FOR IMMEDIATE RELEASE June 26, 1964 



INSECT SURVEY BULLETIN NO . 11 



This is the eleventh in a series of weekly bulletins on the general in- 

 sect 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 impend- 

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

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

 to determine local conditions. 



Corn borer is less important now than it was a week ago. The storm of 

 the past week killed many moths; only those in highly protected spots were able 

 to survive. Also, almost half of the corn is new large enough to attract moths; 

 the few moths that remain will scatter their eggs and not concentrate in any one 

 field. Some eggs will still be deposited during the next two weeks, but only an 

 occasional field of corn may warrant treatment. This statement applies only to 

 field corn. Sweet corn growers should follow the usual practice of examining early 

 fields and treating if necessary. 



Grasshoppers are still hatching, but most of those that had hatched be- 

 fore the heavy rains were killed. The present ones are new and are not plentiful 

 enough to cause concern. We will observe the continued hatching of this pest for 

 the next two weeks. 



Chinch bugs are present in occasional thin stands of wheat and oats in 

 central and eastern Illinois. Recently hatched nymphs are starting to suck sap from 

 the plants. They are bright red at first but turn dark red to black as they ma- 

 ture. Examine thin areas in small grains to see whether bugs are present in dead 

 or dying spots. If there is little or no grass, the bugs will migrate as the grain 

 dries. Grassy weeds like foxtail, if sufficiently abundant in small grains, may 

 supply food for bugs and no migrations will occur. 



If chinch bugs begin to migrate from the grain to corn, apply l/2 pound 

 of actual dieldrin per acre as a border two rods wide in the grain field and into 

 the cornfield as far as the bugs are severe. Do not harvest small grains for one 

 week after treatment. Do not feed the straw to livestock. 



Small nymphs and adults have been observed in cornfields. These chinch 

 bugs will survive only if there is grass in the corn row or a grass crop was plowed 

 down early this spring. 



ComTTion stalk borer have been tunneling in the whorl leaves of occasional 

 corn plants and stalks of oats. These striped worms are whitish-brown with a dis- 

 tinct purple to black band around the middle of their bodies. The unfolding leaves 

 of corn have irregular holes from worm feeding, while the heads of oats turn white 

 prematurely. Damage occurs in plants along fence rows, ditch banks and grass water- 

 ways or where there was a weed problem the previous year. Injury is little conse- 

 quence, and by the time the worms are found it is too late for chemicals to be ef- 

 fective. Keep weeds under control in August and September to help reduce the 

 problem for next year. 



Mimosa webworm feeding is evident on mimosa and honey locust as far 

 north as central Illinois. The small, pale gray to brown larvae web the leaves 

 together to form a nest in which they skeletonize the leaflets. Damaged leaflets 

 become dry and brown. A second generation of worms will occur in August. 



