A plant growth regulator for fruit russet control and fruit size increase on apple, and fruit set increase on pear. On apple, Geolin greatly reduces fruit russet and improves fruit size, finish and quality. It is probable that its controls russet by increasing the elasticity of the outer fruit skin cell and prevents cell rupture when moisture is present. It is probable that increases fruit set by promoting parthenocarpic fruit development when natural fruit setting conditions are poor or when frost damage occurs.