Defoliation Tips and More


Randy Norton AZ
Randy Norton e-mail

Harvest season is upon us. As pickers enter the field, questions related to heat stress effects begin to be answered. Several consecutive days of heat stress during late June and mid-July had a significant impact on boll retention and pollination.

Higher incidence of “hooked-beak” bolls has been observed across the state. This phenomenon is a result of poor pollination where seed formation in one of the boll locks is affected, resulting in a misshapen boll that has the appearance of a hooked beak.

Some of the early harvested cotton in the southwestern part of the state has been at least average and in some cases slightly above. Significant effort has gone into producing this crop and setting it up for high yield and fiber quality. It is important to remember to keep your cotton clean during this stage of the season. Contamination from plastic bags, torn tarps and other foreign material can significantly affect fiber quality. It is important to make every effort to avoid these contamination sources.

Harvest time also provides the opportunity to collect important yield data. As cotton yield monitors become more common, we can collect critical information to support management decisions for the upcoming season. Yield monitor data allow for characterization of yield variability across a field. This can help pinpoint low yield areas, which may be addressed through management decisions next year.

Technology, including variable-rate controllers, allows for site-specific management of cultural inputs such as fertilizers, pesticides and plant growth regulators, just to name a few. Calibration of yield monitor equipment is important to ensure that data collected by the unit accurately reflects what is occurring in the field.
The University of Arizona has resources available to help calibrate yield-monitoring systems and can provide those services at no charge to you as a grower. Feel free to contact your county Extension agent if you are interested or need help calibrating your system.


Bill Robertson AR
Bill Robertson e-mail

The National Agricultural Statistics Service (NASS) September Crop Production report projected Arkansas producers to harvest 1 million bales, unchanged from the Aug. 1 forecast but 160,000 bales above last year. Lint yield is expected to average 1,096 pounds per harvested acre, down 7 pounds from last month but up 21 pounds from 2016 and slightly below our five-year average of 1,101 pounds per acre.

Based on NASS reports, our crop is behind. Mid-September NASS projections reported the crop was 51 percent open compared to 74 percent at this time last year and 61 percent over the past five years. This season, percent open boll indicators are not matching well with the maturity of bolls in the field. This is the result of cooler temperatures, good soil moisture and active plants.

Perhaps the most reliable method of timing a harvest aid application this year is to slice open bolls with a knife to determine boll maturity. Estimating field maturity by evaluating only percent open bolls may underestimate maturity by as much as 10 days.

The last thing farmers want to do is penalize a good variety by getting into discounts because of something completely in their control. In an effort to avoid discounts, carefully evaluate harvest aid timings and application techniques. These include ground speed, spray volume, droplet size and boom height to ensure good leaf coverage and canopy penetration of harvest aid products.

There are still reasons to be optimistic about this crop. We look forward to seeing how 2017 wraps up as we make plans for the 2018 season.


David Wright FL
David Wright e-mail

High winds and rains from Hurricane Irma twisted most of the state’s cotton crop. Many leaves were blown off, which may make defoliation easier. However, most of the cotton areas did not have heavy rain as did some parts of the state. Harvest and defoliation will be slowed due to the twisted cotton, but there is still a chance for good yields.

It is important for growers to have adequate picking capacity as rain fell three to four days per week, with a few exceptions, since early June. Farmers face challenges every year. It is common to have twisted cotton every few years from major weather events, and farmers tend to do a good job of dealing with this problem.
Overall cotton production has been more difficult this year than normal due to the frequent rains that prevented timely management of fertilization, growth regulator application and weed control efforts. We hope harvest season turns out well for everyone.


Dan Fromme LA
Dan Fromme e-mail

Harvest operations began to get under way during the second and third week of September after receiving 11 inches of rain in the month of August. Of this total amount in August, about 6 inches were from the remnants of Hurricane Harvey.

Rains from Hurricane Harvey just compounded the problems we already had from target spot and boll rot. Target spot has caused plants to prematurely defoliate in some fields by as much as 60-70 percent. Rain also has initiated leaf growth, in many fields, which is making it more challenging to defoliate.
Yield projections at this time are about 875-975 pounds of lint per acre. Wet and cloudy conditions throughout the season coupled with heavy pressure from plant bugs and bollworms has made this season a very challenging one.


