Fof"<?SMEDIATE RELEASE August 17, 1962 



INSECT SURVEY BULLETIN NO. 18 



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. This is the last 

 issue for the I962 season. 



Grasshoppers continue to migrate from hay fields, diverted acres, ditch 

 hanks, roadsides and fencerows into soybeans and corn. They are also invading home 

 vegetable gardens. As hay fields are cut and other grass areas dry, they will con- 

 tinue to move to more succulent food. This migration and damage •will occur until 

 the first frost. 



For corn or soybeans, apply l/8 lb. of dieldrin or 1 l/2 lb. of toxaphene 

 per acre. Do not apply toxaphene to corn or soybeans to be used for hay, ensilage 

 or stover for dairy cattle or animals "being finished for slaughter. Dieldrin, 

 1/8 lb. per acre, may "be applied to corn to within 1+0 days of harvest or ensiling, 

 and to soybeans to within 60 days of harvest. Dieldrin, l/k lb., may he applied 

 to corn or soybeans to within 60 days of harvest. Dibrom, malathion and Sevin can 

 also be used on corn for ensilage. 



For home vegetable gardens, flowers and shrubs, use either malathion or 

 Sevin. To mix, use 2 teaspoons of 50 to 57$ malathion emulsion concentrate per 

 gallon of water or 1 l/2 tablespoons of Sevin 85W or 2 tablespoons of Sevin 50W 

 per gallon of water. Do not treat within 7 days of harvest when using malathion 

 or 3 days for Sevin. Leaf lettuce should not be sprayed with malathion within Ik 

 days of harvest. 



Corn borer pupation is complete throughout the state, and emergence of 

 moths is nearly complete in northern Illinois. In central and north-central Illi- 

 nois, 90 percent of the first -generation borers pupated in contrast with only about 

 75 percent in northern Illinois. 



Populations are heaviest in the area west of Highway 51, north of Route 9 

 and south of Route 6. Egg mass counts in late-maturing fields were averaging one 

 to three egg masses per plant this week. Late fields in the central and north- 

 central area east of Highway 51 are averaging about one egg mass per plant. Ap- 

 proximately 50 percent of the eggs have now hatched in these areas. In northern 

 Illinois, egg mass counts are low on late-maturing fields, with the average less 

 than one per plant, and the infestation generally appears light. Egg hatch is just 

 beginning in this area. 



Cool weather this past week has slowed egg -laying in all areas. However, 

 it will increase rapidly with the first warm nights, particularly in the northern 

 area, and will continue for the next two to three weeks. 



All canning companies should be alert to possible infestations in sweet 

 corn fields that are 10 or more days from harvest and should be prepared to treat 

 at first egg hatch. 



Late field corn will 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 apP^Y.., 

 to corn for ensilage or stover for dairy animals or animals that will T»^^j|Mtfi«-'"^ 



