Some factors affecting the response of grapevines to ethephon

Factors influencing the effects of ethephon on fruit abscission and leaf senescence in several Vitis vinifera L. cultivars were studied under field conditions in a series of exploratory experiments. Cultivars appeared to vary greatly in their response to treatment. Ethephon concentration, surfactant concentration, fruit maturity, application conditions and degree of foliage wetting all influenced the degree of response.The experiments were not conducted on a common cultivar, thus limiting the conclusions which can be drawn. It is apparent from the results that a complexity of plant, environmental and application factors affect the response of grapevines to ethephon.