What is in this article?:
- Extreme weather was dominant factor in cotton insect year
- Tarnished plant bugs
- Temperature related
The heat and lack of rainfall knocked about three or four weeks off the Alabama cotton production season this year, and that also cut three or four weeks from the insect year. The weather was the dominant factor in 2010, and overall cotton insects were lighter than normal in Alabama, although that is not true throughout the U.S. Cotton Belt.
Tarnished plant bugs
Tarnished plant bugs were bearable in Alabama this year, says Smith, with large numbers early in the year. “We never know quite how to react to those. Last year, weather conditions were dry early, and it didn’t matter what we did with insect control because we made better yields on our late-planted cotton. It has been just the opposite this year. We’ll make better yields on our earlier planted cotton, and every square we lost to plant bugs is one less boll we’ll pick on that cotton.
“If we could predict the weather, we’d know where to set our thresholds and how hard to go after plant bugs,” he says.
Stink bugs have been in high numbers this year, and it’s predominately the stink bug, says Smith, a species that requires a totally different approach when selecting chemistry for control.
“The brown stink bug is much more difficult to control than the Southern green stink bug, which is the dominant species in most years. We have not found anything in our test work that competes well with Bidrin on the brown stink bug. We have new chemistries out there, but preliminary results show they are not killing brown stink bugs,” he says.
Fall armyworms — the grass strain — are in large numbers on hay crops, pastures and peanuts throughout the southern part of Alabama, up to 30 per square foot on pasture and peanuts, notes Smith.
“They’re often heavier on the field borders than they are out in the field, because many times they are coming in from the grasses on the field border. But that’s not where all of the eggs are being deposited. The choices for control are pyrethroids, Intrepid and Dimilin, or some combination of those products. If you have time, the long-residual materials like Intrepid or Dimilin are good because you’ll get from two weeks to one month control.
“But if you don’t find them until a lot of the damage is done there are large worms there, then you don’t have time to wait four or five days, and you must wait four or five days with Intrepid and Dimilin to get a good evaluation. If you don’t have that, you either need to mix a low rate of pyrethroids with these products or go with a straight pyrethroid.”