Darrin Dodds MS
Darrin Dodds e-mail

College football is back, the weather is cooling, and cotton pickers are finally running after one of the most challenging growing seasons in recent memory. A number of folks are reporting tremendous corn and soybean yields; however, as of this writing very little cotton has been harvested. While Mississippi has received remnants of Hurricanes Harvey and Irma, our thoughts are certainly with those who have suffered devastation from these weather systems.

Our crop as a whole is about two weeks later than normal and as a result, when the aforementioned weather systems rolled through Mississippi there was not a tremendous amount of defoliated cotton. While heavy rainfall hurt in some areas, high winds also laid some cotton on the ground and twisted stalks may make defoliation and harvest challenging. Varying levels of hardlock and/or boll rot have been observed as bolls were in the process of opening naturally when these challenging weather systems arrived.

Mississippi cotton yields have averaged more than 1,000 pounds per acre for the past five years and more than 1,200 pounds per acre in three of the past five years. The crop we have in the field does not appear to be a 1,200-pound-per-acre crop; however, only time will tell what our final yields will be. Regardless, with all of the challenges faced this season, cotton has once again proven it’s resiliency in the face of continued adversity.


Mike Milam MO
Mike Milam e-mail

Missouri cotton producers have certainly had an interesting year. Planting was much earlier than it has been over the past several years. We had a lot of rainfall in spite of the Drought Monitor forecast of conditions being drier than normal. We had a lot of nighttime temperatures of 75 degrees or higher. Currently, the Crop Progress and Condition Report shows we have 17 percent cotton open compared with 18 percent a year ago and 24 percent for the five-year average.

The crop is now rated at 5 percent very poor, 14 percent poor, 49 percent fair, 27 percent good and 5 percent excellent. At this time last year, we had 1 percent very poor, 10 percent poor, 50 percent fair, 35 percent good and 4 percent excellent.

The August Cotton and Wool Outlook projects the Missouri yield at 1,124 pounds per acre. When I saw this, I was somewhat surprised. This projection was before the adverse weather conditions. We had about a 10-day very rainy period that has damaged the crop. Some fields had significant flooding, rank plants, rotten bolls and target spot. We have had target spot before, but this year it caused significant boll loss. So I expect yield projections to drop.

The dicamba issue did not go away quietly. There are lawsuits pending, and the state Legislature had a special hearing to address the issue for next year. Likely, the proposed legislation will increase the fines for using a non-labeled product and place more restrictions on producers.


Guy Collins e-mail
Guy Collins

As I write this on Labor Day evening, the cotton crop in North Carolina is variable but overall good. Compared to this time a year ago, the variation in yield potential across the state, and even field to field, seems greater than in 2016. However, the yield potential of the 2017 crop is still relatively higher than normal at this point compared to most years. Ultimately, we will need a warm and dry September and October to capture this yield potential.

Our current situation makes us nervous as we have observed a rapid erosion of high yield potential during the fall of the past two years due to tropical storms and hurricanes. Our hearts go out to the people of South Texas who have recently experienced the effects of a damaging storm. Hopefully, we will avoid any major storms in 2017 that would cause weathering losses, flooding or even boll rot and hardlock.

Our crop is later than normal. However, defoliation is just around the corner. Growers should watch temperatures and moisture, especially during the early defoliation season. Consider using the appropriate rate of thidiazuron-containing products in tankmixes to address potential regrowth issues. Farmers should also consider nozzle type and application volume when applying harvest aids. Large-droplet nozzles often result in effective defoliation of the top one-third to one-half of the plant. However, they struggle to reach lower leaves effectively. Additionally, we recommend harvest aids be applied at 15 to 20 gallons of water per acre to minimize the need for a second application. Low application volumes (used in ground sprayers) can run the risk of ineffective defoliation, thereby requiring an additional application.


Randy Boman OK
Randy Boman e-mail

The 2017 cotton crop maturity rate has taken a bit of a hit with the cooler August temperatures. We closed out the month at about 19 percent below normal for cotton heat unit accumulation. Nearly all of the daily high temperatures were below normal. Daily low temperatures were normal for most of the month, until the last few days.

As of this writing, cooler-than-normal temperatures have also been encountered during the first 12 days of September. What this means is that we are hoping for a significant warming trend to help us grind out as much maturity as possible, especially for a lot of late-planted dryland fields.

With wheat prices in a continuing slump, producers planted nearly double the historic average for cotton in the state. The September U.S. Department of Agriculture-National Agricultural Statistics Service crop report indicated planted acreage for the state ended up close to 580,000, with the estimated harvested acreage at 555,000. Both of these numbers indicate the highest planted and harvested acreage since 1981.

