Impact of the Mediterranean fruit fly (Medfly) Ceratitis capitata on different peach cultivars: The possible role of peach volatile compounds

The relationship between susceptibility of different peach cultivars (cvs) to the Mediterranean fruit fly (medfly), Ceratitis capitata, and the volatile composition of ripe fruit of each cv has been investigated, since understanding the fruit-insect interaction mechanism is crucial for developing control strategies for such a pest. Volatile compounds were analyzed by SPME–GC–MS in three cvs highly susceptible to medfly attack (Fair Time, Flaminia, Sicilia Piatta), and in two less susceptible cvs (Percoca Romagnola 7 and Doctor Davis). Among the volatile compounds detected, 88 could be identified. The main differences found in the volatile composition of the cvs, concerned the relative abundance of esters. The least susceptible cvs, above all Percoca Romagnola 7, contained the higher amounts of hexenyl, hexyl, 3-methylbutyl, butyl and 2-methylpropyl esters; among these, some C6 derivatives detected, such as (Z)-3-hexenyl acetate, are known to act as priming agents, enhancing plant defence response to insects. Instead, a lower relative content of methyl esters, such as methyl hexanoate and methyl octanoate, known to act as medfly pheromone and attractant respectively, was found in the least susceptible cvs.