If you grow Bt corn this year, you must plant a refuge. It makes no difference what brand or what trait combination you plant--every single traited corn on the market still requires a separate refuge in 2011.
The excitement and hype about totally integrating the corn refuge into the bag might lead you to believe that refuge is totally in one bag this year. It’s not and it’s confusing.
There are now 23 Bt corn products on the market spread between five product lines. If that isn’t complicated enough, the mix of traits, target pests and resistant management requirements vary from product to product.
It is true DuPont company Pioneer Hi-Bred brings a version of the in-the-bag concept to market this spring in Optimum AceMax1 (OAM-1). The base recipe for OAM-1 integrates 90% of a Pioneer brand hybrid with Herculex XTRA (CRW/CB/LL/RR2) and 10% of a Pioneer hybrid of the same genetic family containing the Herculex 1 trait (CB/LL/RR2).
Bill Belzer, Pioneer senior marketing manager for corn, says this integrated product represents the corn industry’s first in-the bag corn rootworm refuge solution. “The 10% Herculex portion satisfies the grower’s corn rootworm refuge requirement,” says Belzer.
Still, with OAM-1, growers must plant separate 20% corn borer refuge. Belzer says that requirement is simplified by the fact that the corn borer refuge can be planted as much as ½ mile away.
In the OAM-1 system, the 20% European corn borer refuge can be planted with conventional or herbicide tolerant hybrids. Those who want 100% corn rootworm trait protection have access to another in-the-bag option via Optimum AcreMax RW. OAM-RW contains 90% of a Pioneer brand hybrid with Herculex RW and 10% of a Pioneer hybrid with RR2 herbicide tolerance.
This month Pioneer announced a new Optimum Intrasect product that reduces the 20% above ground refuge to 5% within the ½ mile parameters. Again, don’t be confused—this Intrasect product is a 2012 product. It will be available in on-farm trials in 2011 and available commercially in 2012. By then, Belzer says Pioneer anticipates approval of its next generation single bag approach.
SmartStax, the trait platform developed by Dow AgroSciences and Monsanto Company currently requires a 5% refuge adjacent to the field where the stacked trait package is planted. Genuity VT Double Pro also dips to 5% refuge with a wider ½ mile stipulation.
Until the 2010 growing season unfolded, a structured 20% refuge requirement was the primary resistance management option for insect pest across the Corn Belt. Many Bt hybrids still require this 20% refuge.
Pyramided products that stack multiple modes of insect protection together have started to change how we view refuges, says University of Illinois entomologist Mike Gray. “I believe it is only a matter of time before the use of seed mixtures (Bt and non-Bt seed) form the foundation of resistance management plants for corn rootworm and lepidopteran insect pests across the Corn Belt,” says Gray.
“Until then, it’s important to continue to develop and follow an integrated insect management plan. Following refuge requirements is important for the commercialization of next generation biotech traits,” he adds.
The National Corn Growers Association has developed a calculator to help clarify the refuge system options and show growers how to execute the requirements properly. Access it here.