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COLLEGE OF 

 AGRICULTURE 

 UNIVERSITY OF 

 ILLINOIS AT 

 URBANA-CHAMPAIGN 

 AND NATURAL 

 HISTORY SURVEY 

 URBANA, ILLINOIS 



NSECT WEED & PLANT DISEASE SURVEY BULLETIN 



ATE/COUNTY/LOCAL GROUPS/U.S. DEPARTMENT OF AGRICULTURE COOPERATING 



FOR IMMEDIATE RELEASE 



No. 20, August 18, 1972 



This is the last weekly issue in this series of bulletins that provides a general look 

 at the insect, weed, and plant disease situation (fruit and commercial vegetables ex- 

 cepted) along with suggested, abbreviated control measures. Each individual should 

 check his own fields to determine local conditions. If circumstances make it neces- 

 sary, other issues will be mailed to you. the library OF THE 



INSECTS SEP g 1972 



CORN INSECTS 



UNIVERSITY OF IUJNOIS 

 AT URBANA-CHAMPAIGN 



Fall arm/worms are appearing in very late field corn. This population will continue 

 to increase until frost. The moths deposit pearl-gray eggs in clumps of about 100 

 eggs on corn leaves. They use their body scales to cover the egg mass. If the worms 

 are found before they penetrate too deeply into the whorl, sprays of carbaryl, diazi- 

 non, Gardona, or toxaphene will control them. Follow label directions for interval 

 between spray application and harvest. Do not apply toxaphene to corn that will be 

 used as ensilage or stover for dairy cattle or animals being finished for slaughter. 



European corn borer moths are still depositing eggs , and we are uncertain of the 

 second-generation potential. We believe the infestation will be only moderate. 



WHEAT INSECTS 



Hessian fly populations are higher in central and southeastern Illinois than in pre- 

 vious years but numbers are quite similar to those of previous years. There was a 

 build-up last fall because some susceptible varieties were planted early, and there 

 also was a second or fall supplemental generation. Observation of proper seeding 

 dates for susceptible varieties is encouraged. Resistant varieties may be planted 

 early . 



Section 



West 



Central 



East 



West Southwest 



East Southeast 



Southwest 



Southeast 



Hessian Fly Populations per 100 Tillers in July 



1971 



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2.3 

 5.5 

 1.2 

 1.2 



1972 





 6 



1 

 4 

 3 



14 



State average per county 



2.0 



4.0 



