SCN Isn’t the Only Nematode Threat to Your Yield

Soybean cyst nematode (SCN) may be the best-known nematode species, but it may not be the only one costing you yield. Other species like root-knot (RKN), root lesion (RLN) and reniform nematode cause yield loss across soybean-production regions. Fortunately, there are several ways you can manage these threats and protect your soybean yield.

Nematode Damage Adds Stress to Crops

Plant-parasitic nematodes like SCN and RKN need a living host to survive; and more than one species can infest a soybean field, sometimes reducing yield without causing visible symptoms.

Much like soil-borne diseases, plant-parasitic nematodes can be spread numerous ways to new fields where they infect plant roots, feed and reproduce. Their feeding limits water and nutrient uptake, reduces nodulation, and slows root development, adding even more stress to the plant. The impact of species like RLN and reniform nematode can extend beyond soybean yield and damage other crops in your rotation.

Tips to Manage Nematodes in Soybeans

Some nematode species reproduce quickly, completing multiple generations in a single growing season. While you can’t eliminate nematodes entirely, these management strategies can help keep nematode populations in check and reduce their impact on your yield:

• Resistant soybean varieties: One of the most widely used management tools, resistant soybean varieties limit nematode reproduction. Keep in mind that not all varieties are effective against all species. Similar to disease, nematodes can adapt when the same resistance source is used repeatedly, so rotating different sources of resistance helps protect these tools’ long-term effectiveness in your fields.
• Crop rotation: Rotating with nonhost crops is one of the most effective management strategies for reducing nematode population levels. Since hosts vary by nematode species, the effectiveness of crop rotation depends on which nematode is present in your field. For example, RLN’s wide host range means crops like corn or wheat could sustain or even increase population densities.
• Seed treatments: By limiting nematode reproduction, Victrato^® seed treatment can deliver early-season soybean protection from multiple nematode species. Powered by TYMIRIUM^® technology, Victrato works to protect soybeans from nematode eggs, juveniles and adults, including SCN, RKN, RLN, reniform and lance nematodes.

No matter the species or population level in your field, employing as many of these nematode management practices as possible is recommended. A post-harvest soil test can help guide your long-term management decisions and track whether your plan is working.

How to Take a Soil Sample for Nematode Management

Soil testing is the most reliable way to monitor, identify and manage soybean nematodes. Nematode populations are typically highest at or before harvest, making this an ideal time to collect soil samples. This gives you enough time to estimate potential population levels for the next season and adjust any management decisions if needed.

The better your soil sample, the clearer your results will be. Use these steps to get the most accurate count:

1. Use a probe to collect soil cores in the root zone that are 6 to 8 inches deep.
2. Collect 15 to 20 samples in a zigzag or “W” pattern for every 20 acres.
3. Sample fields separately based on wet or dry areas, soil type, or cropping history.
4. Mix the cores well in a bucket, put the mixed soil into a sample bag, and send it to your local nematode testing lab. Be sure to request a comprehensive nematode evaluation, as there may be more than one species.

While yearly sampling isn’t necessary, testing fields every two to three soybean crops can help you track nematode population numbers and confirm whether your management strategies are working. Take note of the longer-term trend over the last three to five samples.

National Nematode Day

Nematodes may be difficult to spot, but their impact on yield can be significant. To raise awareness of these hidden yield threats, our partners at The SCN Coalition named the first Monday of October as National Nematode Day, encouraging growers to soil test, identify and take a proactive approach to soybean nematode management.