Owen Taylor, Editor
Defoliation has started on a limited basis in Louisiana, but more fields will be lined up soon as hot weather continues pushing the crop.
Bollworms haven’t bowed out yet. Egg laying continues in many areas. While some cotton is past the point that bollworms matter, the prospects for heavy numbers will complicate decisions about fields that are not quite safe. Plus, most areas have a later crop that will be vulnerable. Additional treatments are likely in Bt cotton. Fall armyworms are turning up in more areas this week, too.
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Scott Stewart, Extension Entomologist, Jackson, Tenn.: "We’re still in a pretty big bollworm moth flight in the southern half of West Tennessee. We’ve already sprayed a lot of the WideStrike cotton and some of the Bollgard II, and I suspect we’ll spray more of the Bollgard II in this coming week in fields that we’re still not ready to let go. In places, cotton is far enough along that maybe we can let it go. But we’ve also got fields that aren’t quite to that point, so deciding what to do about worms won’t be as clear cut. Plus, we’ve got cotton at NAWF 4 or 5 that’s still vulnerable. We’re watching that now for escapes and trying to make treatment decisions. Plant bugs are just kind of hanging in our greener spots, which also are the fields where I’m most concerned about bollworms. Stink bugs are a little hit or miss in cotton and soybeans, but this probably still is a little heavier stink bug year than normal. It’s dry, overall. We keep catching showers here and there, but with all the heat, a lot of cotton still went into cutout early."
Gary Wolfe, La-Ark Agricultural Consulting, Ida, La.: "This continues to be an easy year for insects. Normally, we’d be sitting on about 12 treatments at this point, but we’re only up to 8. Corn harvest usually stirs up a lot of activity, but even that didn’t have much effect because it’s been so dry. To finish up this crop we’re spraying about every 10 days, even on light pressure. We’re keeping brown stink bugs down but have started seeing some whitefly and aphids coming through. We came back with a generic Trimax and a pyrethroid in that cotton. It settled down the aphids and knocked the whitefly back. The crop looks good. We’ve been running with some high rates of Pix. We have some open bolls and have even found some boll rot where dryland cotton caught a little rain."
Barry L. Freeman, Extension Entomologist (Retired), Belle Mina, Ala.: "We can find bollworm eggs around, but we’re so heavy on technology that very little is breaking through. I’ve seen both bollworms and fall armyworms on Bt cotton, but nothing that would alarm me. Some cleanup sprays are going out, but they’re for a combination of stink bugs, tarnished plant bugs and some clouded plant bugs. Most of the stink bugs are browns. A few whitefly are around, but nothing terrible. They’re mainly the banded-wing whitefly. Everybody pretty much needs rain. The northwest part of the state is probably in better shape in terms of moisture, and some storms are coming through now (8/9). But with all this heat lately, the moisture goes away pretty fast. We’re still not in a disaster by any stretch of the imagination. We do have some cotton with less than 700 lbs/acre potential, but a lot of dryland looks like it could average 700 to 800, with some better than that."
Trent LaMastus, Ind. Consultant, Cleveland, Miss.: "We’ve turned some cotton loose, and we could start defoliating some irrigated fields within 2 weeks. We’re still fighting occasional spider mites and dealing with bollworm hatchouts and surviving worms. Generally, we’ve been going after combinations of pests, not just one thing, and we’re trying to do it as inexpensively as possible. Plant bug numbers are way down and have been for 2 weeks, overall. The moth flight has been non-stop or at least had such a small break that it was hard to detect. But we’re about to be done with a lot of cotton and are waiting to see how many worms survive. But anywhere we’ve got green cotton, we’re having to treat because they are surviving in the Bt, both Bollgard II and WideStrike."
Gus Lorenz, Arkansas Extension IPM Specialist: "We’re seeing a lot of bollworm activity in Bollgard II (BGII) cotton from about St. Francis County south and getting reports of it in some areas north of there. And we’re still seeing a lot of moths in the field. I saw several BGII fields Monday (8/9) with a lot of bollworms and recommended treatments with a pyrethroid plus a half-pound of acephate. In places, we’re finding fields with 10% to 20% damage. It’s spooky to see that much damage in BGII cotton. I think this is all due to huge numbers. The technology is being overwhelmed.
