Preparing The Crop For Harvest

ALABAMA | Scott H. Graham

Overall, July was good to our crop. Many fields received abundant rainfall during the month. In fact, one grower (and close friend) in east Alabama changed his prayer requests from “just pray for rain, whatever amount” to “just about an inch a week.” Not every field was so lucky, but much of the crop we have seen in late July and early August looks good. Insect pressure has ranged from intense to sporadic.

As the calendar moves to September, we should consider our last effective bloom date. Depending on where you are in Alabama and who you talk to, this date spans from about Aug. 20 through around Sept. 15. Obviously, the further north, the sooner that date approaches. Keep in mind that this date, whenever it is, represents a 50% chance the boll makes the picker.

Sometimes, we wait so long on the “top crop” that we can hurt what’s below, which represents the bulk of the lint. In terms of insect controls, plant bug applications can be terminated about node above white flower (NAWF) 2, while stink bugs can damage bolls until they are about 25 days old. As the crop matures, fewer susceptible bolls are in the field, and stink bug thresholds move to 30%-50% internal damage. We generally recommend a “clean up” spray before September when cotton begins to lay over. While sprayer tracks won’t run over every row, we would rather not run over any if possible.

With defoliation upcoming, we will have some things to consider. One complication will be regrowth. Some fields started “blooming out the top” in early July following June droughts. Since then, the crop has started growing vegetatively again. This regrowth may cause issues with defoliation. I will let the professionals make comments on products and rates. Just note that sprayer set up (spray volume, nozzles, pressure, etc.) can go a long way in the performance of defoliation and harvest aid products.

Follow along with our “Tales of Cotton Insects” on the Alabama Insects Blog (https://alabama-insects.blogspot.com/) for up-to-date information and recommendations for insect controls. If I can ever be of any help, please don’t hesitate to reach out and let me know. scottg@auburn.edu

ARIZONA | Randy Norton

A majority of the state’s cotton crop will be receiving an application of harvest preparation material, either defoliant or boll opener, or both over the next several  weeks. A few things to keep in mind when making these applications include the maturity and the stress level of the crop. Application of harvest prep materials is really our effort to stimulate and enhance the natural process of crop senescence and leaf drop. Applications of harvest prep materials applied prematurely may lead to poor defoliation and increased leaf trash in seed cotton or the opening of immature bolls thus degrading overall fiber quality.

A general rule of thumb that has proven effective in timing harvest prep applications is that of estimating percent open boll. When 60% of the bolls are open or cracked, then a true defoliant can safely be applied with effective results. Open boll percentages can be effectively estimated by counting the number of nodes above the upper-most first position cracked boll (NACB) to the uppermost harvestable boll. A percent open boll of 60% coincides with a NACB value of 4.

The other factor to consider is crop stress level. Remember that the application of defoliant is an attempt to enhance the already progressing physiological process of senescence. If the crop is too stressed when the defoliant is applied, the physiological activity of the plant has diminished to the point that the plant does not effectively assimilate the chemical defoliant. Under this scenario, abscission layers do not properly form, resulting in leaves that “stick” on the plant and increased leaf content of the harvested seed cotton. On the other hand, if the plant is too lush and actively growing, the defoliant application will be much less effective.

A general rule of thumb is that a harvest prep application should be made at approximately two times the final irrigation interval. This interval may vary depending on weather and soil water-holding capacity. For more information and specifics regarding harvest prep and defoliation, go to extension.arizona.edu/crops-soils. rnorton@cals.arizona.edu

GEORGIA | Camp Hand

In Georgia, August and September can make or break a cotton crop. One of the worst things that I can hear on the news or see on social media is when folks start throwing around the “H-word.” I’m currently sitting in my office staring out the window as Hurricane Debby hovers over Georgia. I hope this is the only storm that makes its way across Georgia this season!

As we are approaching the finish line on this crop, there are a few things to keep in mind. First, the crop in Georgia is ahead of schedule. Many may think that because we were so delayed in planting that we are still behind, but that is not the case. Based on average growing degree days we are certainly ahead of schedule, and some of our later cotton may even be 10 days ahead. Why bring this up?? It is important to keep an eye on this crop and how it is progressing — get out there and check it because it is likely progressing faster than you think. My friends in the peanut business may not like this, but we may even have an opportunity to pick some cotton before peanuts this season.

Other things to keep an eye on as we are approaching the finish line are foliar diseases (primarily areolate mildew) and some insect pests. Make sure to treat when needed and not when thresholds aren’t met.

