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 July 1, I966 



INSECT SURVEY BULLETIN NO. 11 """^W OF lLU» 



JUL Id 19t, 



This eleventh weekly bulletin on the general insect situatron in Illinois 

 (fruit insects excepted), prepared by entomologists of the Ur|iKJ|K&ity of Illinois 

 College of Agriculture, Illinois Natural History Survey and cooperating agencies, 

 reports general trends in insect activity and suggests abbreviated control measures. 

 Each individual should check his own fields to determine local conditions. 



Present Farm Insect Problems 



European corn borer moth emergence is about complete in northern Illinois. 

 Egg laying is being spread over the more advanced fields, and in general these fields 

 are not being seriously affected. Fields were observed in which up to 50 percent 

 of the plants were infested, but 75 percent is used as the threshold for treatment. 

 We do not expect much need to apply insecticide on commercial field corn for first- 

 generation corn borer. 



In the south-central and southern sections, many of the borers have already 

 tunneled into the stalks and it is too late for effective control. 



Thrips are common in the whorl leaves of corn. They are tiny (about l/l6 inch) 

 yellow or black insects with rasping, sucking mouth parts. Their feeding appears 

 as tiny streaks of white on leaves. Corn leaves take on a silvery appearance from 

 heavy feeding. Plants will usually outgrow the damage, and rain helps. If plants 

 are being seriously injured, carbaryl at 1 pound per acre will provide control. 



Small numbers of newly hatched alfalfa weevil larvae can still be found feed- 

 ing on alfalfa in the southern counties, but no controls are needed. We strongly 

 suspect that these are second -generation worms. 



Flies continued to increase this week. Horn fly populations are heavy on some 

 herds, and stable flies are beginning to build up. No problems with face flies have 

 been observed. 



For pastured dairy cattle, apply 1 to 2 ounces of an oil-base spray of 2.0 per- 

 cent Ciodrin, 1.0 percent dichlorvos (DDVP) or 0.1 percent pyrethrins as needed. 



Ciodrin will provide effective control for two or three days, while dichlorvos 

 and pyrethrin are effective for only a day at most. Water-base sprays of the same 

 materials may be used, but control is less effective. Pay particular attention to 

 the legs and undersides of animals when spraying. 



For pastured beef cattle, apply 0.5 percent toxaphene as a water-base spray 

 at 1 to 2 quarts per animal every three weeks. Cover the animals thoroughly with 

 the spray. Allow 28 days to elapse between treatment with toxaphene and slaughter. 



