Turfgrass Nematode Library
Reference profiles for plant-parasitic nematodes — sampling protocols, damage thresholds, and management strategies.
Diagnosis requires laboratory analysis. Nematode damage cannot be confirmed by visual symptoms alone. Always submit soil samples to a certified nematology laboratory for species identification and population counts before making management decisions.
5 nematodes
Sting Nematode
Belonolaimus longicaudatus
The sting nematode is the most destructive plant-parasitic nematode affecting warm-season turfgrass in the southeastern United States. It feeds ectoparasitically on root tips, causing characteristic "stubby roots" that cannot absorb water or nutrients. Damage is most severe in sandy soils where the nematode moves freely and populations can build rapidly.
Damage Threshold
10–30 sting nematodes per 100 cc of soil — depending on soil type and turf species. Sandy soils and sensitive species (bermudagrass) warrant action at lower thresholds.
Lance Nematode
Hoplolaimus spp. (H. galeatus, H. magnistylus)
Lance nematodes are semi-endoparasitic, feeding with part of the body embedded in root tissue and part remaining in the soil. They are aggressive feeders capable of building to high population densities across a wide range of soil textures and turfgrass species. Considered the second most damaging nematode genus in warm-season turfgrass systems.
Damage Threshold
100–200 lance nematodes per 100 cc of soil is generally considered a damaging threshold, but varies by host and soil texture.
Ring Nematode
Criconemella spp. (C. ornata, C. xenoplax)
Ring nematodes are distinctive ectoparasites with heavily annulated (ringed) cuticles and a relatively short stylet. They cause root tip necrosis and general root stunting. While individual species are typically less aggressive than sting or lance nematodes, they commonly occur in mixed populations and contribute to overall nematode damage complexes.
Damage Threshold
200–500 ring nematodes per 100 cc of soil depending on host and conditions. Evaluate in context of overall nematode community.
Root-Knot Nematode
Meloidogyne spp. (M. graminis, M. incognita)
Root-knot nematodes are sedentary endoparasites that induce distinctive galls (knots) on turfgrass roots. Meloidogyne graminis is the primary species attacking warm-season grasses. Females become permanently embedded in root tissue and establish permanent feeding sites (giant cells), causing severe root malformation. The characteristic root galls are diagnostic and visible to the naked eye.
Damage Threshold
50–100 juveniles per 100 cc of soil plus visible galling warrants management consideration. Galling alone at any level is significant.
Spiral Nematode
Helicotylenchus spp. (H. pseudorobustus, H. multicinctus)
Spiral nematodes are ubiquitous in turfgrass systems and are among the most commonly recovered nematodes in soil samples. They feed as semi-endoparasites, causing root cortex necrosis and reduced root branching. While they are generally considered less aggressive than sting or root-knot nematodes, they frequently occur in mixed-species populations where their combined damage can be significant.
Damage Threshold
500–1,000 spiral nematodes per 100 cc of soil may warrant consideration, particularly in mixed populations. Lower thresholds apply when combined with other damaging species.