At-planting treatments for early-season insect control make sense for irrigated High Plains cotton, says Texas A&M Extension entomologist Jim Leser.
Leser recommends in-furrow insecticide applications or seed treatments and then to watch for pest thresholds to build later in the season before treating again.
“My goal is to take care of those early pests (Western Flower Thrips, for instance), and then go clean for as long as possible,” he says.
“Doing something at planting is a good investment. Over any ten-year period, growers will make more than enough additional yield with an at-planting treatment to cover treatment cost and pocket a tidy profit.”
Controlling thrips is the primary objective, he says.
Leser says he has questions whether Cruiser, a seed treatment, or Temik, an in-furrow material, provides the best results.
“We don't have enough yield data,” he says. “Weather and other factors have prevented us from accumulating enough yield information to compare the two adequately. Cruiser is the most promising alternative to Temik for Western Flower Thrips, but numerically may not control them quite as well.”
Leser says Temik controls the pests for a little longer, especially at a 5-pound rate, which is normally used where nematodes are also a factor. “The trend is that farmers get a better yield with a 5-pound Temik application than they do with Cruiser.”
Results are closer with 3.5 pounds of Temik. “Temik still lasts a little longer.”
But Leser is worried that old standby materials such as Temik may not be as effective as they once were. “I used to control thrips with 2 pounds of Temik,” he says. “Now I use at least 3 pounds and usually 3.5.”
He says the difference could be that Temik may be breaking down in the soil from microbial activity or that thrips are staying on cotton longer than before. He's teamed up with Texas A&M plant disease researcher Terry Wheeler on a project to find out what's going on.
“It's not an easy problem to solve,” he says. “We have a greenhouse test underway and we hope to begin field studies in the spring.”
Convenience may play a role, too. “The lock ‘n Load option with Temik has reduced potential for human contact,” he says, “but it's still somewhat inconvenient. Farmers have to have the boxes. Seed treatments are more convenient, but Cruiser still has to prove that it makes comparable yields. We're still looking.”
He hopes to look at a new Gaucho formulation, Gaucho Grande, with double the amount of active ingredient per seed “with no cost increase.” Leser says he hasn't tested the product yet but expects to in the 2005 season. The goal is to improve Western Flower Thrips control.
“The standard rate of the earlier Gaucho treatment did not adequately control western flower thrips although it was effective against other less common species.”
He says a Bayer Temik-like material, without nematode activity, may soon be available with increased residual activity over the old standard Temik. He also says studies are underway to see if Syngenta's new nematode seed treatment product will be effective and compatable with their Cruiser seed treatment.