Varietal preferences of Erythroneura leafhoppers (Homoptera: Cicadellidae) feeding on grapes in New York

Species composition of Erythroneura leafhoppers infesting the 3 major classes of grapes grown in New York was investigated. Eastern grape leafhopper, E. comes (Say), comprised 74-100% of populations collected on the native American (Vitis labrusca Bailey) cultivars 'Concord', 'Niagara', 'Catawba' and 'Delaware'. On interspecific hybrid (Vitis sp.) and Vitis vinifera L. cultivars, E. comes was largely absent, and 97-100% of leafhoppers collected were 2 cryptic species, E. bistrata McAtee and E. vitifex Fitch. On the native American variety 'Elvira', a V. labrusca X V. riparia Michaux hybrid, field populations were 24% E. comes and 74% the E. bistrata/vitifex complex. E. vitis (Harris), E. tricinta Fitch, and E. vulnerata Fitch were also present in commercial grapes, but never exceeded 20% of the populations sampled. Populations on wild V. riparia adjacent to vineyards were comprised of 24% E. comes, 47% E. bistrata/vitifex, 19% E. vitis, and 10% E. tricinta. Dissection revealed that proportions of E. bistrata and E. vitifex in field collections, varied from 97% E. bistrata to 61% E. vitifex. Oviposition of E. comes and E. bistrata on V. vinifera, interspecific hybrid, and native American cultivars was compared in greenhouse choice tests and field no-choice tests. In choice tests, E. comes laid more eggs on Concord and Elvira than on the interspecific hybrid 'Seyval blanc', or the V. vinifera cultivar 'White Riesling'. E. bistrata did not oviposit on Concord when paired with either Elvira, Seyval blanc or White Riesling. When caged to grape leaves in no-choice tests. E. comes laid the most eggs on native American cultivars and the fewest on V. vinifera and interspecific hybrids; E. bistrata laid the most eggs on hybrid and V. vinifera cultivars, and very few eggs on three native American cultivars. These results show that E. bistrata and E. vitifex are the principal pest species on V. vinifera and many interspecific hybrid cultivars in New York, and that E. comes is the principal leafhopper pest on native American V. labrusca cultivars.