Carter Charles, Cyrus, Minn., manages corn rootworms and weeds without using genetically modified seeds.
Charles generally plants half a dozen corn hybrids. Finding the right non-GM hybrids takes a little time, says Griffith, Charles’ crop consultant, and might mean dealing with several seed companies. Independent regional seed companies, in particular, offer “a lot of quality conventional corn,” he adds. “There were quite a few choices.”
To assure a strong early root system on his non-Bt corn, Charles applies 6.5 oz./acre of the insecticide Capture LFR in the seed furrow along with his starter fertilizer. Keep in mind that if corn rootworm populations are low, an insecticide application at planting won’t earn a return, warns Entomologist Bruce Potter, University of Minnesota Extension IPM specialist. But Charles considers a soil insecticide a fairly cheap risk-management strategy. Scouting last August, “I couldn’t find any corn rootworm beetles in the majority of Carter’s fields,” Griffith says.
Last season, Charles sprayed 2 oz./acre of Warrior on about a third of his corn fields to kill European corn borers (ECB), although insect numbers never reached economic thresholds, Griffith says.
Widespread use of Bt-corn has pushed down corn borer populations and lowered the overall threat from this insect, which also benefits conventional crops, Potter says. Indeed, “The trait is so effective that it lessens the economic benefit of using it.”
After Charles switched to non-traited corn, he diversified his herbicide program. In 2012, he applied TripleFLEX pre-emergence, followed by Laudis post-emergence. This chemistry – which is also effective on Roundup corn – supplies four modes of action for good control of waterhemp, lambsquarters, giant ragweed and kochia, Charles’ top weeds, Griffith says.
Charles’ 2012 corn yields averaged 185-200 bu./acre – comparable to triple-stack corn yields in the region, Griffith says. Charles spent $140/bag on seed, about half the cost of triple-stack seed. Even after extra insecticide and herbicide expenses, he cut his cost of production by nearly $50/acre without sacrificing yield, he says.