Ethrel stimulated ripening in coffee

A single pre-harvest spray of aqueous ethrel (ethephon) at various concentrations was tested to accelerate the onset of berry ripening in both the Robusta and Liberica coffees. The main aim of spraying ethrel is that a single harvest may clear the majority of available crop at one time, thus significantly reducing harvesting costs. For commercial application 200 ppm for Robusta and 600 ppm for Liberica are tentatively suggested. From single harvests conducted 3 weeks after spraying treated plots of Robusta and Liberica have given approximately 60 and 40 more ripe fruit, respectively than the control. For Robusta, a once-off harvest for each sprayed crop is envisaged as a high proportion (approx 90) of the treated berries were already ripened at harvest. For Liberica 2 rounds of picking for each sprayed crop are still considered necessary. Cost-benefit analysis indicates that the ripening agent is far more profitable in Robusta because response is good, even at low concentrations. Berry abscission at the various dosages tried is too minimal to be of any importance. Average bean weight has not been shown to be affected by the chemical. Author's summary. (ATA 11(4):54637. 1986)