Cotton – Midsouth/Delta – Pests Ramp Up As Crop Pushes Into August – AgFax

Bollworm attacking green cotton boll. Photo: North Carolina State University

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Laykyn Rainbolt, Contributing Editor

Owen Taylor, Editor

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Here is this week’s issue of AgFax Midsouth Cotton, sponsored by the Midsouth Cotton Team of Amvac Chemical Corporation.

OVERVIEW

Cotton pests ramped up on a wider basis over the last week. Bollworms and plant bugs are the main players, but stink bugs are easing into the picture, too. Pressure from spider mites varies. Aphids are pretty much in the rearview mirror now, thanks to the fungus.

More of the early-planted cotton is hitting cutout.

Rains continue to stall applications and/or raise fears of washoff.

Soybean pests also are trending upwards. A few bollworm treatments have been going out, and stink bug applications are ongoing in parts of our coverage area. Loopers and green cloverworms have appeared earlier than usual, several of our contacts have noted, and scattered populations hit treatment levels.

Corn harvest has started a bit more in Louisiana.

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CROP REPORTS

Andy Graves, Graves Agronomy Service, Clarksdale, Mississippi

“Our cotton ranges from cutout to just starting to bloom. A round of irrigation went out in the cotton, and we’re waiting to see if the forecasted rain materializes before we irrigate again.

“It’s been a weird year for plant growth regulators. I think the early rains prevented plants from growing as much and developing a fuller root system. A lot of my cotton is pretty short-stalked, and we really haven’t had to put out much Pix.

“Plant bug numbers have really fallen off in the last 10 days, even around corn and soybeans. Aphids have crashed, too.

“We are in the middle of a bollworm flight right now (7/28), and we’re pretty much making a diamide application on all the cotton. I’m treating a number of fields for spider mites in the same application. 

“I’ve been very happy with the diamide. I just walked out of a field that was one of the first fields where we saw an egg lay, and I found a couple of dead worms, so I’m thrilled with the performance. I’m not thrilled about the cost, but it works well. Some worms did get through it last year, but I think that was due to the canopy and egg placement. 

“I’m going to start looking in WideStrike and Bt 3 fields today for worms because we found a lot of hatching over the weekend. We’re looking for any survivors because we’re not sure where that technology stands yet. 

“We’re treating a lot of the young beans for podworms, but otherwise the soybean insect pressure has been very light this year. We are picking up a redbanded stink bug once in a while, maybe as few as one or two a week.

“Fungicide applications are still going out on the R3 beans, and bollworm treatments are piggybacking off of that. 

“My oldest corn is almost at black layer, and the youngest is just now tasseling. We are seeing some southern rust and northern leaf blight in a lot of it, but I think the corn is far enough along that those won’t present an issue.”

 

Scott Gifford, Gifford Crop Consulting, Manila, Arkansas

“Plant bug sprays are still going out. We’re about to get them under control, and the numbers have dropped this week compared to last week. We picked up our first worms in cotton this week but they don’t look too bad yet. 

“Spider mites have been a widespread issue in the last two weeks, and we’ve sprayed 70% of our acres for mites over that period.

“Corn is in the dough stage, and we only have a couple of waterings left on it. 

“We have started picking up a good many green cloverworms in soybeans. If the numbers continue to rise, we’ll have to treat them. I have never treated green cloverworms, so that will be a first for me.

“I think we’re on the front end of a worm flight in soybeans because we picked up a few worms, plus plenty of moths are out there this week. I think we will be fighting worms in beans in 7 to 10 days.”

 

Steve Schutz, Ind. Consultant, Coushatta, Louisiana  

“It rained yet again over the weekend. I guess we’ve had wetter years, but 2020 has been incredibly wet. At my house, we’ve hit 53 inches so far this year. The historic average for that same period is 30 inches. I’ve had 2.5 inches in the last seven days and 8 inches in the last 30 days (from 7/27). 

“The cotton really needs some hotter days. It was 69 degrees this morning, and the forecast shows low 70s and mid 80s for this week.  

“Overall, cotton looks good right now, although we are seeing plenty of shed from weather and bugs. In places, we couldn’t apply insecticides in time due to rain, plus the rain washed off a number of treatments. Pix didn’t go out when needed in certain fields, again due to the rain, so we’re seeing shed because the cotton is growing like crazy.  

“Overall, the cotton is 6 to 10 inches taller than I would like it to be, and canopies are pretty thick. All that said, the load still looks pretty good. Between 60% and 70% of the cotton responded pretty well to Pix. 

“We do have cases where you can tell the results weren’t what we wanted. I was in a client’s cotton yesterday that is nearly six feet tall, although it does have fruit from top to bottom. Another client has vegetative growth like that, but the lower fruit load is lacking. The upper load – above the tenth or eleventh node – looks really good since we got the warmer weather a few weeks ago, but it is going to be a little behind the rest of the cotton.   

