Seed Gall - Nematodes

Seed gall nematodes: Seed gall nematodes (Anguina spp.) were the first plant-parasitic nematodes to be described in the scientific literature in 1743 (Figure 20). These nematodes migrate as J2s in water films to the leaves of plants where they feed as ectoparasites at the tips, causing distortion of the leaves. Once the plant starts to flower the J2 penetrates the floral primordia and starts to feed on the developing seed. Once in the seed, the nematode undergoes its molts, continues to feed, and eventually kills the seed to form a blackened "cockle" (seed gall). The adults sexually reproduce, the eggs hatch as J1 and then quickly molt into a J2 survival stage. The environmentally resistant J2 desiccates with the seed gall and overwinters. The nematodes in the seed gall can survive for 30 years if kept in a dry location. When proper moisture and temperature conditions arise, the cryptobiotic J2 becomes active and starts the life cycle over again (Southey 1972).