For many years, phylloxera-resistant rootstocks have been used to prevent vine loss in phylloxerated grape growing regions. Grape phylloxera can vector root-pathogenic fungi when they feed, allowing the fungi to girdle the roots and eventually cause vine death. The level of fungal resistance possessed by phylloxera-resistant rootstocks is not fully known. We conducted a survey of phylloxerated vineyards from three grape-growing regions in California and collected root-pathogenic fungi from each site. Each fungal isolate was assigned a high or low virulence level depending on the amount of root necrosis it caused on excised Vitis vinifera L. roots. After confirming the pathogenicity of each isolate, we will screen high and low virulence fungi on a representative array of rootstocks. We hypothesize that the rootstocks’ resistance to the fungi will vary based on rootstock parentage and fungal virulence.
Species 1: Homoptera Phylloxeridae Daktulosphaira vitifoliae (grape phylloxera)
Keywords: root, rootstock
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA