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Owen Taylor, Editor
Here is this week's issue of AgFax Midsouth Cotton.
Our thanks to SePRO – maker of Brake herbicide – for sponsoring our coverage.
Bollworm activity and treatments are gaining momentum.
Plant bugs continue to press cotton near corn and other hosts.
Aphid populations have picked up in places, as have spider mites.
Except where they're in areas caught by drought, most of our contacts continue to talk about the heavy fruit load their cotton is holding.
A minor amount of target spot is turning up in places.
Sebe Brown, Northeast Louisiana Region Extension Entomologist:
“Calls this week have primarily been about bollworms, and we’re still in the midst of an egg lay. Depending on the area, eggs are very light or very thick, from 5% to as much as 80%. The heaviest are mainly in proximity to corn.
“The 2-gene technology does seem to be holding. I’m seeing that in my plots and hearing that from other people in the field. That’s better than how things evolved last year, and I haven’t heard of anyone going out with oversprays. Where they have light egg percentages, guys are waiting to see what happens. A lot of them say they may not have to go over the top with a diamide, at least not this week.
“They’re finding live worms but also are finding 1- and 2-day-old dead worms in the bracts, on terminals and in flowers. Where they’re finding live worms, consultants say the worms look sick and aren’t making it through.
“That’s not the case in every field, although it’s more the norm than the exception. At least for right now (7/17), we don’t have quite the pressure on the technology that might cause problems, although that can easily change. But compared to this time last year, pressure is much, much lighter.
“Spider mites are still kicking up in a few places. We did receive at least 3 inches of rain last night and today over a lot of areas in northeast Louisiana, which should help with spider mites. In places that missed rain, mites could start showing up. Temperatures are hot and we’re using harsher chemicals, so that would favor mites.”
Gus Lorenz, Arkansas Extension IPM Specialist:
“A lot of folks in south Arkansas began spraying dual-gene Bt cotton 7 to 10 days ago (from 7/18) for bollworms and now they’re looking at a big flight on top of that. People are now finding 50% to 100% egg lays on stuck dried blooms. Most everybody did gain fairly decent control when they applied Besiege or Prevathon on that first round, with just a few worms left behind.
“Now, they’re looking at another big egg lay and asking what to do. Obviously, they can’t ignore this flight and the new egg lay. For economic reasons, though, we’re discouraging people from coming back with another diamide shot. It’s an expensive deal and we’re recommending a shift to less costly options for the next spray.
“If they’re finding eggs in stuck blooms and have plant bugs, we’re suggesting something like bifenthrin plus acephate, hoping that will knock down some of the moths and maybe gain control of worms as the eggs hatch.
“This has turned into a full-blown war with bollworms in south Arkansas and the flight seems to be heading north. We could see bollworm activity building in central Arkansas in 7 to 10 days (from 7/18). We’ve been in this rolling bollworm flight since June and it’s hard to say how far north it might reach.
“We have a really good cotton crop and want to protect it. But we don’t want to blow up the grower’s budget, which is why we’re emphasizing tank mixes in this phase and not back-to-back diamides.
“Our plant bug situation remains intense, certainly in places. We’ve been lucky in terms of plant bugs over the last couple of years. But what we’re dealing with now is heavy pressure like we contended with 3 or 4 years ago. I’m afraid that a lot of people forgot that you can’t spray heavy numbers once a week and expect to do any good.
“These are situations mainly next to corn, wild hosts or early-planted soybeans. With a once-a-week approach in that situation, numbers can be just as bad a week after you spray and maybe you’re seeing lower retention. You’ve got to shorten intervals to 4 or 5 days and it may take 3 applications, depending on how intense those numbers are.
“Spraying just once a week may not be much better than not spraying at all, based on a number of research projects conducted by our Midsouth entomology group. You have to keep your square set at about 80%, and that won’t be possible going every 7 days against huge numbers.
“People are asking what approach to take with products where they’ve made a Diamond application and used Transform. This is the time to move away from single-product approaches. I’m suggesting an acephate-bifenthrin or Bidrin-bifenthrin combinations and similar approaches to keep plant bugs knocked down.
“Keep in mind, too, that we’re transitioning from strictly monitoring square retention to checking for damage on small bolls. Split open those nickel- and quarter-sized bolls and look inside for plant bug damage to help determine treatment needs and timing.
