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UGA Cotton Team Newsletter July, 2018

Considerations for Cotton PGR Programs (Mark Freeman)


Due to the extended rainfall that most of the state saw during the planting window, Georgia’s cotton crop is extremely variable. Within close proximity or adjacent fields we can find blooming cotton next to 1 and 2 leaf cotton. Because of this variability, making any “one size fits all” PGR recommendation is impossible and any PGR decisions must be made on a field by field basis.


So what do PGRs do? Contrary to what many may think, mepiquat does not cause the plant to produce more flowers or bolls. What is can do is limit the amount of vegetative growth which may enhance fruit retention in lower nodes. This early node fruit retention will help with “earliness” or a quicker maturation of the crop, which tends to benefit later planted cotton more so than early planted cotton. Excessive vegetative growth can also decrease harvest efficiency, decrease coverage of insecticides and fungicides below the canopy, decrease below canopy airflow (which may increase risk of foliar diseases and boll rot), and excessive shading of the lower canopy which can impact the fiber quality of bolls of the lower portion of the plant.


When making decisions on a PGR management program careful consideration should be made on several key factors. The first and most important factor is current crop condition. Is the crop growing rapidly or is the crop stressed in any way (usually drought stress)? One way to determine the crop’s growing condition and growth potential is to look at the top five nodes and internodes of the plant. This is the region of the plant were current growth is happening, and any application of mepiquat will have an effect on. If internode lengths between the 4th and 5th nodes from the terminal are longer than 3” then this is a sign that the plant is growing vigorously and a mepiquat application is likely required.


Other factors that should be considered are current soil moisture and future rainfall predictions (mepiquat should not be applied to cotton under any drought stress), a particular field’s history for producing cotton with rank growth, fertility program and available nutrients in the field, and cotton variety. As we know, not all cotton varieties are the same. Some varieties may exhibit strong vegetative growth potential where as others may not need aggressive PGR programs. UGA Extension Agronomists work each year to classify new varieties based on their growth potential and how they respond to PGRs. This classification chart can be used as a guide for growers who may not have experience with a particular variety and how to manage it correctly. The 2018 version of this chart can be found on the webpage here:

Rate and Timings:

The rate of mepiquat needed is directly related to plant size and rate of growth. If pre-bloom applications are needed (usually only with an aggressive variety and under optimal conditions for vegetative growth) rates should most likely be between 4-8oz/ac. Early-bloom application rates may range from as low as 8 oz/ac up to 24 oz/ac if rapid plant growth is occurring and internode lengths are exceeding 3”.  One often over looked aspect of the PGR program is the timing of the sequential application following the early-bloom application. It is important to continue to monitor the growth of the plant after application and initiate the follow-up application around 14 days after early-bloom.


Remember that there is no “one size fits all” program and that these recommendations should only be used as a guideline. Every field has a unique variable and growers must look at the “whole program” and all of the “other factors” to determine what PGR program is best for their crop.



Fertility (Glen Harris)


Sidedressing N (and K?) and  Boron


What is the best source of nitrogen to sidedress cotton with? And are liquids better than solids?  I get these questions all the time and there is not a real clear answer.  It reminds me of cotton varieties, i.e. we have a lot of good ones but overall some may be better than others. Also, what works the best in one area or operation may not work the best in another.  If you are using solid or granular N sidedress fertilizer your choice is basically between ammonium nitrate or urea. Neither of these contain sulfur so ammonium sulfate is often blended with them.  Ammonium nitrate is less concentrated and usually more expensive. However, in research trial it out yielded urea and was the more consistent performer. Ammonium nitrate also has more burn potential than urea.  Urea plus ammonium sulfate blends don’t always spread evenly and can “streak up” a cotton field.  A relatively new fertilizer material, called Amidas (by Yara) is urea and ammonium sulfate homogenized and spreads very evenly. It is a 40-0-0-5.5(S) and is a little more expensive than the blend but performs very well.


I have heard that some folks think that solids are not as good as liquids because they have to dissolve first. I don’t think this is true. However, there are some advantages to liquids over solids, namely that you can dribble them by the row and reduce the burn potential compared to spreading a solid over the top.  One of the disadvantages of liquids is that you cannot cover as many acres as quickly as you can with solids.  The two most common liquids are 28-0-0-5(S) and 18-0-0-3(S).  Both outperformed their counterparts with no sulfur (32% and 19 %) in recent field trials.


