Grape Phylloxera (Daktulosphaira vitifoliae) (Homoptera: Phylloxeridae) Biotypes in California

Grape phylloxera (Daktulosphaira viiifoliae Fitch) obtained from Rutherford, Calif., appeared to overcome the resistance of the hybrid grape rootstock, Ganzin 1, in the field. These insects were reared in the laboratory and compared with phylloxera from another Napa Valley location in an excised root life-table experiment. The Rutherford phylloxera (type B) developed and laid eggs quicker and had a greater fecundity than the Napa phylloxera (type A), as indicated by life-history parameters of generation time, gross and net reproductive rates, and doubling time. On the highly resistant rootstock, St. George, a pure Vitis rupestris (Scheele) selection, the type-B phylloxera were also able to establish and reproduce better than type-A phylloxera. On the susceptible V. vinifera L. variety, Cabernet Sauvignon, both phylloxera types did equally well. These data indicate a potentially serious problem for California vineyards in coastal valleys where phylloxera are established.