For years, the boll weevil was public enemy No. 1 for Tennessee cotton farmers. The boll weevil is gone thanks to the hard work of cotton growers and research scientists. But the malathion sprays that took out the boll weevil and plant bugs are gone as well, creating an environment where plant bugs have become a major problem. The University of Tennessee’s Sandy Steckel talked about the current efforts to control the latter during a stop on the Cotton Tour at the West Tennessee Research and Education Center.
Farmers are not spraying quite as often as they did when they were trying to control boll weevils, but tarnished plant bugs have added another element of expense and uncertainty to cotton production not across the Mid-South. Still, insecticide sprays such as Orthene, Transform, and Diamond are having a significant impact on tarnished plant bugs in cotton, according to Steckel.
“Putting the Transform out early followed by an acephate/Brigade, an OP (organophosphate)-pyrethroid tank mix can really help you out,” she says. “Putting the Diamond out, especially here in Tennessee when you’re picking up immatures maybe in the second week of bloom, is a good timing for Diamond in West Tennessee followed by Orthene and Brigade.”
Cotton producers can be frustrated by the number of sprays needed to make a cotton crop, especially in Bt cotton where sprays for tobacco budworms and bollworms have been reduced. But growers need to remember the big picture, according to Steckel.
"Another point we'd like to make is that if you weren't looking at this untreated check here, you'd be saying my goodness, I've sprayed three times but they're easing up over threshold. I've got to spray again. I never seem to be making any headway. However, if you had to compare with that (peak), look where you could have been.
"We managed this plant bug population at or below threshold the whole season whereas this (peak) was six times the threshold in the untreated check."
Steckel, who stood in for Dr. Scott Stewart, Extension entomologist with the University of Tennessee who was called for jury duty during the Cotton Tour, said Stewart had asked her to emphasize that researchers and Extension personnel used five or six different modes of action in treating for tarnished plant bugs in the field cited by Steckel.
"So we did mix up the modes of action which is really good for resistance management," Steckel said.