Cotton insect pressure building

Mississippi cotton acres treated for spider mites will “reach an all-time high” this season, on a percentage of acres treated, says Angus Catchot, associate Extension professor of entomology and plant pathology at Mississippi State University.

Mite applications have been going out for weeks, he notes in the latest Mississippi Crop Situation Bulletin.

“This latest surge of spider mites is very likely coming out of corn,” he says. “For the last several years we have been able to find spider mites at some level in every corn field we enter in the Delta. As corn dries down there is a mass migration out, and that is what we are dealing with right now. Spider mites balloon out of standing corn on silken threads and can blow for miles.

“In the last couple years, nearly all of the mite applications being made are with generic abamectin,” Catchot says. “There are several very good mite products available that are never utilized because of price. Although we have had no real problems to date with the abamectin products, I am concerned we are putting tremendous selection pressure on this chemistry with a pest that has a history of becoming resistant to pesticides. If the other companies keep their products priced as they are, I suspect they will continue to get no use and we will ride the abamectin horse to the end.”

Application intervals for tarnished plant bugs are being reduced, in many cases, from 7-10 days to 5 days, which he says, is keeping numbers down. Aphids are still building in many areas and there is continuing to be high bollworm egg lays in cotton over much of the Delta, and treatments for bollworms in soybean fields, where some “unbelievable numbers” are being reported, Catchot says.

To read his full report, go to: Mississippi Crop Situation Bulletin.