Management of Columbia Lance Nematode
Soybean Disease Information Note 4
Stephen R. Koenning, Extension Plant Pathologist
[Management Tactics] [Back to Soybean Disease Notes] [Other Resources]
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 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.
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 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.
1. Soybean varieties moderately tolerant to Columbia Lance Nematode.
of these varieties are based on a limited number of tests. Other varieties
not listed may also be tolerant.
For assistance with a specific problem, contact your local North Carolina Cooperative Extension Service personnel.
Published by North Carolina Cooperative Extension Service
Distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914. Employment and program opportunities are offered to all people regardless of race, color, national origin, sex, age, or disability. North Carolina State University at Raleigh, North Carolina A&T State University, U.S. Department of Agriculture, and local governments cooperating.
update to information: May 2000