BioSpectra™ 100SC: a new biorational fungicide to control postharvest diseases of fruits

BioSpectra (TM) 100SC is a newly registered biorational fungicide for postharvest use in the US with exempt-from-tolerance. The active ingredient, natamycin, is a naturally occurring antifungal agent produced by fermentation of Streptomyces natalensis. It binds to ergosterol in fungal cell membranes and causes leakage of the cell wall, leading to cell death. The effectiveness of the fungicide was evaluated when applied alone and/or in combination with other postharvest fungicides on citrus fruit. In laboratory and packingline studies, natamycin effectively controlled the most important postharvest diseases of citrus, green mold and sour rot incited by Penicillium digitatum and Galactomyces citri-aurantii, respectively. It effectively controlled green mold caused by resistant strains of P. digitatum to thiabendazole, fludioxonil, and pyrimethanil. Mucor rot, a newly emerged postharvest disease on mandarins, was also significantly reduced. However, reduced efficacy was observed on late season lemons and oranges. Further studies are being conducted on various fruit crops, including stone fruits, sweet cherries, pome fruits, and tropical fruits. Therefore, it is a valuable tool for broad spectrum decay control and fungicide resistance management in postharvest fungal pathogens.