Performance of Six Genetically Diverse Phylloxera Strains on 5C Teleki (V. berlandieri × V. riparia) Rootstock

Background and Aims. Grapevine phylloxera, Daktulosphaira vitifoliae (Fitch), feeds on roots and leaves of Vitis spp. Susceptibility to phylloxera differs among rootstocks, such that Vitis spp. grafted onto resistant rootstocks can safeguard vineyards from phylloxera-induced damage in the long term. Diverse phylloxera genetic strains, however, vary in their ability to survive on different rootstocks. The 5C Teleki rootstock (V. berlandieri × V. riparia) is widely planted worldwide, but its resistance to phylloxera has not been characterised against the genetically diverse phylloxera strains present in Australia. Methods and Results. 5C Teleki roots and Vitis vinifera L. (positive control), either excised in Petri dishes or planted as whole plants in pots, were inoculated with eggs of six phylloxera strains (G1, G4, G19, G20, G30, and G38). On excised roots, G19, G20, G30, and G38 phylloxera survived to reproductive adults. The G1 and G4 phylloxera did not survive past the first instar stage. In potted vines, G4, G19, G20, G30, and G38 phylloxera strains induced nodosities on roots, but adults were only found on roots inoculated with G19 and G20 phylloxera strains. Conclusions. Results showed that 5C Teleki is resistant to the G1 phylloxera and susceptible to G19 strains. Performance of G4, G20, G30, and G38 differs depending on the assay used. 5C Teleki is likely tolerant of these strains. Significance of the study: the 5C Teleki rootstock is resistant to the G1 phylloxera strain but likely tolerant of others present in Australia. This implies that the rootstock can still host a population of phylloxera, and strict farm-gate hygiene should be employed to stop spread among vineyards and regions.