HPIPM:Nematodes FC

Author: Howard F. Schwartz, David H. Gent, and William M. Brown, Jr.

Taxonomy

Domain	Eukarya
Kingdom	Animalia
Phylum	Nematoda
Class	Chromodorea
Order	Tylenchida
Family	Heteroderidae

Scientific Name

Meloidogyne

Common Name

root-knot nematode

Identification and Life Cycle

Nematodes are microscopic unsegmented roundworms. All nematodes that attack corn are obligate parasites, and include root-knot, and lesion nematodes, and perhaps many others. The life cyclse of different nematodes vary, but generally females lay eggs that hatch in response to root exudates and feed on or infect roots. Eggs generally can overwinter, but some nematodes can survive years in cysts or in dormant states.

Plant Response and Damage

Injury from nematodes in the High Plains is generally not considered important, although nematode injury to corn can be significant in some environments. Symptoms are often subtle and may include stunting and unthrifty growth. Nematode injury often appears very similar to drought stress or nutrient deficiency. Plants can be predisposed to root rots and other soil-borne diseases when nematode injury is significant. When feeding or infection do occur, damaged plants are generally found in patches in the field.

Biological Control

Practical biological control strategies have not been developed most nematodes, but sudangrass cover crops incorporated when green into the soil may provide adequate suppression of nematodes in some environments.

Cultural Control

Crop rotation to non-hosts, and fallowing to a lesser degree, effectively reduce nematode populations and provides a practical cultural control. Resistant varieties are available for a few nematodes, but no variety is resistant to all nematodes. Avoid compaction and other crop stresses that may make the crop more susceptible to nematode damage. The effect of reduced tillage on nematodes is unclear.

Chemical Control

Nematicides can effectively reduce nematode populations, but rarely are economical for control in corn.

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