AgFax Cotton - Louisiana

By AgFax Media LLC, AgFax.com

OVERVIEW  

Bollworms have slacked off in places but are building in others. In some cotton, a third application has either been made or will be soon. They are beginning to turn up slightly more now in the upper Delta.

Plant bug pressure varies widely. No huge train wrecks have occurred, but multiple sprays continue to be needed in spots, particularly near corn.

Aphids linger in parts of the Midsouth and spider mites have required attention in places, too.

LOUISIANA CROP REPORTS

Sebe Brown, Northeast Louisiana Region Extension Entomologist

"Bollworm moth numbers have declined in our traps, but parts of the state are experiencing a pretty heavy egg lay, mainly in northeast and northwest Louisiana. We're into the second generation of this bollworm flight, so everyone needs to be out there scouting if you have WideStrike but even in Bollgard 2 cotton. Take extra time and examine bloom tags, scan the terminals and scout for injury.

"People are asking if the diamide products are still working. They're seeing worms coming through treatments in cotton and want to know if resistance to the chemistry is a factor. Those materials are still working in soybeans and the worms in beans came from the same flight that moved into cotton, so the products are still active.

"The main influence is trying to get materials down in the plant. That's easier in soybeans than in cotton. Remember that bollworms in cotton are a cryptic feeder. They'll stay in squares, blooms and possibly bolls and won't eat as much treated tissue as they would in soybeans.

"LSU does not officially recommend spraying on egg lays but that has to be considered with what we're running up against. The technology is failing all over the state. If you're spraying based on injury, that puts you behind the 8 ball, and I'm seeing too much injury in both Bollgard 2 and WideStrike.

"If worms hatch on Monday and nobody checks again until Thursday or Friday, you've got a 4-day-old worm. But if you can catch the eggs the week before and make an application, you stand a better chance of controlling small larvae before they bore into a square or move inside a bloom tag.

"Plant bug numbers have been fairly low to moderate. I haven't heard of any control issues. More reports are coming in about abamectin failure on resistant spider mites. People are applying a couple of treatments with no success, then have to fall back on newer miticides. If you're going with abamectin, use the highest labeled rate. If you've had resistance issues with it in the past, move to one of the newer miticides right out of the gate.

"In soybeans, redbanded stink bugs are still out there. We've gotten good results with 2 to 4 oz/acre of Belay in combination with 4 oz/acre of bifenthrin."