539 Evaluation of Food Additives and Low-Toxicity Compounds as Non- polluting Means to Control the Main Postharvest Diseases of California Peaches Ll. Palou a Centre de Tecnologia Postcollita Institut Valencià d’Investigacions Agràries (IVIA) Montcada, València Spain J.L. Smilanick USDA-ARS, San Joaquin Valley Agricultural Sciences Center Commodity Protection and Quality Research Unit Parlier, CA USA C.H. Crisosto Department of Plant Sciences University of California, Davis, Kearney Agricultural Center Parlier, CA USA Keywords: Monilinia fructicola, brown rot, potassium sorbate, heat, integrated disease management Abstract More than twenty food additives, GRAS (Generally Regarded as Safe), and low-toxicity compounds were evaluated as nonpolluting means to control postharvest decay. The chemicals were tested at three concentrations in in vivo primary screenings with California-grown ‘Flavorcrest’, ‘O’Henry’, or ‘Last Chance’ peaches that had been artificially inoculated with seven major postharvest pathogens: Monilinia fructicola, Botrytis cinerea, Geotrichum candidum, Alternaria alternata, Penicillium expansum, Mucor piriformis, and Rhizopus stolonifer. Overall, the best compounds were potassium sorbate, sodium benzoate, and sodium sorbate at 200 mM, 2-deoxy-D-glucose at 100 mM, sodium carbonate at 400 mM, and potassium carbonate at 250 mM. Sodium and ammonium molybdates, acid lactic, and hydrogen peroxide were somewhat effective but phytotoxic to fruit skin tissues. The selected compounds, however, lacked effectiveness and persistence when tested against brown rot, caused by M. fructicola, in small-scale trials as 60 s dips in aqueous solutions at ambient temperatures. Heating the solutions to 55 or 60°C significantly increased treatment efficacy and brown rot incidence and severity were reduced by 35 and 25%, respectively, after 7 days of incubation at 20°C on peaches treated with potassium sorbate. However, treatment efficacy was not superior to water alone at these temperatures. Therefore, the potential for use of common food additives or GRAS compounds as alternative chemicals to conventional fungicides for the control of brown rot of California peaches is rather limited and heat treatments appear more suitable than these chemicals to be combined with other environmentally-friendly antifungal treatments for integrated disease control. The control by these means of other important peach postharvest diseases such as gray mold and sour rot, caused by B. cinerea and G. candidum, respectively, deserves further study. INTRODUCTION Fruit losses caused by postharvest diseases are among the main concerns of peach growers in California, Spain, and other important producing areas. Brown rot, caused by Monilinia fructicola, M. laxa, or M. fructigena, is the most important postharvest disease a palou_llu@gva.es Proc. 7 th Intl. Peach Symposium Eds.: J. Girona and J. Marsal Acta Hort. 962, ISHS 2012