Plant-parasitic nematodes are pests of most forage and turf grasses (Bernard et al., 1998; Cook and Yeates, 1993). Damage caused by these nematodes has been documented with pot experiments or field trials comparing experimental units treated with nematicide plots to untreated units. Nematode damage is not recognized widely by producers because the signs can be difficult to distinguish from other plant stresses, such as nutrient deficiencies, drought, heavy grazing, and other root diseases. Worldwide, the major nematode parasites of Lolium spp. are cyst nematodes (Heterodera spp.), root-knot nematodes (Meloidogyne spp.), seed gall nematodes (Anguina spp.), lesion nematodes (Pratylenchus spp.), and spiral nematodes (Helicotylenchus spp.).