Sour Cherry Trees Respond to Foliar Boron Applications

Abstract

Seven trials were conducted over 3 years in several Michigan locations to study the response of sour cherry ( Prunus cerasus L. cv. Montmorency) to foliar B sprays. Orchards ranged in age (6 to 12 years) and leaf B concentrations (19 to 32 μg B/g dry weight). Treatments consisted of a 500 mg B/liter spray applied to leaves in late September or early October, and an untreated control. Boron sprays increased B concentrations in dormant buds and flowers by 94% and 54%, respectively, but did not consistently change leaf levels. Boron applications increased fruit set and production by as much as 100% in one trial, but had no effect in others. Fruit set and production were most consistently increased in trees containing leaf B levels of 19 to 25 μg·g –1 dry weight. In trees with leaf B concentrations of 25 to 32 μg·g –1 , responses to B were less consistent and smaller in magnitude.