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INSECT 



SURVEY 



BULLETIN 



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College of Agriculture 



University of Illinois 



and Natural History Survey, Urbana, Illinois 



tate / County / Local Groups / U. S. Department of Agriculture Cooperating 



FOR IMMEDIATE RELEASE 



May 26, 1967 



INSECT SURVEY BULLETIN NO. 7 



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This series of weekly bulletins provides a general look at the insect situatioifg c > 

 (fruit insects excepted), along with suggested, abbreviated control measures. j§| 

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



Forage Insects 



Alfalfa weevil populations are beginning to decline as larvae rapidly pupate 

 (resting stage) and overwintering adults lay fewer eggs. Spraying of the new 

 growth of the second crop will still be needed in some alfalfa fields south of a 

 line from Paris to Alton. Fields never treated and fields treated only once are 

 the most likely to have problems. Small larvae are still present, so damage is 

 expected to continue for another two to three weeks. 



Watch the new growth of the second crop closely; if it does not green up in a 

 few days and worms are present, treat it promptly. Preliminary results from 

 Dr. Ed Armbrust's research plots indicate that one-half the normal recommended 

 rate of insecticide in as little as 5 gallons of water per acre is effective as 

 a stubble treatment. Other more advanced second- crop fields should be treated 

 in a conventional manner when 50 percent of the terminals show apparent feeding 

 and larvae are still present. 



For control of alfalfa weevil larvae, farmers making their own applications should 

 use either malathion or a commercially prepared methoxychlor-diazinon (Alfatox) 

 mixture. Commercial applicators can use either of the above materials or one of 

 the more toxic insecticides, like methyl parathion or azinphosmethyl (Guthion) . 

 BE SURE AND FOLLOW LABEL DIRECTIONS FOR DOSAGES, HARVEST LIMITATIONS, AND PRECAU- 

 TIONS WHEN USING INSECTICIDES. 



Lesser clover- leaf weevil larvae can be found feeding behind leaf sheaths on red 

 clover in the southern half of the state; they will soon hatch in northern sections. 

 The larvae are small, gray- to-dirty-green worms with a black head. They can be 

 found in a dirty groove or tunnel in the stem behind the leaf sheaths , in the 

 axil of the stem, or in terminal buds. Infested plants are often stunted and 

 stems may wilt and die. Blooms may dry up and brown prematurely. No practical 

 control measures are known at this time. 



Small Grain Insects 



Armyworms can be found in most thick, rank stands of grains and grasses in the 

 southern half of the state. Infestations are heavy in some localized areas (as 

 high as 20 to 30 per linear foot of row) , but infestations are not generally heavy. 



