FOR IMMEDIATE RELEASE August lo, I963 



FINAL ISSUE, INSECT SURVEY BULLETIN, I963 



This is the eighteenth and final issue in a series of weekly bulletins 

 on the general insect situation in Illinois (fruit insects excepted), prepared by 

 entomologists of the University of Illinois College of Agriculture, Illinois Natu- 

 ral History Survey and cooperating agencies. It is designed to forewarn people 

 in Il li nois of impending 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. 



Corn borer moth emergence reached its peak in the northwest section of 

 Illinois this week. Egg counts on field corn averaged 80 to 100 per 100 plants 

 on late-maturing fields and 10 to k-0 per 100 in early-maturing fields. Approxi- 

 mately 50 to 75 percent of these eggs had hatched. Cool nights have slowed egg- 

 laying, which will continue in this area for the next two or three weeks. Total 

 egg accumulations in these fields during this period should be about double the 

 current counts. Corn borer development in western Illinois is slightly ahead of 

 the northwest section, and egg-laying should be over in the next 10 days to two 

 weeks in this area. The area of heaviest borer infestation lies north and west 

 of a line from Quincy to Peoria to Rockford. 



If there are 100 or more egg masses per 100 plants, treatment could be 

 profitable. But do not treat corn that is to be used for ensilage. One pound of 

 DDT per acre in the form of granules or 1 1/2 pounds per acre as a ground spray 

 should provide adequate control on corn to be harvested only as grain. 



Grasshopper populations continued heavy in hay fields, and some damage 

 is apparent. Northwestern Illinois is the focal point. Some 'hoppers have al- 

 ready reached the adult stage, while many others are only 1/3 to 1/2 grown and 

 will feed vigorously for the next few weeks. There appears to be adequate food 

 in the hay fields, and little migration has taken place into adjacent soybeans 

 and corn. Grasshoppers will migrate to the margins and adjoining fence rows when 

 hay fields are cut. This is a good place to treat them while they are confined 

 and before further migrations occur. 



For pasture or hay crops, apply 3/4 pound of sevin, 1 pound of mala- 

 thion or 3/^ pound of dibrom per acre. Sevin does not require any waiting period 

 between application and grazing or cutting for hay, but allow a 7-day interval 

 with malathion and a k-day interval with dibrom. For best results, apply in the 

 late afternoon or early evening. 



If areas will not be grazed or used for hay, apply 1 to 2 ounces of 

 dieldrin or 1 1/2 pounds of toxaphene per acre for control. 



For soybeans or corn for grain, use 1 to 2 ounces of dieldrin or 1 l/2 

 pounds of toxaphene per acre. Allow 60 days to elapse between application of 

 dieldrin and harvest. If corn or soybeans are to be used for ensilage, hay or 

 pasture, use sevin or malathion with a 7-day interval between application and 

 harvest. 



Armyworms have been reported in corn where grass is abundant. One-half 

 pound of dieldrin per acre may be used to control armyworms in corn, provided 60 

 days are allowed to elapse between harvest or cutting for ensilage. Toxaphene at 

 1 1/2 pounds per acre may be used on corn that is not to be used for ensilage or 

 stover. 



