The history of fruit thinning

The history of fruit thinning is reviewed, beginning with hand removal of fruits, the effects upon subsequent flowering, and current attempts to develop mechanical methods of fruit removal. Early experiments with caustic compounds and growth regulators and their subsequent development as commercial practices are discussed, as well as the modes of action of growth regulators. Brief reviews of methods of application, factors affecting response, modeling to improve efficiency, and the economic value of thinning to the grower are also included.