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Symptoms and Signs

Plant roots:

Sting nematodes typically feed on root tips. In response to this feeding, root tips cease to grow, causing an abbreviated or stubby-appearing root system (Figures 1, 2, 3, 4). On turfgrasses, the roots may appear cropped-off just below the soil surface (Figure 5). With high population densities, complete root destruction can occur. Damaged roots have a greatly reduced ability to take up water and nutrients from the soil, and this leads to expression of aboveground symptoms and yield reductions. On tuber or root crops, sting nematodes can cause direct damage by causing stunting and malformation of edible portions (Figure 6).

Figure 1	Figure 2
Figure 3	Figure 4
Figure 5	Figure 6

Aboveground Symptoms:

With moderate initial population densities of sting nematodes, young plants may experience reduced vigor, slow growth, and stunting (Figures 7, 8). With high initial population densities, young plants may stop growing completely following seed germination or transplanting (Figures 9A, 9B, 10) and eventually die. The foliage of affected plants may turn yellow or red (Figures 11, 12) due to nutrient deficiencies in the foliage resulting from an impaired root system or to physiological responses in the plant in response to nematode feeding. On corn, brace roots are not able to develop, and the plant is prone to lodging. Chronic wilting is a common symptom of sting nematode damage (Figure 13).

Figure 7	Figure 8
Figure 9	Figure 10
Figure 11	Figure 12
Figure 13

On turfgrass, damage by sting nematode usually results in reduced tolerance to drought, wear, and other stresses. This often leads to irregularly shaped patches of wilting, declining turf (Figure 14) and increased development of weeds (Figure 15). Severe infestations may cause turf to die (Figure 16).

Figure 14	Figure 15
Figure 16

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