HPIPM:Potato Nematodes

Taxonomy

Domain	Eukarya
Kingdom	Animalia
Phylum	Nematoda
Class	Chromodorea
Order	Tylenchida
Family	Anguinidae
Genus	Ditylenchus

Scientific Name

Ditylenchus destructor

Common Name

potato rot nematode

Author: Howard F. Schwartz, David H. Gent, and Gary D. Franc

Identification and Life Cycle

Several species of nematodes can cause economic damage to potato in the High Plains production region, including root-knot, root-lesion, and stubby-root nematodes. The life cycle of different nematode species vary, and may include feeding on the outside of roots or penetration and development within roots. Some nematodes vector viruses (stubby-root nematode and Tobacco rattle virus) or predispose plants to other diseases (root-lesion nematodes and potato early dying). Nematodes survive between potato crops by feeding on other crops and weeds, and are spread in contaminated soil on machinery, windblown soil, and infested seed pieces.

Plant Response and Damage

Nematode injury varies among species, but can include galls on roots and tubers (root-knot), necrosis of roots (root-lesion), or a subtle stubby-appearance (stubby-root). Above ground plant symptoms may range from no apparent injury to less vigorous growth to stunting, yellowing, wilting, and death. Some nematodes also feed on tubers directly, causing small, shallow lesions or raised, scab-like lesions (root-lesion), internal brown to black necrotic spots and external raised bumps (root-knot), or brown, necrotic rings that may extend from the periderm to deep within the tuber (stubby-root nematodes carrying Tobacco rattle virus).

Biological Control

Incorporation of green manure crops such as sudangrass, sesame, rapeseed, white mustard, or perennial ryegrass the season before potatoes are planted can reduce some nematode populations.

Cultural Control

Plant only high quality seed free from nematodes. Crop rotation may provide suppression or control of some nematode species, but most nematodes that attack potato have host ranges that include many crops and weeds. Therefore, effective weed control is essential for reducing nematode populations. Adequate but not excessive irrigation and fertilization will help potato tolerate some nematode feeding. Early harvesting or planting varieties that mature by late July can escape very high root-knot nematode populations, greatly reducing root-knot nematode damage. Fields with severe root-knot nematode injury should not be stored because the nematode continues to feed on tubers in storage.

Chemical Control

Due to constantly changing labels, laws and regulations, the sponsors of this web site assume no liability for the suggested use of any chemicals noted in the management section. Contact your local pest management personnel for current information on labeled pesticides that can be used for the intended plant disease, insect pest or weed.