Crop Scan AgReport – Welcome Rain, Hot Spots and Watching for Worms
August 10, 2020 
From the field level for mid to late August: Upper areas of the Southeast welcomed some much needed rain, but southern parts of the region are still struggling with heat – especially in dryland fields. Insect treatments and irrigation are both starting to wrap up in parts of the Mid-South, while growers in central and west Texas are still watching insect movement carefully.
Chad Harrell owns and operates Harrell Agronomic Services in Northeastern North Carolina. The NC State graduate is a member of the North Carolina Agricultural Consultants Association and serves on the board of the North Carolina Cotton Producers Association.
“We are doing a lot better than we were on the last CropScan update. Hurricane Isaias brought most of our area 4 inches of rain with more in some places. We even had some rains in spots over the weekend. So, everybody has good soil moisture now. The cotton looks much better than it did two weeks ago.
“We’ve had a pretty heavy moth flight but are beginning to wind down spraying on the 2-gene cotton. The 3-gene cotton held up to the worm pressure pretty well. The fields where we didn’t treat for worms are reaching treatment levels for stink bugs. Plant bugs are present in every field, but treatment levels remain spotty.
“We are probably looking at late September before we start defoliating. I think we are still about two weeks behind normal, but we picked up good heat units during the hot and dry period before the storm and the crop is catching up in maturity. Some of the early planted cotton did lose some fruit during the hot, dry weather. The later planted cotton is loading up well with fruit and will now require more PGRs.”
Wes Briggs is an independent consultant that has worked with growers in Georgia, Alabama and Florida for more than 30 years. The Mississippi State University graduate covers about 10 counties in the tri-state area. He and his scouting team check primarily cotton, corn, peanuts, soybeans and some small grains. His services include weed, disease and insect management, along with fertility recommendations and variable rate soil sampling.
“The last couple three weeks it has been very hot and dry. We have a lot of cotton that’s not had any rain in more than two weeks. We are seeing dryland cotton aborting a lot of fruit, starting last week. I am not sure how much longer the dryland can hang in there with this heat and dry weather. The earlier planted dryland is still looking okay, but it is about to start aborting a good portion of the top crop. We do have some rain predicted this week, but it might be too late for the early planted dryland cotton.
“Overall, our irrigated cotton is looking really good. But we’ve been struggling to keep up with the irrigation. The pivots have been running nonstop. We have seen some irrigated cotton abort some fruit. The crop is at that stage right now where it can’t hold all the fruit. But we have good boll set and retention. I think we have some 1,300-pound and 1,700-pound yields out there and hopefully a lot of three-bale cotton.
“We sprayed a couple of thousand acres for whiteflies last week and will treating more acres than that for the pest this week. With this hot, dry weather, we’ve sprayed a lot for spider mites. This probably is one of the heaviest spider mite pressure seasons I can remember in my 35 years of consulting.
“We could possibly be defoliating dryland cotton here in the next three weeks. For irrigated cotton, we are probably looking at mid-September for defoliation to start up. Probably the worst thing that could happen for the irrigated crop is for it to start raining in late August into September. This cotton is going to mature out fast, and we could run into some problems with boll lock and rot if we get a lot of rain. If the weather stays good and we can manage our moisture with irrigation, I think we have a good crop set.”
UPDATE Aug.11 – “We got .8”-2.0” of rain in spots yesterday, so things could change in hurry. Our pivots needed help. We still have a big area that didn’t get any rain, but this week looks promising.”
Tucker Miller is a Mississippi-based independent private consultant for cotton, soybeans, corn, peanuts, rice and vegetables. He earned a BS in Agronomy and MS in Pest Management from Mississippi State University and is a member and past president of the Mississippi Agricultural Consultants Association.
“We have made our second application for bollworms in our Bollgard II cotton this week. We use mostly Diamide with addition of a plant bug material like Acephate or Transform. We also had to treat several locations for spider mites, using either Zeal or Abamectin depending on the severity of the infestation.
“We are finishing up our irrigation this week. We don’t like to furrow irrigate much past August 10 due to the risk of boll rot if we catch a big rain. We will still have to irrigate the late May planted cotton one more time if it doesn’t rain.
“The July heat has really moved the cotton along rapidly. Most is at NAWF 3 to NAWF 1. The cotton is running out of nitrogen and other nutrients just at the right time. We have a very good fruit set and should be finished with most insect control.
“We will be evaluating our Bollgard 3 varieties this week, looking at management practices for each variety and hope we have some high yielding replacements for the Bollgard II varieties.
“We are probably at least a month away from defoliation but will be mapping out some fields where we can start. We usually do two shots – our first with Dropp and Prep, followed by ET and Prep. This has worked well for us in the past.”
Mark Nemec is a Texas independent agricultural consultant who covers the Blacklands and Brazos River Bottom area of Central Texas. He primarily checks cotton, wheat, grain sorghum and corn, as he has for the last 26 years.
“The hot weather along with sparse rain here in Central Texas has pushed this cotton crop along very fast. Most of my dryland cotton is popping open fast. We have some fields that missed out on the June and early July rains that will probably be defoliated in the next 10-14 days. The lucky guys that caught the rains will be a week or so behind them. The irrigated cotton down toward the Brazos Bottoms looks pretty good if there is enough water.
“Stink bugs have been the biggest issue lately with corn and milo harvest wrapping up and chasing them our way. Some of the edges and hotter ground have seen some spider mites showing up. Growers should watch the later green cotton for stink bugs to make sure they don’t get the later soft bolls.”
Kerry Siders is Texas A&M AgriLife Extension Agent-IPM for Hockley, Cochran and Lamb Counties. A Texas Tech graduate, he has been with Texas AgriLife Extension since 1990, providing education and applied research for weeds, insects, diseases, nematodes, growth regulators and harvest aids in cotton. He is a member of the High Plains Association of Crop Consultants.
“Cotton ranges from just beginning to bloom with more than 6 nodes above white flower (NAWF) to past physiological cutout with 2 NAWF. Using our IPM scouting fields as a representation of the area cotton crop, we see that 68% of fields have reached physiological cutout (<5 NAWF). For those fields, we need approximately 400 more heat units (HU) to accumulate to be safe from bollworms. With the current weather trend of +20 heat units per day, those fields which have reached cutout should be safe from bollworms around August 23-27.
“The remaining 32% of the cotton acreage has such a wide range of maturity levels that it would be difficult to be as certain of when it will be safe from worms. I would approach these later maturing fields from this angle. We historically say our last effective bloom date ranges from August 20 (out on state line) to August 25 (near Ropesville). These are dates in which a boll can be formed, have time to mature, and contribute to yield.
“Therefore, if we continue with this weather pattern into September, and we are accumulating 20 HU/day, we can add 20 days to these dates. This would give us a target of September 9-14 for those late fields needing to be scouted and protected from worm issues. The point being is that NAWF is an important gauge of maturity and can help project time needed to be safe from worms and even manage irrigation.
“Currently, bollworms are infesting area fields and need to be scouted and possibly treated, particularly those varieties with Bollgard II or no Bt technology. Lygus, stink bug and cotton aphids should be included in those scouting procedures. For more information, check out “Managing Cotton Insects in Texas” online.”
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