Oyster mushroom (Pleurotus sajor-caju)
This mushroom gained importance during the last decade and now several species of Pleurotus are available for commercial production such as: P.sajor-caju, P.florida, P.sapidus, P.eryngii, P.columbinus, P. cornucopiae, P. flabellatus. P. platypus, P. opuntiae, P. citrinopileatus
It is now being cultivated in many countries in the subtropical and temperate zones. In China, it is known as abalone mushroom (P. abalonus or P.cystidiosus).
Pleurotus spp. can be grown using various agricultural waste materials. The different species of Pleurotus grow within a temperature range of 200 to 300 C. P. sajor-caju can tolerate temperature up to 300 C although it fruits faster and produces larger mushroom at 250 C. P. fossulatus is the so-called low temperature Pleurotus, fruiting mostly at 12-200C.
The tropical wastes like rice straw, wheat straw, corncobs, dried water hyacinth, sugarcane bagasse, banana leaves, cotton waste or sawdust are used for cultivation. The materials are usually soaked in water chemically sterilized with bavistin (7-10g) and formalin (120-150 ml)/ 100 litre of water for 16-18 hours. Extra water is drained off.
The process of spawn making is the same as for Agaricus species. Pleurotus spawn should be about 15 days old when mycelium has formed complete coating around the grain. The normal rate of spawning in a pasteurized substrate is 2.0-2.5% of the wet substrate. The spawning is usually done thoroughly. Before filling the substrate in polythene bags, holes of about 1 cm diameter are made at 10-15 cm distance all over the surface for free diffusion of gases and heat generated inside.
The optimum temperature for growth of Pleurotus spp. is 23 ±20 C. Relative humidity in growing room should range between 85-90% during spawn-run. Usually 3 to 4 days after opening the bags, mushroom primordia begin to form. Mature mushrooms become ready for harvesting in another 2 to 3 days. An average biological efficiency (fresh weight of mushrooms harvested divided by dry substrate weight x 100) can range between 70-80% and sometimes even more. To harvest the mushrooms, they are grasped by the stalk and gently twisted and pulled. A knife should not be used. The mushrooms remain fresh for up to 3 to 6 days in a refrigerator/cool place.
Cost and Return for Oyster Mushroom (Two Crops)
Particulars Approx. cost (Rs.) Total (Rs.)
1.Wheat Straw 20 Qtl. @ Rs. 200/- =4,000.00
2.Spawn 120 Kg @ Rs. 50/- =6,000.00
3.Chemical treatment =1,500.00
4.Polythene bags @ Rs. 1.50/- each (2400 bags) =3,600.00
5.Electricity, water & labour =2,000.00
6.Miscellaneous (packaging &marketing) =2,000.00
Total Mushroom Production : 14.00 Qtl
Market rate @ Rs.30/- per kg : Rs. 42,000.00
Interest @ 10% : Rs. 1,910.00
Net profit : Rs. 10,990.00