FOR IMMEDIATE RELEASE August 3, 1962 



INSECT SURVEY BULLETIN NO. 16 



These weekly 'bulletins, prepared by entomologists of the University of 

 Illinois College of Agriculture, Illinois Natural History Survey and cooperating 

 agencies, report general trends in insect populations in Illinois (fruit insects 

 excepted). Check your own fields to determine local conditions. 



Pupation of first generation co rn borer is nearly complete in the early 

 fields in central and north-central Illinois, but more pupation is yet to take place 

 in early fields in northern Illinois. Although these early fields supply the highest 

 percentage of the second generation moth population in a community, slightly less 

 mature fields do have some corn borer which are just now starting to pupate. Thus, 

 moth flight and egg laying may extend over a long period of time. 



In early fields, pupation is extremely high and as many as 50$ °f the moths 

 have emerged and are now laying eggs. Since corn borer moths do not migrate readily 

 on cool nights, they are laying their eggs in fields from which they emerged. With 

 several warm nights they will migrate to the less mature fields of corn. 



The highest population of first generation borers is in an area west of 

 Highway 51 and north of a line drawn through Bloomington and Pekin. Although the 

 population is not as high north of this line and east of Jl, there are enough first 

 generation borers present in this area to supply plenty of moths for a second genera- 

 tion. 



Corn borer populations are still expected to be greater this year than last. 



All canning companies should already be observing sweet corn fields that 

 are 10 or more days from harvest, and be prepared to treat at first egg hatch. 



Late field corn may warrant treatment if there are 100 or more egg masses 

 per 100 plants. Use 1 l/2 lb. of DDT per acre on corn for grain, but do not apply 

 to corn for ensilage or stover for dairy animals or animals that will be finished 

 for slaughter. Only one application of l/k lb. (an error last week stated l/2 lb.) 

 of endrin may be used to within k^ days of harvest. Toxaphene granules, 1 1/2 lb. 

 per acre, one application only, can be used, but not on corn for ensilage or stover 

 for dairy cattle or animals being finished for slaughter. 



Grasshoppers are still extremely plentiful in many areas. As hay harvest 

 progresses and the grasshoppers migrate to beans and corn, their numbers will become 

 quite noticeable in western and northwestern Illinois where populations are higher 

 and more general than in eastern and northeastern Illinois. But even here, there are 

 areas of heavy to moderate infestations. 



Some farmers, when mowing hay, are leaving a strip unmowed around the 

 outside and down the center of the field. As the grasshoppers concentrate in these 

 unmowed strips, they are sprayed. 



Our recommendations for control are: For areas that will not be grazed or 

 used as hay for livestock, use l/8 lb. of dieldrin, 1 l/2 lb. of toxaphene, l/k lb. 

 of aldrin or l/k lb. of heptachlor per acre.. This includes such areas as roadsides, 

 diverted acres, etc. 



