Preliminary data on volatile composition of olive fruits of cv. "Simona" and possible relationship to resistance to fly oviposition

By characterizing the volatile compounds of the olive cultivar “Simona” from southern Italy (Apulia region), we identified a way to analyze characteristics possibly linked to this olive’s well-known resistance to fly oviposition. The pool of volatile compounds in the unripe and ripe fruits was identified, and even if the relative amounts of these compounds tended to vary with ripening, the fly repellent action appeared to be related to the sesquiterpenes such as alpha-copaene, cycloisosativene, alpha-muurolene, beta-cubebene and hydrocarbons such as (E)-2-dodecene, undecane, tridecane, and 3-methyl undecane. In agreement with the concept that the collective pool of volatile substances can enhance olfactory pleasure/repulsion more than would the effects of a single compound, the pool of volatile compounds identified in this paper may be among the possible characteristic mixtures with repellent action against Bactrocera oleae. The selection of volatile compounds made by the cuticle and responsible of the headspace quality surrounding the whole olive fruit is also demonstrated to be markedly different from the headspace volatile compounds produced by the extracted oil.