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FOR IMMEDIATE RELEASE April 30, 1 Q 65 



INSECT SURVEY BULLETIN NO. 2 



This is the second in a series of weekly bulletins on the general insect 

 situation in Illinois (fruit insects excepted), prepared by entomologists of the Uni- 

 versity of Illinois College of Agriculture, Illinois Natural History Survey, and co- 

 operating agencies. It is designed to forewarn people in Illinois of impending 

 changes in insect activity and to suggest abbreviated control measures. These reports 

 indicate only general trends. Each individual should check his own fields to deter- 

 mine local conditions. 



Alfalfa weevils are common in alfalfa fields in the extreme southern coun- 

 ties. The larvae resemble the clover leaf weevil which feeds only at night or on 

 cloudy days. However, alfalfa weevil can be readily found feeding on the leaves 

 during the day. The feeding appears as skeletonizing on the new terminal leaves 

 which then dry rapidly and take on a whitish cast. Alfalfa will soon be cut, thus 

 killing many of the worms, but damage on the new shoots may still occur. Feeding 

 will continue for the next few weeks but will start to decline by mid-May. At pres- 

 ent we are not recommending an insecticide control program but may have to do so by 

 next year. 



Pea aphids are common in many alfalfa fields but not numerous enough to be 

 of economic importance. If weather remains unseasonably cool, aphid parasites and 

 predators will not multiply fast enough to help control these aphids. However, a 

 fungus disease was killing aphids this week. This disease could spread causing an 

 aphid-disease epidemic, and will occur if the weather warms up. 



Clover leaf weevil populations are low this spring. This is the green 

 worm with the white or yellow stripe down its back which is found in the debris 

 around clover plants during the day. It feeds on leaves at night or on cloudy days. 

 Furthermore, a parasite present for the past two years has killed many of them. With 

 warm, humid weather, a fungus which attacks this pest will become prevalent. It will 

 infect these larvae and reduce their numbers very rapidly. The rapid growth of al- 

 falfa and red clover is encouraging as it enables plants to recover rapidly from any 

 feeding injury of aphids or clover leaf weevil. 



Potato leafhoppers, a pest of alfalfa in Illinois, migrate into the state 

 each year from the south. The first migrant leafhopper was found in Illinois this 

 week. 



European corn borers have overwintered successfully and seem to be quite 

 healthy. Between 10 and 20 percent of the wintering borers in southern Illinois 

 pupated this week. Pupation in this area will now proceed rapidly if the weather 

 becomes warmer. No pupation has occurred in other areas of the state. 



Armyworm moths have been present for the past 3 weeks. No large numbers 

 have been observed. 



Bagworm eggs have overwintered successfully as usual. Right now it is 

 possible to pick these bags off the shrubs and trees,* destroy them, as they are full 

 of eggs which will hatch in about h weeks. If you hand pick now, you may not have 

 to spray your evergreens for newly hatching bagworms in June. 



