INSECT 



SURVEY 



BULLETIN 





i 



College of Agriculture 



University of Illinois 



and Natural History Survey, Urbana, Illinois 



Local Groups 



FOR IMMEDIATE RELEASE 



S. Department of Agriculture Cooperating 



TEE liirjfflf GF THE 



APR 2 5 1367 

 UNIVERSITY OF ILLINOIS April 14 » 1967 



INSECT SURVEY BULLETIN NO. 1 



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. Before 

 applying insecticides, read the labels carefully and follow all precautions. 

 This will not only insure personal safety, but will also prevent residue hazards. 



The alfalfa weevil is seriously damaging alfalfa south of Highway 13. Infesta- 

 tions and damage vary from field to field. Some fields are already completely 

 defoliated, while others show only limited feeding. In this area, the weevil was 

 active throughout the winter, and pupae (resting stage, between larva and adult) 

 were found as early as March. Many larvae are now pupating. But with overwinter- 

 ing adults still laying eggs, populations of larvae can be expected to remain high 

 for several weeks yet. In one sweep of an insect net, it is not uncommon to find 

 40 to 70 of these larvae- -light green with white stripes down their back, and a 

 black head. A close inspection of the terminal leaf buds will usually produce 

 from 5 to 15 small larvae (these are more yellowish but, with a black head) . 



It is too late to treat fields where the terminal leaves and lower leaves are al- 

 most completely destroyed. Cut the alfalfa and remove the hay, then spray with an 

 insecticide to protect the new growth. 



In the area between Highways 13 and 50, infestations are lower and feeding is not 

 as noticeable. However, some fields in this area will need treatment this week. 



In the area between Highway 50 and a line from Champaign to St. Louis, larvae can 

 be found and feeding is noticeable. But it will be another week or more before 

 the situation becomes critical. 



Apply insecticide sprays when 50 percent or more of the terminals show very appar- 

 ent feeding and live larvae are present. After this feeding level is reached, 

 serious damage can occur in a few days. Some fields will need to be retreated be- 

 fore weevil problems subside. It is expected that two to three sprayings will be 

 required to adequately protect many alfalfa stands south of Highway 50, while one 

 to two sprayings will be needed in the area between Highway 50 and a line from 

 Champaign to St . Louis . 



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

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

 coverage. 