If you have questions about these topics or anything else, feel free to reach out to myself, other members of the cotton team or your local county Extension agent. We are here to help! camphand@uga.edu

MISSOURI | Bradley Wilson

As we move into the latter portion of the growing season, we begin to look toward cotton harvest. In Missouri, we basically have two different cotton crops. Much of the early planted cotton has reached cutout, and maturing bolls will begin to open over the next few weeks, while the later-planted cotton has yet to reach cutout and is still fruiting on the upper part of the plant.

Rainfall in our area has been nonexistent in mid- to late-July; therefore, many producers were irrigating the crop at that time. I believe we will see a number of defoliation applications begin in early to mid-September for the early crop, but we will need heat units pushing into October for the late crop that we have.

Triggering a defoliation generally begins at five nodes above cracked boll, and it is important to pay attention to high daytime temperatures and nighttime temperatures when selecting harvest aid products in our area. Any hormonal application will be reduced when nighttime temperatures fall below 65 degrees Fahrenheit, and herbicidal products can cause sticking of leaves when we have high daytime temperatures at the time of application. brwilson@missouri.edu

MISSISSIPPI | Brian Pieralisi

As I write this on Aug. 4, 2024, summer is showing no signs of loosening its grip, and hot, sunny days rule the forecast. It has a been a hot and dry summer for the most part, but some regions of the state have been fortunate enough to get some timely rains. I always get the question, “How does the crop look in Mississippi?” And it seems that I always have the same answer: “Well, it depends on where you are standing.” There is some truth to that with reasons ranging from planting date, rainfall and fertility. In 2024, cotton planted during the optimal window of May 1 – May 10, including late April, appears to be superior to cotton planted later in May.

Insect pressure, especially plant bugs, has been unusually light this year, and fruit retention is as high as I’ve seen in recent years. Most of the cotton is less than 3 NAWF and almost past the threat of economic injury from insect pests. Late in the season, cotton often looks like its been through battle, and it has to some degree. Often times, late-season disease complexes form on the leaves causing defoliation. Drought-stressed leaves appear leathery and overall appearance is not as lush. All things considered, this means we are nearing defoliation or harvest. As August finishes up the crop, we can hope for hot sunny days and maybe one timely rain. Oh yeah, and a little mercy from the tropics! bkp4@msstate.edu

NORTH CAROLINA | Guy Collins

As I write this on July 26, the crop condition in North Carolina has drastically improved. The ultra-hot and dry June certainly impacted our yield potential, as early to mid-May-planted cotton entered the bloom period adversely short.

Later-planted cotton was also impacted but to a lesser degree. Thankfully, rains came to most areas in the state in very late June or early July as blooming began, and in most areas, rains have been plentiful since then. Some may consider them excessive; however, many creeks and ponds needed refilling even when the crop demands were met. Likewise, we needed somewhat excessive rains to prevent this crop from cutting out abruptly, and thankfully, that has happened.

At this point in time, our yield potential is quite good. That’s not to say the dry June hasn’t cost us….it has. But we still have potential for a great crop. As is the case in most years, August weather will dictate overall yield potential. A few timely rains in August without excessively hot temperatures, to deplete such moisture, will go a long way for our yields.

Then we have to worry about September and October. We badly need — as we always do — a warm and sunny September without excessive rains, prolonged cloudy weather or tropical events. Although it’s too early to tell how much of a top crop we’ll have, in some cases, it may be of interest to growers to pursue a top crop. Recent research has shown that in relatively average fall temperatures, we can make blooms as late as Sept. 5 or Sept. 10 into harvestable bolls IF we defoliate in mid-October with a couple of weeks of a few heat units remaining before first frost. This of course assumes we don’t have abnormally cool weather in September nor an early frost in October.

Making a top crop really only concerns cotton that is either planted very late (early June) or in cases where the bottom crop is less than ideal and conditions in August or early September have favored the development of a strong top crop. At this time, the potential for this is unknown. guy_collins@ncsu.edu

TENNESSEE | Tyson Raper

As I write this on the fifth of August, our earliest planted acres are very near physiological cutout, and our latest planted acres have been blooming for 10-14 days. By the time you read this during the first week of September, those with April cotton will likely note cracked bolls threatening to break mid-canopy.

As we look toward defoliation, I would remind you that we have two distinctly different crops this year, and while both have potential to be very good crops, we should not try to lump the latest planted acres in with the earliest planted acres. I fully expect some acres to be ready for their first shot of defoliant during mid-September.

In contrast, a large portion of our acres will need a favorable October to finish out the top third of our crop. There will be a strong urge to not park the sprayer and/or the picker and “keep rolling.” Resist! While we must keep a close eye on the forecast, rushing the latest crop will most likely reduce our returns.

