How Do Nematodes Damage Grass?
As plant-parasitic nematodes feed they damage the root system and reduce the ability of the grass to obtain water and nutrients from the soil. Roots may be abnormally short and appear darkened or rotten when damaged by plant-parasitic nematodes (Figure 6). Root galls or knots associated with certain nematode damage to other crops are usually not evident on grasses. When nematode population densities get high enough, or when environmental stresses such as high temperatures or drought occur, aboveground symptoms may become evident. Symptoms include yellowing, wilting, browning, thinning out, or death (Figure 7). Often weeds such as spurge, sedges, or Florida pusley become prominent as the grass thins out (Figures 8, 9, 10). Nematode damage usually occurs in irregularly shaped patches that may enlarge slowly over time (Figure 7). Be aware that similar conditions may be caused by other factors such as localized soil conditions, fungi, or insects. Figure 6. Healthy grass roots (left) and da