Cotton Yield (lb lint/a)            4 “Site Year” Average (2013-2014)


What about sidedressing with Potassium? If the full amount of potassium as recommended by soil testing is applied preplant or even soon after planting, then sidedressing K with N should not be necessary.  With the heavy rains in late May and on deep sandy soils you may consider replacing some K that may have leached.  Even then, it is difficult to sidedress with liquid forms of K in order to get enough. There are some liquid K formulations being recommended to add to liquid N sidedress but you are only getting very low amounts of K, in the neighborhood of 3 lb K2O per acre.  Instead, on fields where you may have lost some K due to leaching I would recommend waiting until the cotton starts blooming and foliar feeding K with something like potassium nitrate.


Boron – Our official UGA recommendation is to apply 0.5 lb B/a as foliar between first square and first bloom (the same window for sidedressing N). There are a number of products that recommend a lot less boron than this. For example, 6 oz/a of a 5 % B material only gives you 0.025 lb B/a.  This would be fine if it was 10 or 20 times better than other products. But it is not. In recent field trials it’s effectiveness is very close to the untreated check.  There are also many things added to boron fertilizers with claims they make the B get in the plant faster.  Actually this may be true in some cases. However, boron by itself gets into the plant very well on its own, thank you.

Economics (Serinna Liu)


Generic Base/Seed Cotton Program Timeline

By Yangxuan Liu, Don Shurley and Adam N. Rabinowitz


The Bipartisan Budget Act of 2018 authorized Seed Cotton as a covered commodity under Title 1 of the 2014 farm bill and created eligibility for ARC/PLC effective with the 2018 crop year. The legislation provides owners of a farm with generic base a one-time opportunity to convert the generic base to seed cotton base (option 1-A or 1-B) or base of seed cotton and other covered commodities (option 2) based on the 2009-2012 planting history[1].  Landowners also have a one-time opportunity to update the payment yield used for seed cotton PLC.  Producers on the farm must also select the ARC or PLC program for seed cotton.  A lack of action to select the conversion option for the generic base by the appropriate deadline will result in default selections of option 1-A or 1-B, depending on which one results in a higher seed cotton base. Additionally, PLC is the default selection if no decision is made to select ARC/PLC. On April 18, USDA-FSA released Notice ARCPLC-50.  This Notice provided the approximate timeline for the generic base allocation (conversion), yield updates, and ARC or PLC program election and enrollment.  The table below summarizes the timeline.


May 2018 All owners and operators receive their Notification of Covered Commodity Acreage History letter that includes all farms in all counties. Owners and operators are provided an opportunity to correct acreage history for years 2008 through 2016.
Late Summer 2018 Owners make final base allocation and yield update decision for the farm.
Late Summer 2018 Official 2018 Notice of Base Acre, Yield, and Election report mailed to all owners and operators on the farm, with appeal rights.
Fall 2018 All owners and operators on the farm make

PLC, ARC-CO, or ARC-IC program election for the farm.

Ends September 2018 Annual enrollment into PLC, ARC-CO, or ARC-IC program for seed cotton base acre farms.






China’s Potential Cotton Tariffs and U.S. Cotton Exports

By Yangxuan Liu, John R. C. Robinson, and Don Shurley


On April 4th, 2018, China announced a potential 25 percent increase on import tariffs on major U.S. origin agricultural commodities in retaliation to a series of tariffs proposed by the United States. United States upland cotton is one of the commodities affected by this proposed increase in import tariffs. The export market is an important source of demand for the U.S. cotton industry. The United States is the largest cotton exporting country with around 71.3% of cotton produced in the U.S. exported last year. China is the second largest trading partner with the U.S. for cotton in 2017 and buys 16.7% of the U.S. cotton exports. The total value of cotton exported to China was worth approximately $976 million last year, which is the second highest value among all the other row crops after soybean.