"This is a spotty, variable situation. One field of BGII might be covered up with a lot of worms in blooms, but you walk across the turnrow and there’s nothing there. But where they’re bad, they’re really bad. In other words, don’t take anything for granted. Some fields in south Arkansas have now been sprayed more than once, and it may not be over yet. How much more some of that cotton down there might be treated depends, in part, on how long growers want to stretch things out. We’re getting past the last effective bloom date, so growers will have to decide how much of that crop on top they want to try to protect.
"Spider mites are getting a little worse in drier areas, and a few treatments are going out. A lot of cotton is at NAWF 5 plus 350 heat units, so it’s safe from a number of pests. But it still has to be carried further for mites and fall armyworms (FAW). The FAW levels continue to increase, and we’re seeing a lot of moths in places. A few shots of Diamond are going out. With some of these late-season pests, we’re in a race for the finish line."
Roger Leonard, LSU Research Entomologist, Winnsboro, La.: "A little defoliation started last week and over the weekend (8/7-8), with more applications this week. Some of this is cotton that burned up, but it also includes some dryland fields that look like they could pick 800 lb/acre. We got so many heat units that it really has pushed the crop, especially where fields received rain. Irrigated cotton really took off, too. We probably will see defoliation starting in a little of the irrigated cotton next week.
"Occasional mite problems are turning up, but we’re able to clean those up nicely, partly because we’ve gotten rain and a wetter, more humid situation that works against them. We still have sporadic budworm problems in traited cotton, both Bollgard II and WideStrike, but fewer problems now than 10 days ago. I believe that’s because we’ve gotten good rainfall over the area, which has increased protein expression in new growth at the top of the plant, which is where a lot of the egg laying has been. So, worms are getting a bigger dose. The numbers have been so high that they overwhelmed the system, too. Our pyrethroid sprays, where needed, have generally been very effective, but most were in a tank mix. We started early with that and, despite a few misses, I think we pretty much got ahead of the game. By getting on the co-application kick early and everybody recognizing the problem, we stopped a lot of things before they could happen. Plant bugs are sporadic, and we’re still treating. The ultra-low-volume pyrethroid and malathion applications have been working very well where they’ve been used. Nothing is out of control, but we’ve had persistent numbers that have required weekly sprays in younger cotton."
Robert Wells, CRC Ag Consulting, LLC, Monticello, Ark.: "Plant bug numbers have lightened up some. Egg numbers also had lightened up – I thought – but then I walked into cotton on a farm today (8/10), and plants were plastered. We’ll have to make some hard decisions about whether to treat some of these fields that are about ready to go. Some earlier planted cotton, in fact, is close to being finished, and we’ll look at it next week and probably let it go. Plant bugs averaged 5 treatments on pretty much everything. We included pyrethroids in at least the last 3 treatmetns to take care of egg lays, and that also helped with plant bugs. The egg lay has been going for 6 to 8 weeks. We’ve seen big spikes once in a while. But every time we walked into a field for 6 weeks we could find eggs – sometimes heavy, sometimes light, but always there."
Scott Gifford, Gifford Crop Consulting, Manila, Ark.: "We’re still spraying a few plant bugs on some later cotton and are even still treating them in a few fields of earlier cotton. We’re finding a few worms, mainly in the non-Bt cotton, but we’ve also found them in the Bt. We’re not treating them in the Bt."
Angus Catchot, Mississippi Extension Entomologist: "We’re still finishing up some plant bug sprays in later planted cotton. A few stink bug treatments are going out, particularly on later cotton in the hills and in fields that haven’t had a treatment in a while. Nothing is out of control. Some pretty decent bollworm egg lays are underway in places. A lot of cotton is past the point that it would have to be protected, but a little more than a third is still vulnerable. We’re still getting reports about a lot of bollworm moths being flushed in Bt cotton, so we’re seeing that later generation starting to emerge. It’s not anything that worries me on the Bt cotton, but we do have some non-Bt scattered around. A few mite sprays are still being made, but a lot of that is winding down, too. Although we can let go of a lot of earlier planted cotton in terms of plant bugs, we’ve still got to carry it a little further for spider mites and stink bugs."