Crop load management of apple via induced plant stress

Abstract

Commercial apple (Malus x domestica Borkh.) growers face economic pressures which compel them to minimize production costs. Effective chemical thinning programs significantly reduce labor expenses and increase financial returns. Research has shown bloom thinning programs based on lime sulfur or oil plus lime sulfur combinations decrease fruit set while increasing fruit size and return bloom. Damage to sensitive flower parts combined with transient depression in carbon fixation likely reduce fruit set to levels beyond those seen with other caustic bloom thinners which do not significantly impact photosynthesis. Implications of stress-inducing chemical thinning programs are discussed.