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COLLEGE OF 

 AGRICULTURE 

 UNIVERSITY OF 

 ILLINOIS AT 

 URBANA-CHAMPAIGN 

 AND NATURAL 

 HISTORY SURVEY 

 URBANA. ILLINOIS 



NSECT WEED & PL ANT DISEASE SURVEY BULLETIN 



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













FOR IMMEDIATE RELEASE No. 5, May 5, 1972 



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

 disease situation (fruit and eommeraial vegetables^ excepted) , along with suggested, ab- 

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

 local conditions. 



INSECTS 



FORAGE INSECTS 



Alfalfa weevil populations should have reached a peak this week in the area south of 

 Route 460. Some fields treated in recent weeks now contain small larvae, indicating 

 that some egg- laying and hatching is still going on. Fields in this area that were 

 treated early should be watched closely for damage. Another insecticide treatment may 

 be needed if cutting is delayed. On untreated fields with heavy damage, it would be 

 best to cut the hay, remove it, and treat the new growth- -if needed. 



For the most part south of Route 460, alfalfa weevils are pupating rapidly, 

 ber of larvae will decline as harvest time approaches. 



The num- 



Between Routes 460 and 36, damage to alfalfa is quite apparent in the western and 

 southern areas. If the harvest is late, treatments will be profitable this week in 

 many of the fields that are still untreated. 



Between Routes 36 and 136, an occasional field in the western area has tip-feeding of 

 more than 25 percent. In general, the number of larvae is low. Cool weather has been 

 unfavorable for their development. Fields in this region, particularly in the west, 

 will have to be evaluated individually to determine the need for treatment. 



North of Route 136, the number of alfalfa weevils is still low, and tip feeding is 

 negligible. 



The insecticide recommendations are: 



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

 methyl (Guthion) for good results. Use azinphosmethyl only once per cutting, 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 methoxychlor per 

 acre; (3) a mixture containing at least 1/2 pound of diazinon and 1 pound of meth- 

 oxychlor (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 after application. Do 

 not apply Imidan more than once per cutting. 



