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FOR IMMEDIATE RELEASE Mar 17; 1963 



INSECT SURVEY BULLETIN NO. 5 



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

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

 University of Illinois College of Agriculture, Illinois Natural History Survey and 

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

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

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

 determine local conditions. 



Corn borer pupation increased rapidly this past week in spite of the cool 

 weather. Approximately kO to 80 percent of the borers have pupated in the south 

 central section; 20 to 60 percent in the central and north-central sections; and 



to 20 percent in the northern section, where pupation is just beginning. Both 

 corn and corn borer are ahead of normal. If this situation continues, it will favor 

 survival of first-generation corn borer. The more mature the corn is at the time 

 of first -generation borer hatch, the better the chance for borer survival. 



The most seriously threatened area lies north and west of a line from Rock 

 Island to Peoria to Quincy. 



Pea aphid populations are heavy on alfalfa and clovers in the southern half 

 of Illinois. Damage is not yet apparent except in dry areas, but the situation 

 should be watched closely. 



Insects that feed on aphids, such as lady beetles, aphid lions, syrphid 

 flies and wasps are increasing and may hold aphid populations in check. A few dis- 

 eased aphids were also observed, which may help to lower aphid numbers. However, 

 if plants begin to wilt and injury becomes apparent and the crop is still more than 

 seven days from cutting, apply 1 pound of malathion per acre. 



Armyworms are numerous in lodged and thick areas of wheat, barley and rye. 

 One report of armyworms damaging a bluegrass pasture has been received. Observe 

 downed areas in small grains, and thick stands of small grains and grasses, for the 

 presence of this insect. Do not confuse the unimportant sawfly larva with that of 

 the true armyworm. Sawflies have a transparent skin and six or more pairs of prolegs 

 while armyworms have a nontransparent skin and fewer than six pairs of prolegs. If 

 there are six or more armyworms per linear foot of drill row in grain and they are 

 l/2 inch or more in length, treatment is advisable. Apply \/h pound of dieldrin or 



1 l/2 pounds of toxaphene per acre. When using dieldrin, do not harvest the grain 

 for seven days or the straw for 30 days. Toxaphene- treated barley should not be 

 harvested for grain within Ik days of treatment, but the grain of wheat or oats may 

 be harvested within seven days. Do not feed toxaphene -treated straw to dairy cattle 

 or fattening beef cattle. 



Alfalfa leafhopper adults migrated into Illinois on wind currents from 

 states to the south this past week. The heaviest fallout was in an area north of a 

 line from Pittsfield to Tuscola and south of a line from Mt. Carroll to Joliet. This 

 zone is about 50 miles north of the area normally involved in past years and in- 

 cludes more of the intensive alfalfa- growing area. 



These small green wedge-shaped leaf hoppers will now lay eggs that will 

 produce the young nymphs which, when numerous, cause yellowing of second- and third- 

 cutting alfalfa. It is too soon yet to predict the problems that mafjfj|[t^0|$iflfctfifl&ed 

 with this pest. 



MAY 2 3 1963 



