Occurrence of the Root-knot Eelworm, Meloidogyne hapla, out of doors in Great Britain

Abstract

UNTIL recently, only one species of root-knot eelworm was recognized, namely, Heterodera marioni (Cornu). Renewed interest has been stimulated with the transfer of the eelworm to the genus Meloidogyne and the erection of a number of species¹. In Great Britain, infestations of root-knot are most often recorded under glass, attacking tomatoes, cucumbers and various other glasshouse crops. When attacks occurred in the open, it was usually assumed that the eelworm had originated from glasshouses. Some attacks occurred on sites where glasshouse soil was known to have been deposited, and these infestations appeared to die out fairly rapidly, usually within about two years, and Franklin² has shown that a population obtained from a glasshouse persisted out of doors in pots for at least sixteen months. On other occasions, however, it has been difficult to associate the presence of the eelworm out of doors with a glasshouse source. Triffitt³ has recorded an attack on carrots and parsnips on a field which, so far as could be ascertained, had not been contaminated with soil from glasshouses. Since 1931 there has been a number of other records (in litt.) of attacks in the open on various crops including carrots, parsnips, pyrethrums and scabious, but there must always be some doubt as to whether the eelworm had come from glasshouses.