CLRDV KNOWLEDGE BASE

Cotton Leafroll Dwarf Virus Knowledge Base Grows

BY AMANDA HUBER

SOUTHEAST EDITOR

The list of weeds found to be overwintering hosts for cotton leafroll dwarf virus continues to increase based on research findings. Both weeds and cotton stalks left in the field can act as a green bridge over the winter and a well of inoculum for the onset of disease the next season. Despite the growing data on CLRDV, it has been a significant problem in very few fields.

University of Georgia Extension plant pathologist Bob Kemerait says, “In my estimation, in 2020, CLRDV was present in a small amount in nearly every field in Georgia. How many fields was it a significant problem in last year? I think it was only three or four fields where yield was affected.

“I can’t tell you why it was severe in the one field and not in the field across the road. When a disease is capable of causing significant loss but this randomness cannot be explained, it does cause concern and shows that more research is needed.”

Field Sanitation

Extensive surveys in cotton-growing areas have helped identify weeds that harbor CLRDV over the winter. Both weeds and cotton stalks left in the field may be a primary inoculum source for the onset of disease in the next growing season.

Foliage samples from 57 different weed species were collected from fields formerly planted to cotton and analyzed with CLRDV-specific primers. The virus was detected in 23 weed species belonging to 16 different botanical families. For cotton residue, overwintering cotton stalks and regrowth leaves harbored CLRDV at 48% and 75%, respectively.

UGA crop virologist Sudeep Bag says the current recommendation is to remove overwintering cotton stalks soon after the harvest and maintain field sanitation.

“In 2021, we still see lots of fields with cotton stalks. The presence of CLRDV-positive stalks in the field after the cropping season shows the residual cotton stand to be a suitable reservoir and overwintering host for the virus. Adoption of proper chemical rotation and integration of the cultural practices such as the use of cover crops, trap crops, crop rotation and elimination of weed escapes could help manage weeds as well as reduce the reservoirs of the virus.”

Avoid Late Planting

Besides field sanitation, the other recommendation for producers regarding CLDRV going into 2021 is to avoid planting cotton in late June.

“Late-planted cotton seems to have more significant problems with CLRDV than does early planted cotton or that which is planted during the optimum window. But even that’s not consistent,” Kemerait says.

Symptoms for CLRDV may vary based on crop age; however, one of the difficulties with this disease is the variability in virus expression.

“Early or young plants exhibit drooping and wilting and often may not recover. If it does recover, it will not yield. Leaf curl or crumpling is the most common symptom. We have also seen areas of explosive growth where a section of the plant will grow very tall but have no bolls.”

Other symptoms include reddening or a bronze look to the leaf, internodal shortening, intense dark green foliage and moderate to severe stunting.

Bag says current research objectives involve understanding CLRDV symptoms and disease development in the field and control greenhouse conditions.

“We are also conducting experiments to understand the role of weeds on virus epidemiology and incorporate them into our disease management strategies.”

In Georgia, CLRDV Was Detected On The Following Weed Species:

Pigweed – Amaranthus palmeri, Perennial peanut – Arachis glabrata, Mouse-ear chickweed – Cerastium glomeratum, Daisy fleabane – Erigeron annuus, Cudweed – Gamochaeta pensylvanica, Geranium – Geranium carolinianum, Mock vervain – Glandularia pulchella, Flatweed – Hypochaeris radicata, Smallflower morningglory – Jacquemonita tamnifolia, Henbit – Lamium amplexicaule, Swinecress – Lepidium coronopus, Virginia pepperweed – Lepidium virginicum, Burr clover – Medicago polymorpha, Green carpet weed – Mollugo verticillata, Cut leaf – Oenothera laciniata, Ground cherry – Physalis minima, Pink purslane – Portulaca pilosa, Wild radish – Raphanus raphanistrum, Florida parsley – Richardia scabra, Arrow leaf sida – Sida rhombifolia, Goldenrod – Solidago altissima, Low hop clover – Trifolium campestre, Southern rock bell – Wahlenbergia marginate

Establish A Healthy Cotton Stand

TEXAS Ben McKnight

As of mid-March, the earliest planted cotton in the Lower Rio Grande Valley has been out of the ground for a couple of weeks. Planting in the Coastal Bend region has been wide open the past few weeks, and cotton has started to emerge there, also. Some early plantings have already occurred in areas of the Upper Gulf Coast, but the majority of the acres will be planted in the coming weeks and into April.

