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■ — -^y^ ' Cooperative Extension Service, University of 



Illinois College of Agriculture in Cooperation With 

 the Illinois Natural History Survey and U.S.D.A. 



FOR IMMEDIATE RELEASE May 28, 1965 



INSECT SURVEY BULLETIN NO. 6 



This is the sixth in a series of weekly bulletins on the general insect 

 situation in Illinois (fruit insects excepted), prepared by entomologists of the 

 University of Illinois College of Agriculture, Illinois Natural History Survey and 

 cooperating agencies. It is designed to forewarn people in Illinois of impending 

 changes in insect activity and to suggest abbreviated control measures. These re- 

 ports indicate only general trends. Each individual should check his own fields to 

 determine local conditions. 



Armyworms continue to hold the spotlight. However, only a very few fields 

 have enough worms to justify treatment. 



Here is what has happened: Moths were depositing eggs a few weeks ago and 

 searched out the luxuriant stands of grains and grasses. Such fields were few and 

 far between, but they now have 6 to 15 worms per linear foot of drill row and can be 

 treated profitably. 



The moths also deposited some eggs in other fields of wheat. You can find 

 armyworms in small, thick spots in each field. In some cases there are as many as 

 2 per linear foot throughout the field. These populations do not warrant applica- 

 tions of insecticides. 



In the larger populations, examine worms carefully for signs of disease. 

 Sick worms respond very slowly to any stimulus, such as heat. Their skin may break 

 with a slight touch. After death they soon shrivel up. If there are many sick 

 worms, do not apply an insecticide. 



Above all, do not panic and be talked into using an insecticide unneces- 

 sarily. Do not justify insecticide applications on the basis of worm counts from 

 lodged spots in fields, as the worms concentrate in these spots. Use an average worm 

 count for the entire field to determine need for treatment. 



Use 1 1/2 pounds of toxaphene per acre, but not on dairy farms or fields 

 adjacent to dairy pasture or forage crops. If you use dieldrin, do not apply more 

 than two ounces of actual per acre, and do not apply on dairy farms or fields adja- 

 cent to dairy forage crops or pasture. Do not harvest for one week, and do not use 

 the straw for livestock feed. Trichlorfon (Dylox) has label approval for use on 

 wheat, but it cannot be used within 21 days of harvest , the field cannot be used for 

 grazing livestock and the straw cannot be fed to dairy or beef animals. We have not 

 tried this material for armyworm control in Illinois, so we have no records on its 

 effectiveness, but some states are recommending its use for this purpose. Also, 

 1 l/k pounds of malathion can be used up to within one week of wheat harvest and may 

 be helpful in controlling armyworms on dairy farms. 



Sawflies are yellowish-green, velvety, transparent-appearing worms. They 

 are abundant in wheat fields at the same time as armyworms, which are distinctly 

 striped. Do not confuse the sawfly larvae with armyworms. 



