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Corn "borer populations may increase noticeably this year in the area 

 north and west of a line from Quincy to Bloomington to Rockf ord. First-generation 

 numbers in this area are the highest since 1958, and most of these first-generation 

 borers are pupating now to form a second generation; some moths have already ap- 

 peared. Considering the increase in the first-generation population and the high 

 percentage that are pupating, corn borers could very well be more numerous this fall 

 than in any other year since 1955* The second generation is the one that causes 

 ear drop in late corn. 



Moth emergence, which is one to two weeks earlier than in other years, 

 varied from 5 to 20 percent this past week. These early emerging moths are search- 

 ing for fields of corn in pretassel to early silk in which to deposit eggs. If 

 they are unable to find fields in this stage, they will deposit eggs on any corn. 



Treatment of field corn to control second-generation borers is difficult. 

 If 100 egg masses per hundred plants are present, an application of 1 pound of 

 actual DET as granules will provide good control. Do not apply to fields to be 

 used for livestock grazing or for ensilage. 



Second-generation borers are a severe problem to growers of canning 

 sweet corn. If egg mass counts reach 25 per 100 plants and the corn is 15 or more 

 days from harvest, a control program should be started. Fieldmen should start 

 examining fields immediately for corn borer egg masses. 



Caution : Before applying insecticides, read the labels carefully and 

 follow all precautions. This not only will insure personal safety, but will also 

 eliminate insecticide residue hazards. 



For a list of general precautions to use when handling and applying 

 pesticides, write to 280 Natural Resources Building, University of Illinois, Urbana, 

 Illinois, for "Safe Use of Pesticides." 



This weekly report was prepared by H. B. Petty and Steve Moore, Illinois 

 Natural History Survey and Illinois College of Agriculture, in cooperation with 

 the USDA Agricultural Service, Plant Pest Control Branch, from information gathered 

 by entomologists and cooperators who send in weekly reports from their own locali- 

 ties. 



