Nematodes associated with forest and woodland trees in Scotland

SUMMARY A survey of the nematode genera associated with trees in Scotland showed that Tylenchus sensu lato, Aphelenchoides, Tylencholaimus, Trichodorus, Helicotylenchus, Rotylenchus, Criconemoides s.l., Hemicriconemoides, Tylencho‐rhynchus, Pratylenchus and Paratylenchus s.l. were commonly found in soil samples collected from around the roots of coniferous and deciduous trees. Only Criconemoides s.l. appeared to have a significant preference for deciduous woods. The presence of undergrowth in woods and forests was associated with significantly greater numbers of plant‐parasitic nematodes. Measurements of abiotic factors indicated that, in mineral soils, pH affected the incidence of most genera, but soil type, moisture content and altitude had little effect.