zinc, essential element for healthy vine growth. A deficiency of zinc affects the plant’s ability to synthesize the hormones auxins, deficiency in which results in a failure of the shoots to grow normally. The principal symptoms are chlorosis between the veins of young and old leaves, their small size, and a widened leaf sinus where the petiole attaches. fruit set can also be poor. Zinc deficiency commonly occurs in vineyards on sandy soils and on some high-ph soils, and is treated by daubing pruning wounds with pastes containing zinc, or applying a zinc spray to the leaves in summer.