Interactions of Selected Rootstocks with Ectoparasitic Nematodes

Abstract

The reaction of grape rootstocks on the population growth of three ectoparasitic nematodes was studied in microplots. After 18 months in sandy loam soil, most grape cultivars had grown larger in the presence of <i>Xiphinema americanum</i> than where it was absent. In the presence of <i>Xiphinema index</i>, only Freedom rootstock displayed a significant growth increase, but no grape cultivars received significant damage by its presence. In the presence of <i>Mesocriconema xenoplax</i>, only Schwarzmann rootstock grew significantly larger and most rootstocks were significantly damaged by its presence in sandy soil. Longer exposure periods are necessary for the measurement of tolerance to <i>Xiphinema</i> spp. VR 039-16, Schwarzmann, and Freedom rootstocks were rated as resistant against <i>X. index</i> on the basis of reproduction and vine growth. All other rootstocks were found susceptible to all three nematodes. Resistance to <i>X. index</i> was relatively easy to assess, whereas resistance to <i>X. americanum</i> and <i>M. xenoplax</i> was less clear, perhaps a result of our relatively high nematode inoculation levels.