Grain crop planting in the Brazos Bottom and the Blacklands is nearing completion, and growers will be switching gears to the get the cotton crop planted in April. Farmers in the Rolling Plains still have plenty of time to make some management decisions ahead of planting the 2021 cotton crop.

One glance at the Texas drought monitor map puts into perspective just how dry conditions are statewide. While we can’t control the weather, we can control some things early in the season to ensure a healthy stand during perhaps the most sensitive timeframe in a cotton plant’s lifecycle.

Being mindful of label information on herbicides used in preplant residual programs can minimize early season injury. Applying these products in a timely manner and following the plant-back restrictions are essential for minimizing herbicide injury to cotton seedlings. Additionally, where Topguard Terra is applied for cotton root rot, minimize contact between the seed and fungicide as phytotoxicity can occur. Planting in cool conditions often increases the severity of injury and prolongs the recovery time. This ultimately increases the window for additional stresses to impact young cotton, including early season insect pressure.

Just a friendly reminder that annual auxin training is required for those using auxin-tolerant technologies. If you are not able to attend a local training opportunity, the course is available online at https://bit.ly/ 3ca2oAq. bmcknight@tamu.edu

TEXAS Murilo Maeda

As I write this, the Southern High Plains and Panhandle regions received some much-needed moisture right around the middle of March. Rainfall totals ranged from a few tenths to about 2 inches or, with higher amounts seen generally east of the Interstate 27 corridor. While the Texas High Plains is no stranger to severe weather, the region saw seven confirmed tornadoes during these storms, with wind gusts greater than 80 mph.

We remain hopeful to continue receiving beneficial moisture leading up to planting season. As of March 11, the National Weather Service Drought Monitor puts our region in exceptional drought to the west and “improving” slowly to severe and moderate drought as we move east. With dry soil and high winds prevailing in the past several weeks, producers are scrambling to ensure their fields are “tied down.” Even places where cover crops had been established are currently suffering from dry weather and relentless wind.

As you start firming up plans for the 2021 season, I encourage you to continue keeping an eye on inputs, especially if we don’t see much in the way of moisture between now and planting. When you start booking seed, consider which technology traits you need and try to balance that with what you want as far as varieties are concerned. A good resource is the RACE Trial report found at http://varietytesting.tamu.edu/cotton/.

Hopefully, you have soil sampled your farms and know what their fertility status. Adjust your fertility program according to the soil test results and realistic yield goals. This time of year, movement of heavy farm equipment picks up. Stay safe out there and don’t hesitate to reach out if we can help with anything. mmaeda@ag.tamu.edu

LOUISIANA Matt Foster

With cotton planting just around the corner, a couple factors should be taken into consideration. Early planting is a key component of successful cotton production; however, planting too early can reduce yield potential. Growing up, I often heard farmers say, “The day you plant cotton is the most important day for the crop.” Cotton seedlings are very sensitive to adverse conditions; therefore, it is important to consider details such as soil temperature and heat units (DD60s) before deciding to plant.

Soil temperature is the main factor influencing seedling growth rate. Cool soils (below 50 degrees Fahrenheit) can cause chilling injury to germinating plants. Chilling injury can reduce vigor and increase the likelihood of seedling disease issues.

Good germination and emergence can be expected once the soil temperature at a 4-inch depth is 65 F or greater at 8 a.m. for at least three consecutive days with a good five-day forecast following planting. In Louisiana, cotton is generally planted in mid-April to mid-May, but planting decisions should be based on soil temperature and not the calendar.