It has been several years since “preconditioning” shots have been pushed in this area, but I can feel it coming this year. Our defoliants work by contact, not translocation. The leaves that will intercept the defoliant are the most immature and the most important to developing, immature bolls.

“Preconditioning” shots applied under the pretense of pushing maturity are sure to disappoint. When you decide to defoliate, do so with intent. I’ll be updating news.utcrops.com with concoctions that work as conditions change through the fall. traper@utk.edu

TEXAS | Ben McKnight

As I write this in early August, many growers in Texas are beginning to put together plans for harvesting the 2024 cotton crop. As of the first week of August, the Corpus Christi, Texas Classing Office has classed nearly 55,000 bales thus far from the cotton harvest already underway in the Lower Rio Grande Valley and Coastal Bend.

The month of July brought considerable rainfall amounts to several parts of South, East and Central Texas, along with Hurricane Beryl making landfall in the Upper Gulf Coast and pushing through the eastern portion of Texas. The most significant storm damage occurred in Matagorda and Wharton counties, but neighboring counties also sustained considerable crop damage as well. Late July rains didn’t do any favors for open cotton along the Texas Gulf Coast, and reports of seed sprouting in the boll spanned from the Lower Rio Grande Valley to the Upper Gulf Coast.

Throughout the months of August, September and October, growers will be keeping a close eye on the Atlantic and Gulf of Mexico as tropical weather systems typically ramp up during these months. Chemical harvest aids serve many purposes for preparing the crop to harvest, and expediting the time to harvest can be one very important benefit to Texas producers this time of year. While harvesting your 2024 cotton crop may still be a way off depending on where you farm in Texas, developing a chemical defoliation strategy and ensuring that all application equipment is operating properly now is a great first step to getting ahead of the curve. bmcknight@tamu.edu

TEXAS | Ken Legé

West Texas growers seemingly just finished up stand establishment and weed control, and suddenly, our topic today is “Preparing the Crop for Harvest!” Such is the season in this part of the belt. We are generally blessed to have few insect problems in West Texas, so not much emphasis is paid to insect control cut-off thresholds. Instead, we are more focused on irrigation termination dates, especially after the hot, dry August that is forecast as of this writing for much of the region.

Our last effective blooms range from mid-August in the northwest (higher elevation, higher latitude) portions of the high plains to late-August for the southernmost areas of the high plains. While most West Texans have seen the occasional bloom in early September make it to a harvestable boll, those late-maturing bolls are generally very small and have very low micronaire.

So while it is tempting to push the envelope to chase “phantom” bolls and keep irrigating at full capacity to stretch the bloom period to early September, I recommend against it, as it is a poor use of water, and could potentially cause a deterioration in fiber quality, both in terms of low micronaire from less mature bolls as well as potential leaf trash from late-season vegetative growth. Plus, these late-season bolls don’t contribute significantly to lint yield.

General rules of thumb for irrigation termination include 350-400 DD60s after cutout (for subsurface drip, LEPA pivots or furrow-irrigated fields), or 10% to 20% open boll for pivots that have spray drops (LESA or MESA). For most West Texas fields, this equates to the first week of September. However, it gets tricky if we have a dry August, and there is no rain in the forecast for early September. In those situations, the termination decision is on a field-by-field basis, as growers need to take into account soil moisture and the forecast at that time. There is no straightforward answer, unfortunately.

After terminating irrigation decisions have been made, the next major decision includes harvest aids. I’d like to report that choosing harvest aids for cotton in West Texas has become easier, but that is not the case. Harvest aid timing and chemistry choice involves a lot of art based on science. The science behind abscission and boll dehiscence has not changed, and much is understood. However, the complications stem from the interactions with weather and crop conditions. Firsthand experience should be highly emphasized; that is, growers’ experiences with various products and various timings on individual fields is a key piece of information.

If you have a field that has high yield potential, don’t sacrifice yield and quality by skimping on harvest aids. Conversely, if you have a dryland field that has low yield potential, waiting for a freeze is a legitimate economic strategy in West Texas. Because we predominately use stripper harvest in West Texas, I caution growers about applying harvest aid advice from your buddies in the picker parts of the Cotton Belt. We truly have very unique harvest preparation conditions. For more information on harvest aids for West Texas, see these two factsheets: https://lubbock.tamu.edu/files/2022/08/2022-Texas-High-Plains-Cotton-Harvest-Aid-Guide-2.pdf and https://extension.okstate.edu/fact-sheets/print-publications/pss/2021-oklahoma-cotton-harvest-aid-guide-pss-2182.pdf. ken.lege@ag.tamu.edu