-D  supplemented with IPC on both weeds and  B r i t i s h Sovereign strawberry plants under f i e l d conditions. Materials and Methods; Plots 18£* x 21* were l a i d out i n three randomized blocks.  Strawberries were planted i n rows 3g feet apart  and 18 inches between plants. Young, c e r t i f i e d , B r i t i s h Sovereign plants were planted out i n the spring of 1949.  59.  The treatments were as follows: 1.  1 l b . 2,4-D per acre.  2.  2 l b s . 2,4-D per acre.  3.  3 l b s . 2,4-D per acre.  4.  4 l b s . 2,4-D per acre.  5.  2 l b s . 2,4-D plus 40 l b s . IPC per acre.  6.  Hand weeded.  Note: The amounts of 2,4-D refer to acid equivalent. Treatments were to have been applied to the young plants as weed growth dictated possibly three or four times during the season. However, the f i r s t a p p l i c a t i o n was delayed due to r a i n y weather u n t i l July 2, and consequently the i  weeds were 7-8 inches t a l l and very dense. Both a knapsack sprayer and a Hudson sprayer were used i n applying the f i r s t a p p l i c a t i o n of sprays.  See figure  10 f o r general layout of experiment and method of applying sprays.  Temperature recorded was 68.5°P.  S o i l samples were  taken of the area to be sprayed before the f i r s t a p p l i c a t i o n . The results of the analysis appear i n table 6.  General  notes,  measurements and photographs were taken p e r i o d i c a l l y following the applications of treatments on the following: 1. Weed control, e f f e c t s on various species noted. 2. E f f e c t s on strawberry plants noted.  Table 6 - S o i l Analysis of Strawberry Plots Obtained by Spurway Chemical Tests,  Ppm.  Nitrates  Lb. a/6 i n .  Remarks  10  80  Phosphorus  k  4  Low  Potassium  3  24  Low  40  320  Low  1  8  Low  Calcium Magnesium  Reaction  pH 6.0  Mediumi  61. 3,  Plant growth measured by l e a f counts, runner counts,  and observation r a t i n g s . F e r t i l i z e r (4-10-10) was broadcasted alongside of the rows on July 4 at 700 pounds per acre.  A second  application of f e r t i l i z e r was made on August 1, at the same rate. etc.,  On July 29, after notes had been taken on weed control, a l l plots were hoed and raked o f f . Leaf counts and  growth ratings were taken on September 1.  Second a p p l i c a t i o n  of sprays was applied on September 1, with a knapsack sprayer. A l l materials were applied a t the rate of 100 gallons of solution per acre.  Temperature recorded a t t h i s time was 78°F.  RESULTS  Control of Various Weed Species: The various weed species present i n the strawberry plots and t h e i r approximate percentage at time of spraying were as f o l l o w s : Polygonum P e r s i c a r i a L. (Lady's Thunb) .. 60-65%. Chenopodium album L. (Lamb's Quarters) .. 10%. Spergula arvensis L. (Corn Spurrey)  10%.  Eohinochloa c r u s g a l l i (L) Beaux (Wild M i l l e t ) ..10%. A l l other weeds combined made l e s s than 10 per cent of the t o t a l weed population.  They are l i s t e d below:  62. Roripa p o l u s t r l a (L) Bess. (Yellow Cress) Amaranthus retroflexus L. (Red-root Pigweed) Convolvulus arvensis L. ( F i e l d Bindweed) Agropyron repens (L) Beauv. (Couch Grass) Rapjranus Raphanistrum L. (Wild Radish) Rumex A c e t o s e l l a L. (Sheep Sorrel) Gnaphalium uliginosum (Cudweed) Following are extracts of notes taken on the e f f e c t of the treatments on the weeds: July 2 - Curling of leaves of weeds noticeable within an hour a f t e r spraying even with 1 pound per acre of 2,4-D. July 4 ( 2 flays following sprays) - A l l weeds showing t y p i c a l 2,4-D  i n j u r y such as  c u r l i n g of leaves, twisting and curling of petioles. Treatment 5 (2 l b . 2,4-D  plus IPC)  - no effect of IPC on grass as yet - 2,4-D  injury as i n other p l o t s .  July 8 (6 days following sprays) Treatment 5 (2 l b s . 2,4-D  plus IPC)  - Weeds browning more than i n other p l o t s . - Wild r a d i s h p r a c t i c a l l y dead.  63. - F i e l d Bindweed - browned. - Lady's Thumb - browned. Treatment 4 (4 l b s . 2,4-D) - Some browning, but not near as noticeable as Treatment  5 —  more of a yellowing.  Treatments 1. 2. & 5 (1, 2 & 3 l b s . 2,4-D) - Damage t o weeds appears to be progressively less with lower concentrations. July 28 (26 days following sprays) General observations on the effeot of the sprays on broad-leaved weeds and grasses were recorded numerically as shown i n table 7. Effeot on Strawberry Plants Extracts of notes taken on the e f f e c t of the various treatments on the strawberry plants follows: July 4 (2 days following sprays) - In a l l plots the strawberry plants are exhibiting c u r l i n g of leaves, twisting and c u r l i n g of p e t i o l e s to some degree (see figure 11). July 8 Treatment  4 (4 l b s . 