Ditylenchus dipsaci (Kühn), Filipjev, 1936

Bernard, Ernest C, Chaffin, Angel G & Gwinn, Kimberly D, 2022, Review of nematode interactions with hemp (Cannabis sativa), Journal of Nematology 54 (1), pp. 1-18 : 6-7

Ditylenchus dipsaci (Kühn) (stem nematode) and relatives

This nematode and its host-parasite relationships have been thoroughly reviewed by Sturhan et al. (2008). Ditylenchus dipsaci invades stems of susceptible plants and causes maceration of cortical and pith cells as they feed by secretion of pectinases and other enzymes ( Riedel and Mai, 1971). Mating and reproduction take place inside the stem. Symptoms result in collapse and lodging of affected plants. Kirchner (1906) provided the first description of D. dipsaci infection of hemp, followed soon by Peglion (1901, as Tylenchus devastatrix ); McPartland et al. (2000) provided a list of later European records. This species has many host races ( Dropkin, 1988; Ladygina, 1988; Sturhan and Brzeski, 1991) and an enormous host range, but is most serious on alfalfa (lucerne), onion and a wide range of floral bulbs; historically it also was the most damaging parasite of teasel. Steiner and Buhrer (1932) listed C. sativa as a host for D. dipsaci , but with a question mark and without citing a source. Symptoms of D. dipsaci infestation on hemp have been described and(or) illustrated by Kirchner (1906), Peglion (1901), Kotthoff (1937), Mezzetti (1951), Ferri (1961) and Rak Cizej and Poličnik (2018), and are similar to those on crops such as alfalfa ( Sturhan and Brzeski, 1991). Peglion (1901), summarized by Schumann (1903) and cited in Marcinowski (1909), determined that hemp planted as seed was susceptible to D. dipsaci , but older plants were not infected when nematode-rich soil was spread around them. Sturhan and Brzeski (1991) stated that D. dipsaci caused significant damage to hemp in Turkey, although they did not provide attribution or additional details for the statement.

Stem nematodes on hemp were placed in the rye race by Kotthoff (1950) but in the flax-hemp race by Kir’yanova and Krall’ (1971). Skarbilovich (1951) found slight infection of hemp by the potato race and moderate infection by the onion race. Ladygina (1988) and Janssen (1994) did not mention the flax-hemp race, nor did they list hemp or flax in any other race; however, Sturhan and Brzeski (1991) thought that the flax-hemp and rye races were identical. Ditylenchus dipsaci is now recognized as a species complex ( Subbotin et al., 2005), with several named and economically significant species ( Saadi et al., 2019). The taxonomic status of D. dipsaci populations capable of parasitizing C. sativa has not been studied, but the various results and placements suggest that the relationship of the nematode and C. sativa may involve cryptic members of the D. dipsaci complex.