Chemical Control of Budbreak

Abstract

Abstract Interest in artificial control of budbreak of deciduous fruit trees species is closely connected with commercial attempts to grow these species in warm locations, where the chilling requirements are not fulfilled naturally. This interest developed following attempts to grow such species in warm countries that did not want to or could not import these fruits from cooler regions. In subtropical regions like the Cape zone in South Africa, eastern Australia, and Israel, the problem was more acute in the 1950s and 1960s. Adoption of low-chilling cultivars, or a shift of production to cooler, better-adapted areas, improved tree performance considerably. Nevertheless, sporadic problems after exceptionally warm winters still pose a commercial problem. In other areas, such as southeastern United States, the risk of spring frost is such that low-chilling cultivars with their early budbreak cannot be grown in northern locations, and, in such regions, chemical treatments are needed occasionally.