Getting The Most Out Of Butyrac 200 (2,4-DB Amine)And Buctril (Bromoxynill Applications

Bill B. Fischer*

Abstract:Butyrac 200 (2,4-DB amine) with adjuvants provided as effective control of certainbroadleaved weeds as was obtained with Butoxone (2,4-DB ester). Buctril (bromoxynil) hasbeen repeatedly demonstrated to be effective for the selective control of many broadleavedweeds in newly planted alfalfa. The importance of proper timing of the application of theseherbicides relative to the growth of the weeds and the alfalfa cannot be over emphasized.Their timely use can enhance weed control in alfalfa.

Introduction:It is doubtful whether you could find another person who conducted as many appliedresearch trials during the past 30 years as I have in evaluating 2,4-DB and bromoxynil forselective weed control in alfalfa.

Neither of these compounds are new and it is a sad commentary on the pesticide approvaland labeling procedures in the United States that it required thirty years to obtain a label forthe use of bromoxynil in alfalfa. We knew a quarter century ago how to get the most fromthe application of Buctril in newly planted alfalfa.

Bromoxynil was first synthesized in Germany in 1896 and was patented in the United Statesin 1963. Bromoxynil is an inhibitor of photosynthesis. It moves in the plant to a verylimited extent, therefore it is called a contact herbicide. At present it is classified as arestricted use pesticide hence it can be applied only by certified applicators or persons undertheir supervision.

Twenty-Five Years of TrialsThe past 25 years I have conducted many trials in the San Joaquin Valley evaluating Buctrilon many different varieties of newly planted alfalfa. The trials were conducted in fall,winter and spring planted fields on different soil types and methods of irrigation.

The label on Buctril indicates that it should be applied when the alfalfa has a minimum offour trifoliate leaves. I have applied Buctril on alfalfa having 1 to 2 trifoliate leaves and theonly time I observed injury was when the temperature exceeded 75 to 80°F at the time oftreatment or 2 to 3 days after treatment. The symptoms observed were chlorosis or necrosisof leaflets and some growth retardation, however these symptoms were short lived.

Rather than bore you with the results obtained in trials conducted years ago and reported atnumerous alfalfa symposia, other meetings, and in Runcina, let me briefly outline how toget the most from the application of Buctril.

~Fann Advisor Emeritus, U.C. Cooperative Extension, Fresno County

-92-

Proper weed identification is essential. Buctril does not control grasses neither does itcontrol the following commonly ocurring broadleaved weeds:

fchickweed

henbit

nettle

purslaneclovers .

red maids

There are a number of broadleaved weeds that are effectively controlled with Buctril whenseedlings however, many become more tolerant to the herbicide as they develop beyondtheir seedling stage; a few of the more commonly ocurring ones are filaree, commonknotweed, cud weed and cheeseweed. Therefore proper timing of its application is essential.

In our studies we also found that more effective control was obtained with Buctril when itwas applied in 60 to 70 gallons of water per acre -than was observed when lower gallonagewas used. In fact we have been able to obtain more effective control when injected intosprinkler irrigation systems; it is labeled for this type of application.

In Summary,To get the most from the application of Buctril:

know the weed popula tiona.

h treat weeds in their seedling stage

apply when the alfalfa has 3 to 4 trifoliate leaves

apply in 50 to 60 gallons of water per acre, this is especially importantwhen the weeds are beyond their seedling stage

d.(

don't apply when the temperature is 80°F or abovee.

f. inject into irrigation system if proper conditions can be met

In recent years we have been evaluating the effectiveness of Buctril in combination withother herbicides to obtain a broader spectrum of weed control. However, at present I betterturn to discuss the second part of my original topic.

Getting the Most Out Of 2,4-DB AmineAs bromoxynil, 2,4-DB amine is not a new herbicide. My first evaluation of differentformulations of 2,4-DB for the selective control of weeds in alfalfa dates back to the early

60'5.

