Introduction

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.

Pathogen

Stubby-root nematodes belong to the family of nematodes called the Trichodoridae. These nematodes, like other plant-parasitic nematodes, are microscopic and cannot be seen with the unaided eye. Stubby-root 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.

Host Range

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

Symptoms

Field symptoms of stubby-root nematode infestations in soybean 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.

Disease Cycle and Conditions Favorable for Disease

Stubby-root nematodes are obligate biotrophs, meaning they require living plant roots to feed and reproduce. Stubby-root nematodes are migratory ectoparasites, meaning they migrate outside of roots and retain a worm-like appearance throughout their life cycle. The life cycle ranges from 16 to 27 days, depending on the particular species and temperature conditions. Female stubby-root nematodes lay eggs that remain in soil until conditions for hatching are present. After eggs hatch, juveniles move through the soil, locating a host root and begin feeding. After juveniles begin feeding, they will molt three times before they become egg-laying adults. Where populations are established in the field, stubby-root nematodes may be found at greater depths in the soil, even below the zone of cultivation (greater than 11 inches).

Management

Stubby-root nematodes are difficult to manage in regions with corn/soybean rotations since both crops are susceptible to nematode populations. 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 high populations of stubby-root. Fumigant treatments are not recommended due to the depth that stubby root nematodes occur below where fumigant treatments are placed.

Useful Resources

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.

Acknowledgements

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

This factsheet was reviewed and updated by the NCSU Plant Nematology Lab in 2025.