FOR IMMEDIATE RELEASE June 3, i960 



INSECT SURVEY BULLETIN NO. 7 



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

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

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

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

 changes in insect activity and suggest abbreviated control measures. These reports 

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

 mine local conditions. 



Sawf lies : These drab yellow to grey worms with prolegs on each segment 

 of the abdomen are common in small grain fields and are still being mistaken for 

 armyworms, which often appear in grain and grass fields at this time of year. Army- 

 worms have only four sets of prolegs on the abdomen and are brown or green with 

 orange and white longitudinal stripes on the "body. Control of sawflies is not 

 necessary. 



Armyworms : Moth flights have been observed, hut no serious worm infesta- 

 tions have yet been found. Newly hatched worms were observed in fields this week. 

 Watch thick, luxuriant stands of grains and grasses during the next few weeks. Cool 

 weather favors this insect. 



Black cutworms : Watch low spots in corn fields during the next two to 

 three weeks for damage by these worms. This has been an ideal year for them. If 

 cutting starts, examine the soil around damaged plants for cutworms. Apply 1/2 

 pound of dieldrin, 3 pounds of toxaphene or l/h pound of endrin per acre if needed. 

 Direct the spray onto the soil at the base of the plants. 



Chinch bugs ; Thin stands of oats in central Illinois may develop moderate 

 infestations of chinch bugs during the next two or three weeks. Examine dead and 

 dying spots in the stands of small grains for evidence of these pests. If infesta- 

 tions are heavy, be prepared to apply 1/2 pound of dieldrin on the edge of the grain 

 field to prevent migrations to corn. The grain can be harvested one week after 

 treatment. 



Sod webworms ; Plants may be cut off, but leaf damage and stalk damage may 

 also occur. The grey worm with black spots that is doing the damage is hidden in a 

 neat of webbing and dirt; it is found only by carefully sifting the soil. One to 

 1 1/2 pounds of DDT per acre applied as a spray at the base of the plants will help 

 control webworms. 



Corn borers : Pupation of overwintering borers is complete in central and 

 southern Illinois. Moths have begun to emerge in these areas. Peak emergence 

 should occur from June 6 to 20, with peak egg deposition from June 13 to 27 • 



In northern Illinois pupation varies from 50 to 90 percent. Emergence is 

 just beginning. Peak flight should occur between June 13 and 27, with peak egg- 

 laying taking place between June 15 and July 1. Temperature and rainfall will 

 affect emergence and egg- laying. 



Particularly advanced fields of field corn in the area north of a line 

 from St. Louis to Kankakee should be observed carefully during peak egg- laying and 

 hatching. These fields may profit from treatment. 



Bagworms : These pests should now be hatching in central Illinois and will 

 soon be hatching in northern Illinois. After hatch is complete and while worms are 



