Stimulation of Lateral Branch Development in Young Sweet Cherry Trees in the Orchard Without Bark Injury

Abstract

The goal of the trials reported here was to determine the potential for replacing physical disruption of the bark layer with appropriate surface-active chemical products added to bioregulator solutions applied to unpruned 1-year-old sweet cherry (Prunus avium L.) shoots to induce lateral branching. Two surfactant products, Pentra-bark (Quest Products Corp., Louisberg, KS.) and Syl-Tac (Wilbur-Ellis Co., Fresno, CA), combined with Promalin (PR, Valent BioSciences, Walnut Creek, CA) and applied to uninjured bark resulted in approximately the same increase in branching as produced by PR applications to scoring or nicking cuts. Surfactant concentrations higher than 1% v/v were usually necessary to produce increased branching. High concentrations of PR were not effective unless supplemented with a surfactant. Painting active solutions in 3–4 cm wide bands every 30 cm was just as effective as painting those solutions along the length of the outward-facing side of 1-year-old shoots. Use of appropriate surfactants to penetrate the bark barrier can eliminate hand labor for cutting the bark, reduce risk of worker injury, and reduce the risk for bacterial canker infection of trees during branch induction on 1-year-old shoots of sweet cherry