In 7 



COLLEGE OF 

 AGRICULTURE 

 UNIVERSITY OF 

 ILLINOIS AT 

 URBANA-CHAMPAIGN 

 AND NATURAL 

 HISTORY SURVEY 

 URBANA. ILLINOIS 



NSECT. WEED & PLANT DISEASE SURVEY BULLETIN 



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



FOR IMMEDIATE RELEASE 



No. 7, May 15, 1970 



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

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

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

 local conditions. m U(8MRy Qf ^ 



INSECTS 



JUN 18 1970 



FORAGE 



ynlVeWSITY Of ILLINOIS 

 AT UHBANA^HAMPAIGN 



Alfalfa weevils are heavier this spring than during either of the last two years. 



Populations are high, and damage is evident in most fields south of U.S. Highway 136. 



Pupation is progressing rapidly. Wasp parasites are helping some to reduce the number 



of weevils. Eggs are still hatching, however, so populations are expected to remain 



high for another two to three weeks . 



Larvae can be found north of U.S. Highway 136. Feeding is noticeable but not severe. 

 Some fields north of this line may need treatment within the next week or two. The 

 greatest injury in this area could be on the new growth of second-crop alfalfa. 



As you continue to check fields for damage, judge each field separately. The weevil 

 population varies greatly from field to field. Do not apply insecticides unless they 

 are needed. Applying insecticides is justified when there is apparent feeding on 

 25 percent or more of the terminals and the field is more than two weeks from harvest. 

 If the field is showing moderate to severe damage and is less than two weeks from 

 harvest (particularly in the southern section), cut and remove the crop. Cutting 

 will often reduce the weevil population, since many eggs are removed and a good many 

 larvae are either killed or forced to pupate by exposure to the sun. Watch the new- 

 growth closely; if it does not green-up within a few days and if worms are still 

 present, apply a treatment promptly. 



The insecticide recommendations are: 



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

 methyl (Guthion) . Die" 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 7 



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. 