“I did find a spot of target spot just starting in the southern part of my territory.  

“Insect sprays are lighter this week than they were last week. Plant bugs are pretty consistent in the cotton. We don’t really have the big numbers like they typically deal with in northeast Louisiana, but plant bugs just won’t quit this year.  

“We’re using a little acephate, and I’m using Diamond on 300 acres. This is the first time I’ve ever had a case where I thought Diamond would fit – a big load of juveniles but not many adults. The price for that material is more reasonable than it has been, so if it holds it for two weeks, it’ll be worth it. Otherwise, we’ll go back to acephate.  

“We had a big egg lay about 10 days ago, and freshly hatched worms started showing up last week. Rains held people back from spraying when they wanted, so treatments probably went out a day or two later than needed. 

“The egg lay is moving north because I found a bunch of eggs Friday around Gilliam that were hatching this morning, and we’ll do a shot up there soon. The highest count is maybe 10% to 12% fresh-hatched worms in pink blooms. So, numbers aren’t outrageous but are still above threshold. I also found some green stink bugs in cotton on Sunday morning.

“In places, we’re spraying redbanded stink bugs in soybeans. Most of the corn is at black layer, and the rest should be in 7-10 days.”

 

Blake Foust, Consultant, Southern Heritage Cotton, LLC, Forrest City, Arkansas

“Quite a few of our cotton fields are at cutout. We’ve sprayed about 15% of our acres for egg lay, and all of that so far has been in Bollgard II. Plant bugs are becoming quite an issue on some of it, and we’re fighting them pretty hard.  

“Pivots are running on some cotton, but most of it is holding up fairly well. We’re in pretty good shape in terms of moisture levels, and rain is in the forecast for the end of this week (as of 7/28). 

“We have a few fields that we made the first application for plant bugs all season.

“If we catch any rain at all, 80% of the corn won’t need another irrigation. If it rains this week and dries next week, farmers will flush through the rest and that corn will be done, as well.

“Beans are totally quiet. We sprayed two early-planted fields for stink bugs today (7/28). Moths are showing up in some of the younger beans but no worms yet. A few loopers also are around.”

 

Scott Stewart, Extension Entomologist, Jackson, Tennessee

“Plant bug numbers are still lower than normal, but most everyone has had to treat. Generally, people are finding enough to justify an application, but in certain places, plant bugs don’t seem to be there.

“Anyone who hasn’t already treated will probably spray within the next 7 to 10 days. That’s the typical pattern for this time of the year because populations of immatures are peaking about now. We’re recommending Transform, acephate, Bidrin, Diamond or some combination of those.

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“The bollworm flight still isn’t here. We are seeing a few moths and a few eggs scattered around, but we’re not finding a large number of worms. I was expecting this to be a late flight, and I think it’ll be next week before the moths really pick up in cotton. Treatable infestations of spider mites have been few and far between. Aphids have been close to that same situation.

“Some of our earliest cotton is past NAWF 5, so hopefully it will escape at least part of the worm pressure. Our main concern is in the Bollgard II cotton because we know we’ll have to spray it if pressure gets too bad. I’m not expecting to have to spray the three-gene technology like WideStrike 3 or Bollgard 3, but I’m encouraging everyone to scout it to make sure.

“It’s time to get serious about looking for bollworms in the cotton and soybeans too. Our late-planted soybeans in the Mississippi River bottoms are a typical target for the worms, and we need to keep an eye on any fields that are just starting to bloom, in particular.

“A few kudzu bugs are finally showing up in soybean, but populations are definitely lower and later than in previous years. Bean leaf beetles and cloverworms are turning up as well, but defoliation levels are generally low.

“A few stink bugs are finally showing up in cotton and soybeans, but populations are still really low. Some will treat if they happen to be putting out a fungicide, but we recommend waiting until populations are high enough to justify the cost. Treating at R3 for stink bugs has little or no effect on stink bug populations that typically occur at R5 or R6.

“We’re in wait-n-see mode to see if we run into soybean loopers this year. They don’t usually make it up here until August.

“We have some dry spots, and most everyone is looking forward to rain that’s in the forecast over the next couple of days (from 7/28). Overall, crop conditions are good, but rain would certainly improve prospects in a lot of places. Soybeans are especially looking for a rain.”

 

Bob Griffin, Griffin Ag Consulting, Jonesboro, Arkansas

“Our youngest cotton is in the second week of bloom and at NAWF 8, while our oldest is at NAWF 5.  In 2 to 3 weeks, we’ll drop the first fields. Some fields look better than others, but we have a great crop this year overall. It’s not made until you get it into the gin, of course, but it looks tremendous right now.

“Rainfall has been mostly well timed. We went about 10 days without rain, but another system came along last week.

