The Problem
It’s a hot and humid evening in mid-July in eastern Nebraska. The wind has picked up and dark clouds are building in the southwest in an otherwise clear, blue sky. You swat at a fly and exhale in frustration. Rain. You pick up a wrench and go back to work on the tractor. Normally, you would be happy since rain means water for your corn with no irrigating. But rain AND wind? With the damage corn rootworms caused to most of your field this year, the combination of rain and wind can make your field look like a giant game of Pick-Up-Sticks. You give the wrench a final turn and pray that the corn is still standing in the morning.
Figure 1: Corn field with approaching storm. Credit: G.E. Cardon, Bugwood.org
Figure 2: Corn that has fallen over (lodged) due to a weakened stalk and/or root system. Credit: Richard C. Edwards, Purdue, Bugwood.org
Ask any farmer across the world and they will tell you that their goal at the end of the season is to bring in a big harvest. At a basic level, a big harvest means food for survival and the potential to make a profit. So when a farmer in Nebraska sees corn plants falling over in the field, there is a problem. Small, corn-loving insects called corn rootworms can cause tremendous damage to corn roots if not controlled. The adult stage of the CRW is a beetle but the larval stage is the most damaging to corn plants. The western corn rootworm, Diabrotica virgifera virgifera LeConte, and the northern corn rootworm, Diabrotica barberi Smith and Lawrence, are the key pest species in the U.S. Corn Belt. For more information on CRW see the following links: Corn Rootworm – Part 1 and Corn Rootworm – Part 2.
What is the best way to manage these insects to keep them from causing economic loss in a cornfield? How do we ensure these management methods are available for the long-term? These are questions UNL entomologists, Dr. Lance Meinke and Dr. Blair Siegfried, hope to help answer with their research.