Effects of Tree Shaking, Ethephon and Rootstocks on Fruit Removal, Abscission and Shelf-Life of Citrus Species

SummaryA trunk-shaker harvester was tested on three citrus species on a range of root-stocks. Ethephon at 7.7 g ai/tree was sprayed one week prior to harvest. Fruit removal was highest from grapefruit, lowest from lemons and intermediate but equal from Navel and Valencia orange trees. Ethephon increased fruit removal but its effect was influenced by rootstock and tree size. The majority of the fruit abscised without buttons in grapefruit and Navel orange, with buttons in Valencia orange and with stems in lemons. The force required to detach fruit was lowest five days after treatment with ethephon but depended on species, cultivar and rootstock. Most fruits were removed after shaking for 10 s without significant damage from falling to the ground although up to 12% wastage had developed after two weeks’ storage at room temperature.