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FOR IMMEDIATE RELEASE 



INSECT <*• , ^-'"*- 

 SURVEY 

 BULLETIN "*»,* 



College of Agriculture 



University of Illinois 



and Natural History Survey, Urbana, Illinois 



U. S. Department of Agriculture Cooperating 



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UWV&SI7Y nr .. A P ril 28 » 1967 



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INSECT SURVEY BULLETIN NO. 3 



This series of weekly bulletins provides a general look at the insect situation 

 (fruit insects excepted) along with suggested, abbreviated control measures. Each 

 individual should check his own fields to determine local conditions. 



Forage Insects 



Alfalfa weevil populations remain high and damage is severe in most alfalfa fields 

 south of Highway 40. In the area between Highway 40 and a line from Champaign to 

 Pittsfield, larvae can be found and feeding is noticeable in many fields. Occa- 

 sional fields in this area need treatment, but all fields should be watched closely 

 for the next few weeks. The weevil was found for the first time in Lee County this 

 week. 



The cold weather has slowed plant growth and, to a lesser extent, weevil feeding, 

 but it did not alleviate the weevil problem. It is best to wait a day or two for 

 warmer weather before spraying. However, if feeding damage increases markedly, 

 treat immediately regardless of temperature. 



Fields should be treated immediately when 25 to 50 percent of the terminals show 

 apparent feeding and larvae are still present. Serious injury can occur within a 

 few days after this feeding level is reached. As harvest time nears, it may be 

 wiser to cut the alfalfa a few days early, remove the hay, and then treat the new 

 growth . 



Weevil populations and damage still vary considerably from field to field, and 

 each field should be judged on an individual basis. Populations are expected to 

 cause damage for several weeks yet. 



Plan on applying 20 gallons of water per acre with the correct amount of insecti- 

 cide, except for stubble sprays where 10 to 12 gallons per acre is adequate for 

 coverage. We have observed good results with aerial applications, using 4 gallons 

 of finished spray per acre. Rain immediately following spraying may reduce effec- 

 tiveness, requiring a repeat treatment. 



The following insecticides are suggested for alfalfa weevil control: 



1. Methoxychlor, 1 pound, plus diazinon, 1/2 pound per acre . Such a mixture can 

 be purchased under the trade name Alfatox. It is effective for approximately 

 10 to 14 days. Do not harvest for 7 days after treatment. 



