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Pre-Harvest Considerations

Bob Hutmacher

Bob Hutmacher
California

After some mid- and late-season pest issues (lygus, mites), and a rough summer with high temperatures, most cotton fields still look relatively good going into boll maturation. Late plantings and fields that sustained a lot of early to mid-season lygus losses have top crops that will be important to attaining decent yields. They will need to be irrigated later than usual and protected longer from late-season pests.

Some June and July weather was less favorable to continued expansive growth and fruit retention, with more extreme heat and less even boll set as plants responded to some combinations of water stress and high temperatures.

Hot July and August weather had the potential in some fields to affect fruit set, so it has been important in late August and into September to assess what kind of boll distribution you have in your fields. Some fields in late July or early August had moderate to lower bottom canopy fruit set but large upper canopy fruiting potential. Other fields had good to very good early and mid-canopy fruit retention with signs of reduced vigor, and may not end up with a large, late-developing top crops.

In a year like this, there will be some good yields for growers who properly assessed developing boll loads the second half of August and adjusted water applications to make sure they were able to fill out later-developing bolls. If late-season water supplies are limited or costly, it is more important than ever to assess the top crop for additional yield potential and decide if it represents cotton of adequate value to warrant costs for that last irrigation.

Much of the primary fiber development affecting length and strength takes place in critical periods of about three-plus weeks after bloom. Negative impacts of stress on fiber quality will be much less if severe water stress is avoided through about five weeks after bloom. Making the best crop under limited water situations requires good knowledge of where and when bolls were set to assess likely effects of water stress severity and timing.

In the late summer as you wrap up irrigations, also consider weed issues present in some fields and map out areas in need of future control efforts. Problem areas were evident again this year and may have potential for significant weed expansion if left unchecked. Field bindweed, nutsedge, annual morningglory and, in some areas, pigweed were big problems even in some transgenic fields.

Follow winter weed control practices for crop rotations involving cotton to develop field- and farm-level information on multi-year trends in weedy areas and tradeoffs between cost savings and effectiveness in weed control. rbhutmacher@ucdavis.edu

Galon Morgan, Texas

Galon Morgan,
Texas

With very limited dryland cotton harvested in the Rio Grande Valley, the irrigated cotton harvest wrapped up by late August. Irrigated yields in the RGV were variable as whiteflies caused problems during harvest.

In the Coastal Bend, harvest was about 75 percent completed by mid-August. Yields ranged from 0.75 to 3 bales per acre, depending on when and if rainfall was received. Fiber quality has been average with a few reports of high micronaire. Some seed sprouting has occurred from recent rainfall.

Harvest in the Upper Gulf Coast started the second week of August but has been slowed by rainfall. Yields are expected to be variable, but generally slightly above average. Additionally, the UGC farmers are excited about the opportunity to harvest a cotton crop that has not endured excessive rain, seed sprouting and other issues.

The Blacklands’ cotton crop is two to three weeks ahead of normal due to excessive heat and lack of moisture. This has led to a well below average dryland crop with yields ranging from zero to 1.25 bales. Fiber quality is expected to suffer as well. Much of the Rolling Plains’ dryland crop has been disastered-out, and the limited-irrigation cotton was also suffering due to excessive heat. August rains will help the irrigated crop as we approach the last effective bloom date in late August to early September.

The limited availability of thidiazuron has been the major topic of discussion on harvest-aid applications. With alternatives for the first-shot application, such as combinations of Ginstar, Folex and other products plus boll openers, successful leaf drop is still being obtained. gdmorgan@tamu.edu

Seth Byrd, Oklahoma

Seth Byrd,
Oklahoma

As of mid-August, much of the cotton in Oklahoma has reached cutout, and many dryland fields have reached the end of the blooming period. While much of the southwest part of the state has suffered through a hot and dry summer, there is some very good-looking irrigated cotton in that area.

In other areas of the state, particularly the west and north central, a good portion of dryland cotton appears to be thriving. There’s some excellent irrigated and even some dryland cotton in the panhandle. To speak in broad terms, there’s a lot of good cotton but also some poor cotton in Oklahoma, and not a whole lot in between.

For many dryland fields ahead in development, harvest-aid decisions will likely be made in early September.

Many fields may receive applications during the second half of the month. It’s important to note that scheduling harvest-aid applications, whether by percent open bolls or nodes above cracked boll, should revolve around only the proportion of bolls on the plant that are harvestable, or those we expect to have a realistic chance to open in response to a harvest-aid application.

This prevents bolls of highest quality and value from being exposed to detrimental effects of weathering while we wait for smaller immature bolls to slowly develop in the cooler fall temperatures.

However, for much of the Oklahoma dryland crop, most if not all the bolls should open by harvest, considering mid-August marked the end of the blooming period for many of these acres. This rapid development may allow for an earlier-than-normal harvest. It also will bring the added threat of regrowth as these plants will likely fully mature with warm temperatures still present.

n these cases, all it takes is a rain shower to illicit regrowth. So including a regrowth-inhibiting product, such as one containing thidiazuron, will be key in these situations. The most common regrowth-inhibiting products in Oklahoma will contain thidiazuron + diuron, which has better activity in areas with cool overnight temperatures.

