European stone fruit yellows (ESFY) is caused by the phytoplasma ‘Candidatus Phytoplasma prunorum’, which is transmitted from plant to plant by insects of the genus Cacopsylla. Apricot cultivars show large differences in symptom expression; however, no resistance source is known in apricot. The density of psyllids on apricot cultivars is generally low. The inconsistency between the high mortality rate of certain apricot cultivars and the low level of psyllids on apricot trees has already been reported, but remains unexplained. A deeper insight in vector-host plant interactions could enhance knowledge of vector behavior and is crucial for controlling ESFY disease. The main objective of this study was to evaluate the influence of apricot genotypes and their volatile profiles on psyllids. Experiments were performed with flower branches of 13 apricot genotypes using a six-arm olfactometer, allowing simultaneous observation of insect behavior and odor trapping. Psyllid choices for the tested apricot genotypes were assessed and gave attractiveness differences that allowed clusters of cultivars to be defined according to their potential appetence. Volatile compound analysis of the two extreme clusters (low and high attractiveness) led to the characterization of some important compounds and revealed attractive and repulsive volatile compounds within the apricot genotypes. These volatile compounds could be interesting in the future for the control of the ESFY vector, for example by developing infochemical traps.
