By Bryan Jensen, Department of Entomology, University of Wisconsin Extension
Several growers are making the switch to growing non-Bt corn hybrids. Several reasons are given which include a desire to save money on seed costs, historically low rootworm and European corn borer populations, rootworm resistance management and premiums paid for conventional corn.
From an entomological perspective, this is an interesting time to consider non-Bt hybrids. The above ground traits are essentially purchased as an insurance policy. At the time of seed purchase you do not know if you will get a return on investment from that trait (s). Hybrids with below ground traits can fit into an IPM plan. If you have beetle scouting data from the previous summer, you can decide if, or which, rootworm control method is most economical before purchasing seed.
Although there may be some apprehension when switching from the Bt traits, that concern can be alleviated with timely field scouting. Essentially, field scouting will eliminate the guess work and provide field-specific information from which to base your management decisions. Obviously, scouting will take time and information on the procedure is needed. We have prepared an article, Managing Corn Insects When Growing Non-Bt Hybrids in an effort to provide some background information. Most importantly several references are provided to make the transition effective and risk-free.