Spray treatments by ground or air with 1 pound of malathion or diazinon per acre 

 will control the aphids. When using malathion, allow 5 days between treatment 

 and harvest for grain, ensilage, or stover. Using diazinon, there is no waiting 

 period between treatment and harvest for grain, but allow 10 days to elapse be- 

 fore making ensilage or stover. If corn is still in the late-whorl stage, seed 

 producers may prefer to use 1 pound of either diazinon or phorate (Thimet) per 

 acre as granules. To avoid potential hazards to detasselers, use phorate only 

 on male-sterile corn. 



Corn rootworm larval populations are continuing to increase in cornfields as tiny, 

 -ecently hatched worms can be found in northern Illinois. Eggs are still hatch- 

 ing and the number of larvae is expected to increase or remain constant for 

 another one or two weeks. Pupation of worms is progressing rapidly in many 

 fields and adults are emerging. One field in northern Illinois increased from 

 45 worms per hill on July 10 to 101 per hill on July 17. 



Goosenecking of corn plants, as a result of larval damage, is now evident in 

 many infested cornfields. Wilting and dying plants were observed in some heavily 

 infested fields. 



Northern corn rootworm adults are beginning to emerge from the soil in corn- 

 fields where rootworms have been feeding on the roots of corn plants in the 

 northern and central sections of the state. These green beetles feed on fresh 

 silks and may reduce pollination. 



Western corn rootworm adults are also emerging and they do the same damage. These 

 yellow- and black- striped beetles will appear in the northwestern section of the 

 state. Both of these insects will be emerging during the next few weeks. Treat- 

 ment is justified if there are 5 or more beetles per plant and if not over 50 per- 

 cent of the plants have silked. This situation is likely to exist in many fields 

 about August 1. The beetle population will continue to increase until mid-August. 



Sprays of carbaryl (Sevin) , diazinon, or malathion at 1 pound actual insecticide 

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

 be applied by experienced applicators only . Allow 5 days between treatment and 

 harvest for malathion, 10 days for diazinon, and 12 days for methyl parathion; 

 carbaryl has no waiting period. 



European corn borers have almost completed pupating and are also emerging as moths 

 in the southern half of Illinois. Pupation is just beginning in the northern 

 sections. Second -generation infestations in late cornfields can be handled the 

 same as the first-generation situation: If 75 percent of the plants show whorl 

 feeding, apply carbaryl (Sevin) or diazinon granules. If the corn has tasseled, 

 look for egg masses on the leaves. If the average is 1 or more per plant, apply 

 an insecticide when a few eggs have begun to hatch. 



True arm^vorms have been observed in grassy cornfields in the northern half of 

 Illinois. Watch such fields closely; the worms feed first on the grass and then 

 move onto the com plant. For infestations, apply carbaryl (Sevin) or toxaphene. 



If you use carbaryl (Sevin) , there is no waiting period between application and 

 harvest of the crop for grain or ensilage. If you apply toxaphene, there is no 

 restriction on use of grain, but do not feed treated forage to dairy animals. 

 ) not feed ensilage, fodder, or stover to livestock within 28 days of slaughter. 



