COLLEGE OF 

 AGRICULTURE 

 UNIVERSITY OF 

 ILLINOIS AT 

 URBANA CHAMPAIGN 

 AND NATURAL 

 HISTORY SURVEY 

 URBANA. ILLINOIS 



NSECT WEED & PLANT DISEASE SURVEY BULLETIN 



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





FOR IMMEDIATE RELEASE 







No. 4, April 23, 1971 



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

 plant disease situation (fruit and aommeraial vegetables excepted) , along with 

 suggested, abbreviated control measures. Each individual should check his own 

 fields to determine local conditions. 



GENERAL INFORMATION 



Insect development has been at a practical standstill until recently. When a 

 cool spring suddenly "breaks" into summer, insect development, retarded early, 

 accelerates, and everything seems to happen at once. If warm weather continues 

 generally over the state, expect appearance of insects in northern Illinois about 

 as soon as in southern Illinois. Also expect many species to appear all at once-- 

 some earlier than usual and some later. 



INSECTS 



FORAGE INSECTS 



Alfalfa weevils . Feeding became evident in most alfalfa fields in extreme south- 

 ern Illinois this past week, and severe damage has occurred to some fields. Pop- 

 ulations of the green worms are high, and there are still many eggs to hatch. 

 Spray applications should be made immediately in severely infested fields . Con- 

 sider cutting instead of spraying in severe cases. 



In the area north of Highway 13 and south of Highway 50, larvae are evident and 

 damage is increasing rapidly. Adults are still numerous and continue to deposit 

 eggs in alfalfa stems. The situation will be critical for the next ten days. 



In the area north of Highway 50 to Highway 36, the development is a bit slower. 

 Larvae are numerous but adults are present in large numbers. The next ten days 

 to two weeks are critical in the south part of this area, but it will be two weeks 

 or more before decisions regarding treatment will be required in the north part 

 of this area. 



North of Highway 36 it will still be two to four weeks before infestations are se- 

 rious . 



The above estimates are based on normal temperature and rainfall expectations . 

 Should spring "bust out all over" at the same time and to the same degree, the 

 time lapse in development will be greatly narrowed. 



The insecticide recommendations are: 



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

 inphosmethyl (Guthion) for good results . Use azinphosmethyl only once per 

 cutting. Do not harvest for 15 days after treatment with methyl parathion, 

 or 16 days for azinphosmethyl. Wear protective clothing. 



