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occasion in field corn get down to the tip of the ear where they can puncture a few 

 kernels of corn. Most importantly this silk and kernel-tip feeding can open up the 

 ear for decay later. They are more common in loose-husk hybrids. We do not usually 

 recommend control. After the beetles are down in the silks, they are difficult to 

 reach with chemicals . 



Northern and western corn rootworm development is slightly ahead of 1969. Adults are 

 emerging in abundance in northern and central Illinois and will continue to emerge 

 from the soil for another 3 to 4 weeks. Pupation of larvae is progressing rapidly in 

 many fields. Pollination damage by adults may occur in late-maturing corn since they 

 tend to migrate to these fields to feed on fresh pollen and silks. 



Check the silks for the presence of tan or green northern corn rootworms and the 

 yellow- and black-striped western corn rootworm adults. Treatment is justified if 

 there is an average of 5 or more beetles per silk and less than 50 percent of the plant 

 have silked. Sprays of carbaryl (Sevin) , malathion, or diazinon at 1 pound of actual 

 chemical per acre or 1/4 pound of methyl parathion per acre are effective. Methyl para 

 thion should be used by experienced applicators only. Allow 5 days between treatment 

 and harvest for malathion, 10 days for diazinon, and 12 days for methyl parathion. Car- 

 baryl has no waiting period. 



Rootworm infestations in the demonstration plots conducted by extension advisers in 

 Boone, Mercer, Knox, Ogle, and Woodford counties, this year were generally higher than 

 in past years . Larval counts averaged 20 to 40 worms per plant in some of the untreate 

 plots and extensive lodging was evident. If moisture is plentiful, the damaged plants 

 will partially recover, but without moisture damage may be severe. Goosenecking and 

 lodging of plants as a result of larval feeding are quite evident in some fields . 



Make a note of the fields with lodging and adult rootworms, since these fields may have 

 a recurring problem in 1971. Also, notify your county extension adviser if you have ha 

 failures with one of the organic phosphate or carbamate insecticides used for resistant 

 corn rootworms . 



;cond- generation European corn borer moth emergence is nearing completion in the south; 

 ern section of Illinois, and egg- laying by moths is beginning in some fields in the 

 late-whorl to early-silk stage. Peak egg-laying can be expected about July 25 in that 

 area. Check these fields for egg masses and whorl feeding since the second- generation 

 moths prefer these fields to deposit their eggs in. For corn in the whorl stage, if 75 

 percent or more of the plants are showing recent whorl feeding, apply carbaryl (Sevin) 

 or diazinon granules. If the corn has tasselled, look for egg masses. If the average 

 1 or more egg masses per plant, apply an insecticide after a few eggs have hatched. 

 Aerial sprays on tasselled corn are effective, but on whorl-stage corn, aerial applica- 



;ions should be granules, not sprays. Use 1-1/2 pounds of carbaryl (Sevin), or 1 pound 

 of diazinon, or 1/2 pound of parathion per acre. Allow 10 days between application and 



ilage removal for diazinon and 12 days for parathion. Parathion should be applied 

 only by experienced applicators. No waiting period is required for carbaryl. 



In central sections, borers are pupating rapidly, and moth emergence is about one-third 

 completed. An occasional moth has emerged in the northern section and pupation is 

 underway . 



Woolly bears and cattail caterpillars (brown, orange-striped, and bristly) are present 

 in cornfields. The woolly bears like to feed on silks, the cattail caterpillar on 

 leaves. Insecticide control is seldom needed. 



