Use of Plant Extracts for Substrate Sterilization and Its Effect on Competitor Moulds and Biological Efficiency of Oyster Mushroom

Mushrooms are recognized as nutritionally functional food and a source of physiologically beneficial and nontoxic medicines. Oyster mushroom (Pleurotus spp.) is an efficient lignin degrading mushroom and can grow well on different types of lignocellulosic materials including agricultural and forest waste. Cultivation technique for oyster mushroom is very simple and the production cost is low, which gives consistent growth with high biological efficiency. Plant derivatives have shown considerable promise as an effective alternative of chemicals used in surface sterilization. To develop a suitable method for substrates treatment, six different plants extract were evaluated along with most popular chemical treatment (bavistin 75 ppm + formalin 500 ppm) for cultivation of oyster mushroom (Pleurotus florida). Chemical treatment (bavistin 75 ppm + formalin 500 ppm) was found to be most effective among all the treatments and exhibited 120.50% Biological Efficiency (B.E.). Among the phyto-extracts, Zingiber officinale was found to be excellent in controlling the growth of competitor mould fungi (114% B.E.) followed by Azadirachta indica (109.25%) and Allium cepa (98.75%). Chemically treated substrate was taken minimum (20 days) for spawn run and gave 7.10 gm average weight of sporophore followed by Zingiber officinale (22 days and 6.740 gm). In vitro study revealed the superiority of chemicals and reduced 61.80 to 70.67% mycelium growth of four contaminants. Extract of Zingiber officinale was found excellent in inhibiting the mycelium growth of Penicillium sp., Aspergillus niger and Coprinus sp. but, reported to be less effective against Sclerotium rolfsii. While, Azadirachta indica seed oil was found very effective against the mycelium growth of Sclerotium rolfsii, Penicillium sp, and Coprinus sp. Extract of Allium cepa, Lantana camera, Eucalyptus hybrida and Allium sativum showed moderate effects on the mycelium growth of competitor moulds.