As always, use the crop condition and the five- to seven-day forecast to determine the appropriate rates and combination of harvest-aid products. These decisions should be made on a field-by-field basis. seth.byrd@okstate.edu

Tyson Raper, Tennessee

Tyson Raper,
Tennessee

For several years, boll maturity determined by slicing the uppermost harvestable boll has been my go-to method for determining if the crop is ready to defoliate. Bolls are mature when they are difficult to cut with a sharp knife; there is no jelly within the seed; and the seed coat is darkened.

In Tennessee, nodes above cracked boll (NACB) has fallen behind the old rules-of-thumb for some reason. Over the past few years, the uppermost harvestable boll has been mature at five or even six NACB instead of four NACB.

Delaying defoliation until four NACB can allow fiber to continue to thicken and allow micronaire to fall into a discount range. Fortunately, many of the recently introduced varieties are not as prone to high mic as several of the previously released ones. Still, understanding when the crop is mature and ready to defoliate can support earlier harvest and reduce boll weathering.

For observations from the 2018 season, catch up with us on news.utcrops.com or on twitter @TysonRaper. traper@utk.edu

Calvin Meeks, Missouri

Calvin Meeks,
Missouri

On Aug. 12, I’d rate the average cotton acre in the Missouri Bootheel to be in good shape for the most part. Plant bug pressure has been lighter than normal and fruit retention has been very good when adequate soil moisture was present.

Quite a few of the fields I have observed reached physiological cutout the first week of August as our last effective bloom date closed in. To finish up this growing season we need several good rains. Hopefully, the 14-day forecast holds true and we receive some rain. We have 12 days of rain chances greater than 40 percent.

Regardless, a warm, dry fall is needed to finish the crop and current long-term forecasts are predicting a sunny, dry September. Rains over the past week have helped, but we are still several inches away from normal.

Crop condition has improved slightly since July with 12 percent rated excellent (up from 11 percent), 51 percent good (down from 53 percent), 32 percent fair, and 5 percent poor. Recent rains should improve this further, and the crop is in better shape this year compared to this time last year.

Heat unit accumulation has not been a problem this year either. Five percent of bolls are already rated open, which puts the crop slightly ahead of last year as well as ahead of the five-year average.

For the 2018 harvest, focus on balancing yield and fiber quality when defoliating cotton. Proper timing is needed to balance the pursuit of high yields and the need for high fiber quality. One option is to time the application to coincide with 60 percent open boll.

Another method would be to time the application at four NACB (nodes above cracked boll). From the uppermost first position cracked boll on the plant, count the main stem nodes above it to the uppermost harvestable first position boll, sampling 40-50 plants across the field and averaging them.

Inspections on the upper bolls should also be done prior to defoliation by cutting a boll cross section to determine if the seed coat is dark. Defoliation will not reduce yield on these mature bolls.

Second position bolls should not be used to determine maturity because first position bolls contribute 81 percent of the yield.

They also require 120 heat units to mature a boll further out on a fruiting branch. A first positon boll only requires 60 heat units to mature. meeksc@missouri.edu

Dan Fromme, Louisiana

Dan Fromme,
Louisiana

Yield potential for the 2018 cotton crop continues to look very promising. This year’s crop could be as good as our 2013 and 2014 crops. Defoliation began in the latter part of August, and harvest will begin in the earlier planted fields during early September.

As we prepare the 2018 crop for harvest, we should review the basic defoliation timing principles. There is always a balancing act between yield and fiber quality when defoliating cotton. Several accepted methods to time defoliation all have strengths and weaknesses.

Here is a review of some of the more common defoliation timing techniques. These three methods or options for timing cotton defoliation include 60 percent open boll, four nodes above cracked boll (NAWF=4), or 1,050 heat units beyond cutout.

Most importantly, whatever method farmers employ should include inspecting the uppermost harvestable boll prior to defoliation by cutting a cross-section. A boll is considered mature if it is difficult to slice with a knife and seeds have begun to form a tan/brown or black seed coat. Once a dark seed coat has formed, defoliation will not adversely affect yield of those bolls.

View our Louisiana cotton defoliation guide at lsuagcenter.com>crops>cotton>agronomy. dfromme@agcenter.lsu.edu

Darrin Dodds, Mississippi

Darrin Dodds,
Mississippi

The smell of cotton defoliants and the sight of cotton pickers will be common in September in Mississippi. We will likely apply harvest aids somewhat earlier than the past couple of years, which can present challenges. Given that harvest aid selection could be considered as much art as science, be sure to continually account for weather and crop conditions when deciding the best way to remove leaves and open bolls.

Gaylon Morgan/Texas A&M University Agriculture & Life Sciences

Prior to defoliation, growers should include inspecting the uppermost harvestable boll by cutting a cross-section. If a dark seed coat has not formed, as shown above, the fruit is still immature and not ready to be defoliated.

Harvest aid applications early in September accompanied by warmer temperatures will necessitate rate and product selection decisions to minimize leaf desiccation and potential leaf grade issues. However, as the month progresses and the weather changes, be sure to continually adjust rates and products for maximum performance.

