salt of DNBP at 3/4 to 1 pound in 30 to 50 gallons of water per acre. DNBP 

 is less likely to injure legumes than 2,4-D. K DNBP is used, it should be 

 applied only when the weeds are in the seedling stage. The 2,4-D or MCPA 

 application should be made after cereals are well tillered (usually 4 to 8 

 inches tall), but before reaching boot stage. Thelegunnes are less likely to be 

 injured if a small grain foliage canopy is allowed to develop before applying 

 2,4-D or MCPA. Apply the lowest gallonage possible at low pressure in order 

 to reduce penetration of the canopy with the spray. 



Comments and precautions .- -Avoid use of post-emergence applications 

 of 2,4-D and MCPA unless the weed infestation is serious enough to result 

 in reduction or loss of legume stands and reduced small grain yields. 



Not Underseeded With Legumes 



Post -emergence .- -For control of mustard, wild radish, yellow- rocket, 

 ragweed, wild vetch, lambsquarter s, pigweed, cocklebur, smartweed, sun- 

 flowers, shepherds-purse, prickly lettuce, plaintain, docks, field bindweed, 

 and others: Esters or amine salts of 2,4-D or MCPA at 1/4 to 1/ 2 pound in 

 5 to 20 gallons of water per acre applied after cereals are well tillered 

 (usually 4 to 8 inches tall), but before the early boot stage. Growth of wild 

 onion, wild garlic, Canada thistle, sowthistle, curled dock, buttercup, field 

 bindw^eed, and whitetop in arid areas, and several perennial weeds, such as 

 horsenettle, white cockle, milkweed, and others, will not be controlled by 

 the treatment. 



Comments and precautions .- -In the western Great Plains and Inter- 

 mountain region, 2,4-D should be applied at 1/2 to 1 pound per acre to 

 control most weeds infesting small grains. Here 1 to 2 pounds of 2,4-D 

 may be required to control semitolerant weeds, and these rates may be 

 used without serious injury to the small grains. In other agricultural areas, 

 rates of nnore than 1 pound per acre should be used only when necessary to 

 kill weeds causing serious damage to small grains. 



Both 2,4-D and MCPA at moderate rates of treatment can be used to con- 

 trol weeds in wheat, barley, and oats without injuring crops if treatments 

 are restricted to the most tolerant stages of growth of the cereals. Greatest 

 benefits to the grain crop result from early removal of the weeds. Fall 

 treatments usually are severely injurious to wintersmall grains. 



Applications of 2,4-D or MCPA to cereal crops in the susceptible stages, 

 such as the early seedling stages, before tillering or during the late jointing 

 stages or the boot stage, and earlyheading stages, may result in reductions 

 in yield and associated deleterious effects on the plants, including reduced 

 quality. 



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

 salts of 2,4-D, MCPA, or DNBP necessary to control weeds (See Under- 

 seeded with Legunnes). Most legumes are susceptible to 2,4-D and 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 the early joint stage. Wheat 

 is the most tolerant of these grains to 2,4-D, barley less so, and oats least 



- 20 - 



