Mississippi specialists respond to neonicotinoid review

How important are neonicotinoid seed treatments at a time when soybean futures are falling and an EPA study says they are of no benefit to producers who apply them to their planting seed?

That's a question that Angus Catchot, Extension entomologist with Mississippi State University, raised while speaking to producers about cutting costs during a panel discussion at the Delta Ag Expo in Cleveland, Miss.

"I'm getting calls right now thinking about how we can cut because of commodity prices," Catchot told an audience of more than 100 producers. "One of the things I would tell you if you're looking for ways to save without hurting your bottom line is to use the thresholds we have out there."

"Don't make automatic applications for anything after R6 (soybean growth stage). We routinely have treated soybean loopers after R6. Now we know we don't have to do that and can suffer zero yield loss."

Noting that nearby soybean prices had dipped to $9.62 per bushel the day before he spoke on Jan. 22, Dr. Catchot said the question of whether to apply soybean seed treatments was also coming up in conversations with growers.

The day before he spoke at Delta Ag Expo Dr. Catchot was also involved in discussions with Jim Jones, EPA's assistant administrator for the Office of Chemical Safety and Pollution Prevention, and Yu-Ting Guilaran, a member of EPA's Biological and Economic Analysis Division.

The latter is the office that issued a report last Oct. 22 that said insecticide seed treatments were of no benefit in soybeans. The efficacy of seed treatments and new herbicide-tolerant traits were among several items of discussion during the meeting at Stoneville, Miss.

Catchot agrees that not all producers in the South may see a benefit from neonicotinoid seed treatments in soybeans, particularly in the states of Georgia and North Carolina. But studies show they have a place, especially in early planting systems, in Mississippi.

"In the state of Mississippi over the last 10 years, Jeff Gore, Don Cook and I have conducted 73 university replicated trials," he said. "Now I'm going to tell you what the data said, and you can make the decision on whether you want to make this cut in the time of low commodity prices." (Gore and Cook are Mississippi State University entomologists.)

Catchot said that in those replicated trials, "73 percent of the time we got a positive response. Sixty percent of the time we have a response greater than one bushel. In that 60 percent of the time, the average yield increase is 3.8 bushels."

Looking across all 73 trials, the average response was 2.5 bushels, and the same results occurred for both Cruiser and Gaucho, two of the most common soybean insecticide seed treatments. (Cruiser contains thiomethoxam and Gaucho imidacloprid.)

"The response you could see could be zero or it could be upwards of five bushels an acre," he said. "But the best insect protection that we have is planting early. These beans cost a lot now, and I feel that seed treatments absolutely protect that investment from a risk management standpoint."

Date-of-planting studies show that if planting is delayed beyond the optimum planting window in early April, Mississippi producers lose about seven bushels per acre on average for each week of delay.

"That's a few things that we've been getting questions about recently," he said. "To me, I think the odds are with the data. I understand that in a tight year you might not want to front-end load. But that's what our data would suggest at this point."

For more on insecticide seed treatments, go to http://deltafarmpress.com/cotton/cooperation-may-be-part-key-pollinator-puzzle

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