Stalk Borers on the Move

May 26, 2000
Producers throughout the state need to remain vigilant regarding the movement of stalk borers into cornfields. Robert Scott, Illinois State Water Survey, has provided Figure 2 that reveals the number of heat-unit accumulations (base 41°F) from January 1 to May 22. Stalk borers begin moving into corn when 1,100 heat units have accumulated. This suggests that initial movement across the northern one-third of the state was under way at least by May 22. For the southern one-third of the state, as of May 22, about 50% of the stalk borer movement into corn had already taken place (1,400 to 1,700 heat-unit accumulations). As Kevin Steffey indicated last week, we recommend scouting when 1,300 to 1,400 heat units have accumulated, and a decision to treat with an insecticide should be made between 1,400 to 1,700 heat units. For the full stalk borer "story" take a look at issue 7 of this Bulletin.--Mike Gray

Injury to plants at edge of cornfield caused by stalk borers.

Stalk borer larva.

Injury to corn plant caused by stalk borer.

Author: Mike Gray