COLLEGE OF 

 AGRICULTURE 

 UNIVERSITY OF 

 ILLINOIS AT 

 URBANA-CHAMPAIGN 

 AND NATURAL 

 HISTORY SURVEY 

 URBANA. ILLINOIS 



NSECT WEED & PLANT DISEASE SURVEY BULLETIN 



ATE/COUNTY/LOCAL GROUPS/U.S. DEPARTMEMT OF AGRICULTURE eOOPETOVpNG 



FOR IMMEDIATE RELEASE 



PEG! 



No. 7, May 9, 1969 



i 



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 



FORAGE INSECTS 



Alfalfa weevil development and alfalfa growth have both speeded up this past week. 

 Severe feeding was found in many fields below Highway 40, moderate to light feed- 

 ing in fields in the central section, and very light feeding in the north-central 

 section of the state. Many alfalfa fields have been or will be cut within a week. 



If the first cutting has been removed, be sure to watch the new growth of the 

 second crop. If larvae are present and damage is being done, spray immediately. 

 In the central part of the state, fields are generally within two weeks of harvest 

 and damage is light. Therefore, it would be best to cut early, remove the hay, 

 and treat the new growth. Also, if flower buds are present (regardless of how 

 much damage the weevil has done) and if the field has not been treated, cut the 

 alfalfa, remove it, and spray the second-crop new growth. 



Parasites of the alfalfa weevil were found in some areas of the state in 1968, 

 with the parasitism ranging up to 78 percent. Parasites are small wasp larvae 

 that hatch-out inside the weevil and feed on it. Again this past week, parasitism 

 was found in larvae collected in the southern part of the state. The percent of 

 larvae parasitized varied from area to area, but averaged 85 percent around 

 Lawrenceville . If fields are more than 2 weeks from harvest and 25 percent of 

 the terminals show noticeable feeding, treat them. 



The insecticide recommendations are : 



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

 azinphosmethyl (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) 5/4 pound 

 of malatnion 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. 



