Submitted to: Taxon
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/31/2013
Publication Date: 6/17/2013
Citation: Rossman, A.Y., Castlebury, L.A., Udayanga, D., Hyde, K.D. 2013. Proposal to conserve the name Phomopsis citri H.S. Fawc. (Diaporthe citri), with a conserved type, against Phomopsis citri (Sacc.) Traverso & Spessa (Ascomycota, Diaporthales, Diaporthaceae). Taxon. 62(3):627. Interpretive Summary: Everything needs a name in order to communicate about it including fungi that cause diseases. If two names of fungi are confused, there is a set of rules that dictate which name should be used. Usually the oldest name, that is, the first name applied to a species, is the correct name. Sometimes a name that everyone uses is found to have an older name that no one has heard about. This was the case with a fungus causing a disease of oranges and its relatives. A very old name that had been forgotten and thus not used was discovered and technically this old name should be used for the disease-causing fungus. However, the rules also allow for the use of more common name, rather than obscure names. For this fungus causing a disease of orange a suggestion was made to use the common name rather than the old, unused name. This proposal will allow scientists to use the name they are used to for the fungus causing this disease.
Technical Abstract: The name Diaporthe citri applies to a fungus that causes a disease on Citrus known as melanose or stem end rot of mature fruit after harvest and occurs widely in North America and Asia. Initially described as the illegitimate Phomopsis citri H.S. Fawc. 1912, non P. citri (Sacc.) Traverso & Spessa 1910 (= Phoma citri Sacc. 1876), the Fawcett name was placed in Diaporthe by Wolf; thus, as Diaporthe citri F.A. Wolf, the name currently has priority only from 1926. Plant pathologists have referred to this fungus as Diaporthe citri or Phomopsis citri for the past one hundred years. The genus Phomopsis Sacc. & Roum. (1884) is a synonym of Diaporthe Nitschke (1870). In addition the name Diaporthe medusaea Nitschke (Pyrenomyc. Germ. 2: 251. 1870) has also been used for this disease following Wehmeyer who regarded D. citri as a synonym of D. medusaea. Recent research has clarified the relationship of D. citri with D. medusaea and these two species are now considered distinct. In the course of that research two earlier names were discovered for D. citri, namely Diaporthe citrincola Rehm and Phomopsis caribaea W.T. Horne. Neither of these two names has been used to any extent. Because the name Diaporthe citri has been applied to melanose and stem rot disease of Citrus for decades and Fawcett explicitly stated that he was unaware of any previous Diaporthe or Phomopsis on Citrus, it is proposed that Phomopsis citri H.S. Fawc. be conserved against its earlier homonym P. citri (Sacc.) Traverso & Spessa. This will make the former name available as a basionym for Diaporthe citri (H.S. Fawc.) F.A. Wolf, giving this name priority over what would otherwise be the earlier taxonomic synonyms D. citrincola and Phomopsis caribaea, both of which predate the currently first legitimate publication as Diaporthe citri F.A. Wolf. As no type material of P. citri was found at either BPI or FLAS, leaving only an illustration as a potential, but unsatisfactory, iconotype, a recent specimen from diseased Citrus sp. is proposed as a conserved type for Phomopsis citri.