Nematodes can cause which of the following symptoms in ornamentals?

• A. Root galls, stubby roots, low vigor, and leaf tissue discoloration
• B. Powdery mildew on leaves
• C. Twig dieback only
• D. Chlorosis in fruit leaves only

Answer: (A)

Nematodes injure plant roots, and the resulting root damage is what you most often see reflected in the plant’s overall health. When nematodes feed on roots, they cause galls or knots (a hallmark of root-knot nematodes) and can produce stunted, shortened, or distorted roots. That compromised root system means the plant can’t take up water and nutrients effectively, so the plant grows poorly (low vigor) and the leaves can become discolored or show chlorosis. Among the options, this combination—root galls or stubby roots with reduced vigor and leaf discoloration—best matches the typical symptoms caused by nematodes in ornamentals. The other choices describe diseases or symptoms not primarily associated with nematode activity: powdery mildew is a foliar fungal disease, twig dieback can result from various pests or pathogens, and chlorosis limited to fruit leaves doesn’t capture the root-centric damage nematodes cause.