Effect of pre-harvest applications of an antitranspirant and vegetable oil on cracking and size of cherry (Prunus avium L.) cv. Van fruit

Abstract

A 1% solution of antitranspirant and a 0.3% solution of vegetable oil were applied to cherry trees before rainfall during the 3 weeks preceding harvest to evaluate their efficacy in reducing fruit damaged by cracking in field experiments in South Australia from 1993 to 1998. Between 2 and 14% of fruit were cracked on untreated trees during this period. From 6 to 10% less cracked fruit were found in 2 of the 5 seasons following the application of antitranspirant and oil sprays. In the other 3 seasons, levels of cracked fruit were not significantly different between treatments. In the 2 driest seasons, treatment with oil or antitranspirant resulted in larger fruit than on untreated trees, and as in previous studies this was thought to be a result of reduced water loss. In 4 years, total soluble solids content of fruit were similar in all treatments, but in 1996–97 controls had significantly higher sugar levels than the treated fruit. This being the driest year during the study, it is thought that greater water loss occurred on controls leading to a higher concentration of total soluble sugars. Material costs of oil at A$96/ha per application is less, compared with antitranspirant that cost $4000/ha per application.