X hi 



FOR BMEDIATE RELEASE July 22, i960 



INSECT SURVEY BULLETIN NO. Ik 



This is the fourteenth in a series of weekly bulletins on the general in- 

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

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

 and cooperating agencies. It is designed to forewarn people in Illinois of impend- 

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

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

 to determine local conditions. 



Grasshoppers : Grasshoppers are still in fence rows and ditch banks, where 

 they hatched, but may soon migrate to and damage border rows of soybeans and corn. 

 This damage will be most noticeable in southeastern Illinois and the northern third 

 of the state. The 'hoppers can be controlled better now than after they have mi- 

 grated to cultivated crops. Apply 1/4 pound of dieldrin or 1 1/2 pounds of toxa- 

 phene per acre. If dairy pasture or forage must be sprayed, use 1 pound of 

 malathion, but do not pasture or harvest for 7 days after application. Toxaphene 

 may be used on forage crops to be fed to non-dairy animals, and no preslaughter 

 period is required unless the animals are sprayed with toxaphene to control external 

 parasites, such as lice, flies and mites. If they are sprayed with toxaphene, there 

 must be a 6- week interval between spraying and slaughter. 



Corn borers ; Ten percent of the fields of field corn surveyed in a 

 triangular area from Quincy to Decatur to St. Louis had first-generation corn borer 

 populations of more than one per stalk. Pupation of this first generation averages 

 5 percent in this area and will increase rapidly during the next two weeks. Moth 

 flight and egg- laying for the second generation will begin in about two weeks and 

 extend over a period of 2 to 3 weeks. Pupation has not begun yet in northern Illi- 

 nois but should begin within the next week. 



In general, corn borer populations may increase noticeably this year over 

 last. Furthermore, the damage to late fields from second-generation borers will be 

 more severe than last year. Because the corn is less mature, the damage will resemble 

 that of the first generation. The borers will bore into the stalk during ear forma- 

 tion, causing smaller as well as chaffy ears. 



Examine late fields of corn from August 1 in central and south-central 

 Illinois to August 20 in the north. If eggs are numerous--one or more per plant- 

 apply DDT at 1 1/2 pounds per acre as a spray or 1 pound per acre as granules. Do 

 not apply to corn to be used for ensilage or stover. Endrin can be applied to 

 ensilage corn to within k$ days of harvest. 



Corn leaf aphid : This pest is Just now appearing in tassels in the 

 earliest fields. It is usually most damaging in the late fields. If a population 

 build-up occurs, some control may be warranted. At what stage of development this 

 aphid actually damages the corn is not known, but the damage probably occurs during 

 the pretassel to early tassel stage. In severe infestations, apply 1 pound of mala- 

 thion per acre. Since effect of aphid control on yield is not known, this treatment 

 should be tried only on a small scale, and accurate yield records should be taken. 

 One- fourth pound of parathion or phosdrin may be applied, but only by operators 

 experienced in handling and applying them. One day should elapse between applica- 

 tions of phosdrin and harvest, 7 days with malathion, and 15 days with parathion*^ 



Face flies ; This new pest of cattle is expected to increase* from now^uSj 

 til fall. To control these flies on dairy cattle, apply daily, to the jin^mal^s 



^ >U 

 ^w** 1 



a 



