TiA 7 



COLLEGE OF 

 AGRICULTURE 

 UNIVERSITY OF 

 ILLINOIS AT 

 URBANA-CHAMPAIGN 

 AND NATURAL 

 HISTORY SURVEY 

 URBANA. ILLINOIS 



NSECT, WEED & PLANT DISEASE SURVEY BULLETIN 



TATE/COUNTY/LOCAL GROUPS/US. DEPARTMENT OF AGRICULTURE COOPERATING 



FOR IMMEDIATE RELEASE 



No. 6, May 8, 1970 



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

 disease situation (fruit and commercial vegetables excepted) , along with suggested 

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

 local conditions. 



THE UI8RARY OF THE 



INSECTS 



JUN 18 1970 



FORAGE 



Alfalfa weevil larvae 

 Pupation has already b 

 southern third of the 

 ments started late las 

 may still be profitabl 

 so rapidly that if the 

 and treat the second g 



UNIVERSITY Qf IttiNOIS 

 AT URBANA^HAMPAIQN 



are now very numerous in the southern third to half of Illinois, 

 egun. Severe damage has occurred to some alfalfa fields in the 

 state. Damage is common within most fields in that area. Treat- 

 t week in fields where the weevils developed early. Treatment 

 e in some fields, but damage and crop growth may have progressed 



field is within ten days of harvest, it might be best to cut 

 rowth- -should this become necessary. 



In the central third of the state (latitude, St. Louis to Peoria), weevil development 

 has progressed rapidly and damage is heavy. Now is the time to treat fields in that 

 area. 



In the northern third of Illinois, only moderate damage is expected. Although alfalfa 

 weevils are a severe problem in producing the first cutting of alfalfa in southern 

 Illinois, they may be a second- cutting problem in the north. Therefore, watch the 

 second growth of alfalfa in the northern section. 



Examine each field regularly. Do not apply insecticides unless they are needed. When 

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

 weeks from harvest, an insecticide application may be justified. 



The insecticide recommendations are: 



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

 methyl (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 clothing. 



2. 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 ' 

 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 . 



