Insecticide Resistance a Concern Against Diamondback Moths

Clint Thompson Georgia, Pests, Top Posts

By Clint Thompson

Diamondback moth adult

Diamondback moths are a problem for Georgia vegetable producers. According to Ty Torrance, University of Georgia Cooperative Extension Vegetable Agent for Colquitt, Tift and Worth Counties, the main concern is insecticide resistance.

“I have periodically been taking samples, getting Stormy (Sparks) to come out and take samples of caterpillars. He’ll run a screen basically of all the labeled products to see what’s working and what’s not working,” Torrance said. “The last couple of screens he did, some of the best products were only killing three or four worms out of 10.

“Diamondback pressure has picked up. We’re having issues in multiple fields with insecticide resistance.”

That’s not good news for cabbage producers who are trying to still manage this pest.

“We see it every year. The insect is just incredible at developing resistance. It can be a field-by-field susceptibility. One field, the population may or may not be susceptible to one product. At another field, it’s completely resistant. It’s very tough to fight these,” Torrance said. “They start on the base leaves and they’ll move into the heads. Once they move into the heads there’s nothing that you can spray to kill them.”

Cabbage harvests are continuing in Torrance’s tri-county area. Some fields still haven’t even started cutting yet.

“Once they start cutting, they may be in there for a month or so,” Torrance said.