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Resistant seed-corn beetles and maggots were controlled by planting applications 

 of Dasanit, diazinon, dyfonate , Furadan, and phorate. We have no data on seed- 

 beetle control by the use of planter applications of carbaryl, disulfoton, and 

 parathion. 



In a few fields in central Illinois, an experimental application of 3 ounces of 

 50-percent diazinon wettable powder plus 1-1/2 ounces of graphite per bushel of 

 seed just prior to planting gave excellent seed-corn beetle control. Resistant 

 seed-corn maggots have been controlled with as little as 1/2 ounce of diazinon 

 per bushel of seed in Canada. The rate of diazinon to be used per bushel of 

 seed has not been thoroughly established for seed-corn beetle and seed-corn maggot 

 control in Illinois. It is possible that i ounce per bushel of the actual diazinon 

 may provide excellent control. 



If combinations of diazinon and other insecticides are used as seed treatments, 

 follow the manufacturer's directions to avoid possible germination injury. In 

 using a seed treatment, empty and clean the planter often. This will avoid any 

 accumulation of excess powder in the bottom of the planter box, which could inter- 

 fere with seeding rates. 



To further confuse the soil-insect problem in Illinois cornfields, the garden 

 symphylan (a tiny, white, rapidly-moving, centipede -like pest) appeared in many 

 Illinois cornfields. It feeds on corn roots. Small areas in a field may be 

 generally stunted, or one plant may be knee-high while an adjoining plant may be 

 shoulder-high. These stunted plants do not produce normally. Of the insecticides 

 mentioned for rootworm control, only dyfonate seems to be effective in controlling 

 this pest. Effective control using zinophos and parathion has been reported by 

 some states. 



CONDENSED SOIL INSECTICIDE SUGGESTED USES 



In 1969, suggestions for maximum soil-insect control in Illinois cornfields must 

 be based on individual situations. We have attempted to list them below: 



1. First-year corn, or any corn in areas where rootworms are no problem: 



On nondairy farms : 



Use diazinon as a seed treatment to control resistant seed-corn beetles and 

 seed-corn maggots. If cutworms, wireworms, white grubs, grape colaspis, and 

 others are usually a problem, broadcast and disk-in 1-1/2 pounds of aldrin or 

 heptachlor per acre prior to planting. Row treatments of 1 pound per acre can 

 be used, but will be less effective. 



On dairv farms : 



i. 



If soil insects have been a problem, apply 1 to 1-1/2 pounds of diazinon, or 

 1 pound of Dasanit, dyfonate, or phorate at planting time in a 7-inch band to 

 the surface of the soil ahead of the press wheel. If you do not do this, at 

 least as a minimum, use a diazinon seed-treatment. If you suspect that garden 

 symphylans are present, use dyfonate at planting time. 



