IDENTIFICATION OF ANTAGONISTS FOR CONTROLLING FOLIAR FUNGAL PATHOGENS OF CITRUS

摘要

Four saprophytic fungi producing unknown toxic compounds were identified from citrus groves and were eval-uatedfor control of two citrus foliar fungal diseases, Aiternaria brown spot and melanose. The toxic compounds secreted in cures were antagonistic to pathogens as they reduced the growth of citrus fungal pathogens considerably and induced stubby, swollen and fragmented hyphae. The inhibition was unaffected or slightly increased by heating to 95 deg C for 15 min-utes. Production of the toxic compounds by antagonists was markedly influenced by the composition of the media. Prelim-ease tests revealed that the saprophytic fungi reduced dis-ease incidence of Aiternaria brown spot on tangerine and melanose on grapefruit. The toxic compounds produced by the saprophytic fungi may be useful in developing effective bio fungicides and providing an alternative for disease man-agent for citrus growers in Florida.