Introduction

Lance nematode is not a common problem of soybeans, but can cause local damages in fields where it is found. Because lance nematodes do not form galls or cysts like root knot nematodes or soybean cyst nematodes, diagnosis may be more difficult. 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.

Pathogen

Lance nematodes, Hoplolaimus spp., can cause damages to soybean where found. The most important lance nematode to soybean in North Carolina is the Columbia lance nematode, Hoplolaimus columbus. Lance nematodes are semi-parasitic and endo-parasitic nematode found mostly in the southern portion of the North Carolina Coastal Plains.

Host Range

Lance nematodes can affect a wide range of hosts, but the most common field crop hosts in North Carolina are corn, cotton, and soybean.

Symptoms

Symptoms may include irregular patches of stunting and yellowing of plants and uneven growth in the row. Discrete necrotic lesions may be observed on the roots, which may later coalesce. Roots may become darkened and poorly developed, which may resemble other root rot pathogens. Affected roots bunch together near the soil surface and exhibit a hairy or fibrous appearance. Nodule development may also be poor, leading to yield losses.

Disease Cycle and Conditions Favorable for Disease

Lance nematodes feed both externally and internally on soybean roots. The nematode remains worm-like (vermiform) throughout its life cycle. The nematode survives in soil as eggs, and emerges in its vermiform state when conducive conditions are present. The nematode then feeds inside and outside of the root tissues of nearby hosts. The whole life cycle of the nematode can be completed in 9 to 18 days. Lance nematodes are more common in sandy soils and increased reproduction is documented in warmer temperatures (80-86°F / 26-30°C).

Management

Field sanitation practices is important to limit spread of lance nematodes to unaffected fields. Peanut, tobacco, and small grains are poor hosts and may serve as good crop rotations where this nematode is damaging. Because of the limited acreage of potential rotational crops, this may restrict crop rotational capabilities. Limiting hard pan in affected fields may reduce losses attributed to lance nematode. Chemical seed treatments are not recommended for high populations of nematodes, but may provide early season protection of seedlings.

Useful Resources

The North Carolina Department of Agriculture Nematode Assay Lab provides soil nematode assay information and has sampling strategy recommendations available for producers.

The NC State University Plant Disease and Insect Clinic provides diagnostics and control recommendations.

The Extension Plant Pathology portal provides information on crop disease management.

The North Carolina Agricultural Chemicals Manual provides pesticide information for common diseases of North Carolina. The manual recommendations do not replace those described on the pesticide label, and the label must be followed.

Acknowledgements

This factsheet was prepared by the NC State University Field Crops and Tobacco Pathology Lab in 2020.

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