2,4-D per acre)  - Strawberry plants at present appear poorest of lot. - Curling and crisping of leaves.  64. Table 7 - E f f e c t of the Various Treatments upon the Broad-Leaved Weeds and Grasses as at July 28, 1949. TREATMENTS 2 3  1 (1 l b . 2,4-D)  . 1  B  & lb. 3,4-D) B  G  4  (3 l b . 2,4-D) B  5  (4 l b . 2,4-D)  (2 l b . 2, 4-D -40 l b . IPC)  G  B  G  B  G  BLOCK I  2  1.5  4  2  4.5  2  5  1  5  2  II  3  2  4  1  3  2  5  3  5  2  III  3  1  4  2  5  3  5  3  4  2  Sum.  8  4.5  12  5  12.5  7  15  7  14  6  Legend: B —  Broad-leaved weeds.  G —  Grass  Rating —  I  s  n i l control  5 = complete control  65. Condition of Strawberry Plants: Leaf counts were made on ten plants per plot making 30 plants per treatment. p o s i t i o n i n each p l o t .  Plants were selected from the same The r e s u l t s obtained were of no value  since the variations within plots was great also the l e a f count gave no indication as to the size of l e a f .  For example,  many plants were found to have a large number of leaves but i n many cases the leaves were small.,; while other plants had fewer leaves, but very frequently these leaves were l a r g e r . Other methods were t r i e d such as the spread of the plant, height of plant, production of runners, etc., but a l l were found unsatisfactory since none of these methods or combinations of these methods gave a complete picture of the true condition of the plants.  Thus i t was decided that the best  measure of the condition of the strawberry plants was to rate the plants from observation.  The writer obtained the  cooperation of the H o r t i c u l t u r i s t and the Head Gardener of the Dominion Experimental Farm, Agassiz, B.C., plants.  i n r a t i n g the  Both gentlemen rated the plants independently and  the r e s u l t s obtained are summarized i n table 8. Weed Control: General observations were again made on October  30,  1949 on the e f f e c t of the treatments on weeds and as before a numerical r a t i n g f o r each treatment was recorded as shown i n table 9^  The weeds at t h i s time were mainly grasses such  as oats, m i l l e t , Kentucky blue, and couch grass.  66  Figure 10 - Showing a General View of the Layout o f Experiment V and the Method of Spraying with a Knapsack Sprayer.  67  I  Figure 11 - Showing the E f f e c t s of 2,4-D  upon the Leaves  and P e t i o l e s of B r i t i s h Sovereign StrawberryPlants.  The centre l e a f shows the "burning"  or " c r i s p i n g " e f f e c t caused by 4 l b s . and over of 2,4-D  per acre.  68. Table 8 - The condition of the Strawberry Plants as at September 1, 1949.  TREATMENTS  . 1.  2.  (1 l b . 2,4-D)  3.  (2 l b . 2,4-D)  A  B  A  B  1  4  4  II  5  4  4  III  5  4*  4  4.  (3 l b . 2,4-D)  A  (4 l b . 2,4-D)  B  i  A  B  5. (2 l b . 2,4-D • 4G l b . IPC A  B  2#  3# 4  BLOCK  Sum. 14  4  4  12* 12  +  +  3  2  3  3  3  3  3  3  3"  4  3  3  3*  2  2  4  8"  10  10  9  8  +  8  +  4  +  11  Legend; Rating:  1  to 5  (poorest to best condition) (hand-weeded plots = 5) A. By Head Gardener. B. By H o r t i c u l t u r i s t . # D i f f i c u l t to assess condition of plants i n t h i s plot since many of the plants appeared to be damaged by other than sprays (carelessness of a l a b o r e r ) .  69. Table 9 - E f f e c t of the Various Treatments upon the Weeds as at October 30, 1949.  TREATMENTS  -  1.  8.  3.  4.  5.  6.  (1 l b . 2,4-D)  (8 l b . 8,4-D)  (3 l b . 8.4-D)  (4 l b . 8,4-D)  (5 lb.8,4-D +40 lb.IPC)  (Check)  BLOCK I  8  3  3  8  4  5  II  1  1~  8  4  5  4  III  1  1  3  3"  5  5  Sum.  4  5"  8  9"  14  14  Legend; Rating:  1  to  5  (poor to good oontrol)  70  DISCUSSION  This experiment was designed to study the effect of various concentrations of 2,4-D and 2,4-D supplemented  with  IPC on both weeds and B r i t i s h Sovereign strawberry plants under f i e l d conditions.  The treatments used i n t h i s experi-  ment were determined i n part from the r e s u l t s of the four preceding experiments. Weed Control: From the r e s u l t s i t i s noted that c u r l i n g of leaves was apparent on the broad-leaved weeds within an hour after spraying even i n those plots sprayed with 1 pound per acre.  Within two days a l l the broad-leaved weeds present were  showing t y p i c a l 2,4-D injury such as curling of the leaves, twisting and curling of the p e t i o l e s . Harvey and Robbins  (11) state that the f i r s t notice-  able effect of 2,4-D i s i n the stems and leaves which become twisted and bent, with the leaves showing varying epinastic conditions.  