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COLLEGE OF 

 AGRICULTURE 

 UNIVERSITY OF 

 ILLINOIS AT 

 URBANA-CHAMPAIGN 

 AND NATURAL 

 HISTORY SURVEY 

 URBANA, ILLINOIS 



INSECT. WEED & PLANT DISEASE SURVEY BULLETIN 



STATE/COUNTY/LOCAL GROUPS/U S. DEPARTMEMT OF AGRICULTURE COOPERATIM&. r VT" ">,' .'■'■''" 



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FOR IMMEDIATE RELEASE 



001 



No. 3, April 11, 1969 



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, ab- 

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

 local conditions. 



INSECTS 



FORAGE 



Alfalfa weevil development continues to be slow in the area south of a line from St. Louis 

 to Lawrenceville. A few fields in this area had very light feeding on 10 to 30 percent of 

 the terminals, but visible damage is not readily apparent. Most larvae are small and are 

 found only by close examination of the buds of the plants. Further north, the hatch has 

 been delayed. 



Adult alfalfa weevil populations started to build up this week south of Route 50, ranging 

 from 20 to 90 per 100 sweeps. The warm days recently caused these adults to become very 

 active. Egg laying is increasing rapidly. 



Depending on the weather conditions, insecticide treatments will not be necessary for 7 to 

 10 days. Egg- laying and egg-hatch will increase at a rapid rate if the warm weather con- 

 tinues. Watch your fields closely during the next week for increasing larval populations 

 and feeding damage, particularly on south slopes. As soon as 25 percent of the terminals 

 show noticeable feeding, it is time to treat. 



The insecticide recommendations are: 



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

 methyl (Guthion) with good results. Use azinphosmethyl only once per cutting. Do not 

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

 Wear protective clothing. 



2. Persons not equipped with protective clothing can use a mixture of (1) 3/4 pound of 

 malathion and 3/4 pound of methoxychlor per acre, (2) a mixture containing at least 

 1/2 pound of diazinon and 1 pound of methoxychlor per acre, or (3) 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 methoxychlor, 

 diazinon, or mixtures of them. There is no waiting period for malathion. 



The 24-county European corn borer survival survey is now completed. Nearly all areas in 

 the state revealed higher- than -normal survival rates. Several county Extension advisers 

 report corn borer survival of 70 to 98 percent. 



