Response of peach bark tissues to inoculation with epiphytic fungi alone and in combination with Leucostoma cincta

Abstract

Wounded peach bark was inoculated with the fungal epiphytes Alternaria alternata (Fr.:Fr.) Keissl., Trichodenna harzianum Rifai, and Epicoccum nigrum Link alone and in combination with the peach canker pathogen Leucostoma cincta (Fr.:Fr.) Höhn. Bark tissues were sampled over a time series for light and fluorescence microscopic examination to determine the influence of inoculations on the ontogeny of tissues associated with wound healing, specifically the extent of formation of the polysaccharide-impregnated zone, the ligno-suberized boundary layer, and the necrophylactic (wound) periderm. None of the inoculations with epiphytic fungi were associated with as quick a formation of wound-related tissues as observed in the noninoculated control wounds. Inoculation of wounds with T. harzianum resulted in delayed formation, but not prevention, of tissues critical to normal wound healing. Combined inoculations of L. cincta and epiphytes resulting in wound healing similar to that of inoculations with the epiphyte alone were observed consistently. Inoculation of wounds with E. nigrum alone, or in combination with L. cincta, did not cause any deleterious effects on the wound responses examined in this study. Key words: Alternaria, biological control, Epicoccum, Trichodenna, wounding.