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Defending Against Yield-Robbing Soybean Diseases

Every season, soybean fields are at risk of plant diseases that can significantly impact yield. Recognizing the disease pressures that typically threaten their crops can help farmers put a comprehensive management plan in place.

Changes in color, shape or function of soybean plants, leaf spots or blights, discoloration of plant tissue and stunting or wilting are telltale signs of soybean diseases. All developmental stages can be attacked, from the seed to mature plants. To maximize yield potential and grain quality, it’s essential to protect soybeans from key diseases, such as frogeye leaf spot, white mold, brown spot and sudden death syndrome, throughout the growing season.

An integrated approach of best management practices includes:

Seed treatments

Fungicide seed treatments can help soybean plants get off to a strong start, especially during cool, wet weather, by protecting seeds and seedlings immediately following planting from damaging diseases such as Rhizoctonia solani, Fusarium, Pythium and Phytophthora. Acceleron® Seed Applied Solutions seed treatments help defend against these diseases through an exclusive combination of fungicides and offer more rapid and increased emergence of seedlings under certain cold conditions.


Scouting soybean fields is an important step in identifying which diseases are present in the field and planning management strategies. Scouting should be conducted in a pattern that covers a wide variety of field locations to increase the likelihood of intercepting an area of diseased plants. Scouting areas first that have a perennial disease problem may help determine the proper timing of early disease management strategies.

Fungicide applications

Timely fungicide application is critical for achieving a successful defense. For most soybean diseases, the most effective applications will come around the beginning of pod set, or about R3. Delaro® Complete fungicide offers unique chemistries in all three modes of action. These ingredients work together to provide consistent control of most major soybean diseases, improved plant health and higher yield potential.

Variety selection

Select soybean products with the appropriate resistance genes and/or best tolerance when there is a known risk of a disease. Asgrow® XtendFlex® products offer resistance to the top soybean diseases, including white mold, Phytophthora, brown stem rot and iron deficiency chlorosis. The combination of disease resistance and the superior weed control offered by the Roundup Ready® Xtend Crop System is designed to protect the high yield potential of the brand’s exclusive genetics.

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Several other management practices can also bolster disease protection. Crop rotation, for example, can reduce some pathogen populations due to the absence of soybean plants. Tillage can also be effective in reducing the risk of foliar and stem diseases because infested crop residues are buried in soil and the fungi die. Keeping a history of disease pressure in certain high-risk fields can be helpful in formulating management strategies. Climate FieldView™ is a powerful tool to collect this disease pressure data. For a closer look at soybean diseases affecting your area, check out the Soybean Disease Risks Maps.

Following an integrated approach that includes planting disease-resistant varieties, the use of seed treatments, timely in-season fungicide applications and regular scouting offers farmers the best defense against yield-robbing diseases. Read “Managing Soybean Disease” for more information.

For additional information, contact your Asgrow technical agronomist or seed dealer, or visit Asgrow.com.

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