“Aphids are building in spots, although I think that’s directly related to which chemistries people have used for plant bugs. Acephate, for example, will make aphids worse. If you haven’t used your Transform shot yet, that’s an option for aphids, plus it provides good plant bug control.
“In soybeans, loopers are building quickly and are approaching treatment level in places. They’re moving up from the south and have made it into central Arkansas. This is a mix of cabbage loopers and soybean loopers but enough soybean loopers are in the population that you’ll need to treat as if soybean loopers are the only insect involved. Soybean loopers are harder to control and applying a pyrethroid only makes them mad.
“Check for bollworms in beans that are blooming and just now setting pods in those fields that have not lapped. Everyone is kicking up bollworm moths in soybeans and we’re finding them at least through our central counties. Stink bugs are still coming into early-planted soybeans and have hit treatment levels in places.
“Just a few redbanded stink bugs have been observed. Populations are nothing like what we dealt with last year, and that’s the good news in Arkansas about stink bugs in soybeans.”
Phillip McKibben, McKibben Ag Services, Mathiston, Mississippi:
“Most of our cotton is hovering between 5 and 7 NAWF and we’re hoping to keep it within that range for at least another couple of weeks. We are still applying some Pix on certain fields with a history of aggressive growth. We’ve done a better job this year with Pix, I think. I’ve been super aggressive, myself, and that’s worked really well so far.
“We’re treating plant bugs in some areas. Aphids have really just started showing up, which is a lot later than usual. I’ve seen evidence of the fungus in a couple of fields. This usually is one of the first areas where it appears in the state, although it still might be 3 weeks before the fungus helps us much.
“Spider mites have shown up in a couple of places, which is unusual for us, and we’ve treated two fields.
“Corn is well past dent but not quite to black layer. Some has adequate moisture. Where we can irrigate corn, it’s running.”
Scott Stewart, Extension Entomologist, Jackson, Tennessee:
“We had some good scattered rains and the crop looks great. We’re doing quite a bit of spraying for plant bugs, which isn’t really too surprising. It’s just that time of the year when we see populations pretty consistently.
“I’d describe the populations as moderate. Still, we’re having to do a lot of treatments. We do have more stink bugs in the mix, so the trick is to come up with combinations to cover both plant bugs and stink bugs.
“I’m hearing more and more mentions of spider mites. Fortunately, with these frequent rains in places, our cotton isn’t under a lot of stress and is tolerating mites pretty good. In the last couple of days, a number of people – particularly in the southern counties – have started seeing the bollworm moth flight kick up.”
Tyler Hydrick, Hydrick’s Crop Consulting, Inc., Jonesboro, Arkansas:
“We are at 20 nodes and are aggressively spraying plant bugs in certain places. A lot of that is due to corn in particular areas and/or a lot of beans. They seem to be really thick from Bay up to a point south of Paragould.
“We’ve sprayed some cotton 4 weeks in a row and treated several fields on a 5-day schedule, plus we’ve been trying to keep chemistries rotated to prevent resistance. With these numbers, resistance could turn this into a massive train wreck. We’re throwing the phone book at them and they’re throwing it right back.
“Plant bugs have been really frustrating – especially coming off last year when they were light. In the Lake City area, this might be one of the worst plant bug years we’ve had. Across the rest of our cotton, it’s been more of an average year for plant bugs. In places, we actually haven’t had to spray at all.
“Cotton is growing so fast and has all this heat, so we’re struggling to get water across everything while still watering beans. Plus, we still have 2 to 3 weeks of irrigation ahead of us on some corn. We’re losing fruit because we have so much heat but not enough water, and cotton is trying to finish out too early.
“We’re starting to pick up bollworms in some of our younger soybeans.”
Tucker Miller, Ind. Consultant, Drew, Mississippi:
“We’ve either sprayed all of our Bollgard 2 cotton for the egg threshold or have lined up the applications. We’ve gone out with Besiege or Prevathon and included Transform for aphids in certain cases. I have not sprayed any of the Bollgard 3 with eggs in it and have been monitoring to determine if the technology holds, which I sure hope it does.
