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FOR IMMEDIATE RELEASE August 10, I962 



INSECT SURVEY BULLETIN NO. 17 



These weekly bulletins, prepared "by entomologists of the University of 

 Illinois College of Agriculture, Illinois Natural History Survey and cooperating 

 agencies, report general trends in insect populations in Illinois (fruit insects 

 excepted). Check your own fields to determine local conditions. 



Corn "bo r er pupation in early fields in central and north central Illinois 

 has now reached §Ofo, with J5§ emergence of moths. These moths are migrating to late 

 developing fields where they are laying eggs for the second generation of borers. 

 Egg counts in late developing fields ranged from 1 per stalk in the eastern part of 

 the state to about 2 per stalk in the western part of the state. Depending on weather, 

 egg laying should reach its peak during the next two weeks but will be spread 

 out over the next four weeks. 



In northern Illinois 60% of the first generation borers have pupated and 

 approximately 50% emergence has occurred. The moths just began to lay eggs this 

 past week in northern Illinois; they will concentrate on late developing fields 

 this week. Egg laying should reach its peak in the next two to three weeks but will 

 extend over a five -week period. 



All canning companies should be alert to possible infestations in sweet 

 corn fields that are 10 or more days from harvest and should be prepared to treat 

 them at first egg hatch. 



Late field corn may warrant treatment if there are 100 or more egg masses 

 per 100 plants. Use 1 1/2 lb. of DDT per acre on corn for grain, but do not apply 

 to corn for ensilage or stover for dairy animals or animals that will be finished 

 for slaughter. One application only of l/k lb. of endrin may be used to within h$ 

 days of harvest. Toxaphene granules, 1 l/2 lb. per acre, one application only, can 

 be used, but not on corn for ensilage or stover for dairy cattle or animals being 

 finished for slaughter. 



Grasshopper control measures have been very effective as farmers have been 

 controlling 'hoppers since early summer. This early action has prevented extensive 

 grasshopper damage. 



There are, however, many fields where grasshoppers are still extremely 

 abundant. This week many "hoppers began to migrate from fence rows, diverted acres, 

 hay fields and ditch banks to beans and corn where leaf feeding is now beginning to 

 show. Estimating damage to beans is difficult in some instances, since 'hoppers 

 feed mainly on the leaves but may also feed on pods and blossoms. 



Our recommendations are: For hay crops, apply 3/4 lb. of dibrom, 1 lb. of 

 malathion or 1 to 1 1/2 lb. of Sevin per acre. No interval between application and 

 harvest is required for Sevin. Allow h days when using dibrom and 7 days for mala- 

 thion. Diazinon, l/2 lb. per acre, can be used on alfalfa, with 7 days between 

 application and harvest. A single treatment of 1 oz. of dieldrin per acre may be 

 applied to hay crops, but not after the new growth is over six to eight inches high 

 or within 35 days of harvest. 



For corn or soybeans, apply l/8 lb. of dieldrin or 1 l/2 lb. of toxaphene 

 per acre. Do not apply toxaphene to corn or soybeans to be used for hay, ensilage 

 or stover for dairy cattle or animals being finished for slaughter. Dieldrin, 



