Grapevine Yellows is a lethal disease of winegrapes resulting in fruit abortion, shoot tip die-back and yellowing of leaves. Often infected grapevines will die within months of the onset of symptoms and significant losses of vines have been observed. The causal agents of grapevine yellows in Virginia are at least two strains of phytoplasmas, or bacterial-like organisms. Because many phytoplasma-caused plant diseases, including grapevine yellows in Europe, are transmitted by phloem-feeding leafhoppers, planthoppers or, occasionally, psyllids, an insect vector is suspected of spreading grapevine yellows in Virginia. Using sweep netting and yellow sticky traps, surveys of the population dynamics of potential vector species in and around infected vineyards began in spring 2002. Captured insects were bulked by species and their bodies assayed by polymerase chain reaction (PCR) for the presence of grapevine yellows phytoplasmas. Because non-vector species also can test positive for phytoplasma, transmission experiments using commonly observed candidate vector species were initiated to determine which species could acquire and transmit grapevine yellows. Membrane feeding trials also were performed to determine which candidate species released target phytoplasmas along with saliva into sucrose solutions during feeding. Findings from field surveys and transmission experiments will be presented.
Keywords: grapevine yellows, phloem feeding insect vector
Back to Ten-Minute Papers, Subsection Cc. Insect Vectors in Relation to Plant Disease, Cf. Quantitative Ecology
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Back to The 2002 ESA Annual Meeting and Exhibition