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Southwest Cotton: Aphids – To Spray or Not to Spray?

August 26, 2021August 26, 2021
AgFax Staff

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Aphids on cotton leaf.

Larry Stalcup, Contributing Editor

Katie Humphreys, Editor

Ernst Undesser, Editor

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Here is this week’s issue of AgFax Southwest Cotton, sponsored by the Southwest team of PhytoGen cottonseed.

OVERVIEW

Cotton aphids are in many fields – and there’s a dilemma on whether to spray. AgriLife entomologist Megha Parajulee contends that unless there is a major flareup in the next few weeks, beneficial insects should hold down aphids.

Defoliation is two weeks late in the Blacklands, as the crop tries to catch up after being behind all season long. Upper Coast defoliation is just starting.

Oklahoma cotton has caught up in much of the southern growing areas after plenty of heat and late summer rain.

Herbicide effectiveness? Peter Dotray, Texas Tech weed specialist, says herbicides were challenged by weed flush after weed flush caused by rain much of the season.

CROP REPORTS

Randy Norton, University of Arizona Extension Cotton Specialist, Safford:

“Bollworms have caused issues in Pima and other non-Bt cotton. Treatments were needed. That’s uncommon for us, but heavy rain in the monsoon season made it a perfect environment for worms. Some acres were sprayed once for lygus in the central production area, while others didn’t see strong enough lygus pressure.

“Early harvest has started around Yuma. We’ll pick research plots there in early September. From my observations, yields are average to slightly above average. I’m also optimistic about the eastern part of the state. Some places got 8 inches of rain. That was highly unusual. Heat stress moderated lower, which helped the crop.

“In central Arizona, however, we see gaps in fruit retention due primarily to heat stress. We can recover from the heat stress if we have a decent fall, and it doesn’t turn off cold.”

Megha Parajulee, Texas A&M AgriLife Extension Entomologist, Lubbock:

“We’re drying out after not being able to get into the field last week. That’s a good problem to have in West Texas in late August. The crop is mid- to late season, and with late planting caused by the cool, wet spring and early summer, we need good weather this fall.

“Insects remain fairly light. Even though cotton aphids are popping up here and there — don’t jump the gun on spraying. Predators should clean them up. We’re nearly at full bloom and plants can tolerate 50 to 100 aphids per leaf for a couple of weeks. I discourage farmers from pulling the trigger unless it’s necessary. The aphids were expected, due to the recent lower temperatures and moisture. It was the perfect setup. But since we have not had much insecticide activity, there should be plenty of opportunities for predators to go in and keep aphids in check.

“Even if fields have shiny leaves, it’s not necessarily time to spray. The field needs to be nearly covered in aphids before spraying. Otherwise, if temperatures remain in the 90s and there are predators, I don’t think aphids will blow up. And the rainfall we’ve been receiving will wash them off.

“We’re fortunate that we have not seen much bollworm activity. From 25% to 30% of our cotton acres are still non-Bt. But even in our traps, we’re not catching large numbers of moths. Others may be finding more moths. That does not translate into larvae activity, but it warns growers to scout their fields closer, especially if they are non-Bt.”

Mark Nemec, MJN Consulting, Waco, Texas:

“Cotton is popping open and we’re probably two weeks away from the start of defoliation. However, we’re still nearly two weeks behind. I’m making the last Pix application on late cotton tomorrow (Aug. 24) to stop it from growing off. Fields have a lot of fruit and it looks like a decent crop. Fields that didn’t drown out early look very good.

“Insects are quiet. I sprayed our last stink bugs a week ago, but we’re still watching a few fields. We just don’t need a big rain at harvest time.

“Guys are cutting corn now and it’s looking better than we thought. Areas that had wet periods in low spots are hurting a little. But high ground corn has been very good.

The early sorghum harvest has been disappointing. That’s mainly because of low wet spots in the field. That killed us. Average yields will probably be 1,000 to 2,000 pounds lower than we thought.”

Murilo Maeda, Texas A&M AgriLife Extension Cotton Specialist, Lubbock:

“Most of the region received rainfall the past week. It should benefit most of the crop, particularly the dryland fields. Because of delays in planting, we still have a good range of cotton maturity — from fields that are way past cutout to fields that are just now approaching cutout. Blooms set in the next 7 to 15 days will likely be among the last ones to contribute to yield.

“As always, weather is the main driver. We continue to run about 230 heat units behind south of Lubbock to about 135 to 140 behind around Amarillo, based on a May 15th planting date. Even with the heat this week, it does not seem like we’ll be catching up anytime soon.

“Folks need to recognize that by mid-October, we historically stop accumulating heat units. Either way we look at it, the region as a whole could probably benefit from a good fall.