The stems and leaves may remain green f o r several  weeks after treatment before dying, or they may recover i f the treatment was l i g h t .  Carlson (4) reporting on the control of  weeds i n strawberry plantings by the use of 2,4-D states that many weeds showed deformative e f f e c t s at the low concentrations of 400 and 800 parts per m i l l i o n and yellow dock, dandelion and f i e l d v i o l e t s were k i l l e d .  Canada t h i s t l e  71. was injured severely a t these concentrations recovered.  but slowly  A l s i k e clover was not severely affected at the  low concentrations  (400 to 800 parts per m i l l i o n ) , but was  k i l l e d at 2,000 t o 2,400 parts per m i l l i o n .  According to  Warren and Hernandez (20) 2,4-D at the rates of 2, 3 and 4 pounds of the a c i d equivalent per acre gave generally good control of pigweed, lambsquarters, purslane,  shepherds-purse,  witchgrass and f o x t a i l for a period of 4 to 6 weeks, but annual smartweeds were only s l i g h t l y affected.  The weed  Committee of the B.C. Agronomists' Association (22) states that weed species vary considerably i n t h e i r r e a c t i o n to 2,4-D, ranging from very susceptible t o highly r e s i s t a n t . Furthermore the stage of growth i s an important f a c t o r .  A species of weed  may be highly susceptible at one stage while at a l a t e r stage i t may become quite r e s i s t a n t . S o i l and c l i m a t i c conditions also give marked differences i n the e f f e c t of 2,4-D on weeds. Most annual weeds, other than those belonging to the grass family, are generally susceptible at the young succulent  stage  of growth, while many become quite r e s i s t a n t at the flowering or seed stage.  Perennial weeds show greater v a r i a t i o n i n  s u s c e p t i b i l i t y to 2,4-D than do annual weeds.  In general, the  perennial weeds require somewhat higher rates of a p p l i c a t i o n of 2,4-D than do the annuals.  Susceptible perennial weeds  respond more r e a d i l y to the action of 2,4-D from bud stage to flower stage rather than at e a r l i e r stages of growth.  72. Six days a f t e r treatment the weeds i n the p l o t s sprayed with a mixture of 2,4-D  and IPC were showing the  greatest injury with many weeds p r a c t i c a l l y dead. weeds sprayed with 4 pounds of 2,4-D injury.  Even the  were not showing as much  This would appear to he further evidence of the  supplementing value of these chemicals f o r one another as mentioned i n the preceding experiment. An examination of table 7 shows that the control of the broad-leaved weeds increased with increase i n the concent r a t i o n of 2,4-D  u n t i l at 4 pounds per acre the broad-leaved  weed control i s 100 per cent.  However, i t w i l l be noted that  t h i s improvement i n weed control i s not i n proportion to the increase i n amount of 2,4-D  applied.  These r e s u l t s are i n  agreement with those obtained by Warren  and Hernandez (20) i n  weed control i n certain vegetable crops with s o i l applications of 2,4-D. 2,4-D  Of p a r t i c u l a r interest i s treatment 5 (2 l b s .  plus 40 l b s . IPC) which shows a broad-leaved weed control  of 93.9 per cent.  Again, further evidence of supplementing  value of these chemicals. The control of grass at t h i s time was not too encouraging as can be seen from table 7. improved with increase i n 2,4-D  Control of grass  but as with the broad-leaved  weeds t h i s improvement i s not i n proportion to the increase i n amount of 2,4-D  applied.  I t w i l l be noted that 2 and 3  pounds of 2,4-D  gave the same r e s u l t .  the mixture of 2 pounds of 2,4-D  The p l o t s sprayed with  and 40 pounds IPC showed a  73. s l i g h t improvement i n grass control over plots treated with 2 pounds of 2,4-D alone, but the improvement was s l i g h t l y less than that obtained by use of 3 and 4 pounds of 2,4-D alone.  However, since much of the grass present i n the p l o t s  at t h i s time was annual hog m i l l e t , such r e s u l t s are as expected i n view of the r e s u l t s obtained with t h i s grass i n Experiment  IV.  This provides further evidence of the high  degree of resistance of annual hog m i l l e t t o IPC i n comparison with the other grasses present. Now an examination of table 9, on the effect of the various treatments upon the weeds as at October 30, two months following the second a p p l i c a t i o n of treatments, shows that weed control improved with increase i n the concentrat i o n of 2,4-D.  