Root-knot nematodes (RKN, Meloidogynespp.) are microscopic roundworms that feed on plant roots.
M. incognita, the Southern root-knot nematode, is the most common RKN species in the region.
Once RKN are established in a field, they are very difficult to fully eliminate and must be managed using an integrated approach.

Identification

Above-ground symptoms can include stunting (Fig 1), wilting, chlorosis or yellowing of the leaves, decreased plant vigor, and patchy growth throughout the field (Fig 2).
Symptoms of RKN can be confused with nutrient deficiencies and several other diseases.
Roots of susceptible plants can be examined for the presence of swellings called galls (Fig 3).

Fig 1: Soybean plants from the same field with various levels of stunting due to RKN

Fig 2: Field with widespread RKN causing yellowing of leaves and premature death of plants

Fig 3: Soybean root systems with different levels of galling from RKN

Management

RKN is favored by sandy soils and has a wide host range, making crop rotation difficult.
Fall soil samples monitor soil populations and types of nematodes present.
Varieties with RKN resistance are primarily available in higher maturity groups (group V and above), but some group III and IV options are beginning to enter the market.
Multiple nematode-protectant seed treatments are available. Results will vary among different products, growing seasons, and soil environments.

References

Crop Protection Network (2022, Jan 28). Root-

Knot Nematode of Soybean. Retrieved from:

https://cropprotectionnetwork.org/encyclope

dia/root-knot-nematode-of-soybean

Authors: Eboni Traverso and Dr. Alyssa Koehler

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