Stem nematodes (Ditylenchus dipsaci) live in the above-ground parts of the plant. They reside mainly in the stems, flower buds and leaf sheaths of a plant. These nematodes occur on all soil types
, but are primarily a problem around heavier soils.
Stem nematodes have a short life cycle (3 weeks at 15°C) and lay up to 500 eggs per generation. A low infestation can therefore get out of control within one growing season. Especially in cold and humid weather, the infested areas quickly become larger.
Stem nematodes can survive for many years, both in the soil and on plant material and seed. Infested fields are difficult to rid again of stem nematodes.