The plots treated with 2 pounds of 2,4-D  plus 40 pounds of IPC show extremely good control of the weeds.  I t i s also noted that the weeds present i n the p l o t s •  at t h i s time were mainly grasses. were p r a c t i c a l l y extinct.  The broad-leaved weeds  Treatment 5 made a much better  showing t h i s time; possibly because the broad-leaved weeds and grasses were much more immature at the time of the second spraying than the weeds were f o r the f i r s t spraying. I t must be remembered that the plots were cleaned up and weeds raked o f f a f t e r complete r e s u l t s were recorded on the f i r s t spraying.  According to Freed (9) IPC acts p r i n c i p a l l y  as a mitotic poison (prevention of c e l l d i v i s i o n ) , which means i t i s most e f f e c t i v e during early growth.  Another  74. explanation f o r the disappointing r e s u l t s obtained from the f i r s t spraying i s the p o s s i b i l i t y that the IPC was  inactivated  by the excess moisture i n the s o i l at the time of spraying. As mentioned e a r l i e r , there had been considerable rainy weather before the f i r s t sprays were applied.  According to  M i t c h e l l and Marth (16) IPC i s inactivated i n the presence of moist, f e r t i l e s o i l as i s the case with 2,4-D. The E f f e c t on Strawberry Plants: Two days following a p p l i c a t i o n of the sprays t y p i c a l 2,4-D  i n j u r y was noted on the strawberry plants i n  a l l treated p l o t s .  This i n j u r y was the same as described  previously for the broad-leaved weeds; namely, c u r l i n g of leaves and t w i s t i n g and c u r l i n g of the p e t i o l e s . l a t e r the plants sprayed with 4 pounds of 2,4-D much more extreme 2,4-D  injury.  Four days showed a  The leaves had extreme  c u r l i n g and were becoming c r i s p . Carlson (4) having sprayed Premier strawberries with 1000 parts per m i l l i o n of 2,4-D weeks after a p p l i c a t i o n of 2,4-D  reported that about  two  the strawberry plants i n  the second-year planting took on a darker green colour, and younger a c t i v e l y growing leaves showed twisting of the petioles.  The larger plants showed no deformative e f f e c t .  The spring planting which was producing runners showed similar responses.  There was some i n d i c a t i o n of c u r l i n g  of the young tender shoots but t h i s was of short duration.  75. In the same paper Carlson reports on another experiment i n which he used various concentrations of 2,4-D after harvest and found that the low concentrations 400 and 800 parts per m i l l i o n had no e f f e c t on the strawberry plants.  Concentra-  tions of 1200, 1600 and 2000 parts per m i l l i o n resulted i n s l i g h t to moderate twisting of the strawberry p e t i o l e s , and at 2400 parts per m i l l i o n the petioles were badly twisted. The deformative e f f e c t s caused by the higher concentrations soon disappeared from the strawberry plants and a f t e r 4 to 5 weeks they appeared normal.  He further states that when  flowers of the everbearing v a r i e t i e s were h i t with the spray small and misshapen f r u i t s were produced. Many methods were t r i e d i n an attempt to f i n d an accurate estimation of the condition of the strawberry plants. But as pointed out i n the r e s u l t s such measurements as leaf counts, spread of plant, production of runners, etc., either singly or i n combination l e f t much to be desired.  Observa-  t i o n ratings appeared to be the best method of recording the condition of the strawberry plants.  These ratings are  summarized i n table 8 and an examination of t h i s t a b l e shows that i n a l l treated plots the strawberry plants were l e s s vigorous than i n the hand-weeded p l o t s .  The vigour decreased  as the concentration of 2,4-D was increased. from previous experiments,  As expected  the IPC apparently d i d not a f f e c t  the strawberry plants to any appreciable degree.  I t would  appear from these r e s u l t s that three or four pounds of 2,4-D  76.  per acre i s too much f o r B r i t i s h Sovereign strawberry plants. This injurious effect was much l e s s with the lower concentrations of 2,4-D.  I t must be appreciated that t h i s loss i n  vigour i s not necessarily due e n t i r e l y to the 2,4-D, but i n part, at l e a s t , some loss would be due to competition with weeds.  For i t must be remembered that due to r a i n y weather  the weeds were allowed to become t a l l and dense before sprays were applied.  