Control of post-harvest brown rot on nectarine by Epicoccum nigrum and physico-chemical treatments

Post-harvest physico-chemical treatments - water at 40 degrees C or 60 degrees C (HW), and sodium bicarbonate at 1 or 2.5% (SBC) at 20, 40 and 60 degrees C - were tested on peaches and nectarines in order to control brown rot caused by Monilinia spp. and to select the best physico-chemical treatment to be used in combination with pre-harvest applications of the biological control agent Epicoccum nigrum (ATCC number 96794). Experiments were carried out in France, Italy and Spain in order to test different experimental conditions. Monilinia rot was reduced in peach and nectarine treated with HW (40 degrees C for 2 min) in all three countries, the percentage of rot reduction was similar for France, Italy and Spain (over 40%). A synergistic effect between HW at 40 degrees C during 150 s or at 60 degrees C during 20s and SBC was observed in all three countries. After preliminary experiments post-harvest treatment of HW (60 degrees C) + SBC (1%) during 20s was selected to combine it with field treatments. Pre-harvest treatments with fungicide or E. nigrum did not reduce brown rot in any country. However, pre-harvest treatments with E. nigrum, chemical fungicide, and their integration followed by post-harvest physico-chemical treatment significantly reduced Monilinia rot compared to pre-harvest untreated fruits followed by post-harvest physicochemical treatment in Italy (over 70%). Post-harvest treatments with E. nigrum were also tested in Italy on natural and artificial infections in nectarine over 3 years. E. nigrum, as fresh or formulated cells, at a concentration of 108 conidia mL(-1) were effective, significantly reducing the incidence of brown rot compared to control, both under artificial and natural infection, from 43 to 100%. (C) 2007 Society of Chemical Industry.