Tylenchus emarginatus and Tylenchorhynchus dubius associated with Sitka Spruce ( Picea sitchensis ) Seedlings

SUMMARY Experiments in tubes showed that Sitka spruce was a good host for Tylenchus emarginatus and Tylenchorhynchus dubius and that these nematodes were able to stunt root growth. Both species were more abundant in plots at Wobum, Bedfordshire, where Sitka spruce was grown repeatedly than in nearby land under other crops. In 1968 nematodes were more numerous in plots with nitrogen fertilizer than in those without. In 1969 they were fewer, possibly because populations remaining from 1968 were too great for the seedlings to support and/or because rainfall was much less.