DEVELOPING A STABLE CLASSIFICATION OF THE GLASSY-WINGED SHARPSHOOTER GENUS HOMALODISCA

• Author(s): McKamey, Stuart; Gaiani, Marco; Godoy, Carolina; Hicks, Andrew; Rakitov, Roman; Raygoza, Gustavo; Takiya, Daniela;
• Abstract: The glassy-winged sharpshooter (GWSS), the leafhopper principally responsible for the spread of Pierces disease on grape in California, is the species Homalodisca coagulata. This special capacity relates to the tissue upon which all sharpshooters (leafhopper subfamily Cicadellinae) feed: xylem, and the invasive status of the GWSS in California. It is noteworthy that of the19 species in the genus, only one other species occurs in California and 18 species occur outside the USA (6 of these also occur in the USA). The genus is common in Mexico and also occurs southward through Central America, northern South America, and southeastern Brazil and Paraguay. That is, most species of Homalodisca, were they to reach California, have a destructive potential equal to the GWSS regarding the grape industry. The genus Homalodisca contains two other species that are already known to vector phytopathogens and it is practically expected that all species in the genus have the capacity to be, or become, serious vectors. Clearly, in a situation like this, we need to be clear about which species we are studying. The genus has never been revised. Words are the tools of efficient communication and taxonomy is the vocabulary of species. By linking information to genus and species names, a classification of species becomes at once a very efficient system for storage and retrieval of information, and hence for meaningful communication, and a predictive tool, provided that classification is sound. Linking that information to species names that may be based on misidentifications, or belong to entirely different genera, will only add confusion to vector studies. In order to communicate effectively about the GWSS and its congeners, it is essential that everybody use the same names for the same species. Access to all information on any group of organisms, including Homalodisca, is severely impeded by arbitrary generic limits, multiple names for some species and no name for others, or the absence of authoritative identification tools, or all three factors. The status of Homalodisca in this regard is below acceptable levels for a group of such economic importance.
• Publication Date: Dec 2002
• Journal: 2002 Pierce's Disease Research Symposium