No pupation has been noted in northern Illinois. 



Fall armyworm numbers have decreased in corn fields that were infested earlier. These 

 worms have pupated in the soil and will emerge as moths to produce another generation 

 in August. Egg-laying will be continuous until frost. These worms not only feed in 

 the whorl of the corn plant, but occasionally they will cut into the stalk. They of- 

 ten feed on the ear, as an earworm does. 



Corn earworms were found in the whorls of field corn as far north as Galesburg. These 

 were found in late whorl to early tassel stage. Even though the number of infested 

 plants in a field may be small, the total number of worms over a large area can be 

 great. These earworms will be mature worms in about ten days; they will drop to the 

 ground and pupate in the soil. They will remain in the soil for two to three weeks 

 before emerging as moths to deposit eggs on fresh silks. 



Com in the late -whorl to pollinating stage after August 10 may have moderate to se- 

 vere infestations of com earworms, fall armyworms, and European corn borers. Corn 

 earworm moths prefer fresh silk to wilting silks for egg-laying; corn borer moths pre- 

 fer the late-whorl to early silk stage; and fall armyworm moths prefer the late -whorl 

 stage. However, if these preferred sites are not present, these moths will deposit 

 their eggs in corn fields where corn development is closest to their choice. It is 

 likely that all three may be found in abundance in the same field. 



Low infestations of larvae in a large acreage of early to mid-season corn will supply 

 large numbers of moths. They will concentrate their egg-laying in the smaller acre- 

 age of later corn. For this reason, some late fields may have enough infestations 

 from all three species to cause very serious damage. Unfortunately, we cannot sug- 

 gest an excellent control measure. Sprays of carbaryl (Sevin) , diazinon, or Gardona 

 are used. There is no waiting period between the application of carbaryl and harvest. 

 Gardona requires a five-day interval; and diazinon, 10 days. 



We hope these three corn worms will just disappear. But the potential for damage is 

 there, and we feel we must mention it. 



Special note to sweet corn growers and processors, and to hybrid seed producers . Take 

 note of the statements about European corn borers, fall armyworms, and earworms. Egg- 

 laying by these three could start by August 1, but is more likely by August 10. 



Alert your field men. You know the European corn borer and corn earworm eggs. The 

 fall armyworm eggs look like a grey, cottony mass. They are usually layed on the un- 

 dersides of leaves, but not always. There are dozens of eggs in one bunch. 



True armyworms have been reported from several fields. Usually, they are not present 

 in great enough numbers to present a serious problem, but we have had reports of a 

 few heavily infested fields. At this late date, it is difficult to settle back and 

 relax when armyworms are feeding on the corn leaves --even if this feeding is not too 

 serious. In the rare situations where armyworms are numerous and stripping plants, 

 several insecticides will effectively control them. 



Northern and western corn rootworm beetles are beginning to appear on silks in some 

 corn fields. If pollination has occurred, silk feeding is usually of no importance. 

 But if 50 percent or fewer of the ears have been pollinated, five or more beetles per 

 ear may be damaging. Applications of carbaryl (Sevin), diazinon, or malathion are 

 effective. 



