By Clint Thompson
Diamide insecticide resistance in beet armyworms has been reported in Georgia and detected in multiple locations.
While it is not yet known how widespread the resistance is, growers should abstain from duplicating chemical applications if they do not achieve initial control, says Stormy Sparks, University of Georgia (UGA) Cooperative Extension vegetable entomologist.
“If they’ve got a product that works and it works on other pests, the tendency is to think may be something other than resistance is the issue rather than assume resistance is the issue. We’re at the point where I would assume resistance is the issue,” Sparks said. “It’s not a coverage issue, and it’s not, it rained an hour after I sprayed. It’s probably a resistance issue at this point.
“There still may be some populations that will work on, but if you spray and it doesn’t work, absolutely change chemistries. It’s the same with the corn earworm.”
Sparks added that the Group 28 insecticides or Diamide resistance in beet armyworm is probably three or four years old now. It appears to be fairly consistent. Diamides may work on some populations but are probably not the preferred management method at this time for beet armyworm.