Vitisspp. Rootstocks Are Poor Hosts forMeloidogyne hapla, a Nematode Commonly Found in Washington Winegrape Vineyards

Abstract

The majority of winegrape (Vitis vinifera) vineyards in Washington are planted with own-rooted grapevines, as opposed to grapevines grafted onto rootstock varieties. The plant-parasitic nematode Meloidogyne hapla (common name: northern root-knot nematode) is commonly found in Washington winegrape vineyards, and own-rooted grapevines are susceptible to this nematode. Before rootstocks are used to manage M. hapla or other horticultural characteristics in Washington, their host status for M. hapla should be defined. In greenhouse experiments, 10 commercially available rootstock varieties were evaluated for their M. hapla host status. Additionally, the reproductive potential of different M. hapla populations collected from Oregon and Washington, and of another root-knot nematode, M. chitwoodi, on rootstock varieties and own-rooted V. vinifera Chardonnay was evaluated. The rootstocks Salt Creek, Freedom, Harmony, St. George, Riparia Gloire, 101-14 Mgt, 3309C, 110R, 420A, and Matador were poor hosts for M. hapla. Populations of M. hapla varied in reproductive potential and virulence on own-rooted Chardonnay. An M. hapla population collected from a V. vinifera vineyard in Paterson, WA had 33 to 78% greater reproduction than the other M. hapla populations. An M. hapla population collected from a V. vinifera vineyard in Alderdale, WA was consistently more virulent than the other M. hapla populations. Own-rooted Chardonnay and the rootstock Matador were poor hosts for M. chitwoodi. This is the first report of the host status of several grapevine rootstocks for M. hapla.