Further these herbicides required considerable  time to a f f e c t the more mature annual weeds.  During t h i s  time the weeds were s t i l l competing with the strawberry plants While, on the other hand, i n the hand-weeded p l o t s the weeds were removed immediately.  Thus, the importance of applying  the herbicides when the weeds are small and succulent.  CONCLUSIONS  Six treatments (2,4-D and 2,4-D plus IPC) were l a i d out i n three replicates on a maiden B r i t i s h Sovereign strawberry plantation, and 1, 2, 3 and 4 pounds of 2,4-D per acre and 2 pounds of 2,4-D plus 40 pounds of IPC per acre were the spray treatments compared with a hand-weeded check. I t was found that up to 2 pounds of 2,4-D per acre d i d not . seriously damage strawberry plants and gave s a t i s f a c t o r y control of both broad-leaved weeds and grasses.  A l l plots  treated with herbicides resulted i n s l i g h t l y less vigorous strawberry plants than the hand-weeded check.  I t was  77. explained that t h i s decrease i n vigour was a r e s u l t , i n part, at l e a s t , of allowing the weeds to become t a l l and  very  dense before applying the sprays (unavoidable i n t h i s experiment due to weather conditions).  Thus these weeds  oompeted with the strawberry plants for a considerable time after sprays were applied while i n the hand-weeded p l o t s the weeds were removed Immediately. pounds of 2,4-D  I t i s appreciated that 2  and 40 pounds of IPC per adre w i l l not be  required f o r weed control i n a l l strawberry plantations. The amounts to be used w i l l depend upon the age and species of weeds present.  In t h i s experiment i t w i l l be remembered that  60 - 65% of the t o t a l weed population consisted of Lady's thumb (Polygonum P e r s i c a r i a L.) which i s very r e s i s t a n t to 2,4-D. Also wild m i l l e t (Echinochloa c r u s g a l l l L. Beaux) made up 10% of the t o t a l weed population and t h i s grass shows considerable resistance to IPC.  In addition i t must be  pointed out that there are many new formulations of IPC coming on the market which are e f f e c t i v e at much lower concentrations than the formulation used i n t h i s experiment. Of the herbioides a v a i l a b l e to-day there appears to be no glose r i v a l f o r the mixture of 2,4-D  and IPC as a seleotive  herbicide for strawberries. Under conditions of t h i s experiment a mixture of up to 2 pounds of 2,4-D  plus 40 pounds of IPC can be s a f e l y  recommended for the deweeding o f B r i t i s h Sovereign strawberry plantations, provided i t i s not used when the plants are i n blossom.  78. SUMMARY  Information on the use of herbicides for weed control i n strawberries i s l i m i t e d , but grower interest has increased to the point where recommendations f o r safe usage are needed.  I t has been shown that strawberry v a r i e t a l  responses to 2,4-D  are wide and therefore i t i s necessary to  determine the concentration of 2,4-D  suitable for each variety.  Some newer herbicides, toxic to grasses, have recently been introduced which might have a place either alone or i n a mixture with 2,4-D  i n a weed control program f o r strawberries.  With these two points i n mind the following -experiments were conducted on B r i t i s h Sovereign strawberry plants and various grasses at the Dominion Experimental Farm, Agassiz i n 1949. Five experiments i n a l l were carried out with the object of studying the use of selective herbicides on strawberries.  Before laying out a.large,replicated experi-  ment i t was f e l t that (a) the general response of strawberry plants to various herbicides and (b) the e f f e c t of these herbicides on both broad-leaved weeds and grasses should be determined.  Small plots were l a i d out on a three year old  strawberry plantation and subjected to 34 d i f f e r e n t t r e a t ments (Experiment I ) . Similar treatments were applied i n Experiments I I and I I I to newly seeded and established grasses These treatments consisted of d i f f e r e n t concentrations and mixtures of the following:  79.  2,4-dichlorophenoxyacetic acid  (2,4-D)  Sodium salt of t r i c h l o r o a c e t i c acid  (TCA)  Ammonium salt of Isopropyl N-phenyl carbamate (IPC) 2 methyl-4-chlorophenoxyacetic Sodium pentaohlorophenate  acid  (MCP)  (PCP)  Ammonium s a l t of dinitro-O-secondary butyl phenol (DNOSBP/ Potassium  cyanate  Emulsifiable  pentaehlorophenol  E f f e c t on Strawberry Plants IPC at 5 to 80 pounds per acre had no e f f e c t on established of 1000 ppm,  strawberry plants.  