If Chinese tariffs are imposed on U.S. cotton, global cotton suppliers like India, Australia, and Brazil may experience a near-term opportunity to supply more cotton to China. In the short run, the market disruption could be a shock to the U.S. cotton futures market, particularly if hedge fund speculators sell off their long positions. However, the longer-term situation could see more U.S. exports rerouted to other cotton importing countries. This recent history of the change in China’s internal cotton policy suggests a similar reshuffling effect from a bilateral Chinese tariff on imported U.S. cotton. Chinese raw cotton import tariffs would continue to stimulate imports of duty-free yarn from Vietnam, Indonesia, and the Indian subcontinent.


Diseases (Bob Kemerait)


There was a time not too long ago when the most important disease we expected to find in Georgia’s cotton fields was “soreshin” or Rhizoctonia seedling blight.  That disease is still important and we had a significant amount of it this year with the very wet conditions at planting.  However, there are a number of other important diseases that cotton growers must deal with and NOW is the time that there diseases will become apparent.  Weather conditions remain perfect for development and spread of disease; excessive wet weather in some areas, and our cotton crop is developing to a point where the foliage of the inner canopy is remaining wetter longer with high humidity, rainfall and irrigation.  Also, as the crop begins to flower and as bolls develop, we are likely to find spread of diseases as well.  Below are four of the most important diseases cotton growers in the state should be prepared for now.  Unfortunately, there is little-to-nothing that can be done for three of the four.  But recognizing damage and loss this season can help growers to make improved management decisions (variety selection, crop rotation, use of in-furrow nematicides, etc.) next season.


Disease watch:  STEMPHYLIUM LEAF SPOT on cotton is associated with a potassium deficiency in the cotton crop and CANNOT be controlled with a fungicide.  I expect to see more Stemphylium leaf spot this year (characterized by red-yellow foliage and numerous spots with papery/gray centers with premature defoliation) because of leaching of fertilizer with heavy rains.  My experience is that once symptoms begin to appear in the field, there is no opportunity for correcting the problem by foliar-feeding potassium, but this is a question better answered by Dr. Glen Harris.  Stemphylium leaf spot typically occurs in the same fields and sandier fields on a regular basis.


Disease watch:  TARGET SPOT in cotton is expected because the season is shaping up to be perfect conditions with extended periods of high humidity with wet foliage and good growing conditions.  Growers should begin scouting their cotton prior to first bloom and to consider fungicide applications as early as sometime between 1st and 3rd weeks of bloom if disease is detected or has been a chronic problem in the past.  The disease is difficult to control because coverage is problematic in the interior of the canopy where the disease is first found.  However, fungicide applications early in the development of the disease are critical if there is any hope to slow its progress where occurs.  Not every cotton grower needs to treat for target spot; however every grower should be aware of the opportunity to protect their crop.  The earlier target spot occurs in a cotton crop, the more likely significant yield loss will occur.


Disease watch:  Bacterial blight appeared early in 2018 and continues to be an issue; however reports are slowing of new finds.  I expect with recent rains we will see a resurgence of this disease in the field.  There is nothing to be done now to control it, but if bacterial blight is an issue in your cotton fields then you should consider other varieties in the future.


Disease watch:  Fusarium wilt of cotton is affecting younger and younger plants and seems to be spreading in the state, or at least our growers are becoming more aware of it.  Fusarium wilt is characterized by smaller stunted plants showing foliage with clear striping and interveinal chlorosis.  The vascular tissue of the plants is stained brown or dark.  This disease is a “one-two” punch brought on by the Fusarium fungus and parasitic nematodes.  Once the seed is planted, there is nothing to be done’ however recognizing the disease this season can help tp make aggressive, effective management decisions for next year.

As a final comment, “vigilance” and “timeliness” are critical components for disease and nematode management in our cotton fields.  Be observant and prepared to make aggressive decisions, either now or in the next season.


Important Dates:

Field Days:

Watkinsville – Cotton Field Day – J Phil Campbell Research and Education Center – July 19th

Midville – Southeast Research and Education Center – August 15th

Tifton – Cotton and Peanut Field Day – September 5th

Scout Schools:

Northwest Georgia Crop Scout School – Cartersville, Ga – July 25th – Contact Paul Pugliese for more information: 770-387-5142


For more information on any of the discussed topics please contact your local UGA Extension Agent.

[1] For more information about the conversion options for generic base, please refer to the factsheet Ag Policy Update within the Bipartisan Budget Act of 2018, available on UGA Georgia Agricultural Policy webpage.