Once soil temperature is optimal, calculate the number of DD60s for the next five days to determine if planting conditions are right. Emergence generally occurs after the accumulation of 50 to 80 DD60s after planting. If the five-day forecast after planting predicts the accumulation of fewer than 26 DD60s, planting should be postponed. Also, the low temperature for the next five days should remain above 50 F. Basing planting decisions on soil temperature and the five-day forecast for DD60s can help ensure a healthy cotton stand.

Best of luck during the upcoming planting season. mfoster@agcenter.

lsu.edu

ARKANSAS Bill Robertson

The first step toward a successful season is establishing a healthy stand. Cotton does not tolerate difficulties encountered during its first few weeks of growth nearly as well as most of our insect and weed pests do. While last year we were only about 50% planted the middle of May, our statewide yield set a record. Historically, early planting translates into better yields. However, this trend has not held the past few years. Just remember that early planting does not equal earliness.

Optimum conditions for planting include a mid-morning 68-degree Fahrenheit soil temperature at our desired planting depth for three consecutive days and favorable five-day forecast. We often see good results with 25 or more heat units (DD60s) being accumulated during the fiveday period after planting.

It is important to start with the best quality seed to increase the chances of getting a good uniform stand if conditions are less than optimum. Remember that as seed size decreases, the importance of having good soil temperatures increases.

There are many signals or signs that people use to indicate the right time to plant. Getting off to a good, quick start will pay dividends season long if we do it right the first time. brobertson@uada.edu

MISSISSIPPI Brian Pieralisi

Achieving a healthy stand should be the primary focus for growers as we transition to planting. Input decisions about marketing, fertility and weed control are meaningless without a healthy stand. Last year, the bulk of Mississippi cotton acres were seeded during the optimal window of May 1-10. During this time, warm soil and adequate DD60s (20-25 heat units) contributed to a healthy stand across most of the state. Risk aversion is key to achieving target plant populations.

Managing risks associated with planting include monitoring warm and cool germination of the seed lots, observing field conditions and watching weather forecasts. Often, seeding rates need to be increased over the targeted population, particularly if germination is less than 80%. Planting into cover crops can present challenges. I visited several cover-cropped fields last year with erratic stands that were directly related to seed placement.

It is critical to have proper equipment installed on your planter to remove debris from the drill pass. A narrow, debris-free strip is necessary for proper seed placement into adequate moisture. There are several planter modifications to increase seed-to-soil contact, including row cleaners and hydraulic down pressure systems.

Weather is the greatest factor influencing a healthy stand. It is never a good idea to plant in front of a strong weather maker. Poor vigor and substandard emergence resulting from hasty planting decisions are far worse than waiting on proper planting windows. Five consecutive days of warm, dry weather with properly placed seeds will contribute to successful emergence.

This is an exciting time of year as we prepare for the 2021 cotton crop. As I write this on St. Patrick’s Day, I wish all of you the best of luck!

bkp4@msstate.edu

ALABAMA Steve M. Brown

I once heard a farmer say, “The only way to win at this game is with input costs.” He meant saving a dollar up front, specifically on seed and associated technology. I was quick to criticize his logic, at least to myself. I took exception because I thought he was looking solely for a bargain. I didn’t say it out loud but was thinking, “Yes, you can save on this and that, and you’ll probably save in picking, hauling and ginning costs, too.”

I’ve moderated my opinion somewhat and realize variety selection could appropriately reflect yield goals and yield potential on a field-byfield basis. If I know my farm, I know that X, Y and Z fields have topend yield potential because of soil type, fertility, minimal pest pressure, irrigation or normal rainfall patterns. If weather cooperates, these fields make GOOD cotton. Fields P and U are less productive, even in a good year. I’ve never made big yields in P and U.

