This year, many Midwest farmers discovered first-hand the effect of root infection by the fungal pathogen that causes sudden death syndrome (SDS): yield losses of 40 percent were recorded in some fields. But it’s not just SDS that is limiting yield in soybean fields. Wounds caused by soybean cyst nematodes (SCN) and by maturing females serve as entry points for other soilborne pathogens. Brown stem rot (BSR) also infects roots of young seedlings and is often found in the presence of SCN.

Each disease can cause significant yield loss, up to 50 percent under optimal conditions. Even worse is the interaction between SCN and the fungal pathogens that cause SDS and BSR which can cause even more yield loss.

First discovered in 1971 in Arkansas, SDS has quickly spread throughout the Soybean Belt and is now found in areas of South Dakota and in 23 counties in Minnesota. It is likely spreading north with the movement of SCN; the SDS fungus is commonly found in the cysts. Because of this close association with between SDS and SCN, assume that if you have one or the other, you probably have both.

BSR has been found in nearly all Midwest soybean producing states. The increase in the incidence of BSR is thought to be a result of a monoculture created by the traditional soybean corn rotation which encourages a build-up of the BSR pathogen in the soil. Like SDS, the fungus that results in BSR infects the root early in the growing season and is favored by cool, wet soils.

Minimizing yield loss from SDS and BSR begins with managing SCN in fields where combinations of these stressors co-exist. SCN cannot be eliminated once it becomes established in a field, but its influence on other soilborne pathogens can be reduced with proper management.

A new publication is now available to help soybean producers manage SCN. The SCN Management Guide, fifth edition provides soybean producers with science-based information generated from many years of checkoff funded research that is proven to reduce SCN populations.

With currently available management options, it is much easier to keep low numbers low than it is to try and drive high SCN numbers down. By managing SCN you can:

• Improve soybean root and plant health and yield;
• Keep SCN numbers low; and
• Preserve the yield potential of resistant varieties

Because no single management practice will meet all three goals, you must use an integrated approach that combines several components. Chief among these are the use of varieties resistant to SCN and with good field tolerance to SDS and BSR, rotation with non-host crops when possible, maintaining a well-drained seedbed, use of fungicide and insecticide seed treatments to promote early seedling health.

Click on the Free Publications link above to receive your free print copy of the SCN Management Guide, or view online – see sidebar to the right.