A new heart rot disease in Ailanthus excelsa Roxb. caused by Navisporus floccosus (Bres.) Ryvarden

A wood decay fungus was defined based on the zone of tree that invades. N. floccosus causing heart rot was recorded in living trees of A. excelsa for the first time. The cultural characters of N. floccosus were described for the first time. Heart rot fungus i.e. N. floccosus decayed mostly heartwood of living tree. It colonized in the central portion of tree and begins decaying of wood which ultimately lead to death of A. excelsa tree was recognized for the first time. When decay proceed to the top of tree, the fruiting bodies grown in large size at butt region. During July 2007 i.e. monsoon months, due to the high wind velocity the weak tree was up rooted, which indicates that the fungus severely decayed heartwood of A. excelsa tree. After falling the tree, fungal hyphae in heart wood were very active so it produced fruiting bodies outside the trunk. On the malt agar plates containing tannic acid, it showed a positive reaction for oxidase and laccase and negative reaction for tyrosinase. Peroxidase test was positive with growth rate of >70 mm in 7 days.