The 2018 crop has looked good for the majority of the growing season. In some areas, lack of rainfall in August hurt the crop. In other areas, the crop is as good or better than we have ever seen. As a whole, our crop will likely be above average to outstanding.

If the weather cooperates, we should yield well over 1,000 pounds per acre again in 2018. Early U.S. Department of Agriculture predictions have us at 1,211 pounds per acre. If realized, this would be four years out of the past seven that we have averaged more than 1,200 pounds per acre as a state.

State average yields such as these were unheard of 20 years ago and are a testament to our growers, all who help them make decisions and the germplasm they plant. Have a safe and fruitful harvest season. dmd76@pss.msstate.edu

Bill Robertson, Arkansas

Bill Robertson,
Arkansas

The August U.S. Department of Agriculture-National Agricultural Statistics Service Crop Production Report estimated Upland cotton production at 1.10 million bales, up 2 percent, or 26,000 bales more than last year.

Yield is expected to average 1,112 pounds per harvested acre, down 65 pounds from 2017. The current yield projection is just 2 pounds below our fourth highest recorded yield obtained in 2004. Producers expect to harvest 475,000 acres of cotton, up 37,000 acres from 2017.

Our cotton crop continues to progress ahead of previous years. The most recent NASS Crop Progress and Condition report for Arkansas reported open bolls in 7 percent of fields compared to 6 percent both last year and for our five-year average. The optimism for this crop is evident. Thirty-seven percent of the cotton is rated excellent and 47 percent as good.

This season has not been easy. Conflicts between timely weed management and irrigation initiation were exaggerated with the lack of rainfall in June. We have seen a lot of variability in Nodes Above White Flower (NAWF) in our crop. The dominant factor for this variability is related to available soil moisture. Fields with NAWF values of 6 or 7 at first flower appear to still have the potential to meet our yield goals.

We’ve also seen boron deficiencies in the field for the first time in a very long time. Boron, potassium, sulfur and other nutrients are in the soil, but poor soil structure and a limited root system is reducing their uptake, resulting in deficiency symptoms. Soil health must be improved to fix this problem.

It is important to identify cutout and then base input termination using heat units beyond cutout. Our yield potential is very good at this time. As we close this season, we must continue to manage the crop in a timely fashion. The goal is to maintain yield potential while keeping expenses in check and hope that Mother Nature does not throw us more curveballs. brobertson@uaex.edu

Keith Edmisten

Keith Edmisten
North Carolina

The North Carolina cotton crop is variable from a couple different angles. It has received rainfall ranging from way too much to less than desired. Areas that have seen adequate to too much rain will likely have less residual nitrogen and be less likely to have significant regrowth problems.

Higher levels of regrowth control will likely be needed in areas with lower levels of rainfall because less nitrogen has leached out of the rooting zone. Residual nitrogen is a significant factor in the amount of regrowth pressure in cotton.

Higher rates of thidiazuron (3.2 ounces of Dropp or equivalent generic thidiazuron) will be needed for regrowth prevention for more that two weeks after defoliation. Lower rates can be used to help with juvenile leaves if the cotton will be harvested within 10-14 days of defoliation.

Remember that thidiazuron activity is temperature dependent, and higher rates are needed when temperatures at time of defoliation are lower. We have early cotton that likely will be defoliated under warm temperatures conducive to regrowth pressure.

Thidiazuron will be of more benefit on early cotton. Late-planted cotton is not likely to see warm conditions favorable for regrowth at the time of defoliation or the period following defoliation.

Boll openers are also temperature dependent, and higher rates of them will be needed on the late crop. The need for thidiazuron defoliant mixtures will be most important for the early crop in drier areas and least important for late cotton in areas with a good boll load. Boll openers may be needed for any of the cotton, and higher rates will likely be needed for late-planted cotton. keith_edmisten@ncsu.edu

David Wright, Florida

David Wright,
Florida

Every year is a learning experience for growers no matter how long they have been farming. Weather changes or price fluctuations in inputs, commodities, embargoes, etc. alter the playing field each year. Producers have little influence over many things that happen during the growing season, but certain management decisions can minimize risks to yield and quality.

Keep fields weed-free or to a minimum, defoliate in a timely manner, use the right harvest aids and prevent late-season insect damage. These practices can be beneficial toward the end of the season. Weather is one factor over which none of us have control, but we all have an opinion on how we could have done something better had we planted, defoliated or done something else at a different time.

Growers in the deep Southeast typically have a peanut/cotton rotation with corn in the mix at times. A timely harvest can prevent quality as well as yield loss. We often have late-season tropical storms that influence when we defoliate and pick. In most cases, if the crop is picked and at the gin, there is much less stress and worry to the farmer.

Have the equipment and manpower there when the crop is ready and do not leave mature, open cotton in the field for several weeks or more waiting until peanuts are harvested. The same amount of time and effort will be expended late in the season as early in the season. Quality and yield can be reduced due to cotton being blown out of the boll during heavy rains and wind.

Letting seed germinate in the boll reduces both cottonseed and fiber value.
With the possibility of a decent price, I hope the best for cotton producers following a successful growing season. wright@ufl.edu