2,4-DB was discovered in 1942 as a foliar absorbed synthetic growth regulator. It is readilytranslocated in plants principally to meristematic areas of high metobolic activity where itinterferes with nucleic acid formation, disruption of translocation, metabolism andphotosynthesis. There are numerous salts and formulations of 2,4-DB and Butyrac 200 is anamine salt of 2,4 dichlorophenoxybutyric acid.

2,4-DB is not an effective herbicide but in certain plants it is converted to 2,4-D acid throughbeta oxydation. In alfalfa and clovers this does not occur as effectively as in other broadleafplants, hence the selectivity. l

"

-93-

During the early 60'5 we learned that the ester formulation of 2,4-DB provided significantlybetter control at lower rates than was obtained with the amine formulation. Consequently2.4-DB ester was used by alfalfa growers until 1990 when its manufacturer discontinued its

marketing.

2,4-DB Amine vs 2,4-DB EsterTrials were initiated during 1990 to reevaluate the amine formulation of 2,4-DB incombination with different adjuvants and other herbicides to study whether itseffectiveness could be enhanced. These studies were summarized and published inRuncina V 01. 45.

2,4-DB amine plus adjuvants were applied on alfalfa at different stages of its growth. It wasalso evaluated in combination with Buctril, and several grass herbicides. The results of thestudies and observations can be briefly summarized as follows:

2,4-DB amine (Butyrac 200) with an adjuvant provided as effective control ofbroadleaved weeds as was obtained with the 2,4-DB ester formulation (see tables).

. The addition of X-77 at 1/4 and 1/2% of the spray volume or a paraffin based adjuvantat 1.0 quart per acre resulted in equally as effective control of the susceptibleweOOswith Butyrac 200 as was obtained with 2,4-DB ester.

Bor~'forrnurations of 2,4-DB (ester...and,amincl,-,ca.used tempora~"retardation.,in.,the.growt~{vigt)F)o.orthe"alfa.t~chowever this was short lived.

2,4-DB amine with X-77 or a paraffin based adjuvant caused chlorosis and necrosis ofsome leaflets.

The alfalfa seedlings exhibited greater tolerance to 2,4-0B amine when treated in thefirst trifoliate leaf than in later stages of its growth. See the following tables.

. When applied in combination with Poast (sethoxydim) or Select (clethodym) plus aparaffin based adjuvant good broadleaf and grass control was obtained with excellentalfalfa tolerance.

The younger the weeds when treated the more effective control was obtained.

Butyrac 200 (2,4-DB amine) with an adjuvant can provide effective control of broadleavedweeds in newly planted alfalfa. Timing of its application relative to the weed growth iscritical. Many species of weeds effectively controlled in their seedling stage became moretolerant to the herbicide as they grow. Cheeseweed, chickweed, cud weed and several otherspecies of broadleaved weeds are not controlled by 2,4-DB as shown in chart 1.

In SummaryButyrac 200 plus an adjuvant and Buctril are effective herbicides for the selective control ofbroadleaved weeds. Alfalfa growers can obtain the most from their application onlythrough correct identification of the weed population and proper timing of their applicationrelative to the growth of the weeds and the alfalfa. If the conditions outlined above are metthese herbicides can be effective tools in the arsenal of alfalfa growers for the control ofunwanted competing vegetation in their fields.

-94-

* N

OT

LA

BE

LED

F

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crS

B

IN

CH

AR

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1S

usceptibility of W

eeds to

Herbicides

Evaluated

in Alfalfa

Production

-95-

--

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CHART 2Summary of Herbicide Performance Evaluated in Alfalfa Production in the Central San Joaquin Valley

Method of

ApplIcationConditions Th.t R.sult8d In

Most Effectlv. ControlConditions That Resulted In Poor

Poor C~:1trol or b1juryH8rtIlcjde

Balan~(beneffn)

Shallow incorporated in well prepa'U.-seed bed. When »mperature wasfavora~e for rapid seeding growU1.

