Table olives in California have historically been hand-harvested. Hand labor crews are increasingly difficult to attract to small acreage orchards and are often prohibitively expensive when available. Mechanical harvesting equipment is available; however, harvest efficiencies typically range from 55-65%, leaving 35-45% of the crop on the tree. While much less expensive than hand-harvesting, the harvest efficiency is not adequate and leaves growers to decide whether to glean the remaining crop or forfeit the income from that portion of the crop. This low efficiency is partially due to the inherent architecture and physiology of olive trees. Additionally, the force required to remove an olive fruit from the tree is relatively high because table olives are harvested before their physiological maturity. In 2024 we conducted a study to evaluate the effects of altering tree architecture by skirting trees in May, removing lower limbs up to 4 feet from the ground to avoid any contact with the harvest machinery. This led to a 15.5% increase in harvest efficiency over trees where lower limbs were left, without affecting total yield. In addition, we examined the effect of a foliar application of 1-aminocyclopropane-1-carboxylic acid (ACC, commercially available as Accede®), an ethylene precursor, at 100 gallons per acre of 1500ppm solution a week before harvest. ACC applications reduced the amount of force required to remove fruit from the tree by 26% and increased harvest efficiency by up to 10.7%. The combination of both removing the skirts of the trees and applying ACC improved harvest efficiency by 23%. These strategies provide clear pathways to improving the economic sustainability of the table olive industry in California.
