Cooperative Extension Service, University of 

 Illinois College of Agriculture in Cooperation With 



the Illinois Natural History Survey and USDA .... 



FOR IMMEDIATE RELEASE July 8, 1966 



INSECT SURVEY BULLETIN NO. 12 



This twelfth weekly bulletin on the general insect situation in Illinois 

 (fruit insects excepted), prepared by entomologists of the University of Illinois 

 College of Agriculture, Illinois Natural History Survey, and cooperating agencies, 

 reports general trends in insect activity and suggests abbreviated control meas- 

 ures. Each individual should check his own fields to determine local conditions. 



Present Farm Insect P roble ms 



Occasional reports of chinch bug ny rphs in grass waterways, grain fields, 

 and cornfields have been received from east-central Illinois . They have also been 

 reported on corn where a grass or grain crop was plowed down before planting. 



Dieldrin should not be used for chinch bugs or for any treatment for in- 

 sects on field crops. The label for all uses on field crops was withdrawn Janu- 

 ary 28, 1966, with the exception of the use as a seed treatment for corn. 



Carbaryl (Sevin) at 1 pound p^r acre is effective against chinch bugs. 

 Direct the spray at the bottom half of the plants. If migration from small grain 

 to corn appears likely, treat a strip two rods wide into the grain and the same 

 distance into the corn just as migration begins. Carbaryl should not be used on 

 unharvested grain — only on grain stubble. 



Nor t hern corn rootworm larvae can be found feeding on the roots of corn. 

 Damage has been reported in a few fields of continuous corn where aldrin or hepta- 

 chlor has been used for several years. This shows the development of resistance, 

 as reported during the pas + years. Also the phosphate insecticides applied as row 

 treatments before early May are failing to control rcotworm larvae in some fields. 



The worms are maturing rapidly, and there will be little to gain from 

 applying a granular phosphate insecticide (diazinon, parathion, or phorate) at the 

 base of plants as a lay-by treatment. A mature rootworm larva is about 1/2 inch 

 long. If worms are still small it may pay to make this application, but do so 

 immediately. Cultivate immediately to cover the granules in the row. 



Common stalk borers are still present in the whorl leaves of occasional 

 corn plants and stalks of oats. These striped worms are whitish brown with a dis- 

 tinct purple to black band around the middle of their bodies. Corn leaves show 

 irregular holes as they unfold, and the heads of oats turn white prematurely. Dam- 

 age occurs in plants along fence rows, ditch banks, and grass waterways. Injury 

 is of little consequence, and by the time the worms are found it is too late for 

 chemicals to be effective. Keep grass and weeds in fields under control in August 

 and September to help reduce borers for next year. 



Mites are present in some soybean fields in southern Illinois. These 

 tiny mites feed on the undersides of the leaves, giving them a mottled appearance. 

 In addition, they spin webs on the andersides of leaves. These mites increase dur- 

 ing hot, dry weather. The best control is carbophenothion (Trithion) which can be 

 used to within 7 days of harvest. It is a toxic insecticide, and should be applied 

 only by experienced operators. 



