There's a long, cold winter between now and the 2012 planting season, but corn growers are already planning for spring. Kansas State University scientists encourage producers to keep some things in mind as they consider corn hybrids.
"Since Bt (Bacillus thuringiensis) corn first came on the market several years ago, there have been many changes," said K-State Research and Extension agronomist Kraig Roozeboom. "Now there are several different Bt products on the market, and various versions with different traits."
Roozeboom, along with K-State entomologist Jeff Whitworth, said there are many considerations for corn growers when the contemplate which Bt corn traits they might want to use.
One thing they suggest is that growers avoid using hybrids with traits that are not necessary. Using such hybrids will increase the chances of insects developing resistance to the traits. For example, producers who are not in a continuous corn system probably do not need corn rootworm Bt hybrids.
They also suggest growers consider rotating hybrids with different Bt proteins (events) for a given insect. Much like rotating different classes of insecticides, it doesn't hurt to use hybrids with different events and different modes of action for a specific pest.
For example, the Agrisure, Herculex/Optimum and YieldGard/Genuity hybrids use different events. This may help delay resistance. It is also important to pay attention to whether an insect is controlled or suppressed in a hybrid.
A critical message to all growers is to follow refuge requirements for the various traits and trait stacks as applicable to their location. Their seed suppliers should provide that information as part of the grower agreement.
More information, including charts showing genes, events, and insects controlled by each of the different products, is available in the Nov. 11, 2011 extension agronomy e-Update newsletter: http://www.agronomy.ksu.edu/extension/p.aspx?tabid=58.