The ‘giant race’ of Ditylenchus dipsaci is considered to be a distinct species: Ditylenchus gigas n. sp.
The ‘giant race’ of Ditylenchus dipsaci (EPPO A2 List) was first recorded in 1986 on broad beans (Vicia faba) in Algeria. In this population, adult nematodes were considerably larger than those commonly observed for D. dipsaci. This ‘giant race’ was then observed in other countries around the Mediterranean Basin. Symptoms caused the ‘giant race’ on V. faba crops are generally more severe than those caused by other races of D. dipsaci, and more infested seeds are produced. Several authors have suggested that D. dipsaci was a complex species (comprising at least 7 species) and in particular, that the ‘giant race’ should be considered as a distinct taxon. On the basis of morphological, biochemical and molecular data obtained from several populations of D. dipsaci collected on V. faba from Southern Italy, Southern Spain and Lebanon, Vovlas et al. (2011) are now considering that the ‘giant race’ is a new and distinct nematode species and proposed to name it: Ditylenchus gigas.
Sources
Vovlas N, Troccoli A, Palomares-Rius JE, Luca F, de Liébanas G, Landa BB, Subbotin SA, Castillo P (2011) Ditylenchus gigas n. sp. parasitizing broad bean: a new stem nematode singled out from the Ditylenchus dipsaci species complex using a polyphasic approach with molecular phylogeny. Plant Pathology 60(4), 762-775.