THE POTATO TUBER NEMATODE, DITYLENCHUS DESTRUCTOR THORNE, 1945; THE CAUSE OF EELWORM DISEASE IN BULBOUS IRIS

Abstract

For about twenty‐five years a fairly widespread disease of bulbous iris has been known, the cause of which has always been attributed to a biologic race of the stem eelworm Ditylenchus dipsaci (Kühn, 1857), Filipjev, 1936.Thorne (1945) showed that the nematode causing rot in potato tubers is different from D. dipsaci and named it D. destructor. This nematode has since been reported from Mentha arvensis L. by Hurst (1948) and from Sonchus arvensis L. by Goodey & Goodey (1949).Examination of nematodes from diseased iris bulbs showed them to possess rounded tail tips and six incisures on each lateral field; characters by which Ditylenchus destructor is distinguished from D. dipsaci.Cross‐inoculation experiments showed that the eelworm causing disease in potato tubers would invade and set up characteristic symptoms in iris bulbs and, in the opposite direction, the eelworm responsible for disease in iris bulbs would give rise to characteristic symptoms in potato tubers. Transfer was also effected from potato and iris to Mentha arvensis and from iris to Sonchus arvensis.The history of the disease in bulbous iris is briefly reviewed and the biology of Ditylenchus destructor discussed and compared with that of D. dipsaci.The conclusion that D. destructor is the nematode causing eelworm disease of bulbous iris has been reported earlier (Goodey, J. B. 1950).