In Tennessee Bt insecticides are helping producers fight off nasty corn pests

Tennessee’s farmers harvested nearly one million acres of corn in 2020, but some producers still had to battle a pests.

The corn crop at UT’s West Tennessee AgResearch Center was harvested weeks ago, but there are still living things staying behind in this field, trying to eat, survive and reach adulthood and reproduce. Center Director, Scott Stewart, an entomologist, only has to rip apart a stalk or two to find trouble.

The southwestern corn borer is a pest that has a taste for corn. They can drain nutrients from the plan and inhibit water flow to corn ears.

“It’s a pretty significant, historical pest, one we have chronic problems with year in and year out with certain geographies in west Tennessee,” Stewart states. “They can be mild to really, really bad.”

The past several years, soybeans have been Tennessee’s top row crop, but it still grows a ton or corn-- nearly a million acres this past year, and statewide yields were pretty solid.

However, farmers had plenty of challenges, most notably pests like the corn borer. A mild winter meant their population was plentiful, but there is a way to fight this pest-- Bt technology insecticides.

“Bt stands for bacillus thuringiensis. It’s a bacteria, but they’re taking genes from that Bt bacteria that produce toxins. Those toxins are very specific to certain insects and they’ve actually put that into the genome of the corn or cotton plant,” according to Stewart.

The benefits of Bt are documented and visible. Stewart and other researchers had Bt corn in parts of this field, but not in others. Where there was no Bt, there were plenty of corn borers and damage to the crop.

“I’ve got data... we probably saw about a 15 to 20-bushel yield decline where we had non-Bt corn that was infested pretty heavily with the southwestern corn borer,” he adds. “I’ve done tests in west Tennessee where we’ve seen 40 to 50-bushel declines in these same kinds of tests.”

As farmers walk their fields this fall, accessing the damage from pests, they can prepare for next season, and researcher tells them Bt technology could be a good option when it comes to protecting their crops.

In regards to Bt corn, the EPA has proposed some changes to the Federal Insecticide, Fungicide, and Rodenticide Act, or FIFRA. Comments on those changes are due by November 9th. It could phase out all Bt corn hybrids and cotton that do not include Syngenta’s VIP 3A protein.

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