- At- / 



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/US. DEPARTMENT OF AGRICULTURE COOPERATING 



FOR IMMEDIATE RELEASE 



No. 10, June 4, 1971 



This series of weekly bulletins provides a general look at the insect, weed, and 

 plant disease situation (fruit and oommercial vegetables excepted) , along with 

 suggested, abbreviated control measures. Each individual should check his own 

 fields to determine local conditions. 



INSECTS 



CORN INSECTS 



Wireworms . This week the number of complaints increased. They involved a variety 

 of rotations , but were most common about corn in fields that were in wheat in 1969. 



This pest lives as a larva in the soil for two to six years. A wireworm problem 

 this year usually means there will also be one in the same spot next year, so 

 plan accordingly. 



Wireworm damage usually declines by mid- June because the worms go deeper into the 

 ground when the soil becomes warmer and drier. 



In cases ivhere replanting in necessary, use one of the organic phosphate 

 insecticides --Thimet, Dyfonate, and Dasanit at 1 pound or diazinon at 2 pounds 

 per acre. These will control small wireworms, but may not control the large ones. 

 A rain after application is helpful. We have had several reports of wireworm- 

 control failure with row treatments of aldrin, heptachlor, and chlordane. 



It may also be possible to straddle the rows and replant leaving the old stand. 

 Later, you can cultivate- out the poorer stand. Do not use an insecticide if 

 replanting to beans. The only insecticide with label approval for soybean soil 

 treatment is diazinon. 



Cutworms . A few new infestations were reported this week. Later ones are still 

 possible, but this depends on the weather. Cool, wet weather would encourage the 

 development of the second generation, particularly in northern Illinois. 



European corn borers . It is still impossible to determine the exact situation. 

 The most advanced fields in western Illinois should be observed carefully in 

 about two to three weeks. The survival of borers in these fields will be high, 

 and the moths will tend to concentrate their egg-laying in such fields. The 

 large amount of early planted corn will provide the moths with lots of places 

 to deposit eggs. The first generation population, therefore, should be scattered 

 over a large area while the second generation may be concentrated in the smaller 

 acreages of late-planted fields. 



