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FOR IMMEDIATE RELEASE May 18, 1962 



INSECT SURVEY BULLETIN NO. 5 



This is the fifth 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 Natural History Survey and 

 cooperating agencies. These reports indicate only general trends. Check your own 

 fields to determine local conditions. 



Pea aphid populations in alfalfa and clover fields are increasing. Some 

 fields have potentially damaging numbers of aphids but as yet little harm is being 

 done. The number of aphid predators, like lady beetle and syrphid flies, are in- 

 creasing and these may hold the aphids in check. Drying winds this past week slowed 

 the spread of a fungus disease of aphids. 



If chemical treatment becomes necessary, apply 1 pound of malathion, l/k 

 pound of parathion or phosdrin, or l/8 pound of demeton per acre before severe wilt- 

 ing and discoloration of plants occur. Allow 1 week between treatment and harvest 

 when using malathion, 1 day with phosdrin, 15 days with parathion, and 21 days with 

 demeton. Only one application of demeton can be made per cutting. Demeton, para- 

 thion and phosdrin should be applied only by an applicator experienced in handling 

 toxic organic phosphates. 



Spittlebugs and clover leaf weevils: Spittlebug froth masses are becoming 

 apparent but counts generally remain low with only occasional fields having damaging 

 numbers of spittlebugs. It is too late for good control of spittlebugs because of 

 the tallness of the plants. Clover leaf weevil larvae are dying from disease and 

 can be found on the upper parts of the plants. It is also too late for profitable 

 control of this insect. 



Armyworms are still small and no large concentrations have been located. 

 However, they may be present and overlooked. There is no way of determining how 

 heavy egg laying has been from moths which are migrating from the south. Examine 

 rank growths of grasses and grains. 



If there is an average of six worms (l/2 inch or longer) or more per 

 linear foot of row, treatment is profitable. Toxaphene, 1 l/2 pounds, or dieldrin^ 

 l/k pound per acre, is recommended for small grains. Allow 7 days between treat- 

 ment with dieldrin and harvest, and 7 days for toxaphene on wheat but 14 days on 

 barley. 



For beef pastures, use toxaphene but allow 28 days between last grazing 

 and slaughter, or k-2 days if the animals are being sprayed with toxaphene, For 

 dairy pastures use 1 l/2 pounds of sevin or 2 pounds of methoxychlor per acre. Sevin 

 has no waiting period but do not graze cattle for 7 days when using methoxychlor. 



Corn borer pupation increased rapidly this past week with warm weather. 

 Approximately 70-80 percent of the borers have pupated in the south central section; 

 20-50 percent in the central and north central section; and 0-20 percent in the 

 northern section where pupation is just beginning. Development of corn borer is 

 ahead of last year and slightly ahead of normal. Corn development is later than 

 normal with only occasional fields showing through. This situation, if it continues, 

 coupled with the general low overwintering population of corn borer, indicates that 

 problems with first generation corn borer will be light, with the possible exception 

 of the early planted fields. 