“Plant bugs have been light. But like everyone else, we’ve treated 3 to 4 times on specific fields near or adjoining corn. If corn isn’t around, plant bugs are much lighter. I actually treated fields today (7/27) for the first time all year. 

“We’ve been kicking up moths and finding a few eggs, but we are not seeing large numbers. We have only treated a few fields thus far. I haven’t treated any spider mites or aphids, either.

“My youngest soybeans range from R1 to R5 and have not been treated at all. We did put out a fungicide on all the beans when they reached R3.5, but no diseases have shown up. We do that on every acre because I have found that we increase yield enough to pay for that application.

“In corn, we’ve seen southern rust in some fields, but we put out a fungicide on all the corn last week. We’ll be done with the earliest corn in 2 to 3 weeks.”

 

Ashley Peters, Peters Crop Consulting, Crowville, Louisiana

“Every other day it seems to rain somewhere, and more scattered showers fell yesterday (7/26), with rain expected into the week. Most of the crops don’t need rain at this point. 

“Cotton looks pretty good overall. Our earliest planted cotton is somewhere around 2 to 3 NAWF and the majority of the rest is quickly approaching cutout. Over the last 10 to 12 days, we have sprayed all of our dual-gene cotton with a diamide for eggs or small larvae. We are monitoring the WideStrike 3 and Bollgard 3 but nothing has required a treatment so far. 

“Plant bug pressure is normal. They are bad in the typical hot spots but more manageable in other areas, depending on location and surrounding fields.

“Aphids weren’t a huge issue this year. We controlled a few in conjunction with the first plant bug shot, but we really haven’t had to deal with them much past that. Knock on wood, we also haven’t had spider mite issues at all. 

“We’re spraying some of the younger soybeans for bollworms, and we’re starting to treat more fields for redbanded stink bugs. Redbanded numbers aren’t terribly high, but we’re dealing with them as they show up. We did do a lot of fungicide applications last week in the beans.

“One of my clients has started cutting corn, and a few more farmers in the area are cutting, too.”

 

Sebe Brown, Louisiana Extension Field Crops Entomologist

“More people are seeing another heavy egg lay in the cotton, and our trap catches are spiking again. We expect to be in another moth flight this time of the year, and eggs aren’t hard to find in the cotton. 

“I have heard of one case where the three-gene cotton technology failed to control bollworms. The dual-gene technology is clearly falling apart under the bollworm pressure.

“A lot of treatments are going out in the dual-gene cotton, while applications are situational in the three-gene fields. It really depends on how heavy the egg lay is and if damage is occurring. Diamides appear to be working very well for bollworm control.

“Spider mites were picking up, but we received some much-needed rain and the numbers have dwindled with the rainfall. But mites are still out there, so keep watching for them as everyone transitions to more broad-spectrum insecticides that can allow mites to build.

“Plant bug numbers are starting to decrease, but they are still present. 

“Cotton is anywhere from 2 to 5 NAWF, and guys are starting to see the finish line for some of the April-planted cotton.

“Stink bugs are starting to pick up in cotton. We are at threshold in places for greens and browns, so be on the lookout. In drop-cloth sampling in certain spots, we are averaging one stink bug in every drop.

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START BLOCK 3

“Soybeans are mostly between R5 and R6 right now. Redbanded stink bugs (RBSB) are picking up across the state, which has been the trend the past few weeks. People in north Louisiana are consistently finding higher RBSB numbers, and a lot of applications are going out. 

“In addition to RBSB, stink bug numbers are increasing in general, and the insects are starting to concentrate. Folks in the northern part of the state are beginning to fight stink bugs pretty hard.

“Velvetbean caterpillars have made a big entrance in north Louisiana, as well. If defoliation approaches 20%, especially after R1, folks are making applications. They don’t want to treat them, but some of the velvetbean populations are so bad that applications will be going out, regardless of stink bug numbers. Reports of soybean loopers are picking up, too, in the northern part of the state.”

 

Ty Edwards, Edwards Ag Consulting, LLC, Water Valley, Mississippi

“Cotton looks really good, and it’s in great shape as far as Pix goes. The crop ranges from 8 to 5 NAWF. Aphids crashed last week. No mites to speak of.

“We sprayed about 2,000 acres for bollworms in the last week in the Holcomb area and also in a few fields around here. Plant bugs seem to be hit or miss. On some farms, counts are climbing back up, while on other farms they’re nonexistent. However, they are still consistent around this corn.

“Stink bugs are in that same situation, although in some areas they are extremely heavy. Green stink bugs are the ones I’m most commonly seeing. We have been treating most of the stink bugs with Bidrin with the rain chances every day.

“So far, we have not done a single thing in soybeans. I have not found any bollworms in the beans. Late last week, the moths looked like quail coming out. Around Charleston, a few fields are loading up with cloverworms and loopers, and I do expect to treat in those cases pretty soon. 

