Alabama Cotton Shorts
February 16, 2023
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February 16, 2023
Situation. The 2022 crop is still being ginned and classed, and a few acres are yet to be harvested. Last week’s USDA gin report indicated 8 of 27 gins still sending cotton for classing, with around 4,700 samples submitted last week. The numbers compel me to believe that we may not reach the projected 938 lb/A average. Admittedly, I was hoping for better. Overall fiber quality is good. Color grades are very good, no doubt attributable to the open weather from mid-September until well into October.
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Old (March) and new crop (December) futures prices are trading close to 83 cents/lb, down from recent trends between 85 and 86 cents. The outlook for 2023 remains uncertain. Drought still persists in Texas. Forecasts predict 2023 plantings to be around 11.5 million acres or slightly below. Brown
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Futures Prices, February 15, at market close:
March '23 (old crop) - 82.55
December '23 - 83.00
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Auburn University Variety Trial data can be accessed at https://aaes.auburn.edu/variety-tests/
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2023 Variety Selection. Check variety performance data from both AU OVTs and AU On-Farm trials at the Auburn University Variety Testing Website: https://aaes.auburn.edu/variety-tests/. The AU Variety Selection Platform is an excellent tool for yield comparisons and analysis but also includes production information, pest ratings, field pictures, weather data and calendar events. Brown
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Managing Nematodes in Cotton. Plant parasitic nematodes are a serious threat to Alabama cotton and are responsible for losses averaging almost 6.5 percent annually. There are many of nematode species that parasitize cotton, but only two cause significant economic damage in Alabama. The first is the southern cotton root-knot nematode (Meloidogyne incognita), which is most often found in sandy soils in south Alabama. The other is the reniform nematode (Rotylenchulus reniformis), which is most common in finely textured, silty soils. These are the two major species of nematodes that attack cotton in Alabama, but others such as lance and stubby-root nematodes may occasionally be a problem.
Nematodes cause damage to the root systems of plants, which leads to stunting, yellowing of leaves, wilting, and general symptoms of plant stress. Root-knot nematodes also can produce galls on the root system of cotton plants (see the figure below). Management decisions to reduce yield impacts of root-knot and lesion nematodes must be made before the furrow is closed.
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Root-knot nematode damage to cotton roots.
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Nematode management largely focuses on the using resistant cotton varieties and nematicides. Management decisions should be based on nematode population levels determined by testing soils sampled in the fall (Sep to Oct) when populations are at their highest. Nematicides are a very important tool in nematode management but should only be applied when and where needed. If you don’t have nematodes, then you won’t see a yield gain by applying nematicides. Use of nematicides and the manner in which they are applied, varies according to nematode pressure (table below). Telone II, a pre-plant fumigant, is the only “stand alone” nematicide for use in fields with high nematode pressure. The remaining nematicides can be used in fields with low to moderate nematode populations. Vydate C-LV be applied as a post-emergence in combination with seed treatments such as Aeris, Avicta Duo, and Poncho/Votivo for additional control in fields with low to moderate nematode pressure. When planting a susceptible variety, nematicides are most successful under low to moderate pressure and can be used to provide yield protection.
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Variety selection is a key aspect of nematode management as they can reduce nematode populations and root damage. Think of a nematode resistant vareity like planting a non-host crop -- both greatly reduced nematodes for future seasons. There are several commercial varieties resistant to either southern root-knot nematodes or both root-knot and reniform nematodes. Southern root-knot nematode resistant varieties include PHY 350 W3FE, PHY 360 W3FE, PHY 400 W3FE, PHY 415 W3FE, PHY 480 W3FE, PHY 500 W3FE, PHY 545 W3FE, PHY 580 W3FE, DP 1747 NR B2XF and DP 2349 NR B3XF. More recently, cotton varieties with dual resistance to both root-knot and reniform nematode have become available including DP 2141NR B3XF, PHY 332 W3FE, PHY 411 W3FE, and PHY 443 W3FE. Before planting a selecting a nematode resistant variety, producers should determine the species of nematode(s) present in the field and should take a look at the Auburn University Variety Selection Platform to explore vareity performance data. Scherer
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ThryvOn Cotton Commercially Available in 2023. The new cotton technology expressing the Bacillus thuringiensis (Bt) protein Cry51Aa2, referred to as “ThryvOn” and developed by Bayer CropScience, will be commercially available beginning in the 2023 growing season. ThryvOn is unique from all other currently used technologies in cotton integrated pest management (IPM). This technology has activity against two key insect pest species of cotton, thrips (importantly, tobacco thrips, Frankliniella fusca), and tarnished plant bug (Lygus lineolaris). ThryvOn has been documented to reduce populations of both species during the critical periods of the season in which they cause economic losses.