For productive fields, I study available data and listen for coffee shop talk about local experience to learn about the latest and greatest. But for the latter group, the “tough” acre as some call it, I may be willing to look for what might be a solid middle of the pack performer.… that comes at some sort of discount.

A discount can take the form of reduced price, free bags or even a special trip. I recently asked a West Alabama farmer about his choice of varieties. He said he planted A and some of B. He and I both knew A was a top performer, but I inquired further about B. He said, “Yes, I bought four bags, and they filled my other eight hoppers.” I considered B a respectable choice but not a world beater. I thought that was a good deal, and for the seed seller, it gave him some exposure and perhaps future opportunity.

Sometimes a deal is a good deal. Sometimes it’s not. cottonbrown@

auburn.edu

FLORIDA David Wright

Many of our growers are anticipating planting cotton with higher prices and a clean slate for 2021. There is much to be excited about with new varieties offered by all companies with new traits that can help overcome challenges from old enemies such as nematodes or plant bugs and thrips, etc. During planting, a high percentage of our cotton growers use some form of conservation tillage, which can be a source of problems if the cover crop was not adequately killed or was not killed timely. At times, cover crops can be too rank to use row cleaners, which means planting depth may not be controlled adequately.

It is more important to have the right planting depth for cotton than most crops since seeds are planted shallower. A clean seedbed helps maintain consistent planting depth. This is why cotton is often planted earlier while there is good moisture in the top inch of soil compared to peanuts that can be planted two to four times deeper than cotton and still emerge.

Most cottonseed is treated with a fungicide and an insecticide to protect seedlings from plant diseases and thrips. This becomes more important for getting stands when soils are cool, and germination and growth are slowed. As more traits are stacked in cotton and the price of seed has increased, a good, initial stand is needed to maintain yield potential. Not only is it important to establish cotton stands the first time around for good yield, but it is important not to slow the planting of rotation crops, which would reduce their yield potential.

Where cotton is strip-tilled following winter grazing without irrigation, it may take longer for emergence as cover crops may be grazed up to the day of planting. Growing plants dries the soil out versus killing the cover crops early, which stops soil moisture uptake. Seed treatments may be more important as seeds are slower to germinate. Our data shows that non-irrigated cotton planted after winter grazing will catch up and surpass cotton planted into non-grazed cover crops and will yield more. wright@ufl.edu

GEORGIA Camp Hand

Greetings from Tifton, Georgia! My name is Camp Hand, and I am the new cotton specialist at the University of Georgia. For our Georgia growers, if we haven’t met yet, I am sorry. In terms of meeting people, starting a job in the middle of a pandemic hasn’t been ideal. But nonetheless, I know we will meet in person soon, and I am ready for that day. I’m looking forward to working closely with our county Extension agents and other specialists for the good of the cotton industry in the state of Georgia.

At this point, corn planting is well under way, and some people are considering taking advantage of the wide cotton planting window in Georgia. The state is unique in cotton production, in that we can start planting cotton in April and plant well into June. So planting should just be getting started!

Although many of the kinks may already be worked out since corn is being planted, one of the first things to do is make sure your planter is ready to go. Drs. Simer Virk and Wes Porter (precision ag specialists at UGA) put together a great checklist to make sure your planter is field ready. For that information, go to https://bit.ly/2PcBkro.

Another great tool for planting decisions is the Cotton Planting Conditions Calculator, developed by our friends in North Carolina. You can select the location of your farm and based on current and forecasted temperatures (and calculated DD60s with those temperatures), it advises whether planting conditions are favorable. This tool can be found at https://climate.ncsu.edu/cotton_planting.

If you have any questions, your local UGA county Extension agents, myself and the other specialists, are here to help. I look forward to meeting you all this coming season. Happy planting! camphand@uga.edu

NORTH CAROLINA Keith Edmisten

Several things can contribute to poor stands in North Carolina. Cool weather is often the culprit where we do not get good stands. The effect of cool weather can be exacerbated by planting too deep, using poorer quality seed and/or soil crusting caused by rain following planting. The more of these factors we have, the less likely we will be satisfied with the resulting cotton stand. Unfortunately, the weather during planting season often alternates from warm to cold, and the grower has no control over it.