“Aphids have been showing up the past few weeks. They’re on sorghum and are moving to cotton. While the economic threshold for them is fairly high early, it will drop significantly once bolls start cracking open. Growers should keep an eye out for them to make sure they don’t end up in a sticky situation.”

Ben Crumley, Crumley Agricultural Consulting, El Campo, Texas:

“The thermometer says 93, but with high humidity, it feels much hotter in the Upper Coast. It’s not too pleasant. But we still have to get out there and scout. With cotton nearing defoliation, there are still a few stink bugs at the top of plants. Since many growers have locked in a strong cotton price, some are making late insecticide applications at a time when it’s typically beyond the need to spray.

“Overall, the first shots of defoliation are just going out, depending on whether the field had good drainage. A few guys went out earlier and are already starting to pick. With corn harvest just finishing up, most will likely jump off the combine and get in the spray rig for defoliation.

“Those who could plant early and have good drainage should see good yields. But most of the crop will likely be mediocre.

“Soybeans are also close to finish. They’ve pushed into the R7 stage. Guys are hoping for good yields there.”

Cody Noggler, Crop Quest Consulting, Northwestern Texas Panhandle:

“The heat has helped us catch up to where we’re just a few days behind after the slow start. The dryland looks good and could make up to 1 bale per acre in various fields. The irrigated could see 2 to 3.5 bales. The rains helped and enabled growers to save on watering costs. But even with the rains, we haven’t needed many PGR applications.

“Insects are light. Other than treating for few plant bugs, nothing else really needs spraying. I’m seeing a few moths this morning (Aug. 24) and will keep an eye on them. But most of my cotton is 3-gene so bollworms shouldn’t be a problem.

“Corn should finish up strong. We’re close to shutting off the pivots. Yields could be slightly above our average of 250 to 280 bushels per acre. Sorghum looks good, but we had to spray quite a few fields for sugarcane aphids. They can blow up like crazy in a week to 10 days.”

Kerry Siders, Texas A&M AgriLife IPM Agent, Hockley, Cochran & Lamb Counties:

“The crop has made much progress the past four to five days after warmer weather. Most is reaching hard cutout, with fewer than 3 NAWF. With the beneficial rains, many dryland fields have close to 13 bolls per plant. That is the main bright spot this year. Since dryland fields typically have smaller bolls, they could still produce 2 bales per acre. With warm temperatures expected all of this week and a good fall, the overall dryland crop could average from 500 to 800 pounds per acre.

“The timely rains helped guys back off irrigation. Other fields might have been overfertilized or overwatered. That pushed maturity, and various fields are still at 5 to 6 NAWF. It may not reach the finish line with full yield potential.

“Insect-wise, cotton aphids are highly variable. Some fields saw aphids crash, while some reached threshold and needed treatment. There are a few lygus issues but nothing serious. Bollworm activity has increased but few fields have required treatment. High corn and sorghum acres took some of the pressure off cotton. Whorl feeding by sorghum headworms caused pre-boot damage and required spraying. They are easy to treat. High grain prices made spraying more feasible.

“Peanuts are also making fast progress. It may be an early crop. Pods set early, are mature and fairly uniform. We could be digging and thrashing by late September instead of in mid-October.

“The strong soil profile is promising for winter wheat. Guys are getting ready to plant into the good moisture.”

Chris Locke, CSL Consulting Inc., Sudan, Texas/Eastern New Mexico:

“The earliest cotton is at cutout. The latest is at 5 to 7 NAWF. Everything has held on pretty well and we’re seeing good boll loads on both dryland and irrigated. Plenty of mid-August rain really helped.

“With an open fall, the drip-irrigated fields should yield 3 to 3.5 bales. Most pivot-irrigated fields could see 2.5 to 3 bales. Dryland should yield 1.5 to 2 bales.

“Insects remain light, but we can’t let down our guard this late in the season. I’m still seeing an occasional stink bug. Weeds are mostly under control, although we’ve had late-season Kochia that has been around all year. Overall, weeds are well managed where guys got good control early. Where they started late, they have a mess.

“For sorghum, I’ve treated one field for sugarcane aphids in the Levelland area. There is also light headworm pressure. Spider mites were heavy in corn and needed spraying. All my corn is silage corn, and we’ll start chopping next week.”

Peter Dotray, Texas Tech University Weed Scientist (joint appointment with Texas A&M AgriLife), Lubbock:

“Since we continue to get rain, the heat has been good for cotton and weeds as well. With each rain comes another flush of weeds. If there’s a residual already out there, hopefully, it will still have activity and diminish the flush. But if it has played out, rain will bring more weeds.

“Even these late-emerging weeds can produce lots of seed. Even though they may not be competitive for cotton this far along or cause issues at harvest, they’re still producing seed we will have to fight in future growing seasons. One large pigweed can produce a half-million or more seeds. Even small ones can produce a few. If it’s not too late for layby, there are lots of good layby herbicides that will help with resistant weeds.

