The list of recorded hosts of A. dipsaci given by Goodey (1929 and 1933) includes rhubarb, and records and observations in Yorkshire show that infestation by this eelworm is widespread in the rhubarb-growing districts of the county. It is important, at the outset, to note that as far as the writer's observations are concerned the eelworm invariably occurs in rhubarb plants suffering from a disease well-known among growers as Rhubarb Disease or Crown Rot. The following account must therefore include recurring references to this disease with which the eelworm appears to have an intimate association. The earliest records with regard to the disease appeared in the Journal of the Northern Horticultural Society but as this Society has been discontinued a brief summary of these records is given. In the February 1913 issue of this Journal, Hector and Taylor (1913) summarised various notes on the disease. They referred to an editorial in “The Fruit Grower” (9th January, 1913) concerning examination of diseased rhubarb roots received from Yorkshire in 1909 and again in 1913.