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COLLEGE OF 

 AGRICULTURE 

 UNIVERSITY OF 

 ILLINOIS AT 

 URBANA-CHAMPAIGN 

 AND NATURAL 

 HISTORY SURVEY 

 URBANA, ILLINOIS 



INSECT WEED & PLANT DISEASE SURVEY BULLETIN 



STATE/COUNTY/LOCAL GROUPS/US. DEPARTMENT OF AGRICULTURE COOPERATING 





FOR IMMEDIATE RELEASE 



UNIV 



No. 23, August 24, 1973 



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. 



INSECTS 



WHEAT INSECTS 



Hessian fly populations are about the same as last year in Illinois. Highest popu- 

 lations were found in the southern section of the state and the east -southeast sec- 

 tion. Observation of proper seeding dates for susceptible varieties is encouraged. 

 Resistant varieties may be planted early. 



Hessian Fly Populations per 100 Tillers in July 



Section 



1972 



1973 



West 



Central 



East 



West southwest 



East southeast 



Southwest 



Southeast 



State average per county 







6 



1 



'! 



3 



14 



4.0 





 







1.3 

 5.6 

 6.0 



2.2 



FORAGE CROP INSECTS 



Alfalfa weevil adults will begin migrating back into alfalfa fields in another month 

 or so. For the south half of the state, we encourage the application of an insecti- 

 cide in November. This will control the adults before they deposit many eggs in the 

 stems. Such a treatment in most instances replaces a spring application. There will 

 still be weevils feeding on the alfalfa in the spring but usually not in great enough 

 numbers to be of economic importance. Spring treatments kill natural enemies of the 

 weevil such as wasp parasites, but fall treatment does not. 



For fall treatments use methyl parathion, malathion, or diazinon in combination with 

 methoxychlor , or try Imidan, carbofuran, or Supracide. Methyl parathion, carbofuran, 

 and Supracide should be applied only by experienced applicators. 



We do not yet recommend this fall application in the northern half of Illinois. 