Only suscepti~ weeds were present

Cool .~ture. deep i~rpora1ionvolun-r cereals and ottler resistant~ species were ~esenl

PREPLANTINCORP-ORATED

Eptam~

(EPrC)

Thorough i~rporation early fag orin spring planted fields. Wl'-.re

rXJtsedge was present; wtlere 4 to 8

-ks conb"ol was needed.

Win8r application, daddy seed OOdaM resistant weeds present. Wherelonger tt1an 6 weeks of residualcontrol -.s needed.

Butyrac 200(2,4-08 arrine +

a~uvant)

WMn broadeaf weeds in their seedingSlage were the only weeds present

Broadeal weeds beyoOO tt1eirseedling stage ~re IX'8senl

KQ(b<!)(pronamide )

When alfalfa had two trifoliate leavesa 00 weeds were not emerged or intheir seedling stage; rainfall orSfX'inkler irrigation was appiedfollowing trearnent.

When alfalfa was in the seedleaf orunfoliate leaf stage of growth severeinjury occurred. When -005 -rebeyoOO tt1eir seedling stage. Whenwater was not applied soon aftertreatment.

Buclril~..

(bromoxynil)

When the alfalfa had 2 to 3 bifoliateleaves and 1fIe broadleaf weedswere in their seedling stage. Appliedin 60 gallons of water per acre andtt1e alfalfa and broadleat weeds were

growing vigorously.

When grasses, chickweed andredmaids were rxevalent. Weedswere beyond 1h!ir seedling stageand air a~icalion in 10 gpa wasused. When U1e temperawre wasabove 80°F temporary yellowing ofIt1e alfalfa was observed.

POST-EMERGENCE

Poast~

(sethoxydim)

When grasses are in their seedlingstage and growing vigorously.

Grasses beyom their seedling stageam moisture stressed.

Alfatfa well established with a welldeveloped root system 6. long oror longer with a top growth that is6. to 8., Most effective on weeds intheir seedling stage. Sprinklerirrigation or rainfall shortly afterappication is desira~ lor ITKJsteffective control.

Velpar~(hexazinone) Alfalfa seedlings oot having

6. long roots. Weeds predominantlygraS5es and broadleaf -ds 5. to 6.or older. No rainfall or irrigationfollowing 'realmenl

Eptam~(EPTC)

Ap~ied in tt1e irrigaDon water andonly when ~rough wetting of ~bed top was obtained. Timelyrepeated ap~ication was made.

Poor water distribuuon and not

wetting the bed top. Re~ated

a~ication was not made.

Kar~x~(diuron)

Applied on trashy or cloddy soil.Applied after Feb. 1 st on non-dormant varieties resulted in injury

When applied on soil free of clods andvolunteer alfalfa seed germination.A(Xjition of paraQuat improved weed controlwhen groundseVwas present.

Treflan~

(Irinuralin)Thoroughly irx:orporated with rollingcultivators in fields tree ot established'\Weds. Sum~r annual grasses,pigweeds am lambsquarter, theonly -ds rxesenl

Not irw:orporated thoroughlyor when resistant weed species

predominated.ESTABUSHEDSTANDS

Treflan TR-10(trifluralin 10%

granular)

Unifom1ly distributed by mid Feb'uary beforebefore dodder seed gem1ination. Rainfalloccurs or irrigation applied within 4 to 6 daysfollowing application. Will provide effectivepreernerge~ grass control.

Ap~ied after dodder is attached. Rainfalldoes not occur or field not irrigated withina week following ap~ication.

Alfalfa was established one year or

longer .Ap~ied during December

and January 'M1en ItMi alfalfa growth

was soon (4 to 6 inches). Rainfall

occurred shortly after ap~ication

and weeds were 2 to 4 irK:hes tall.

Established grasses were ~predomnant -ds. Broadleatweeds 8 10 10 inches taIlor taller.ApPied at1Br the middle ot February

Velpar~

(hexazinoM)

.This is not a recommendation for the use of herbicides. It is a progress report of obselVaDons made in applied research trials conductedin Fresno County.

