EFFECTS OF PROHEXADIONE-CALCIUM (APOGEE¿) ON BLOSSOMING, PRODUCTION, AND FRUIT QUALITY IN PEAR

Prohexadione-Ca (Apogee™, BASF) was applied to several pear cultivars in Medford and Hood River, Oregon and Wenatchee, Washington, USA, in 1998 and 1999. Most trees received treatment at concentrations from 83 to 500 ppm at 2.5-6.0 cm of new shoot growth and some received subsequent applications according to various treatment schedules. Several treatments resulted in reduced fruit weight in unthinned ‘Bartlett’ pears at Medford in 1999, but not where fruit had been thinned. Other fruit characteristics were not detectably affected. Return bloom in 'Bosc' in 2000 was significantly reduced at all locations following several 1999 treatments, regardless of whether or not fruit had been thinned. Return bloom was also reduced in ‘Anjou’, ‘Red Anjou’, and ‘Bartlett’ at Hood River, and in ‘Anjou’ in Medford in 1999 (following 1998 treatments).