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-j— ^ Cooperative Extension Service ur '»(■ 



J~-^n- / University of Illinois CoHege of Agriculture JUL b •"■>£«.£ 

 in cooperation with the Illinois Natural 



History Survey and U.S.D.A. WuretSfJYflf KJJMMt 



FOR IMMEDIATE RELEASE July 9, I965 



INSECT SURVEY BULLETIN NO. 12 



This is the twelfth 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. 



Chinch hugs are still migrating from small grains to corn hut in general 

 migrations are ahout completed. The rains this week undoubtedly killed many of 

 the small red nymphs, and now nearly mature "black nymphs and adult hugs are pre- 

 dominant in most fields. The winged adults will soon fly to weak, thin spots in 

 cornfields and to other grasses and sorghums. Here they will deposit eggs and 

 another generation will develop. We can predict that a moderate to heavy second 

 generation will develop and he damaging in an area hounded "by a line from Joliet 

 to Peoria to Paris to the Indiana "border. Greatest numbers of hugs will he present 

 in areas that had the least rain in the past month. 



Dieldrin provided excellent control of first generation. It cannot he 

 used for second generation hugs in any fields except those to he used for cash 

 grain. The organic phosphates such as diazinon and malathion were tried on first 

 generation hugs and were comparatively ineffective. We used carharyl (Sevin) as 

 80 percent sprayahle at 1 l/h pounds per acre and it was effective. This can he 

 used on sorghums with no time limitation if it is to he used as forage, hut allow 

 an interval of 21 days between application and harvest for sorghum to be harvested 

 as grain. 



Corn borer moths can be found in the southern tip of Illinois. Ahout one- 

 third of the first generation have now emerged as moths. This moth emergence will 

 continue for at least two more weeks. The moths will deposit eggs for a second 

 generation in fields now in pretassel to early silk stage. There undoubtedly will 

 be a third generation in this area. 



Pupation has begun in central and south- central Illinois, and emergence of 

 moths will begin in about two weeks. Moth emergence for a second generation in 

 northern Illinois will not take place for three weeks. However, there has been some 

 late emergence of moths from overwintering borers during the past ten days. 



At present, we do not expect a generally severe second generation corn 

 borer infestation. 



Northern corn rootworm damage has been reported in a few fields where 

 corn has been grown each year for several years and soil insecticides have been 

 used annually. These white worms devour the corn roots. Such isolated instances 

 indicate an enlargement of the resistant corn rootworm area we have reported during 

 the past years. In most instances the worms are nearly mature and there will be 

 little to gain by applying one pound of diazinon per acre at the base of the plants. 

 If the worms are still small it may pay to make this application. A mature root- 

 worm larva is about l/2 inch long. 