2,4-D  at 150 gallons per acre  either alone or with IPC, l e f t the plants normal  a f t e r 2 months although there was  s l i g h t curvature of  p e t i o l e s produced a f t e r 3 weeks.  A l l other treatments either  k i l l e d the strawberry plants or l e f t them i n a very weakened condition.  A mixture of 2,4-D  and IPC appeared promising.  E f f e c t on Grasses As reported by other workers, a l l herbicides but 2,4-D  controlled grasses while 2,4-D  controlled the broad-  leaved weeds.  IPC at 80 pounds per acre i n a spray alone  and with 2,4-D  controlled or seriously stunted the grass  species present. effective.  I t took 4 weeks to become completely  Applied as a dust, 40 pounds per acre gave  complete k i l l of seedling grass mixture.  80. Experiment IV was l a i d out i n the greenhouse with mixtures of three l e v e l s of 2,4-D and f i v e l e v e l s of IPC on four species of grass.  This experiment has shown that 2  pounds of 2,4-D and 40 pounds of IPC gives very s a t i s f a c t o r y control of perennial rye grass, creeping red fescue, and orchard grass ( a l l perennial grasses), hut not of the annual hog m i l l e t .  M i l l e t , fortunately, i s r a r e l y found as a weed,  but was present i n the plots of the experiment In the f i n a l experiment  to follow.  s i x treatments (2,4-D and  2,4-D plus IPC) were l a i d out i n three r e p l i c a t e s on a maiden B r i t i s h Sovereign strawberry plantation.  Treatments  of 1, 2, 3 and 4 pounds of 2,4-D per acre and 2 pounds of 2,4-D plus 40 pounds of IPC per acre were compared with a hand-weeded check.  I t was found that up to 2 pounds of  2,4-D per acre did not seriously damage strawberry plants and gave s a t i s f a c t o r y control of the broad-leaved weeds. A mixture of 2 pounds of 2,4-D and 40 pounds of IPC per acre gave satisfactory control of both broad-leaved weeds and grasses.  A l l p l o t s treated with herbicides resulted  i n s l i g h t l y l e s s vigorous strawberry plants than the handweeded check.  I t was explained that t h i s decrease i n  vigour was a r e s u l t , i n part, at l e a s t , of allowing the weeds to become t a l l and very dense before applying sprays (unavoidable i n t h i s experiment  due to weather conditions).  Thus, these weeds competed with the strawberry plants f o r a considerable time after sprays were applied D 4 i i l e i n the  81. hand-weeded p l o t s the weeds were removed immediately. In general, the conclusions from these experiments are: (1) that the sprays should i f possible be applied when the weeds are small and succulent, e s p e c i a l l y i s t h i s true for annuals;  (2) under conditions of t h i s experiment a  mixture of up to 2 pounds of 2,4-D plus 40 pounds of IPC can be s a f e l y recommended f o r the deweeding of B r i t i s h  Sovereign  strawberry plantations provided i t i s not used when the plants are i n blossom.  83. LITERATURE CITED  1.  Barrons, K.C.,  TCA ... A promising new chemical f o r  grass control. Down to Earth, Dow  Chemical Comp-  any, Midland, Michigan, Vol.4, No.4, 1949, pp 2.  8-9.  Bush R., T a r - O i l weed k i l l e r for strawberry beds. Grower, 1948,  3.  Spring,  Carder, A.C,  30:613.  Control of dandelions i n strawberries by  2.4-D. F i f t h Annual North Central Weed Control Conference Research Report, S p r i n g f i e l d , I l l i n o i s , 1948. 4.  Carlson,R.F.,  Control of weeds i n strawberry plantings  by the use of 2.4-dichlorophenoz:yacetic aoid. Proc. Amer. Soc. Hort. S c i . , W.E. Inc., Geneva, N.T., 5.  Humphrey Press  1947, 49:221-3.  Carlson, R.F. and Moulton, J.E.,  Use of the ammonium  s a l t of triohloroacetate. the sodium s a l t of t r l c h l o r o a c e t a t e . ammonium thiocyanate. and herbicide "PB . W  i n the eradication of grasses.  and the e f f e c t of these chemicals on strawberry and raspberry plants. The Quarterly B u l l e t i n , Michigan State College, East Lansing, 38:413-21.  1948,  83. 6., Davidson, J.H., Weed control i n an established  straw-  berry (Variety Premier) planting with 2.4-diohlorophenoxvacetic a c i d . F i f t h Annual North Central Weed Control Conference Research Report, Springfield, Illinois, 7.  Doxey, D.,  1948.  The effeot of Isopropvl N-phenol  carbamate  on mitosis i n rye (Secale cereale) and onion (Allium cepa). Annals of Botany, New  Series,  v o l . 13, No.51, July 1949, pp. 329-334. 8.  Elder, W.C.,  E l w e l l , H.M.,  and Romshe, F.A.,  Chemical  Control of weeds and brush i n Oklahoma, Oklahoma A g r i c u l t u r a l Experiment Station, Oklahoma A. & M. College, S t i l l w a t e r , B u l l e t i n B-335, June, 1949. 