X AL / 



COLLEGE OF 

 AGRICULTURE 

 UNIVERSITY OF 

 ILLINOIS AT 

 URBANACHAMPAIGN 

 AND NATURAL 

 HISTORY SURVEY 

 URBANA, ILLINOIS 



NSECT WEED & PLANT DISEASE SURVEY BULLETIN 



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



FOR IMMEDIATE RELEASE 



No. 3, April 6, 1973 



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 deter- 

 mine local conditions. 



INSECTS 



FORAGE INSECTS 



Alfalfa weevil adults are now very active in southern Illinois, and egg-laying is 

 progressing rapidly. Many very small weevil larvae are present. Feeding is com- 

 mon in some fields, but alfalfa growth is comparatively good. Within the next two 

 weeks if we have average weather, applications of insecticide will be justified in 

 some fields. The alfalfa may grow rapidly enough to overcome severe damage in some 

 fields. If so, early cutting could be sufficient --but do not depend on this. Examine 

 fields about twice a week during this critical stage. 



Egg-laying has begun further north. Eggs can be found easily, but not in large 

 numbers, as far north as central Illinois. An evaluation of the possible infesta- 

 tion north of Highway route 13 (Harrisburg to Marion to Carbondale) is difficult at 

 this time. 



If 50 percent of the terminals now have alfalfa weevil feeding, using an insecti- 

 cide is justified. But you can still delay application a few days to allow more 

 eggs to hatch. As numbers of larvae increase, a lower percent of terminal feeding 

 justifies insecticide application, particularly if alfalfa growth is slow. 



The insecticide recommendations are: 



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

 methyl (Guthion) , or Supracide--or 1/4 pound of carbofuran (Furadan) . Use azin- 

 phosmethyl only once per cutting, and do not harvest for 16 days. Do not har- 

 vest for 15 days after a treatment with methyl parathion, 7 days after using 1/4 

 pound of carbofuran, or 10 days after using 1/2 pound of Supracide. As a general 

 precaution, wear protective clothing. Higher dosages of carbofuran will require 

 longer waiting periods. 



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 (Alfa-Tox) per acre; or (4) 1-1/4 pounds of malathion per acre on 

 days when air temperatures will be about 60° F. for several hours after appli- 

 cation. Do not harvest for 7 days after treatment with Imidan, methoxychlor, 



