Heads Up! Pest Alerts

With much of the corn planted late this spring, growers should monitor their whorl stage corn for fall armyworm. Fortunately, fall armyworm numbers have been low, but some corn fields may stay in the whorl stage through the end of July.

Fall armyworm cannot overwinter in Kentucky and must invade the state from overwintering sties along the gulf coast each summer. It prefers to attack whorl stage corn, and in most years usually does not reach damaging levels until corn has tasseled. Because of the late planting, corn will stay vulnerable to fall armyworm attack much longer this summer.

Fall armyworm can be a difficult insect to control with insecticide sprays. As with European corn borer, timing is critical for effective control. Small larvae feed in the whorl and are relatively easy to control. But older larvae expel large amounts of frass into the whorl which forms a plug and limits penetration in insecticides deep into the whorl.

Many growers used Bt corn with their late plantings to avoid problems with corn borers. But the Bt corn used by growers only suppresses fall armyworm feeding. Late- planted Bt corn will still need to be monitored for fall armyworm this summer.

(first published in Kentucky Pest News, Number 958, July 1, 2002)

Previous Pest Alerts

	Original document: 2 July 2002 Last updated: 2 July 2002