Didymella vitalbina, Didymella urticicola and Neodidymelliopsis cannabis
Woudenberg et al. (2009) reassessed the genetic and taxonomic diversity of isolates that earlier had been referred to P. clematidina on the basis of host preference. This publication was prompted by Adrian Spiers research on the biological control of Clematis vitalba in New Zealand, where he referred all the Phoma isolates he collected from Clematis in Europe and North America to P. clematidina (Gourlay et al., 2000).
Woudenberg et al. (2009) designated an epitype for P. clematidina; none of Adrian Spiers’s isolates matched this species. Woudenberg et al. (2009) designated the dried fungarium specimen PDD 69378 as the epitype for another Clematis-associated Phoma-like fungus, D. vital- bina (ex-epitype culture ICMP 13663). This specimen was collected by Adrian Spiers (specimen AGS 9) from C. vitalba from Austria. Sequencing of the ex-epitype culture ICMP 13663, and of DNA extracted from mycelium from the dried culture deposited as PDD 69378, showed that it matched an ex-type culture of Didymella urticicola (CBS 121.75 = ATCC 32164; Aveskamp et al., 2010). The implication of this is that D. urticicola, first described in 1976 (Boerema, 1976), is a synonym of D. vitalbina, first described in 1940 (Petrak, 1940). Chen et al. (2015) placed D. urticicola in synonymy with D. cannabis on the basis of DNA sequences from a CBS culture from Cannabis sativa matching the ex-type cul- ture of D. urticicola. At the same time they transferred D. cannabis to their new genus Neodidymelliopsis. If the synonymy with N. cannabis (basionym Sphaeria canna- bis Winter 1872) is confirmed, this will provide an earlier name for D. vitalbina.
Woudenberg et al. (2009) cited DNA sequences of what they regarded as D. vitalbina from the culture CBS 123707, a putative duplicate of Adrian Spiers’s ex-epitype culture, AGS 9. However, the sequences from CBS 123707 do not match those that were generated from the actual epitype specimen of D. vitalbina, PDD 69378, and ex-epitype culture ICMP 13663. Thus, D. vitalbina sensu Woudenberg et al. (2009) represents a different fungus, as yet apparently unnamed. These authors reported several other specimens of the same species from Clematis from several countries in Europe. The same fungus also occurs on Clematis in New Zealand, detected by Paynter et al. (2006) in a survey of C. vitalba at two sites where the P. ‘clematidina’ biological control agent had been released by Adrian Spiers in 1996. They found Phoma associated with minor damage and deposited two isolates in ICMP (ICMP 15898, ICMP 15899), both of which were found, in the present study, to match ‘D. vitalbina’ sensu Woudenberg et al. (2009). The Phoma strain deliberately released into New Zealand as a biological control agent was ICMP 13664, the ex-holotype culture of a third Clematis pathogen, Didymella clematidis. This strain was selected for release because of its high pathogenicity to C. vitalba (Wouden- berg et al., 2009). It has not been found from the field in New Zealand and it is possible that the released biological control strain never successfully established.