What is in this article?:
- Target spot disease continues its march into Southeast cotton
- Drop nozzle advantage
- Target spot first began showing up on Alabama cotton in 2011.
- There are differences in the sensitivities of cotton varieties to the disease.
- Cotton with a high yield potential is more susceptible to target spot.
Drop nozzle advantage
Headline and Quadris are getting being tested for their effectiveness against target spot, he says. “In Brewton, there was a definite advantage to having a drop nozzle versus a broadcast over-the-top nozzle arrangement. You have less target spot with a drop nozzle, regardless of the fungicide. In Shorter in central Alabama, it doesn’t look like nozzle placement has any effect on disease, and there’s no difference in the performance of the fungicide. The only difference is that there’s less target spot on DPL 1252 than on Phytogen 499.
Target spot is not an easy disease to control, notes Hagan. “Last year, the only treatment that increased yield above that of the non-treated control was 9 fluid ounces of Headline. It is a more serious issue the closer you get to the Gulf Coast and on really good cotton.”
As for cotton insect control, Extension Entomologist Ron Smith says work is continuing to fine-tune thrips control.
“The seed treatment just doesn’t last long enough — it runs out a week or so before our cotton outgrows the thrips injury stage,” says Smith.
This year, researchers looked at what growers can do at planting time to avoid the need to come back with an over-spray, he adds. “If you plant early, and particularly if you use conventional-tillage and other factors, the thrips situation can be made worse. If you plant in reduced-tillage, the more litter you’ve got on the ground, the less thrips pressure you’ll have.
“We’re looking at adding an in-furrow insecticide on top of the seed treatment at planting. This year, we looked at Admire Pro. In central Alabama and in the Wiregrass, it really didn’t add enough to justify the cost. But my counterparts in Virginia and North Carolina are pleased with the results they’ve seen from that product.”
Also getting a look is a new class of chemistry that has been registered for thrips control — Radiant by Dow, says Smith. “It doesn’t flare spider mites. Most everything else you put in that early season window will aggravate spider mites, and that’s a major concern in some areas. The farther we get away from Temik, the greater the spider mite problems will be.
“Of course, spider mites are associated with dry weather, and we didn’t see that this year. But we’ll have to be concerned about spider mites on seedling cotton in the future.”
Plant bugs were very light in Alabama this season, he says, and aphids didn’t amount to anything. “We did have more stink bugs than we’ve had in several years now, but they were not in every field. They’ve been in some fields at treatable levels at multiple times, and they’ve been in some fields that haven’t been sprayed all year.”
We’ve got a new product that’s being sold and promoted for stink bug control called Belay, and we’ve had pretty good success with it. We had good success with it last year on soybeans. In the Wiregrass, it’s not measuring up to Bidrin on cotton.”
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