Stalk Borer Heat-Unit Update

May 28, 1999
As we have indicated several times, stalk borers first begin to move into cornfields when 1,100 heat units (base 41°F, from January 1) have accumulated. Fifty percent movement occurs when approximately 1,400 to 1,700 heat units have been reached. Figure 2 suggests that as of May 24, initial movement of stalk borers into susceptible cornfields should begin across many northern counties. By Memorial Day weekend, don't be surprised to learn of stalk borer injury even in the northernmost areas of the state. Please refer to issue no. 8 (May 14, 1999) of the Bulletin for the complete story on this troublesome insect pest. As Kevin Steffey indicated previously, timing is everything for stalk borers.--Mike Gray

Author: Mike Gray