“With any luck, this will be an in-and-out moth flight and won’t linger, but we’re still seeing new moths where we sprayed earlier. Where we sprayed last Thursday and Friday, we aren’t finding live worms and it looks like we took them out and also cleaned up plant bugs. It would be great if the diamides held for a couple of weeks.
“I came across some target spot today in one field. It wasn’t terrible but I didn’t have any problem finding it, either.
“In corn, we’re 7 to 10 days away from black layer. We’re trying to water one more time to move it along. In soybeans, we’ve found one or two spots with thresholds of stink bugs and made treatments. One field had about a third of a threshold of bollworms and we’ll wait and see what those do. Overall, though, soybeans are quiet.”
Dale Wells, Ind. Cotton Services, Inc., Leachville, Arkansas:
“Cotton is doing pretty good. We’re starting to see a lot of fields close to NAWF 5. That’s happening a little earlier than I would like, but plants are carrying a heavy fruit load and all this heat is imposing a high demand for carbohydrates. So, cotton is cutting out a little sooner than normal.
“But, all things considered, we still have plenty of crop on the plants and are simply trying to hold onto what’s on it. We’re treating plant bugs here and there. In spots, they’re pretty ornery and we’re having to treat more often than we’d like. By and large, though, applications are working.
“Moth traps in our area aren’t picking up a lot, and I’m finding just a worm here and there in blooms. Typically, worms aren’t a big deal in our area like the pressure they deal with south of us.”
Gary Wolfe, La-Ark Agricultural Consulting, Ida, Louisiana:
“Any rain lately has been spotty and people have been irrigating. Plant bugs are out there but seem reasonably light. I’ve gone with Diamond on pretty much everything.
“We saw a little bleed-through with this moth flight on the 2-gene cotton, and that mainly happened in ranker spots. In our area, soils vary pretty distinctly across fields from sand to clay, so we see spots with more growth where you get into sand. Where I’m finding worms, it’s mostly in those spots.
“I checked more than 3 hours on 1,600 acres on one farm and only found 6 worms, and they were in parts of the field where the canopy had closed. A lot of little bolls had shed but I never found worms where I pulled the dried bloom tags. Worms were hitting a lot of terminal fruit but were dying, and that was in the 2-gene Bt varieties.
“Of all of my growers with the 3-gene cotton, only one so far didn’t want to go with an over-spray for worms. That cotton is holding so far. You’ll see low-level damage under a pivot where the worm hit a boll but then it backed out and water got into the boll. In dryland cotton, I’m not finding that.”
Angus Catchot, Mississippi Extension Entomologist:
“With plant bugs, it looks like the big adult migration has wound down in most places. Some pretty good numbers of immatures are being found in some fields, but I’m not hearing people complain about plant bugs like they were earlier. Don’t get me wrong -- they are still tough in some places but the focus is moving to bollworms.
"The bollworm egg lay seems to be increasing and also moving farther north and east. In places, egg percentages are high and in other places they’re low – and that mostly depends on how close cotton is to corn. I’m hearing about some worms behind diamides, and there’s been a lot of discussion about this among Midsouth Extension folks over the last week.
"With some of this, people maybe waited to spray until they had higher numbers. In the meantime, some of those first eggs hatched and moved to protected areas, so the diamide didn’t get them. For the most part it’s low numbers that we can live with. We will know a lot more in 7 days when everyone is walking behind these initial sprays. That’s my idea right now.
"I’m getting more calls this week about bollworms in soybeans, so we’re on the front end of that but it’s gaining steam every day, especially on late planted beans.”
Louisiana: Bt Cotton Performing Better on Bollworms, Don’t Let Your Guard Down 7-18
Tennessee Soybeans: New Palmer Pigweed Control Option for 2019 7-18
Louisiana Corn: Top Leaf Death or Dieback 7-18
Cotton: China’s Potential Tariffs and U.S. Exports – Lessons from History 7-18
Mississippi Cotton, Soy: Bollworms – Resistance – Podcast 7-16
Cotton – Southwest – Growing Fast – PGR Time | Keep a Hoe in the Truck – AgFax 7-18
Cotton Outlook: Record Global Mill Use in 2018/19 7-18
Tennessee: No-Till Crop Production Field Day, Milan, July 26 7-17
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