“The corn is basically done other than irrigation timing. We put a fungicide out on everything that needed it for southern rust, diplodia leaf streak and leaf blight. That amounted to 20% to 25% of our acres. Southern rust was the main push for applying a fungicide.

“Right now, we’re trying to schedule irrigation and stretch the intervals a little to just keep everything wet.”

 

Angus Catchot, Mississippi Extension Entomologist

“Last week, we started seeing a big change in insect pressures in cotton. Bollworms and plant bugs are more concentrated now and are showing up across a wider geographical area. Late last week, a lot of fields hit threshold for bollworm egg counts and were treated. This was a fairly widespread issue in the Delta and part of the hills.

“All the treatments going out so far have been in dual-gene cotton. We are finding eggs in Bollgard 3 and WideStrike 3. But in multiple cases, we’ve let large egg lays go, and everything so far has been good when we return to check those fields. Right now, we haven’t heard of any breakthroughs, which is very positive for the three-gene cotton.

“Plant bug numbers really increased last week, as well, and have built even further this week. Counts in some of our own plots in the Delta have doubled or tripled just since last week.

“A few isolated areas are presenting an even greater plant bug challenge, and those spots required applications 5 days apart to maintain control. Other areas are just at threshold and are requiring treatments, but applications are more spaced out.

“Spider mites are picking up, particularly in the north Delta. But we’re detecting an increase in other areas, as well, and some treatments are going out. Certain growers are using abamectin, which is fine as long as it’s working, but others are starting out with materials like Zeal or Portal.

“Aphids are really crashing in cotton. Aphids are still present in a few isolated spots in north Mississippi, but those numbers also are decreasing. Overall, it looks like the aphid fungus has spread across the state for now, and I don’t expect many more targeted sprays for aphids. It’s the right time of the year for the fungus to start spreading. 

“As with cotton, this week was a turning point for insects in soybeans. We started picking up a few bollworms in later-planted beans last week, and quite a few people have reported them this week. Several treatments have gone out in beans that are still flowering to R3 – maybe even in a few early R4 beans.

“If you’re in that growth stage in the Delta, be aware that a lot more bollworms are being picked up this week (as of 7/29) and sprays are going out. 

“Stink bug pressure is still gradually increasing, and we are spraying redbanded stink bugs (RBSB) in a number of areas but are more confined south of U.S. 82. Although they haven’t gotten really bad, RBSB are hitting treatment levels, with up to 2X threshold in some areas.

“Control had been good on the numbers we are dealing with now. However, as some of the earliest beans start drying down in coming weeks, those remaining green spots will be highly attractive to stink bugs. I still expect stink bug numbers to pick up in those locations, with potentially high numbers.

“It seems a little early, but we are finding loopers in a couple of areas, and a few fields hit threshold. It’s not a widespread infestation yet, but this is something to watch for. Treatments are going out in those isolated fields that hit threshold.”

 

Gus Lorenz, Arkansas Extension IPM Specialist

“Bollworms and eggs have blown up, particularly in the southern half of Arkansas. In places, tremendous numbers are turning up, and the activity started late last week. Oddly, though, this huge moth movement isn’t being reflected in our trap counts. Yet, you can walk in cotton and soybean fields in southeast Arkansas and kick up big numbers of moths.

“We’ve seen this before. It may be that so many moths and pheromone are spread across the landscape that the traps aren’t as enticing.

“One consultant found 34 bollworm eggs on 25 dried stuck blooms. That’s how heavy this flight is. Our own plots are covered up with eggs, and larvae are hatching. This is carrying over into soybeans. In one case, 40 bollworms turned up in 25 sweeps.

“A couple of people said they’ve found damaged bolls in 3-gene cotton. By and large, though, that technology is holding up, based on reports and what I’m seeing. This is a huge flight and could continue for a while, so things might change. Bollworms will put a good deal of pressure on that technology for maybe the next 10 days, so keep scouting those fields.

“Worms are coming through the Bollgard II pretty handily and are feeding on squares and blooms, not just bolls.

“These moths are coming out of late corn where populations have built up and then built up some more. This is definitely the time to scout R2 to R3 soybeans. In soybeans, the bollworm flight has progressed through at least two-thirds of the state. Mostly, numbers are still low, but plenty of fields are at half a threshold, with some just hitting threshold.

“Redbanded stink bugs (RBSB) continue to get a little worse, and more calls are coming in from southwest Arkansas where people already have been treating. In certain cases, we have sub-threshold levels of both RBSB and native stink bugs, but the combined numbers would justify an application.

“Looper numbers are still low but picking up in south Arkansas.”

AgFax Midsouth Cotton is published by AgFax Media LLC
Owen Taylor, Editorial Director.
 
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