Monpotasium Phosphate (PO4H2K) for olive fruit abscission

Recent experiments indicate that MonoPotassium Phosphate (MKP) has great potential for the chemical induction of fruit abscission in the olive. Leaf absorption tests indicated maximum MKP absorption in 2 - 4% solution, and confirmed the potential value of the use of surfactants. Field tests were performed with the varieties 'Picual' and 'Arbequina', using 3% MKP and 1 ppm commercial surfactant. Fruit Retention Force (FRF) was reduced from I - 2 weeks until 10 weeks after product application. The maximum reduction in FRF was expressed at 4 weeks, and represented a 25% decrease in that parameter relative to controls. The percentage of fruit obtained by mechanical harvesting (vibration) was substantially increased by MKP treatment, following FRF reduction. Three fruit separation zones were defined and contrasted following product application and mechanical harvest: (1) Peduncle - branch, (2) Pedicel - rachis and (3) Fruit - pedicel. Fruit separation was considerable in all three zones, but predominated in zone (1).