Pest Management Program Associate

Nematodes are pests of lawns in Arkansas, particularly in sandy soils. Nematodes are microscopic, unseg-mented roundworms, 1/300 to 1/3 inch in length (8) (Figure 1), that live in the soil and can parasitize turfgrasses. Although most nematodes are beneficial and feed on fungi, bacteria and insects or help in breaking down organic matter, there are a few species that parasitize turfgrasses and cause damage, especially in sandy soils. All parasitic nematodes have a stylet (Figure 1), a protruding, needle-like mouthpart, which is used to punc-ture the turfgrass root and feed (Figure 2). Nematodes feed on turf-grass roots and are most abundant when the turfgrass is actively growing in the spring and fall for cool-season grasses and the summer months for warm-season grasses. There are six stages in the nematode life cycle including an egg stage and the adult. There are four juvenile stages that allow the nematode to increase in size and in some species to change shape. These juvenile stages are similar to the larval stages found in insects. Nematodes are aquatic animals and, therefore, require water to survive. Nematodes live and move in the water film that surrounds soil particles. Soil type, particularly sand content, has a major impact on the ability of nema-todes to move, infect roots and repro-duce. For most nematodes that are a problem in turf, well-drained sandy soils with soil moisture at or near field capacity are optimum for nema-todes to flourish. For this reason, nematodes are most problematic on high-maintenance lawn areas that receive frequent irrigation and on lawns with sandy soils