Effects of Gibberellin and Alar Sprays upon Fruit Set, Seed Development, and Flowering of ‘Bartlett’ Pear1

Spray applications of gibberellic acid (GA 3 ) were tested for their effects in increasing fruit set when applied during bloom in two commercial pear orchards in which cross-pollination was limited. No beneficial effects were obtained, and flower bud formation was inhibited at concentrations of 20 to 100 ppm. In one year, the inhibitory effect of GA 3 upon flowering was partially offset by spraying with 500 or 1000 ppm of succinic acid, 2,2-dimethylhydrazide (Alar) at petal fall.