COLLEGE OF 

 AGRICULTURE 

 UNIVERSITY OF 

 ILLINOIS AT 

 URBANA-CHAMPAIGN 

 AND NATURAL 

 HISTORY SURVEY 

 URBANA, ILLINOIS 



MSECT. WEED & PLANT DISEASE SURVEY BULLETIN 



! IVTE/COUNTY/LOCAL GROUPS U.S. DEPARTMENT OF AGRICULTURE COOPERATING 



OR IMMEDIATE RELEASE No. 2, April 9, 1971 



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

 isease situation (fruit and commercial vegetables excepted) , along with suggested, ab- 

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

 ocal conditions. 



INSECTS 



ORAGE INSECTS 



lfalfa weevil. Their development and that of the crops has been slowed down by the cold 

 eather this past week. Insects usually develop at a slightly faster rate than plants 

 uring these cool periods. 



he likelihood of serious damage by alfalfa weevil larvae is greater if temperatures re- 

 ain on the cool side. 



dult weevils are continuing to lay eggs and young larvae are hatching. These tiny, 

 ream-colored larvae (not green yet) can be found tunnelling into leaf buds and working 

 nto folded leaves. Presently, this feeding is minor and hardly noticeable. 



opulations of this insect will vary greatly from area to area and even from field to 

 ield. Treatment with an insecticide is justified when 25 percent of the tips show 

 eeding and the larvae are still present. Do not apply insecticides unless they are 

 eeded. We would expect insecticide applications to be warranted within 10 days to two 

 eeks in the extreme southern section of the state, two to three weeks in the south - 

 entral section, and three to five weeks in the central section. 



tie insecticide recommendations are: 



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

 (Guthion) for good results. Use azinphosmethyl only once per cutting. Do not harvest 

 for 15 days after treatment with methyl parathion, or 16 days for azinphosmethyl. Wear 

 protective clothing. 



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

 (2) a mixture of 3/4 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 waiting period 

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



Using ground equipment . 

 4 gallons by air. 



Apply a minimum of 20 gallons of finished spray per acre, or 



