Cooperative Extension Service, University of 

 -J->^v *7 Illinois College of Agriculture in Cooperation with 



the Illinois Natural History Survey and U.S.D.A. 



FOR IMMEDIATE RELEASE May lh, I965 



INSECT SURVEY BULLETIN NO. k 



This is the fourth in a series of weekly bulletins on the general insect 

 situation in Illinois (fruit insects excepted), prepared by entomologists of the Uni- 

 versity of Illinois College of Agriculture, Illinois Natural History Survey and coop- 

 erating agencies. It is designated to forewarn people in Illinois of impending changer 

 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 bug adults are common in thin stands of small grains in the area east 

 of a line from Elgin to Peoria to Effingham. They are not yet permanently established 

 but are still moving around in search of a field that Is to their liking. If small 

 grains heavily infested with chinch bugs are plowed down and planted to corn, the corn 

 may be injured. Occasional wheat fields are showing damage which appears as small 

 spots of drying plants. Chinch bug adults are mating and starting to lay eggs. The re- 

 sult could be a large buildup of nymphs in the next few weeks. 



Warm wet weather is conducive to spread of a fungus that kills chinch bugs 

 and can almost eliminate a large population. In contrast, dry weather and thin stands 

 of grain are favorable to chinch bug development. Do not apply insecticides unless 

 damage is apparent ; weather conditions can still control the problem. However, if 

 treatment is definitely necessary, apply l/k pound of actual dieldrin per acre or, on 

 dairy farms, 1 pound of actual carbaryl per acre to the grain. Do not harvest 

 dieldrin-treated grain for seven days after treatment, and do not feed straw or ensi- 

 lage to dairy animals or animals being fattened for slaughter. Do not apply dieldrin 

 to grain fields adjacent to dairy pastures or forage crops. Use carbaryl instead. Do 

 not contaminate fish-bearing waters with dieldrin. 



Armyworms are appearing in luxuriant stands of small grains. The worms are 

 still small and are concentrated in thick, rank spots in these fields. Worm numbers 

 have been low, but continued egg-laying and hatch could change the situation rapidly. 

 It is too soon to assess the importance of the problem. 



Corn borer pupation is nearly complete in the southern tip of Illinois this 

 week; moth emergence has begun and will progress rapidly during the next two or three 

 weeks. Our best estimate is that peak egg-laying and hatch will occur late this month 

 and into early June. At that time, observe early, rapidly developing fields of corn 

 for borer infestations. 



Pupation of overwintering borers reached 15 percent this week in central and 

 western Illinois. Moth emergence should start by June 5 to 10 in this area, with 

 peak egg- laying and hatch between June 15 and 30. There are a few early-planted field 

 in this area that may bear the brunt of the egg-laying, and borer survival in these 

 fields will be high. 



The tassel ratio method sh/vuia be used for correct timing of insecticide 

 amplications where they are needed- We prefer d.ia^.innn or oaa-bsryl (Sevin) granule 

 in place of DDT. THt LliMRlf 8t lUt 



MAY 17 



fa^q pf HUMP!* 



