-4- 



Iligh- clearance equipment will be needed in many fields and "drop nozzles" will usually 

 be necessary. If nozzles are directed in toward the row, reduce the amount of 2,4-1) 

 ;md adjust the nozzles to prevent too much spray from being applied directly on the 

 corn. Do not spray from the tasseling to dough stage. Because 2,4-1) can make corn 

 brittle for a week or so, it is best not to treat if windstorms can be expected during 

 the next week. 



There is always some risk involved when using 2,4-D. So follow the precautions care- 

 fully and realize that there may still be some risk beyond your control. 



For the state as a whole, the benefits from 2,4-D will far exceed the disadvantages. 

 Having weeds at harvest has its risks, too. 



Forget about using atrazine and oil this late. If atrazine has been applied as late 

 as July, do not plant soybeans next year, because of the likelihood of residue. Most 

 grass weeds are now too large for control with atrazine postemergence. 2,4-1) is more 

 economical and practical for most broadleaved weeds now. 



The rainj have brought on late small weeds, both between and in the rows. With high 

 populations and narrow rows, corn and beans should provide enough shade to discourage 

 weed growth in many of these fields. However, some small weeds may come along; 

 although not very competitive, they can produce seed. 2,4-D is still best for late- 

 germinating broadleaved weeds in corn. 



A few farmers have considered Dowpon or Lorox for grass, but not many of them have 

 appropriate equipment; and care is needed to avoid corn injury. If very much Dowpon 

 contacts corn leaves , it can translocate in the plant and adversely affect ear and 

 grain development. To be effective, Lorox should be applied before the weeds are 

 8 inches high- -preferably when they are 5 or 6 inches high. Corn should be at least 

 15 inches high and you must carefully direct the spray to avoid corn injury. 



Postemergence herbicides for soybeans were discussed in the Insect, Weed, and Plant 

 Disease Survey Bulletin No. 12 (June 15, 1969), on page 6. The portion on 2,4-D 

 should have read 2,4-DB . You can still use 2,4-DB for really serious cocklebur, 

 annual morning glory, and giant ragweed in soybeans. But check the timing and rates 

 carefully. 



There seems to be increased interest in Banvel this year. It is approved only for 

 corn up to 56 inches high and has done well on smartweed and many other broadleaved 

 weeds. Corn has relatively good tolerance to Banvel postemergence, but the problem 

 of possible injury to nearby plants (such as soybeans) still discourages its use. 



Because of damage from 2,4-D plus atrazine and oil, we have suggested not to add 

 Banvel to an atrazine -and -oil mixture. Atrazine does so well on smartweed that there 

 is little reason to add the Banvel. Banvel has been cleared for pasture and range- 

 land use too. It is better than 2,4-D on some perennial weeds. 



There is no waiting period between treatment and grazing for animals other than 

 dairy cows, but do not graze meat animals in treated fields within 50 days ol~ 

 slaughter. And do not use the seed from treated grass for feed or food. 



The restrictions on dairy cattle grazing and dry-hay usage are shown on the following 

 page. 