9.  Freed, V., Letter to the writer, from Paul Logue, Phosphate D i v i s i o n , Monsanto Limited, St. Louis, July 7, 1949.  10.  Hance, F.E., Recent developments i n weed onntrol i n sugar cane, Science, Washington, D.C.,  1948,  108:278-9. 11.  Harvey, and Robbins,  2.4-D  as a weed k i l l e r .  College  Agriculture, University of C a l i f o r n i a , Berkeley, C i r c u l a r 133, June, 1947.  84. 12.  Hitchcock, A.E., and Zimmerman, P.W., 2.4-D  A c t i v a t i o n of  by various adjuvants. Boyce Thompson  I n s t i t u t e , 1948, 15:173-93. 13.  K l e i n , L.G.,  Strawberries and 2.4-D. Canadian Grower,  1947, 70:7: 14.  Lachman, W.H.,  8-16.  Some studies using isopropyl N-phenyl  carbamate as a selective herbicide. Prooi Amer. Hort. S c i . , W.E. N.Y., 15.  Humphrey Press Inc., Geneva,  1948, 51:541-4.  M i t c h e l l , J.W.  and Marth, P.C.,  E f f e c t s of  2.4-dioh-  lorophenoxyacetic acid on the growth of grass plants. Botanical Gazette, 1945, No.2, 16.  vol.107,  pp. 282-84.  M i t c h e l l , J.W.  and Marth, P.C.,  S e n s i t i v i t y of grasses  and some crop plants to isopropyl N-phenyl carbamate. Science, Washington, D.C,  1947,  106:15-7. 17.  Nylund, R.E.,  A study on the use of 2.4-D  for weed  control i n strawberries. F i f t h Annual North Central Weed Control Conference Report, S p r i n g f i e l d , I l l i n o i s , 18.  Otis, C.E.,  Research 1948.  Strawberry weed control i n the P a c i f i c  Northwest. Down t o Earth, The Dow  Chemical  85. Company, Midland, Michigan, 1947, vol.3, No.3, p.16. 19.  S l i f e , F.W. and B a l l , H.L., A preliminary report on spray*strawberries with 2.4-D and TCA, F i f t h Annual North Central Weed Control Conference Research Report, S p r i n g f i e l d , I l l i n o i s , 1948.  20.  Warren, G.F., and Hernandez, T.P., Weed control i n certain vegetable crops with s o i l applications of 2.4-D. Proc. Amer. Soc. Hort. S o i . , W.F. Humphrey Press Inc., Geneva, N.Y. 1948, 51:515-25.  21.  , Investigations of weed control methods i n h o r t i c u l t u r e and truck crops. F i f t h Annual North Central Weed Control Conference Research Report, S p r i n g f i e l d , I l l i n o i s , 1948.  22.  , Recommendations on the use of 2.4-D, Weed Committee of the B.C. Agronomists' Association, V i c t o r i a , B r i t i s h Columbia Department of Agriculture, F i e l d Crop S t e n c i l No.l, 1948.  23.  , Report of a c t i v i t i e s of the D i v i s i o n of Horticulture f o r the months of A p r i l . May and June. 1948, Dominion Experimental Farm Service, Ottawa, 1948.  86.  APPENDIX  Following are complete s t a t i s t i c a l analyses of the effect of applications of various amounts of 2,4-D and mixtures of 2,4-D and IPC on the height of hog m i l l e t (Panicum miliaceum) as at September 11, 1949, and of the effect of applications of various amounts of 2,4-D and mixtures of 2,4-D and IPC on the weight of c l i p p i n g s from the various grasses, as shown, as at September 30, 1949. Data obtained from Experiment IV.  E f f e c t of Applications of Various Amounts of 2,4-D  87.  and Mixtures of 2,4-D and IPC on the Height of Hog M i l l e t (Panicum miliaceum) as at September 11, 1949. Block I  II  III  13 11 9 8 8 8 11 12 8 7 8 6 8 9 9 10 5 6 0 0 2 4 14  10 13 10 12 12 8 14 12 11 9 8 9 10 11 9 7 7 6 1 4 4 4 14  14 14 15 12 10 9 9 11 12 11 8 6 9 15 7 6 10 5 0 1 3 3 15  Blk.Totals  178  215  205  Blk.Mean  7.7  9.3  8.9  Treatments 1 2 3 4 5 6 7 8 9 10 11 12 13 14 16 16 17 18 19 20 21 22 23  Sum. 37 38 34 32 30 25 34 35 31 27 24 23 27 35 25 23 22 17 1 5 9 11 43  Grand Total  598  General Mean  8.7  Treatment Mean :  12.3 12.7 11.3 10.7 10.0 8.3 11.3 11.7 10.3 9.0 8.0 7.7 9.0 11.7 8.3 7.7 7.3 5.7 0.3 1.7 3.0 3.7 14.3  88  ANALYSIS OF VARIANCE  Source of Variation  Degrees of Sum of Freedom Squares  Variance  Table Variance value F r a t i o i n F. at P = .05  Total  68  847  Treatment  22  662  30.1  8.60  1.81  2  32  16.0  4.57  3.21  44  153  3.5  Blocks  Error  M.S.D. for Treatments at .05 l e v e l  =  1.08  E f f e c t of Applications of Various Amounts of 2,4-D  89.  and Mixtures of 2,4-D and IPC on the weight of Clippings from Creeping Red Fescue (Festuca rubra) as at Sept. 30, 1949.  (M.S.D. at .05 l e v e l = 0.5)  Block II  III  Sum.  