frost damage, occurs in vineyards mostly in spring but also in autumn and occasionally summer, when the air temperature drops below freezing (see also frost). Ice forms in the plant tissue of buds which have begun to break, young shoots, leaves, and inflorescences, which may subsequently turn brown and die. The vine can respond by growing more shoots from basal buds, but these are typically less fruitful and the crop is reduced and delayed. Frost in the autumn causes defoliation, which is a problem if the fruit is not ripe and the vine’s reserves of carbohydrates have not been restored. Frost has much more impact on yield than on wine quality, although if sprinkler irrigation is used before harvest to ward off autumn frost, it can have serious consequences for ripening.