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How ThryvOn Works: Tarnished Plant Bugs
In addition to thrips, ThryvOn technology also has activity on tarnished plant bugs. Insecticide resistance and other changes in the landscape have led to an increase in the pest status of plant bugs across the Southeast. Like thrips, adult non-preference plays a role in the reduced plant bug populations and damage found in ThryvOn cotton. In addition to feeding less, adult plant bugs also deposit fewer eggs in ThryvOn. Although populations and injury are less in ThryvOn cotton compared to non-ThryvOn cotton, threshold populations and injury can be observed and may require treatment.
In pre-bloom cotton, the currently recommended threshold is 8 adult plant bugs per 100 sweeps or to maintain 80% square retention. The use of an either/or approach is critical for plant bug management in current varieties and will likely be important in ThryvOn cotton as well. Although the threshold population of 8 bugs may not often result in >20% pinhead square loss, adult plant bugs are also depositing eggs that will hatch out into immatures over the following weeks. Proper scouting and insecticide timing can help to reduce the populations of immature plant bugs observed in cotton in early bloom.
As cotton develops into bloom, immature plant bugs become the focus for scouting efforts as fewer adults are observed during the first two weeks of bloom. Immature plant bugs prefer to feed on larger squares, often hidden inside bracts, making insecticide coverage difficult. One way that ThryvOn helps with plant bug management is increased efficacy of insecticides. This is likely due to a couple of factors. One factor is that immature plant bugs are thought to move around more in the plant canopy as they, like adults, are looking for other sources of food. Unlike adults, however, they are unable to move from the field to other hosts. This likely leads to immature plant bugs coming into more contact with insecticides as they are moving around the plant and outside of bracts on large squares. Another factor that helps control immature plant bugs is delayed maturity of immature plant bugs. After feeding on ThryvOn, immature plant bugs do not develop as quickly (i.e., get as large) as they normally do. Much like humans, or any other animal, plant bugs feed (i.e., damage) more as they get larger. This leads to less damage, such as dirty squares and blooms, in cotton even if threshold populations of plant bugs are observed.
The recommended threshold for immature plant bugs is 3 per 5 row feet, sampled with a block drop cloth. To date, research done in the Southeast suggests this threshold should be followed in ThryvOn cotton as it is in non-ThryvOn cotton. One advantage of ThryvOn cotton is that often, in low plant bug pressure areas, populations build slower than in non-ThryvOn cotton. This means that the window of opportunity to spray is longer. In other words, in rainy periods or in areas where fields are spaced out across large areas, the timeliness of the insecticide application is not as great. While timeliness will still be important, plant bugs are not doing as much damage in the lag time between sprays.
How to Utilize ThryvOn: Plant Bugs
Often, plant bug infestations are heaviest in earlier planted cotton. This is because as adult plant bugs begin to migrate from weedy hosts to cotton in June, older fields are the most attractive because more food sources (squares) are present. One way to maximize the impacts of ThryvOn cotton for plant bugs in the Southeast is to plant these varieties earliest, as they have the highest likelihood of plant bug infestations. Another consideration is planting near corn. Often, plant bug pressure is higher on field borders next to corn. ThryvOn varieties could be placed on these borders to take advantage of the reduced injury found under high pressure, compared to non-ThryvOn varieties. However, another consideration is that insecticide applications will still be needed, likely the same number of applications needed in non-ThryvOn cotton. Thus, ThryvOn varieties could also be planted in blocks away from corn or other sources of plant bugs. By placing ThryvOn in areas with lower expected plant bug pressure, the likelihood of reducing or eliminating plant bug applications may be increased. These decisions will need to be made on a farm-to-farm basis.
ThryvOn Take Home Points: Plant Bugs
The impacts of the ThryvOn on plant bugs may not always be as obvious as thrips, but this technology will have a fit in Southeastern cotton. Some benefits, such as reduced injury and delayed population development, may be “hidden.” In other words, while this technology may not always eliminate or reduce the need for insecticide applications for plant bugs, less damage incurred helps preserve yield in other ways. Proper scouting, monitoring, use of thresholds and insecticide selection will still be critical for plant bug management in ThryvOn cotton.
