WOOD DECAYING AGARIC FUNGI AND THEIR PREFERENCE TO SOME SRI LANKAN TIMBER SPECIES.

Abstract

For satisfactory use of wood products in indoors and outdoors it is necessaryto understand the agents and conditions that decay or deteriorate timber. SriLanka being a tropical Country, loss of wood due to fungal attack isrelatively high. Basidiomycetes and Ascomycetes are the major wooddestroying fungi, which cause three types of decay brown rot, white rot andsoft rot.

Main objective of the study was to determine the susceptibility and resistanceof different wood species to fungal attack in the natural environment. Largenumbers of wood inhabiting fungi were found in different wood speciesobserved in natural habitats, out of these species only lignicolous agaricswere studied in the present study.

These agarics were collected from indoor and outdoor habitats andmacroscopic features were studied. The microscopic examination followed,together with the documentation and photographs. The identification of theagarics was undertaken by using reliable keys, illustrations and suitabledescriptions. 22 agarics spp were identified. and out of them Lentinus sppwere identified as brown rot fungi while Armillaria mellea, Schizophyllumcommune and Pleurotus spp were identified as white rot fungi.

Schizophyllum commune was found on a large number of wood speciesfollowed by genus Lentinus. The appearance of mushroom fruiting bodiescoincided with the rain. Fruiting bodies of Pleurotus reticulates, Coprinusmacropus appeared during rainy seasons while Schizophyllum commune wasfound throughout the year. Most of the wood inhabiting agarics appeared asclumps.

Coprinus spp and Marasmius spp were found on old rotting logs and stumps,while Schizophyllum commune, Lentinus spp and Cantharellus spp werefound on intermediately decayed tree trunks, stumps and building timbers.Schizophyllum commune was found on outer barks as well as sapwood andheartwood regions of logs and building timber. They appeared throughout the year and fruiting bodies were fresh under moist conditions, dry and leatheryin dry seasons. Schizophyllum commune was able to attack wide range ofhardwood and softwood species.

Chloroxylone swietenia, Vitex altissima, Manilkara hexandra were found tobe resistant to fungal attack; therefore could be categorized as durable timberspecies in terms of fungal decay while Swietenia macrophylla, Artocarpusheterophyllus and Pericopsis mooniana were less attacked by fungi. Heveabrasiliensis, Mangifera indica were mostly attacked by fungi and hence canbe categorized as susceptible timber species. It is recommended to usepreservative treatments for the effective utilization of these perishable timberspecies,