HPIPM:Nematodes Spinach

Author: Howard F. Schwartz and David H. Gent

Identification and Life Cycle

Several species of nematodes can cause economic damage to spinach in the High Plains production region, including root lesion, cyst, needle, sting, and root-knot nematodes. Other nematode species have not been studied extensively in the High Plains and are not known to cause economic damage to spinach in the High Plains. The life cycle of different nematode species vary, and may include feeding on the outside of roots or penetration and development within roots. Nematodes survive between susceptible crops by feeding on other crops and weeds, and, sometimes, as dormant cysts. Nematodes can be spread in and among fields by contaminated soil on machinery, windblown soil, irrigation water, and infested transplants.

Plant Response and Damage

Above ground symptoms of nematode injury appear as patches of stunted or dying plants. When roots are examined they appear pruned, but some nematodes (such as the cyst nematode) can cause a proliferation of lateral feeder roots. Other nematodes can cause round to spindle-shaped galls on roots (root knot), reddish-orange to brown lesions (lesion), swelling and distortion (needle), and necrotic lesions that girdle roots (sting). Infected plants may wilt when stressed by high temperature or moisture stress.

Biological Control

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

Cultural Control

Prevent the introduction of nematodes in clean fields by thoroughly cleaning equipment between fields. Plant transplants free from nematodes. Avoid the reuse of irrigation water. Provide adequate fertilizer and irrigation for crop development to reduce the impact of nematode feeding. Sprinkler irrigation tends to be more effective than furrow irrigation for supplying uniform water to nematode-damaged plants. Practice a three-year or longer crop rotation to non-hosts such as small grains. Control weeds that may serve as alternate hosts of nematodes. Promptly incorporate crop residues after harvest to limit nematode reproduction. Few if any spinach varieties are resistant or tolerant to nematodes.

Chemical Control

Nematicides and soil fumigation effectively suppress many nematode species, but are most effective when combined with cultural practices that reduce nematode populations. Chemical controls are generally only cost effective when nematode injury is severe and widespread. Nematode injury often only occurs in localized areas in fields, and these areas can be effectively managed by spot-treatments with nematicides.

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.