The most critical period for cottonseed is when it first imbibes water. Consider stopping planting a day or two before cold weather moves in to avoid chilling injury to cottonseed. Growers can use the cotton planting conditions calculator to help navigate the changing weather during the planting season (https://climate.ncsu.edu/cotton_planting).

Being aware of the cool germ results for seed lots can help match seed quality with planting conditions and avoid planting lower quality seed in less-than-optimum conditions. Minimize soil crusting effects on cottonseed by planting shallow and using the hill-drop method and proper use of crust-busting where needed. Growers can also increase seeding rates in more challenging conditions. We tend to think of planting solely in terms of seeding rates that do not change during the season, but we need to think about the number of plants we need to have and adjust seeding rates for conditions and possibly seed quality. keith_edmisten@ncsu.edu

TENNESSEE Tyson Raper

Finding a planting window in late April has been a challenge for Tennessee in recent years. Wet, cool conditions pushed us well into May in 2020, and only a handful of acres were planted in late April during 2019. Cotton planted in the late April-early May window can be stressed. Ideal soil temperatures are often abandoned for temperatures that are barely adequate.

Add a blackberry winter and a hard, packing rain and we occasionally get to start over again. . . in late May. Although it seems that every seed planted in late May emerges in a third of the time it took that early planted seed to emerge, our earliest planted acres almost always outperform our late-planted acres when an adequate stand is achieved.

What can we do to maximize the likelihood of achieving an adequate stand? Monitor planting depth continuously — especially as conditions change — and make sure you have excellent seed-to-soil contact. Watch the forecast. If planting during adverse conditions, try to plant the highest quality seed you have on the acres you think can make it. Save the marginal acres and marginal seed for a better window. If you find yourself in the “should I keep or replant” situation, remember that if you’re on the fence, you’ll generally do better to keep it. Cotton’s ability to compensate is a wonderful characteristic. traper@utk.edu

KANSAS Stu Duncan

Kansas’ short-season environment dictates that cotton growers do everything possible to “get it right” because there is rarely a chance for a successful “do-over.” Establishing a successful crop starts with good seed being planted into a sound seedbed. Our prime planting window for successful stands and profitable lint yields is roughly May 10 through June 1. Environmental conditions in Kansas can fluctuate wildly during this period, something that germinating seed and seedlings have difficulty handling. Ideally, late morning soil temperatures should be at or above 60 degrees Fahrenheit at 2-4 inches for three days before planting with a favorable five-day forecast. This includes sunny days with a minimum of 25-30 accumulated heat units (DD60s).

Chances of rain this time of year usually include variable to heavy cloud cover, cold rain and cooler soil temperatures. K-State researchers have documented 3 to 5 degrees F warmer soil temperatures up through early May in clean or strip-till seedbeds versus no-till seedbeds with good residue levels. Keep that in mind, too.

Seed should have a minimum combined warm/cold germination test score of 145, with 160 or higher being optimum. Don’t scrimp on seed-applied fungicides since seed and seedlings may be subject to extreme air and soil temperature swings from planting through establishment. Researchers report the best seed fungicide and insecticide treatments are effective for about 21-28 days, depending on weather conditions.

If you plant seed not treated with an insecticide, have a good scout (or be one) employed and be ready to treat for thrips if an infestation occurs. Severe thrip infestations may not result in loss of stand, but the cotton plant development delay will linger throughout the growing season. Kansas growers cannot afford to lose any extra days. sduncan@ksu.edu

ARIZONA Randy Norton

There is a lot of truth to the adage “start sick, stay sick” when it comes to cotton farming as it applies to early seedling establishment through crop maturity. This may not hold up in every situation. But I have seen enough to know if poor conditions are experienced during planting and germination resulting in significant seedling disease pressure, the plant seems to suffer all season long.

