Thinning Peaches with Bloom and Postbloom Applications of 2-Chloroethylphosphonic Acid1

Abstract

Abstract Bloom or postbloom sprays of 2-chloroethylphosphonic acid (Ethrel) thinned peaches. Applications at full bloom did not produce consistent thinning in ‘Cardinal’. Postbloom sprays applied approximately at endosperm cytokinesis produced consistent thinning of 3 cultivars. Degree of thinning was related to time of Ethrel application. Most thinning was obtained when Ethrel was applied near the end of Stage I or during Stage II. Ethrel sprays within a month after full bloom caused significant fruit size reduction that persisted 2 months or more after treatment. Ethrel sprays within 50 days of harvest accelerated maturity of several cultivars.