Excerpt from the report Introduction: The removal of excess fruit from apple trees is an essential orchard practice. Chemical thinning of apples reduces biennial bearing and increases fruit size, color, and quality. Fruit size at harvest is directly related to the earliness and degree of fruit thinning, provided the tree and spur vigor are adequate. In the past, thinning was done by hand. Chemical thinning has been developed and is now used with some followup hand thinning.