Phylogenetic Relatedness of Maize Chlorotic Dwarf Virus Leafhopper Vectors. L. R. Nault, Professor, Department of Entomology, Ohio Agricultural Research and Development Center (OARDC), The Ohio State University (OSU), Wooster, 44691; L. V. Madden, Associate professor, Department of Plant Pathology, Ohio Agricultural Research and Development Center (OARDC), The Ohio State University (OSU), Wooster, 44691. Phytopathology 78:1683-1687. Accepted for publication 19 July 1988. Copyright 1988 The American Phytopathological Society. DOI: 10.1094/Phyto-78-1683.
Twenty-five leafhopper (Cicadellidae) species from 13 genera representing three tribes (Deltocephalini, Euscelini, and Macrostelini) in the subfamily Deltocephalinae were tested as vectors of the semipersistently transmitted maize chlorotic dwarf virus (MCDV). Vectors and their estimated percent transmission by single insects when maize served as the virus source and inoculation test plant were: Graminella nigrifrons, 35.9%; Amblysellus grex, 24.8%; Stirellus bicolor, 13.7%; Planicephalus flavocostatus, 12.9%; Exitianus exitiosus, 12.6%; G. sonora, 10.5%; Macrosteles severini, 1.9%; and Endria inimica, 1.5%. Leafhopper species that did not transmit MCDV from maize to maize were Baldulus tripsaci, Cicadulina mbila, nine Dalbulus species, Euscelidius variegatus, G. fitchii, G. oquaka, M. fascifrons, Ollarianus strictus, and Psammotettix lividellus. When johnsongrass rather than maize was used as a virus source and test plant, G. oquaka transmitted MCDV. When the relationship between transmission rate of MCDV by a leafhopper species and its phylogenetic (evolutionary) relatedness to G. nigrifons (the principal field vector) was evaluated by Kendall's tau correlation analysis, there was a significant positive relationship for phylogeny with one (P < 0.05), but not a second (P > 0.10) proposed phylogeny, when all leafhopper species used in this study were considered. When grass-specializing leafhoppers whose developmental hosts that do not include maize were excluded from the analysis, both phylogenies were significantly correlated (P <0.01) with MCDV transmission. From this study, it can be predicted that leafhopper species from the tribes Deltocephalini or recent (advanced) Euscelini that use maize as a feeding and breeding host have a high probability of being MCDV vectors, whereas leafhoppers from those taxa that do not feed well on maize or those from the primitive Euscelini or Macrostelini, even if maize is a preferred host, have a low probability of being vectors.
Additional keywords: semipersistent transmission, vector specificity, Zea mays.