Treatment Mean  6.2 2.5 2.5 4.0 0.9 0.5 5 .0 8.0 3.5 1.5 4.0 1.0 5.5 3.0 1.5 1.5 1.5 1.5 6.0 2.3 5.0 6.0 9.0  17.0 9.0 4.0 2.0 3.0 3.0 10.0 3.0 4.0 2.0 0.0 2.0 4.0 4.0 4.0 1.0 2.0 o.o 11.0 6.0 12.0 8.0 7.0  30.2 16.0 7.5 6.5 4.4 4.5 26.5 12.0 17.5 11.5 8.0 5.0 18.5 15.0 11.0 6.5 5.5 5.0 26.0 11.3 24.0 27.0 27.5  10.1 5.3 2.5 2.2 1.5 1.5 8.8 4.0 5.8 3.8 2.7 1.7 6.2 5.0 3.7 2.2 1.8 1.7 8.7 3.8 8.0 9.0 9.2  -  I  Treatments 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23  7.0 4.5 1.0 0.5 0.5 1.0 11.5 1.0 10.0 8.0 4.0 2.0 9.0 8.0 5.5 4.0 2.0 3.5 9.0 3.0 7.0 13.0 11.5  Blk.Totals 126.5 Blk.Mean Grand T o t a l General Mean  5.5  82.4 3.6  118.0 5.1 326.9 4.7  90. ANALYSIS OTP VARIANCE  Table Source of Degrees of Sum of Variance Variance value E Variation Freedom Squares , r a t i o i n E. at P =.05 Tout  68  914  Treatment  22  528  24  3.12  1.81  2  48  24  3.12  3.21  44  338  7.7  Blocks Error  M.S.D. f o r Treatments = 0.507 at .05 l e v e l .  E f f e c t of Applications of Various Amounts of 2,4-D and Mixtures of 2,4-D and IPC on the weight of Clippings from Perennial Rye Grass (Lolium as at Sept. 30, 1949. (1/[.S.D. at .05 l e v e l BlOCk Treatments 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23  I 33.0 8.0 1.5 1.0 1.5 1.5 40.0 8.0 23.5 10.5 9.0 5.5 20.0 13.0 19.0 13.0 9.0 7.0 22.5 13.5 7.0 27.5 18.0  Blk.Totals 312.5 Blk. Mean  13.6  II 10.0 8.0 4.0 6.0 3.5 0.5 18.5 12.0 8.5 2.0 3.0 2.5 11.5 10.5 6.5 2.5 2.5 3.5 13.5 13.5 11.2 14.8 10.0  =  3.7)  ±11  Sum.  Treatment Mean  37.0 25.0 6.0 7.0 7.0 10.0 22.0 12.0 15.0 10.5 1.0 5.0 15.0 19.0 12.0 1.5 9.0 1.0 50.0 12.0 /17.0 13.0 19.0  80.0 41.0 11.5 14.0 12.0 12.0 80.5 32.0 47.0 23.0 13.0 13.0 46.5 42.5 37.5 17.0 20.5 11.5 86.0 39.0 35.2 55.3 47.0  26.7 13.7 3.8 4.7 4.0 4.0 26.8 10.7 15.7 7.7 4.7 4.3 15.5 14.2 12.5 5.7 6.8 3.8 28.7 13.0 11.7 18.4 15.7  178.5 326.0 7.8  perenne)  14.2  Grand T o t a l  817  General Mean  11.9  91.  ANALYSIS OF VARIANCE  Source of Variation  Total Treatment Blocks Error  Degrees of Sum of Freedom Squares  Variance  Table Variance value F r a t i o i n F. at P =.05  68  6390.33  22  3965.21  180.24  4.29  2  578.18  289.09  6.89  44  1846.94  41.98  [.S.D. f o r Treatments = 3.7 at .05 l e v e l .  18.1 3.21  E f f e c t of Applications of Various Amounts of 2,4-D and Mixtures of 2,4<*D and IPC on the weight of Clippings from Orchard Grass (Dactylis glomerata) as at Sept.30, 1949.  (M.S.D. at .05 l e v e l = 2.8)  I  Block  I  Treatments  ;  •  II  III  Sum.  Treatment Mean  41.5 37.0 15.0 8.5 5.0 5.0 31.5 19.0 20.5 8.5 7.0 5.0 20.0 19.5 18.5 7.0 6.5 4.5 17.0 5.0 30.0 54.0 38.0  13.8 12.3 5.0 2.8 1.7 1.7 10.5 6.3 6.8 2.8 2.3 1.7 6.7 6.5 6.2 2.3 2.2 1.5 5.7 1.7 10.0 18.0 12.7  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23  20.5 25.0 4.0 1.0 1.0 1.0 16.5 9.0 14.0 5.5 2.0 2.0 11.0 9.5 11.5 4.0 3.5 1.5 4.5 1.5 6.0 38.0 18.0  6.0 2.0 4.0 2.5 2.0 1.0 5.0 5.0 4.5 2.0 4.0 2.0 5.0 4.0 3.0 2.0 1.0 2.0 2.5 0.5 7.0 7.0 9.0  15.0 10.0 7.0 5.0 2.0 3.0 10.0 5.0 2.0 1.0 1.0 1.0 4.0 6.0 4.0 1.0 2.0 1.0 10.0 3.0 17.0 9.0 11.0  Blk.Totals  210.5  83.0  130.0  Blk.Mean Grand Total General Mean  9.15  3.61  5.65 ... 423.5 6.1  94.  ANALYSIS OF VARIANCE  Source of Variation  Total Treatment Blocks Error  Degrees of Freedom  Sum o f Squares  Variance Variance ration i n F  Table value F at P =.05  68  2876.94  22  1456.11  66.19  2.75  1.81  2  361.53  180.77  7.51  3.21  44  1059.30  24.08  I.S.D. f o r Treatments at .05 l e v e l .  s  2.8  .  . . . 9 5 .  E f f e c t of Applications of Various Amounts o f 2,4-D and Mixtures of 2,4-D and IPC on the weight of Clippings from Hog M i l l e t  (Fanlcum miliaoeum) (M.S.D. at .D5 l e v e l = 6.9) Block  Treatments 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23  I 44..0 42.0 42.0 44.0 45.0 49.0 33.0 50.0 26.0 26.0 33.0 39.0 31.0 24.0 34.5 33.0 20.0 31.5 o.o 1.5 5.5 26.0 49.0  Blk.Totals  729  Blk. Mean  51.7  Grand Total General Mean  II 16.0 35.0 17.5 29.0 28.0 37.0 42.5 38.0 19.0 34.0 14.5 38.5 20.5 24.0 18.5 25.0 20.0 9.0 4.5 22.0 18.5 10.0 30.5  III 44.0 69.0 72.0 64.0 82.0 80.0 35.0 49.0 57.0 65.0 32.0 41.0 57.0 41.0 34.0 32.0 61.0 30.0 o.o 4.0 1.3 7.0 54.0  Sum. 104.0 146.0 131.5 137.0 155.0 166.0 110.5 137.0 102.0 125.0 79.5 118.5 108.5 89.0 87.0 90.0 101.0 70.5 4.5 27.5 37.0 43.0 133.5  551.5 1023.0 23.9  44.5 2303.5 33.3  Treatment Mean 34.7 48.7 43.8 45.7 51.7 55.3 36.8 45.7 34.0 41.7 26.5 39.5 36.2 29.7 29.0 30.0 33.7 23.5 1.5 9.2 12.3 14.3 44.5  ANALYSIS OF VARIANCE  Source of Degrees of , Sum of Variation Freedom Squares  Table Variance Variance . value F r a t i o n i n F. at P • .05  Total  68  24,144.08  Treatment  22  12,931.58  2  4,931.23  2465.6  44  6,281.27  142.8  Blocks Error  587.8  4.12  1.81  17.26  3.21  M.S.D. f o r Treatments * 6.9 at .05 l e v e l .  

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