Acta Alimentaria, Vol. 33 (3), pp. 249257 (2004) 0139-3006/$ 20.00  2004 AkadØmiai Kiad, Budapest GROWTH OF MYCELIUM OF PLEUROTUS SPP. ON DIFFERENT GRAINS AND DETERMINATION OF THEIR COMPETITION WITH SOME CONTAMINANT FUNGI A. SAIR a * and A. YILDIZ b a Department of Plant Protection, Faculty of Agriculture, Dicle University, 21 280 Diyarbak9r. Turkey b Department of Biology, Faculty of Science, Dicle University, 21 280 Diyarbak9r. Turkey (Received: 25 June 2003; accepted: 26 November 2003) Five mushroom species, P. ostreatus, P. ostreatus var. salignus, P. eryngii, P. florida, P. sajor-caju, three contaminant fungi A. niger, P. italicum, R. stonolifera, and barley, sorghum and wheat grains were used in the study. The purpose of this work was to determine mycelial growth of Pleurotus spp. and their competition with contaminant fungi. The Pleurotus spp. were grown better on the sorghum grains than the barley and wheat grains according to mycelial growth and density. The colony growth of Pleurotus spp. was inhibited by A. niger, P. italicum and R. stonolifera by 13.84%, 1.58% and 24.48%; 9.84%, 20.31% and 18.06%; 14.48%, 100.00% and 100.00% on the 3 rd, 5 th and 7 th days after inoculation, respectively. The mushrooms were completely suppressed by R. stonolifera on the 5 th day. Keywords: Pleurotus spp. growth, contaminant fungi, inhibition, Aspergillus niger, Penicillium italicum, Rhizopus stonolifera More than 45000 mushroom species exist in nature but only approximately 22 species are intensively cultivated for commercial purposes on ground or wood by utilising particular environmental and nutritional conditions. Mushroom mycelia (vegetative phase) are important in the ecosystem because they are able to biodegrade the substratum, and therefore the wastes of agricultural production should be used. Fruit bodies (reproductive phase) are appreciated, not only for texture and flavour but also for their chemical and nutritional characteristics (MANZI et al., 2001). The oyster mushroom (Pleurotus ostreatus (Jacq. ex Fr.) Kummer) is one of the most widely cultivated mushrooms in the world (BANO & RAJARATHNNAM, 1987). Techniques for its cultivation are easier than those used for Agaricus bisporus (Lange) Singer, in which the fungi are cultivated on various vegetal wastes. If properly composted, a wide range of plant wastes, e.g. cereal straw, corn cobs, cornstalks, sawdust, bagasse, wood pulp, cotton and oil palm waste, coconut husks, poultry wastes, tree bark and leaves, paddy straw, stalks and leaves of bananas can be used as substrates for Pleurotus spp. production (BAHUKHANDI & MUNJAL, 1989; KHAN & CHAUDHARY, 1989; HADAR et al., 1992; CURVETTO et al., 2002; RAGUNATHAN & SWAMINATHAN, * To whom correspondence should be addressed. Fax: 00 90 412 248 81 53; e-mail: asagir@dicle.edu.tr