Applications of 2,4-D or MCPA to cereal crops in the early seedling stages prior 

 to tillering or during the late jointing stages or the boot stage, and early heading 

 stages nnay result in serious reductions in yield, lowered germination of grain, 

 changes in protein content of grain, and lowered quality of products made from the 

 treated crops. If cereal crops are underseeded to legumes, use minimum rate of 

 amine salts of 2,4-D, MCPA, or DNBP necessary to control weeds. All legumes are 

 susceptible to 2,4-D and most are susceptible to MCPA, and serious injury may 

 result if these herbicides are applied at rates greater than 1/4 pound per acre. If 

 cereals are underseeded with legumes, application of MCPA or 2,4-D should be 

 delayed until the maximum small grain canopy has developed, but not later than early 

 joint stage. The order of tolerance of these crops to 2,4-D is as follows with the most 

 tolerant first: wheat, barley, and oats. If oats are not heavily infested with weeds, 

 yields may be reduced by applications of 2,4-D made at any time from emergence to 

 heading. Oats, however, are nnore tolerant to MCPA than to 2,4-D. 



FLAX 



(1) Post-ennergence.--For control of broadleaved weeds --mustard, lambsquarters, 

 pigweed, pennycress, cocklebur, marsh elder, and ragweed: Amine salt of MCPA or 

 2,4-D at 1/8 to 1/4 pound in 5 to 20 gallons of water applied when weeds are small and 

 flax is 3 to 6 inches tall. For southwestern flax growing area: 2,4-D or MCPA at 1/2 

 to 3/4 pound per acre. 



For annual grasses--green foxtail, yellow foxtail, giant foxtail, and barnyard grass: 

 Mixture of 1/4 pound MCPA and 5 pounds TCA in 10 to 20 gallons of water per acre 

 applied when weeds are small and flax is 3 to 6 inches tall. Will also control broad- 

 leaved weeds listed above. 



To prevent seed production by Canada thistle and to control Russian thistle: Esters 

 of MCPA and 2,4-D at 1/4 to 1/2 pound in 5 to 20 gallons of water per acre applied on 

 a spot-treatnaent basis. 



Comments and precautions . --Will not control wild oats, quackgrass, milkweed, 

 white cockle, and Russian knapweed. Applications to flax should be avoided from 

 early bud through bloom stages. 



COTTON 



A. Humid Cotton Belt 



(1) Pre -emergence. --For control of annual grasses and many broad-leaved weeds 

 for 4 to 6 weeks: CIPC at 5 to 10 pounds in 20 to 40 gallons of water per acre applied 

 during the planting operation. To reduce cost, apply CIPC at 1-1/2 to 3 pounds per 

 acre immediately behind planter wheel or press wheel to 12- to 14-inch band centered 

 over row (rows 40 inches apart). Lower rate { 1 - 1 /2 pounds on a 12-inch band basis, or 

 about 5 pounds per acre on a complete coverage basis) suggested for sandy loam or 

 lighter textured soils; heavier rates suggested for loams and heavier textured soils. 

 Complete coverage applications are more desirable than band treatments but they have 

 not been used because of the higher cost. 



The substituted urea herbicides, monuron and diuron, are being extensively investi- 

 gated for pre -emergence weed control in cotton, but are not suggested for general use. 

 Research information is also needed on the residual effect of these herbicides on crops 

 following cotton in the rotation. They are available commercially for trial under the 

 technical assistance and supervisory program of the manufacturer. 



Performance of DNBP compounds as pre-emergence herbicides has been erratic, 

 and, therefore they are not presently being used for weed control in cotton. 



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