The per-acre yield estimate was increased from 768 pounds per acre in the August report to 848 pounds per acre in the September report. The math from all this results in an astounding 980,000 bale forecast for the 2017 Oklahoma crop. If realized, the 2017 crop will be the highest bale production in the state since 1933 when 1.27 million bales were harvested from 2.86 million acres.

Both harvesting and ginning infrastructure will be severely tested by this abnormally large crop. Producers are encouraged to get the crop harvested as early as possible to maintain fiber quality. Properly constructing and then installing high-quality module covers on conventional modules will be critical. Watching those module covers in an effort to maintain their integrity will be important, especially if modules cannot be ginned for several weeks or even months.

New cotton producers need to be concerned and get educated about this important management consideration. Many publications are available to provide valuable insight.


Tyson Raper TN
Tyson Raper e-mail

Harvest aid applications picked up mid-September and a large number of acres received their first application Sept. 18. Pickers will be running in the earliest defoliated cotton by Oct. 1. Several of our small plot trials were defoliated by Sept. 15. I suspect our variety trial publication will be released by Dec. 15 this year. I’ll comment on it when we get into November.

Last year in my October entry to Specialists Speaking, I highlighted two items to keep in mind as you move into harvest. I think these are still extremely relevant and worth mentioning again. First, properly calibrate yield monitors and protect this valuable data. As we move into the coming years, carefully collected yield data and records have the potential to pay dividends.

Second, remove any plastic trash from the field prior to harvest. I’ve personally walked several of my trials adjacent to residences and retail outlets to remove plastic bags, which are a major issue in some production areas. Contamination levels of U.S. cotton are low, but it only takes a few contaminated bales to affect demand. This effort may not positively impact your bottom line during 2017, but will result in the world market continuing to seek out U.S. cotton.


Galon Morgan TX
Gaylon Morgan e-mail

With few exceptions, the yield and fiber quality for the Lower Rio Grande Valley have been quite good, and the region has been catching some rainfall since harvesting its cotton. The Coastal Bend harvested the best cotton crop in a long time, and even topped the superb 2016 crop. When Hurricane Harvey hit, the Coastal Bend was more than 90 percent harvested; however, high winds and excessive rain in these flat clay soils still wreaked havoc on cotton modules and thus seed and fiber quality.

Moving to the Upper Gulf Coast, things were even worse, primarily due to excessive rain and water in cotton fields. More than half the cotton crop had not been harvested, and much of the harvested cotton was in modules on field edges. As a result, there are many questions with few timely answers about how to deal with unharvested fields, wet modules, lint quality, seed marketability, crop insurance, whether to harvest or not, etc.
Hurricane Harvey also detrimentally affected the southern end of the Blacklands, especially the river bottoms, with 20-plus inches of rain. In the remainder of the Blacklands, harvest resumed the second week of September. Yields are variable, but the crop is generally good for this region. In the Rolling Plains, the crop remains behind schedule, but it has a lot of promise after decent August rains were received. The cotton crop was about 5-10 percent open as of mid-September.
Aphids and some bollworms were problematic earlier in the season but have been brought into check. The weed management situation remains good, with effective weed control and minimal complaints from off-target movement of labeled herbicides when applied over XtendFlex and Enlist varieties.


Seth Byrd TX
Seth Byrd e-mail

Several weather systems that moved through during late August and early September bought rainfall to the majority of the High Plains. Totals for this period ranged from less than an inch to 6 inches or more, highly variable as one looks across the region.

This rainfall could have been more beneficial had it been received a month earlier. However, these showers still had a positive impact on most of the crop and helped finish boll set in late August on upper nodes and second or third fruiting positions. As of Sept.12, most of the region had received the rain needed to finish the crop and allow for an early end to irrigation applications in many fields.

Harvest had yet to begin as of early September, but a few early planted or dryland fields were stripped toward the end of the month. Depending on rainfall, defoliation should begin on a large proportion of the acres in the region near the end of September or early October. Harvest could be in full force in mid- to late October.

The most recent U.S. Department of Agriculture-National Agricultural Statistics Service yield projections for the region range from 540 to 746 pounds per acre, slightly down compared to August numbers in two regions that comprise the majority of cotton acreage in the High Plains. However, projected overall production in bales is still up compared to 2016, likely due to increased acreage.

With good boll retention and rain finally falling at the end of bloom period, a warm, dry stretch the rest of September and into October would lead to optimal conditions for boll maturity and could leave the crop in a favorable place by harvest.

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