Stubby root nematodes (Trichodorus spp.) get their name from the stubby or stunted appearance of roots that have been fed on by this nematode. These nematodes have a wide host range, which makes management difficult in field crops like soybean and corn. They are found globally and widespread within the United States and in field crops production in North Carolina.

Stubby root nematodes belong to the genus Trichodorus. Nematodes are microscopic and cannot be seen with the unaided eye. These nematodes are ectoparasitic, meaning that they feed on plant roots while remaining outside of the root in the soil. They are also worm-like (vermiform) for their mobile life stages, and do not create visible structures in/on roots like root knot nematode or soybean cyst nematode.

Stubby root nematode has a wide host range including corn, soybean, sorghum, peanut, turf grasses, potato, and other vegetables.

Field symptoms of stubby root nematode infestations include irregularly-shaped patches of poor growth in an affected field. Aboveground symptoms include stunting, poor stand, wilting, and symptoms of nutrient deficiency. Roots appear “stubby” and stunted, often with brown lesions on the tips where feeding is evident. Because nematodes cannot be seen without aid and other pathogens can also cause similar symptoms, a soil assay is necessary for accurate diagnosis.

Stubby root nematodes are parthenogenic, meaning that they do not require a male to reproduce. Female nematodes lay eggs that remain in soil until conditions for hatch are present. After eggs hatch, juveniles move through the soil to a host root and begins feeding. After several molts, egg-laying adult nematodes are capable of continuing to produce more eggs. The life cycle can be completed in just over two weeks at optimal temperatures (86°F / 30°C).

Stubby root nematodes are difficult to manage in regions with corn/soybean rotations since both crops are susceptible to nematode populations. Rotation to a non-host crop where possible may reduce soil populations in host crops. Maintaining optimal growth conditions (adequate moisture and fertilization) for soybeans may help support plants that are affected by stubby root nematode populations.

Nematicide seed treatments are not effective on high populations of nematodes, and may not be beneficial for managing stubby root. Fumigant treatments are not recommended due to the depth that stubby root nematodes occur below where fumigant treatments are placed.

The North Carolina Department of Agriculture Nematode Assay Lab provides soil nematode assay information and has sampling strategy recommendations available for producers.

The NC State University Plant Disease and Insect Clinic provides diagnostics and control recommendations.

The Extension Plant Pathology portal provides information on crop disease management.

The North Carolina Agricultural Chemicals Manual provides pesticide information for common diseases of North Carolina. The manual recommendations do not replace those described on the pesticide label, and the label must be followed.

This factsheet was prepared by the NC State University Field Crops and Tobacco Pathology Lab in 2020.

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