Ethephon (2-chloroethyl phosphonic acid) and Alsol (2-chloroethyl-tris-(2-methoxy-ethoxy)-silane) are effective in reducing the fruit removal force (FRF) required for harvesting fruit of olive (Olea europaea L.). The lowest FRF value was achieved with Alsol within 2 to 3 days after treatment, but only after 7 to 8 days with ethephon. Raising the pH of the ethephon spraying solution to 7.0 increased ethylene evolution markedly and decreased both the FRF value and the time needed to achieve this reduced value.
Sprays of (2-chloroethyl)phosphonic acid (ethephon), applied at the beginning of the harvest season (usually January), resulted in more than 90% nut drop of ‘Beaumont’ macadamia nuts, without causing damage to foliage or next year’s crop.
Ethylene gas promoted abscission of mature-green fruits of olive (olea europaea L.) but did not induce endogenous ethylene production. Ethylene readily penetrated and moved through olive fruits. Mature-black olives did not respond to ethylene.