“We must always watch for potential herbicide resistance. Folks should check their fields and be aware of problem weeds and spots — or weeds that don’t respond to herbicides, even those with the newest technology. They need to consider diversifying herbicides next year as much as possible.

“We’ve had good results from the newer technologies. But so much rain and so many flushes made weed management more challenging. If your herbicide is not working as well as it has in the past, look for different residual herbicides and post-emerge products to use next year.

“Folks have been fighting weeds all year and will need to continue to fight them. Don’t over-rely on any one particular herbicide.”

Jerry Stuckey, farmer–Kansas Cotton Association boll weevil consultant, Moscow, Kansas:

“Southwest Kansas cotton is looking pretty good. I run boll weevil traps from here over to the Colorado state line. Cotton is clean everywhere, especially in irrigated fields. Where farmers got rain, dryland looks nearly as good as irrigated.

“Hot weather, like the 103 we’re seeing in Moscow today (Aug. 24), has helped where we’ve had rain. Overall, most fields are cutting out as they should be. They’re blooming at the top.

“Our average irrigated yields are 2 bales per acre. But better producers can make an average of 3 bales or more. If it stays warm through September, I think we will have above average yields.”

Emi Kimura, Texas A&M AgriLife Extension Area Agronomist, Vernon:

“Today is especially hot. It’s over 100 and humid. That will help because we’re still a little behind on heat units. But the cotton looks good. Rain earlier this month helped. That was unusual for August and often means we’ll see a good crop.

“Most dryland growth is already at cutout and some plants are still flowering. There are plenty of small bolls. The irrigated also looks nice.

“There are still weed flushes, but it’s hard to take care of them due to muddy fields. Producers hope to get into the fields soon. Other than a little fleahopper damage earlier, insects remain calm.

“We still need another good rain. Everything depends on how much heat we can get in September. And we don’t need an early freeze like we had last year.”

Todd Baughman, Oklahoma State University Institute for Agricultural Biosciences, Research Professor, Ardmore:

“After being so far behind, the crop has jumped through itself the past couple of weeks with all of the hot weather. I feel better about it. Amazingly, much of this country keeps catching a shower here and there. I think the crop has much potential. So do a lot of guys who are spending money on Pix to manage growth after the rains. With strong cotton prices, they feel the crop is worth the extra input costs. There’s even the chance for a good dryland crop, but some dryland still needs some time.

“Weed flushes are still an issue after all of the rain. The crop didn’t develop a canopy fast enough to hold weeds back this late in the season. Most cotton fields missed damage from armyworms that hurt sudangrass, Bermuda pasture and even peanuts. Many sprays were made. We hope armyworms don’t interfere with winter wheat being planted.

“The good soil moisture should benefit wheat along with our cotton. But to finish the crop, we need a good September and open October. If that happens, we’re on our way to having a good crop.”

Jaime Lopez, Texas A&M AgriLife Extension Agent, Frio County:

“We’re 10 days from defoliation and running late. But cotton is looking good and there’s a high boll load. Growers in this South Texas area should easily see 3 to 3.5 bales per acre.

“We’re at the end of corn harvest and yields have been strong. Sorghum yields are also good, but quality is an issue. There was sprouting out the head after all of the rain.

“Insects are light and cotton fields are still seeing a few weeds. However, weeds are a problem on peanuts and have required herbicide treatments. We’re used to clean peanut fields, but there is more and more carelessweed to deal with.”

ALSO OF NOTE

Texas Field Reports: Alternative Crops Provide Grower Options

Texas Plains Pest Management: Lots Happening in Fields, Get Out and Scout

Texas Blacklands Cotton: Foliar Diseases and Premature Defoliation an Arising Issue

Texas West Plains Cotton: Mostly Pest Free with Some Problem Pockets

Oklahoma Cotton: When to Terminate Irrigation

Texas LRGV Cotton: Harvest in Full Swing

Thompson on Cotton: A Host of Uncertainties Creeping into Market

Weekly Cotton Market Review – USDA

Drought Monitor Weekly: West Remains Dry, Minnesota River Levels Near 1988 Lows

NOAA Seasonal Drought Outlook – Sept., Oct., Nov.

Cleveland on Cotton: Market Bulls Still Have Horns

AgFax Southwest Cotton is published by AgFax Media LLC

Ernst Undesser, Editorial Director. It covers cotton production in Arizona, Kansas, New Mexico, Oklahoma and Texas.

This weekly report is distributed during the main cotton growing season. It is available to United States residents engaged in cotton farming, field scouting and other qualifying ag professions. Mailing address: Farm Journal, 8725 Rosehill Rd., Suite 200, Lenexa, KS 66215