Non-conventional methods for postharvest management of bull’s eye rot of apple

Abstract: Bull’s eye rot caused by Neofabraea spp. represents one of the main postharvest pathogens affecting ‘Cripps Pink’ apple during storage. The aim of the work was to investigate two non-conventional methods: fruit sorting with DA-meter and hot water treatment (HWT) for disease control. Immediately after harvest, ‘Cripps Pink’ apples, harvested from two different orchards, were sorted by DA-meter, and divided in two classes according to their chlorophyll content, expressed as Index of Absorbance Difference (IAD): class H (IAD > 0.8) with high chlorophyll content and class L (IAD < 0.75) with a chlorophyll content lower than class H. Control fruit were represented by apples not sorted by the DA-meter. Other apples, derived from four different orchards, were treated by dipping in water at 45 °C for 10 min using a prototype machine for HWT, for semi-commercial trials. Control apples were represented by apples dipped in water at 14-15 °C. All apples were stored for 4 months at 0 °C and then evaluated for bull’s eye rot incidence. Among IAD, the results showed that apple of class H were significantly less susceptible to bull’s eye rot than apple of class L, especially after 90 days of storage. In addition, also HWT reduced the bull’s eye rot incidence, with efficacy ranging from 62.7 to 85.3% compared to the controls, depending on year of trial and harvest time. The evaluation of the integration of these two methods for a further improvement of bull’s eye rot control is in progress.