A new Heart rot disease in Ailanthus excelsa Roxb. caused by Navisporus floccosus (Bres.) Ryvarden Praveen Kumar Nagadesi 1, *, Arun Arya 2, ** 1 Department of Botany, P.G. Section, Andhra Loyola College, Vijayawada - 520008, Andhra Pradesh, India 2 Department of Botany, Faculty of Science, The Maharaja Sayajirao University of Baroda, Vadodara - 390002, Gujarat, India * , **E-mail address: aryaarunarya@rediffmail.com , nagadesipraveenkumar@yahoo.com ABSTRACT 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. Keywords: Heart rot; Navisporus floccosus; Ailanthus excelsa; cultural characters; Disease cycle 1. INTRODUCTION Ailanthus excelsa Roxb. was a multipurpose tree species of arid region because of its ability to grow well at low rainfalls (from 400 to 1900 mm) and in strong light conditions (Bhimya et al, 1963). It play an important role in management of land resources and securing livelihoods of economically poor people through agro-forestry system to meet the increasing demand for food, fodder and fuel wood (Jat et al, 2011). Stem bark of this tree was bitter in taste but it was used as astringent, febrifuge, stomachic, antihelmintic, antispasmodic, expectorant and used for the treatment of bronchitis, cold, cough, skin diseases, trouble of rectum, diarrhoea, dysentery, dropsy, fever due to tridosha, guinea- worms, snakebite and also used as contraceptive (Kumar et al, 2010). An antifungal-activity containing two new dammarane-type triterpenes, namely ailexcelone and ailexcelol was isolated from heartwood of A. excelsa (Srinivas, et al 2006). The wood was white and very light in weight. The timber can be used especially for making catamarans for fishing, packing cases, sword sheaths and matchboxes. It produces grade-III commercial and grade-IV moisture proof plywood. It also supplies the wood to International Letters of Natural Sciences Vol. 6 (2014) pp 1-7 Online: 2013-11-29 © (2014) SciPress Ltd., Switzerland doi:10.18052/www.scipress.com/ILNS.6.1 All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of SciPress Ltd., www.scipress.com. (ID: 203.129.197.100-29/06/15,07:33:30)