FOR IM/iEDIATE RELEASE July 26, 1963 



INSECT SURVEY BULLETIN NO. 15 



This is the fifteenth 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 reports indicate only general trends. Each individual should check his own 

 fields to determine local conditions. 



Grasshoppers have been hatching in hay crop fields for the past three 

 weeks. Although dry weather this year delayed hatching of the overwintering eggs, 

 most of them have now hatched. The rains of the past week did kill some of the 

 small grasshoppers, but not enough to reduce the problem. 



Infestations are more common and grasshoppers are present in greater 

 numbers in the northwestern area than elsewhere. Here the effects of their feed- 

 ing on the growth of alfalfa and red clover, although just now appearing, will 

 become progressively more apparent during the next two weeks. Not only will yields 

 of hay be reduced in many fields, but the grasshoppers may migrate to corn and soy- 

 beans either before or just as the hay is being cut. In many fields control now 

 will save hay yields and can almost eliminate later migrations to corn and soybean 

 fields . 



To avoid killing pollinating insects if alfalfa or clovers are in bloom, 

 apply insecticides only in the late afternoon or early evening. If your sprayer 

 has been used for 2,h-~D, clean it out thoroughly before spraying legumes or soy- 

 beans. 



For pasture or hay crops, apply 3A pound of sevin, 1 pound of malathion 

 or 3 A pound of dibrom per acre. Sevin does not require any waiting period between 

 application and grazing or cutting for hay, but with malathion allow a 7-day in- 

 terval and with dibrom a U-day interval. Diazinon may be used only on alfalfa, 

 provided a 7~day waiting period is observed. For best results, apply in the late 

 afternoon. These four insecticides are the only ones recommended for hay crops or 

 pastures for dairy animals or livestock fattening for slaughter. 



Occasionally grasshoppers can be trapped into narrow uncut strips of 

 clover or alfalfa and then sprayed, reducing the overall cost of materials. Leave 

 a few uncut swaths around the margin of the field and one swath a rod or so wide 

 through the center of the field. As you cut the remainder of the field, the 'hop- 

 pers will concentrate in them. Then spray these uncut strips. 



If areas will not be grazed or used for hay, apply 1 to 2 ounces of 

 dieldrin or 1 1/2 pounds of toxaphene per acre to control small 'hoppers. 



For soybeans or corn for grain, use 1 to 2 ounces of dieldrin or 1 l/2 

 pounds of toxaphene per acre. Allow 60 days to elapse between application of 

 dieldrin and harvest. If corn or soybeans are to be used for ensilage, hay or 

 pasture, use sevin or malathion with a 7-day interval between application and 

 harvest. Diazinon can be used on ensilage corn with a 1^-day interval between 

 application and harvest. 



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1961 



