County 



Local Groups 



INSECT 



SURVEY 



BULLETIN 





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College of Agriculture 



University of Illinois 



and Natural History Survey, Urbana, Illinois 



U. S. Department of Agriculture Cooperating 



FOR IMMEDIATE RELEASE 



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INSECT SURVEY BULLETIN NO .,-6 





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May 19, 1967 





This series of weekly bulletins provides a general look at the insect situation 

 (fruit insects excepted), along with suggested, abbreviated control measures. 

 Each individual should check his own fields to determine local conditions. 



Forage Insects 



Alfalfa weevil populations continue high in most alfalfa fields south of a line 

 from Paris to Alton. Populations are expected to be damaging for another two to 

 three weeks. The prolonged period of cool weather slowed weevil development and 

 populations did not increase greatly. With warm weather, populations could still 

 increase before the final rapid decline occurs. North of this line (Paris to 

 Alton), weevil feeding is noticeable, but is not of economic importance. 



Many larvae are now pupating; new spring adults are already abundant in many fields. 

 Generally, these adults will not lay eggs until fall or next spring. Adult feed- 

 ing damage appears as feathering of the leaf margins, in contrast to the the skele- 

 tonizing injur)' of the larvae. 



In most of the current problem fields, it is too late to spray the first-growth 

 alfalfa. Cut it, remove the hay, and spray the new growth of the second crop im- 

 mediately. If the crop has been cut, but the new growth of the second crop not 

 sprayed, watch it closely for evidence of weevil damage. If it does not green-up 

 in two or three days and worms are present, treat it promptly. Other fields should 

 be treated immediately when 25 to 50 percent of the terminals show apparent feeding 

 and larvae are still present. There are many second-crop fields in southern sec- 

 tions that need another spraying. 



For control of alfalfa weevil larvae, farmers making their own applications should 

 use either malathion or a commercially prepared methoxychlor-diazinon (Alfatox) 

 mixture. Commercial applicators can use either of the above materials or one of 

 the more toxic insecticides like methyl parathion or azinphosmethyl (Guthion) . 

 Be sure and follow label directions for dosages, harvest limitations, and precau- 

 tions when using insecticides. 



Potato leafhoppers continue their migration into the state from the south. These 

 tiny, green, wedge-shaped insects that skid sideways when disturbed cause yellow- 

 ing of second and third cutting alfalfa. No control measures are recommended at 

 this time. 



