Recovery phenomena in apricot trees cv. Bergeron infected by European stone fruit yellows in the province of Trento (Italy)

Recovery phenomena have been intensively studied for apple proliferation and grapevine yellows. Several recent findings in apricot orchards in Friuli-Venezia Giulia indicate the importance of this strategy also for the control of European Stone Fruit Yellows (ESFY) infections, caused by ‘Candidatus Phytoplasma prunorum’. The aim of this work was to investigate the occurrence of recovery in 2 experimental orchards of apricot cv. Bergeron on ‘Wavit’, located in the province of Trento, where the disease has been spreading since 2000. This included visual inspections for typical symptoms and a diagnostic method based on a Spot Real-Time Reverse Transcription PCR assay. The results obtained showed that there were three different groups of plants infected by ESFY: many plants with typical symptoms, some recovered and some symptomless infected plants. To date no interesting plant genotypes showing resistance to ESFY are available, moreover most of the insecticide applications have no efficacy in controlling the vector than the disease. The use of both pathogenfree propagation material and resorting to natural recovery could be adopted as an integrated approach for the control of this phytoplasma disease. For these reasons the research will continue with the aim of quantifying the concentration of the pathogen in the recovered plants