In a later edition of the Alabama Cotton Shorts, we will detail how to maximize thrips control in ThryvOn cotton. Graham and Smith
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ThryvOn Cotton Brings New Technology in NEW Varieties. ThryvOn technology, new from Bayer for enhanced management of thrips and plant bugs, recently received full approvals and will be available in multiples varieties and seed brands in 2023. Designation for the technology is “B3TXF”, with the “T” in the middle indicating ThryvOn. While Bayer is responsible for discovery and development of the trait and is committing the future Deltapine portfolio to ThryvOn, seed company partners Armor (GreenPoint, AgriAFC), Dyna-Gro (Nutrien) and NexGen will also offer the technology this year and going forward. All reports are that seed supplies are limited and that yield comparisons with present industry-leading varieties are few.
Past introductions of new traited technologies have not come with significant advancements in cotton yield or fiber quality. The focus has been improved pest management options, either for worm control or tolerance to specific herbicides. Yield improvement has not been the primary goal, and the TIME required for trait introgression, back-crossing and testing, all protracted activities, require entering the genetic breeding and development cycle several years back in the advancement process. At best, new varieties with new technologies rank toward the middle of standard OVTs or similar trials. Typically, a couple of years or more are needed to bring forward and advance the yield performance with the new trait package.
Each B3TXF offering will be a new variety, and despite its similarity of genetic parentage to a given known, each will be distinctly NEW. Each new variety thus will have its unique growth pattern, and maximizing its potential requires time and experience. What are some of its strengths and weaknesses? Does it emerge with good vigor? Does it require aggressive PGR or not? Is it vulnerable or tolerant to certain pests? Does it have a tendency to lodge? Is it easy to defoliate? How early or late is it? Does it hold in the bur well? Does it pick clean?
Over the past couple of years we have had limited testing of ThryvOn lines from Deltapine, Armor and NexGen. Data from a 2022 trial are below. Stands were good – we planted 3 seed/ft and produced populations of at least 2 plants/ft. Node of 1st square was slightly higher than expected, which is an environmental response to warmer weather. DP 1646 B2XF and DP 2038 B3XF were the tallest of the entries, while DP 2115 B3XF was the shortest. Nodes of uppermost cracked (NUCB) and harvestable (NUHB) bolls provide a gross measure of maturity. These and total node counts were not greatly different among varieties. Yields were not great – the field was plagued by excessively wet weather in August through mid-September which affected stink bug management and overall productivity. Lint yields were calculated assuming a 40 percent turnout – obviously, lint percent will vary with actual gin data. ThryvOn entries are highlighted in yellow and commercial Deltapine varieties are included. Altogether there were 24 entries; not all are shown because some were experimental lines.
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Supply will no doubt limit acreage planted to ThryvOn in 2023. Its availability does provide opportunity to TEST the system in a large scale manner, to evaluate the trait package for thrips and plant bug control, to see how it fits in the overall farm management landscape. The technology comes with a higher price but not necessarily higher yield potential… top-end yields should come with time and variety advancement. For this year, think about the best situations to test its value
– plantings in the time window expected to have the most intense thrips pressure
-- situations in which distance or other factors hinder the timeliness of applications
-- early plantings which often coincide with greatest early plant bug pressure.
Brown
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Spray Drone User Conference. Auburn University and the Alabama Cooperative Extension System will host a spray drone user Zoom conference on Mar 18-19, 2023. It is intended for growers and drone operators interested in using spray/spread drones in agricultural, forestry and natural resource management. Information will include drone applications in specialty crops and row crops such as cotton, corn and peanuts. This conference will be conducted completely via Zoom and is open to anyone interested in this new technology. Registration is $50 per person. Students, faculty, university and extension system staff can register for the event at a discount rate of $30 per person. If you qualify for this discount, please contact Dr. Steve Li, steveli@auburn.edu for the discount code. The registration link is:
https://secure.touchnet.net/C20021_ustores/web/product_detail.jsp?PRODUCTID=5362&SINGLEST ”
Li
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The program can be found at
Drone Program
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This issue contributors:
Dr. Scott Graham, Extension Entomologist
Dr. Steve Li, Extension Weed Scientist
Dr. Amanda Scherer, Extension Plant Pathologist
Dr. Ron Smith, Professor Emeritus and Extension Entomologist
Dr. Steve M. Brown, Extension Cotton Agronomist (Editor) typos and mistakes are mine
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About the Alabama Cotton Shorts Newsletter
Alabama Cotton Shorts is a newsletter designed to keep cotton producers in the know. From planting dates to crop inputs—there are many factors to consider. The Alabama Cooperative Extension System is dedicated to providing science- and research-based information, derived from field experience and observations. A team of Extension specialists are working to provide Alabama farmers with timely information throughout the growing and harvest seasons.
By subscribing to the newsletter you will receive pest updates, weed management suggestions, market updates, industry news, and other information. Specialists are making field observations and reporting their findings in hopes of helping producers make more informed choices in the field.
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