J- L 7 



COLLEGE OF i 



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 COOPERATING 



;qr immediate release 



II 



No. 5, April 25, 1969 



!%is series of weekly bulletins provides a general look at the insect, weed, and plant 

 iisease situation (fruit and commercial vegetables excepted) , along with suggested, 

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

 teoal conditions. 



INSECTS 



'ORAGE INSECTS 



U.falf a weevil varies greatly from field to field and from area to area. In some fields 

 vhere alfalfa growth is extremely slow, weevil development is equally slow; where alfalfa 

 Is growing rapidly, weevil development is also progressing rapidly. This reflects the 

 jffect of wind breaks, field slopes (south and west exposures warm up earlier) , and similar 

 factors that affect early growth. Each field must be examined to determine the weevil in- 

 festation. 



Since last week, weevil populations have jumped visibly in the area south of a line from 

 Carmi to Pinckneyville to Sparta. This week, we found up to 2,300 larvae per 100 sweeps 

 )f an insect net- -compared to only 200 last week. Terminal feeding varied from a low of 

 .0 percent in some fields to a high of 75 percent in others. The ideal treatment period 

 started this week and will continue into next week (the week of April 28) . If a field is 

 athin 2 weeks of harvest, you may choose to cut early, remove the hay, and spray the new 

 growth. 



! rom the Carmi- to- Sparta line north to Highway 50, the weevil populations are not high 

 ret. They range from 100 to 300 per hundred sweeps of an insect net. In this area and 

 iust to the north of it, the variation between fields is quite noticeable; so each field 

 iust be examined. Populations are increasing here and insecticide treatments may be 

 leeded by the middle or latter part of the week of April 28. Early cutting may also be 

 i partial answer to weevil control there. 



Tie weevil situation varies greatly in the area between Highway 50 and a line from Paris 

 :o Mattoon to Carlinville. Although treatment may be warranted in an occasional field 

 .ate the week of April 28, treatment generally will not be necessary until the week of 

 lay 5- -unless weather becomes unseasonably warm. Early cutting, hay removal, and spray - 

 ng new growth may help answer the weevil problem by then. 



Ms year, as last, one application may be enough to protect the first cutting, but watch 

 he new growth carefully because new shoots may need protection. If fields are more than 

 ! weeks from harvest and 25 percent of the terminals show noticeable feeding, treat them. 



he insecticide recommendations are: 



Commercial applications 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. 



