COLLEGE OF 

 AGRICULTURE 

 UNIVERSITY OF 

 ILLINOIS AT 

 URBAN A-CH AMP AIGN 

 AND NATURAL 

 HISTORY SURVEY 

 URBANA. ILLINOIS 



NSECT WEED & PLANT DISEASE SURVEY BULLETIN 



ATE/COUNTY/LOCAL GROUPS/U.S. DEPARTMENT OF AGRICULTURE COOPERATING 



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-OR IMMEDIATE RELEASE 



ytPtfP' No. 3, April 17, 1970 



Fhis series of weekly bulletins provides a general look at the insect, weed, and plant 

 lisease situation (fruit and aommeroial vegetables excepted) , along with, suggested, ab- 

 breviated control measures. Each individual should check his own fields to determine 

 local conditions. 



INSECTS 



?0RAGE INSECTS 



Ufalfa weevil development is slightly behind last year. Generally, alfalfa growth is 

 ;ood, and damage from alfalfa weevil larvae should not be much different than last year, 

 fhese green larvae have a light stripe down the back and shiny black head. 



(n southern Illinois this week, they were still very small and hardly noticeable at a 

 luick glance. Some feeding was observed, but only by careful examination of the new 

 shoots. Applications of insecticides, where needed, probably should not be made until 

 late next week at the earliest. 



tn south-central and central Illinois, an occasional larva can be found. The adults, 

 low present in moderate numbers, are laying their eggs. With normal temperatures, treat- 

 ments with insecticides will not be needed for at least 10 days to two weeks in south- 

 :entral Illinois, and not for 3 weeks in central Illinois. 



vhen there is feeding on 25 percent or more of the terminals and the field is more than 

 ;wo weeks from harvest, an insecticide application is justified. 



ihe insecticide recommendations are: 



Commercial applicators . Apply 1/2 pound per acre of methyl parathion or azinphosmethyl 



(Guthion) . Use azinphosmethyl only once per cutting. Do not harvest for 15 days after 



treatment with methyl parathion, or 16 days for azinphosmethyl. Wear protective cloth- 

 ing. 



Persons not equipped with protective clothing . Use (1) Imidan at 1 pound per acre, 

 (2) a mixture of 5/4 pound of malathion and 3/4 pound of methoxychlor per acre, (3) a 

 mixture containing at least 1/2 pound of diazinon and 1 pound of methoxychlor per 

 acre, or (4) 1-1/4 pounds of malathion per acre on days when air temperatures will be 

 above 60° F. for several hours after application. Do not harvest for 7 days after 

 treatment with Imidan, methoxychlor, diazinon, or mixtures of them. There is no wait- 

 ing period for malathion. Do not apply Imidan more than once per cutting. 



Tover leaf weevil larvae are very numerous in some red clover fields in southern Illinois, 

 "he clover is growing, however, and damage is still minor, although it may become more 

 ipparent soon. 