Getting a good start is critical to achieving our agronomic potential, and this starts with planting. It is sometimes advisable to wait for a window of good weather, or to speed up planting to ensure the seed is placed in soil with adequate moisture for germination. There are a whole host of factors that can affect seedling emergence and stand establishment. Unfortunately, the main one, weather, is completely out of our control.

There are some things, however, we can do to ensure the best chances for a healthy start. Seed quality and all that that it encompasses is a hot topic in the cotton industry right now. You can obtain warm and cool germ test data for every lot of seed you purchase from your supplier. Our experience has shown that within a variety, there can be significant differences in germination tests among lots of seed.

If you have that data, you can make a more informed decision regarding when to plant certain seed lots. If a particular lot has a lower warm germ test, perhaps it is better to wait until conditions are more conducive and soil temperatures are higher. Long standing recommendations are to not begin planting prior to 400 heat units accumulated since Jan. 1. This information along with current soil temperatures and other weather-related data for various locations can be found at the AZMET weather site (cals.arizona.edu/azmet) to assist you in making critical planting decisions. rnorton@cals.arizona.edu

Let’s Talk Logos

The Seal Of Cotton Is Recognized And Respected In The Marketplace

Let’s talk about logos. What is the value of a good trademark? Well, when it comes to the Seal of Cotton trademark, the value is pretty significant. In fact, more than eight out of 10 consumers are aware of the seal. That’s more than any other fiber-related logo today.

But where does the seal come from, and who owns it? The Seal of Cotton trademark is owned by Cotton Incorporated. The organization created it with checkoff funds paid by America’s cotton producers and importers into the Cotton Research and Promotion Program.

The initial idea for designing a cotton trademark came in 1971 when Dukes Wooters, Cotton Incorporated’s first president, wanted a symbol that would convert cotton from a commonplace agricultural commodity into an identifiable consumer brand. The logo, known as the Seal of Cotton, was created in 1973 by San Francisco-based creative agency Landor Associates, who also designed

BY STACEY GORMAN

WARREN, ARKANSAS

Levi Strauss & Co.’s patch and CocaCola’s trademark.

Today, 94% of consumers say the seal helps them easily identify cotton products, and 85% say they associate it with softness, comfort, natural and durability.

Cotton In The Spotlight

There are no royalty fees required for brands and retailers to use the Seal of Cotton trademark on their products. However, there is one essential requirement — the product must contain cotton. In fact, Cotton Incorporated has an entire team dedicated to making sure the Seal of Cotton trademark is used correctly and in accordance with qualifying guidelines.

“We are proud to offer brands and retailers the opportunity to leverage the visibility of and positive connections to the Seal of Cotton trademark,” says Kim Kitchings, Cotton Incorporated’s senior vice president of consumer marketing. “At Cotton Incorporated, our mission is to promote the use of and desire for all things cotton.

“We want everyone to care about the clothes, sheets, towels and personal hygiene products made from the fabric we love. By calling attention to cotton, through the Seal of Cotton trademark, brands and retailers can tell a story consumers identify with, in addition to aligning with the perceptions of quality and trust that are associated with cotton.”

Value Of The Seal

More than 75% of consumers say brands using the Seal of Cotton trademark help them make an informed purchase decision and their shopping experience easier. Consumers expect quality in the apparel and home fashions they purchase. The Seal of Cotton ensures that the cotton products they purchase will meet those expectations.

The creation of the Seal of Cotton trademark is just one of the many ways Cotton Incorporated has worked relentlessly over the course of the past 50 years to educate consumers about the benefits of cotton and increase demand for cotton and cotton products. You grow the cotton. The Cotton Research and Promotion Program helps grow the value.

The data referenced in this story is from Cotton Incorporated’s Lifestyle Monitor Survey and 2016 Seal of Cotton Survey. Gorman is The Cotton Board’s director of communications. Contact her at sgorman@ cottonboard.org.