Abstract
Three replicated, split plot design harvesting experiments were conducted in 1997 and 1998 to study the effects of using prosulfuron abscission chemical and a trunk shaker on the fruit removal efficiency and yield in Valencia orange trees. The 2 main plot treatments were prosulfuron and no prosulfuron, and the subplot treatments were harvesting with a trunk shaker and handpicking. Prosulfuron was sprayed at 30 ppm in 250 gal per acre on 3 dates (late April, mid May, late May) in 1997 and harvested 2 to 3 weeks post spray. Averaged over all 3 dates, prosulfuron increased mature fruit removals by the trunk shakers an average of 6 percentage points from 82 to 88%. In 1998, prosulfuron reduced the yields of the handpicked trees by 15, 34, and 6% at the 3 dates, compared to reductions of 17, 42, and 26% by the combination of prosulfuron and the trunk shaker.
