Management of Columbia Lance Nematode
on Soybean
Soybean Disease Information Note 4
Stephen R. Koenning, Extension Plant Pathologist

The Columbia lance nematode, Hoplolaimus columbus, has become established in much of the southern portion of the North Carolina coastal plain. The distribution of this nematode seems to be restricted to the sandier soils found in these areas. This pest can severely damage cotton and soybean. It may occur with other nematodes such as soybean cyst, reniform, lesion, root-knot and sting. A related species, Hoplolaimus galeatus, is common to the Northeastern portion of the state, but has not been associated with damage to soybean. Nematodes should be suspected as a possible production problem if any of the following apply: 1) irregular patches of stunted and/or yellow soybeans - an up-and-down pattern of soybean growth is common; 2) yields declining over several years or yields lower than expected; 3) a positive report on lance nematode from the Plant Disease and Insect Clinic or the North Carolina Department of Agriculture Nematode Advisory Service; and 4) failures in weed control (weed problems are frequently more severe in nematode-infested fields.

Diagnosis

Accurate diagnosis of nematode problems on soybean can be accomplished by several means. A soil sample must be processed in order to positively identify a lance nematode problem. If you suspect a nematode problem, take systematic (stratified) soil samples preferably in the fall when nematode numbers are high. Samples should be taken from the plant row. If samples for diagnostic purposes are taken during the growing season, be certain to sample in the root zone. Samples from dead or dying plants may reveal few if any nematodes. Pull 20 to 30 soil cores 6 to 8 inches deep from 4 to 5 acres. Send soil in a plastic bag and appropriate box (obtained from county extension agent) and fees to the North Carolina Department of Agriculture, Nematode Advisory and Diagnostic Lab, 4300 Reedy Creek Road, Raleigh, NC 27607-6465. When sending plants to the Plant Disease and Insect Clinic for diagnosis, include roots and a soil sample. The Nematode Advisory Service does not inform us as to results of their nematode assays.

Life Cycle, Host Range and Pathology

The Columbia lance nematode feeds both externally and internally on soybean roots. Lesions may develop on the roots which can coalesce and give the appearance of a root rot. This nematode remains wormlike throughout its life cycle and can only be identified microscopically. The population densities of this nematode fluctuate only slightly during the course of a year. Columbia lance nematode can usually be detected in soil samples regardless of time of year, but fall assays still are best for predictive purposes. The amount of damage to soybean and subsequent yield loss will be directly proportional to the density of this nematode at soybean planting. Corn, cotton, and soybean are good hosts for this nematode. Nematode densities are generally in the moderate-to-high range following these crops. Peanut, tobacco and small grains are poor or nonhosts for Columbia lance nematode.

Management Tactics

Management of this nematode is difficult because of the limited acreage of rotational crops available (peanut, tobacco and small grains). Several tactics to restrict soybean yield suppression caused by this pest can be utilized however. Soils in the affected part of the state tend to have hard pans. Sub-soiling has often been as effective as a nematicide treatment in increasing soybean yield. Hard-pan management should thus be a primary concern if this nematode is present in a field. Soybean varieties with moderate levels of tolerance to this nematode have been identified (Table 1). Tolerant varieties are not resistant, but these varieties will suffer only about a 10% yield loss if this nematode is at damaging levels. Growers should use tolerant soybean varieties with caution, since a cotton crop grown in rotation with a tolerant soybean variety can still be damaged. Planting early has been recommended as a tactic to manage this nematode because it does not become active until soil temperatures become warm. Research on planting date and damage caused by Columbia lance nematode on soybean has not been conclusive. There are indications that damage may be just as great or greater in early planted soybean.

Table 1. Soybean varieties moderately tolerant to Columbia Lance Nematode.

AG6101	DP5644RR	Mott
Centennial	DP6880RR	Musen
Benning	Hagood	Northrup King S83-30
Bogge	Maxcy	Pritchard
Dillon

The tolerance of these varieties are based on a limited number of tests. Other varieties not listed may also be tolerant.

Other Resources

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For assistance with a specific problem, contact your local North Carolina Cooperative Extension Service personnel.

Last update to information: May 2000
Last checked by author: May 2000
Web page last updated on November 2000 by A.V. Lemay.