Foliar nematodes live and feed inside the leaves. When plants are wet, they move to the surface and travel in films of water to other plants or plant parts.

Early stage of disease can be noted as small circular lesions as seen in the picture. The lesions will enlarge (check next picture) and can cause defoliation.

Fallen leaves contain many nematodes, which can survive in a dried condition for long periods of time. The nematodes become active again when moisture becomes available can move up the stems to new leaves.

Angular water soaked leaf spots are a key symptom for foliar nematodes. Defoliation can occur under high nematode pressure.