The root knot nematode injures cotton roots, allowing entry for Fusarium, which spreads through the vascular system of the plant.
With the profit potential of high-yield cotton, it makes sense for growers to take proactive steps to thwart common cotton diseases.
According to North Carolina State University, cotton yield losses of 5 percent can occur annually without proper disease management. The economic impact of cotton disease may be even greater when ideal environmental conditions exist.
Soilborne fungi common to cultivated soils occur in U.S. cotton-growing regions every year, leading to cotton seedling diseases. The most common pathogens develop when cotton is planted early and soil conditions are wet and cool. These environmental conditions delay seedling emergence and growth.
Proactive management throughout the growing season can protect this year’s yields as well as help protect future crops.
Managing Cotton Diseases
By following an integrated pest management (IPM) program, growers can help control and avoid many yield-robbing diseases in cotton. This plan should be built upon preventative rather than curative measures that integrate cultural practices with seed selection, seed treatment and fungicide applications. This approach offers the best protection to enhance young cotton growth and make environmental conditions less suitable for diseases to attack.
To manage cotton diseases, researchers recommend cotton growers choose varieties with proven characteristics for a high germination rate in cool temperatures. When available, resistant varieties provide the best disease protection, yet not all varieties are resistant to all diseases. For this reason, experts recommend selecting two to three varieties with the highest level of resistance to the most common diseases found on your farm.
Planting multiple varieties that carry different genetic resistances is one way to spread risk and eliminate the threat that all your cotton acres could be wiped out by a single disease. Also, planting varieties with different maturities helps protect against unpredictable environmental risk factors such as weather and soil temperatures.
Follow your local university planting forecasts to plant cottonseed under the most optimal conditions. Avoid planting when soil temperatures at mid-morning are under 68 degrees F at the planting depth, and avoid irrigating cotton immediately after planting. Cool soil can cause chilling injury as well as create conditions conducive to seedling diseases. Planting into wet soil can also create compaction, which can augment disease development and weaken roots that are trying to grow.
The seedling disease complex that includes Pythium (damping off), Rhizoctonia (soreshin), Thielaviopsis (black root rot) and Fusarium wilt/root knot nematode represents the most common diseases found across the Cotton Belt. Fungicide seed treatments provide economical risk insurance and protection against these and other cotton diseases.
Also, consider using a seed treatment that includes an insecticide/nematicide for added pest protection. Seed treatments can help enhance seed vigor, increase stands, and control diseases to result in increased yield.
Develop a strategy for crop rotation. Repeated years of cotton cultivation reduces soil diversity and can lead to more rapid, frequent disease prevalence, particularly when susceptible cotton varieties are grown. Crop rotation can help reduce—but not eliminate—pathogens such as Verticillium wilt, bacterial blight, damping off diseases and Fusarium/root knot nematode complex. Residue management can also be helpful in managing bacterial blight.
For effective and economical disease control, frequently scout fields to identify diseases before they become severe and rob yields. Yearly scouting also helps build a disease database for your fields so you can be proactive in managing future crops. Many disease symptoms look similar, and correct diagnosis is critical to determine the best control options. Consult with your Extension agent or refer to a cotton disease identification guide.
Scouting also allows cotton growers to monitor disease levels and determine if infections surpass economic thresholds and possibly warrant in-season fungicide treatments.
Some growers with a field history of common cotton diseases may want to supplement fungicide seed treatments with an in-furrow fungicide liquid or granular fungicide application as an additional risk-management tool.
Bayer Solutions for Managing Cotton Diseases
In addition to best management practices for cotton, several products can help manage disease resistance and greatly increase success.
Starting off with a good seed treatment is an excellent way to control seedling diseases and protect cotton above and below the ground. The Bayer portfolio of seed treatments includes products that offer protection against seedling diseases as well as early-season control of yield-robbing insects and nematodes.
For cotton-growing areas with a history of disease pressure and/or conditions that are conducive to seedling disease problems, growers can maximize their stands by planting in optimal soil temperatures and protect their cottonseed investment with a premium fungicide seed treatment such as Trilex® Advanced. It protects against a broad range of cotton seedling diseases, including Fusarium, Rhizoctonia, Pythium and Thielaviopsis basicola and is the preferred fungicide partner for Aeris® insecticide/nematicide seed treatment.
Additionally, Bayer offers cotton growers EverGol® Prime, an innovative seed treatment fungicide that promotes root growth for faster crop establishment. When applied on cotton, EverGol Prime controls soil-borne pathogens such as Rhizoctonia. EverGol Prime is available on all FiberMax® and Stoneville® cotton seed varieties.
FiberMax and Stoneville varieties also help offset several diseases. For example, Stoneville 4946GLB2, FM 2011GT and FM 1911GLT provide good resistance to root knot nematode/Fusarium wilt, while several FiberMax varieties have the best tolerance in the industry to Verticillium wilt, for which no chemical controls are available. These options include FM 2322GL, FM 1830GLT and FM 2334GLT. Additionally, Bayer has several FiberMax and Stoneville varieties that are resistant to bacterial blight.
View our products section to learn more about the portfolio of products from Bayer to help you manage disease in your cotton crops or contact your local Bayer representative.