..As of December 1990. registered by EPA but not labeled for use in California.

-96-

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Table 4- Effect of Postemergence Applied Herbicideson Weed Control in Alfalfa

02,43,425,94,10,91-2

LOCA naN :SOIL TYPE:V ARIETY:TREATED:

IRRIGAnON: Flood,1/31/91PLOT SIZE: 10' x 20', Reps 4PLANTED: 10/31/90EV ALUATED: 5/24/91

Keamey Agricultural CenterHanford sand y loamHay mix2/23/91; Alfalfa,4 to 7 trifol. lvs.

.Weeds in bud stage

Yield in Grams Per 4 ft ~ Area. Avg: of 4 Re12lications

Lbai/ Total Pineapple- Shepherd's OtherHeroiddes Acre Yield Cudweed ~ ~ Weeds

A 2,4-DB amine

X-77

1.01/2%

753 719 21 11 1

B 2,4-DB amineX-77

1.01/4%

744 708 26 9 1 0

c 2,4-DB amineX-77

1.51/4%

656 629 18 7 2 0

o 2,4- OB amine

X-77

1.51/2%

698 664 22 10 1

F 0.1250.331/2%

PursuitBuctrilX-77

726 681 34 8 1 1

F Buctril 0.33 705 690 1 s 0 9

0.1251.01/2%

G Pursuit

2,4-DB amine

X-77

692 683 0 3 0 6

H Untreated 704 643 49 s 0 7

Statistical Notation: LSD @5%C.V.

NS 17.9586.74%

NS NS 4.54

142.8%

..Other Weeds: fiddleneck, groundsel, horseweed, sowthistle

-100-

I

f

Table 5- Effect of Postemergence Applied Herbicideson Vigor, Injury and Weed Control in Alfalfa

02, 43, 425, 94, 10, 91-2

LOCATION:SOIL TYPE:VARIETY:TREATED:

IRRIGA TION :PLOT SIZE:PLANTED:EVALUATED:

Flood

10' x 20', Reps 4

10/31/90

See below

Keamey Agricultural CenterHanford sandy loamHay mix2/23/91: Alfalfa 4 to 7 trifol. lvs.

Weeds in bud to early flower stage

Vigor, Injury and Weed Control Evaluationsf Avg. 4 Re!2s.

91

Lbai/ Weed fa

Herbicides Acre Vi Control Vi

A 2,4-DB amine

X-77

1.01/2%

8.5 2.5 39 9.5 1.8 0 0 0

1.01/4%

9.0 1.8 49 10.0 0.5B 2,4-DB amineX-77

25 0 0

c

(c 2,4-DB amine

X-77

1.51/4%

8.3 2.3 46 9.3 1.8 19 6 0 9.8

D 2,4-DB amine

X-77

1.5

1/2%

7.8 2.5 44 9.3 1.5 39 31 19

0.1250.331/2%

E PursuitBuctrilX-77

7.5 2.8 69 8.0 2.3 49 13 19 9.8

F Buctril 0.33 8.5 0.8 81 9.3 1.8 99 18 13

G 0.1251.01/2%

8.3 0.5 78 9.0 0.5 94 56 46 9.8Pursuit2,4-DB amineX-77

H Untreated 10.0 0 0 10.0 0 0 0 0

0.60 0.676.89% 39.72%

11.4 0.6421.81% 6.71%

0.54

41.86%

35.6884.6%

23.51 15.88146.16% 126.92%

Statistical Notation: LSD @5%

C. V.

.Vigor rating based on a scale of 0 to 10; 0 = dead plants, 10 = vigorously growing plants.Injury rating based on a scale of 0 to 10; 0 = no injury; 10 = severe injury or death.

Weed abbreviations: Sp = shepherd's purse, y = pineappleweed, R = redmaids.

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t

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-101-