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FOR IMMEDIATE RELEASE June 29, 1962 



INSECT SURVEY BULLETIN NO. 11 



These -weekly bulletins, prepared by entomologists of the University of 

 Illinois College of Agriculture, Illinois Natural History Survey and cooperating 

 agencies, report general trends in insect populations in Illinois (fruit insects 

 excepted). Check your own fields to determine local conditions. 



Grasshoppers ; Populations still vary greatly from one area to another. 

 The only new development this week took place in the northern third of Illinois, 

 ■where grasshoppers started hatching in large numbers in clover and alfalfa fields. 

 These tiny 'hoppers are very difficult to see and can easily be overlooked. How- 

 ever, within a few weeks they will become more apparent. 



Hard, beating rains can still help control grasshoppers now, but will be 

 of little help later. No signs of grasshopper diseases or parasites have been 

 observed. 



If small'hoppers are extremely numerous in diverted acres, fence rows, 

 ditch banks, grass waterways, roadsides and similar areas, apply 1/8 lb. of dieldrin 

 or 1 1/2 lb. of toxaphene to areas that will not be grazed or used as hay for dairy 

 animals or livestock fattening for slaughter. Aldrin or heptachlor can also be used 

 in these areas at l/h lb. per acre. 



If treating hay crops or pastures, use 1 lb. or malathion or 3/k to 1 1/2 

 lb. of Sevin. (From now on, the rate of Sevin depends on the size of the grasshop- 

 pers.) Allow one week to elapse between application of malathion and grazing or 

 cutting. No interval is required with Sevin. Diazinon can be used on alfalfa only, 

 at 1/2 lb. per acre, with a 7-day interval between application and harvest. Dibrom, 

 a comparatively new insecticide, can be used on alfalfa or red clover hay or pasture. 

 Allow h days to elapse between treatment and harvest. Toxaphene, 1 l/2 lb. per acre, 

 can be used on permanent pastures only, and for beef cattle only. If toxaphene is 

 also being applied to the cattle for fly control, allow k-2 days to elapse between 

 last grazing and slaughter. Do not graze dairy animals on toxaphene- treated forage 

 or pasture. 



For corn or soybeans, apply 1 or 2 oz. of dieldrin or 1 1/2 lb. of toxa- 

 phene. To protect seedings in small grain, apply 2 oz. of dieldrin or 1 1/2 lb. 

 of toxaphene. Do not treat within one week of harvest of the grain except for toxa- 

 phene on barley, when a two-week interval is required. 



Corn borer : Egg laying is about complete except in northern Illinois. 

 Extremely advanced field corn in this area warranting treatment may still be treated 

 this week, but in most areas of Illinois it is too late for maximum control, since 

 borers are beginning to enter the stalk. 



To determine need for treatment, examine 50 to 100 plants for signs of 

 borer feeding on the whorl leaves. If 75 percent or more of the plants show recent 

 whorl feeding, check the tassel ratio. Measure from the base to the tip of the 

 plant with the leaves e:ctended. Split the plant lengthwise, and measure from the 

 base of the plant to the tip of the developing tassel. Divide tassel height by plant 

 height, and multiply Dy 100. Take an average for five representative plants per 



