%0 Journal Article %A A. J. Wapshere %A K. F. Helm %T Phylloxera and Vitis: An Experimentally Testable Coevolutionary Hypothesis %D 1987 %R 10.5344/ajev.1987.38.3.216 %J American Journal of Enology and Viticulture %P 216-222 %V 38 %N 3 %X Results of a survey of the resistance, tolerance, and susceptibility to the grape phylloxera of different Vitis species from both eastern North America (where phylloxera originated) and from other parts of the world previously uninfested by phylloxera leads to the proposal that the coevolution of Vitis and phylloxera in eastern North America has led to a non-obligatory succession of generations alternately on different Vitis species. These species are separately tolerant of heavy leaf galling or heavy root galling by the aphid. The importance of phylloxera as a driving force in the evolution of Vitis is discussed. The possibility is considered of testing this coevolutionary hypothesis by suitable experimentation in eastern North America using chimaeras of grafted tolerant leaf-galled and tolerant root-galled Vitis species. %U https://www.ajevonline.org/content/ajev/38/3/216.full.pdf