Wound age and infection of peach bark by Cytospora leucostoma

Abstract

Peach bark wounds of varying ages were inoculated with mycelium of Cytospora leucostoma (Pers.) Fr., and colonization frequency and extent were determined. Noninoculated wounds of similar ages and in close proximity to inoculated wounds were also sampled and examined histologically for morphological and histochemical changes associated with nonspecific plant defense reactions, including lignification and formation of lignosuberized tissue and new periderm. Results demonstrated that lignified and lignosuberized tissues significantly decreased the rate of fungal colonization, whereas new periderm with at least three cells thickness of new phellem completely inhibited fungal colonization. The critical period regarding effective periderm formation was between 10 and 14 days postwounding.