'/H, 7 



COLLEGE OF 

 AGRICULTURE 

 UNIVERSITY OF 

 ILLINOIS AT 

 URBANA-CHAMPAIGN 

 AND NATURAL 

 HISTORY SURVEY 

 URBANA. ILLINOIS 



NSECT. WEED & PLANT DISEASE SURVEY BULLETIN 



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



FOR IMMEDIATE RELEASE 



No. 3, April 21, 1972 



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. 



INSECTS 



THE LIBRARY. OE IHE 



iviAr % W2 



FORAGE INSECTS 



UNlVfcKSlTY OF ILLINOIS 



Alfalfa weevils . The populations remain high in maiiy iareas . Severe rams this 

 • past week may have killed some larvae just as they were hatching; but in general, 

 the rains did not reduce the problem. Since alfalfa in some fields may grow away 

 from feeding damage, each field should be judged on its own merits; also, popula- 

 tions vary from field to field. 



South of highway 13, damage is serious in unsprayed fields but many fields have 

 been sprayed. Parasitic wasps have been observed in this area. Watch treated 

 fields for reinfestations . 



In the area between highways 13 and 50, damage is very severe in some unsprayed 

 fields; and for many fields, treatment is in order. Some are beginning to take 

 on a silvery appearance. Damage to unsprayed, infested fields on the west side 

 of this area will continue to increase because the number of weevils is quite 

 high. 



Between highways 50 and 16, damage is apparent but the larvae are still small. 



More eggs will be hatching. It may be possible to delay spraying for several 



more days to see if the alfalfa can grow away from the weevil feeding. If so, 

 further damage can be reduced by early cutting. 



The insecticide recommendations are: 



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

 phosmethyl (Guthion) for good results. Use azinphosmethyl only once per cut- 

 ting, and do not harvest for 16 days. Do not harvest for 15 days after a 

 treatment with methyl parathion. As a general precaution, 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 methoxy- 

 chlor 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 above 60°F. for several hours 



