-5- 



and can increase lodging in soybeans. The stems may show some cracking and prolifera- 

 tion at the base. We suggest using 2,4-DB only where these weeds are serious and only 

 if the grower is willing to risk some injury to soybeans. 



POSTEMERGENCE TREATMENTS FOR CORN 



2,4-DB and Banvel (dicamba) are the two top choices for broadleaved weed control in 

 corn. 



2,4-D will control most of the annual broadleaved weeds effectively and economically. 

 Use "drop pipes," or nozzle extensions from the boom, to keep the spray out of the 

 corn whorl if you spray after the corn is more than eight inches tall . Do not spray 

 with 2,4-D after corn begins to tassel. 



The rate of 2,4-D to apply depends on the strength of the concentrate and the type of 

 2,4-D used--amine or ester. If you use the amine form, apply one-half pound of the 

 active ingredient per acre. That is 1 pint of the 4 -pound material per gallon of 

 material. If you use the ester form, apply one-sixth to one-fourth pound per acre. 



The amine form is less likely to cause drift problems, but most farmers consider the 

 ester form more active and less likely to wash-off with a rain. Weeds are easier to 

 kill when they are small, so adjust the rate of application to the weed size. 



CORN INJURY 



Each year 2,4-D damages some corn. The symptoms are an elbowing of the stalk, abnormal 

 brace roots, and "onion leafing." Corn seems most susceptible to 2,4-D damage when it 

 is under cool, wet-weather stress, or when it is growing fast during hot, humid periods. 

 Corn stalks are often brittle for 7 to 10 days after spraying with 2,4-D, so delay culti- 

 vation if possible. 



Banvel is cleared for use on corn until the crop is 56 inches high, or until 10 days 

 before the tassels emerge. Banvel is similar to 2,4-D, but it provides improved smart- 

 weed control. Banvel often affects soybeans near treated cornfields, causing a cupping 

 of the soybean leaflets about two weeks after the drift occurs. The soybeans generally 

 outgrow the injury, and yields are not affected. To minimize Banvel drift, use a low 

 pressure and avoid spraying when the wind velocity is more than 5 miles per hour. 



Both Banvel and 2,4-D can injure corn. Banvel is cleared for use over the top of the 

 corn, but the use of drop nozzles generally lessens the chance of corn injury. Remember: 

 injury most often occurs when the corn has been under cool, wet -weather stress. 



READ THE LABEL AND FOLLOW ALL PRECAUTIONS 



This weekly report was prepared as follows: 



INSECTS: H.B. Petty, Steve Moore, Roscoe Randell , Don Kuhlman, and Tim Cooley , College 

 of Agriculture , University of Illinois at Urbana-Champaign , and the Illinois Natural 

 History Survey. 



WEEDS: M.D. McGlamery and E.L. Knake , Department of Agronomy. 



AG COMMUNICATIONS: Del Dahl . 



The information for this report was gathered by these people, staff members, county 

 Extension advisers, and others, in cooperation with the USDA Agricultural Research 

 Service, Plant Pest Control Branch. 



