Grape Phylloxera (Homoptera: Phylloxeridae): Comparison of Leaf Damage to Grape Cultivars Grown in Arkansas

Grape cultivars (Vitis) grown in northwestern Arkansas varied significantly in gall counts per leaf produced by the foliar grape phylloxera Daktulosphaira vitifoliae (Fitch). ‘Saturn’, ‘Fredonia’, ‘Campbells Early’, ‘Verdelet’, ‘Concord’, ‘Venus’, ‘Mars’, and ‘Cimarron’ had significantly fewer galls per leaf than did ‘Villard Noir’, ‘Himrod’, ‘Reliance’, and ‘Lakemont’. Gall counts significantly increased linearly as leaf width and hair density on the lower leaf surface decreased. Only grape cultivars with significantly larger gall counts per leaf had significant reductions in leaf widths relative to leaf widths on gall-free leaves. The relationship between leaf width and leaf hair density to grape cultivar susceptibility to foliar grape phylloxera is yet to be explained. A review of the mechanisms and suggested studies of leaf gall formation and prevention are presented.