Shiitake Mushroom

(Lentinula deodes)

It is known as "shiitake" in Japan. Origin of this mushroom is China. The shiitake mushroom grows on old wood from dead residues of trees. Various hardwood species of trees have been used in the bed log production of shitake.

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Paddy Straw Mushroom

(Volvariella sp.)

The paddy straw mushroom is the most popular Southeast Asia. Several species of Volvariella have been grown for food V. bombycina (Schaellff. Ex.Fr.) Sing. And V. diplasia (Berk. & Br.) Sing. have been cultivated in India. V. diplasia is white V.Volvacea is blackish V. bombycina differs from the cultivated V.volvacea in terms of habitat as well as colour.

Volvariella volvacea thrives in a temperature range of 28 to 360C and relative humidity of 75-85%. This mushroom can be grown by various methods.

 Composting the Substrate:

A good substrate should provide good anchorage, good aeration and have the right water holding capacity and also contain the necessary nutrients, released from the raw compost materials during fermentation. After these two stages of fermentation, the compost becomes a selective substrate. When the mushroom spawn is planted, it can spread throughout the compost in short time with little competition. Volvariella mycelium grows both on composed and non-composted substrates.

 

Substrate Preparation and Spawning:

1.       Box-type (Nonpasteurized) Portable Outdoor or Indoor Beds: -

Production of Volvariella mushroom in open portable wooden boxes provides for the easier management of pests and diseases. Materials needed are wooden boxes, paddy straw/banana leaves and plastic sheets/growing houses. The frames are 60 x 45 x 20 cm size, open on all sides.

The bedding materials are cut to a uniform length of 20 cm. The boxes are filled with the bedding materials, lightly packed in parallel rows. The bedding materials may be bundled to facilitate the filling of the boxes. The packed materials loosen when soaked in water so the initial packing should be as tight as possible. The boxes of bedding materials are soaked in water for at least 3 hours. With proper soaking, the straw becomes dark brown and the banana leaves become more transparent. The boxes are removed from the soaking area and excess water is drained away. The soaked substrate is spawned by inserting pieces of spawn along the edges of the packed substrates.

The spawned substrate in the boxes may be placed in a specially built incubation room with a high temperature (35 to 380C) and high relative humidity (at least 5%), or it may be covered with plastic sheets and placed under shade outdoors. A good spawn run takes about 5 to 7 days. Subsequently, small pinheads begin to form along the open edges of the boxes.

 

2.       Nonpasteurized Outdoor Beds by Bundles: -

The bundled paddy straw is soaked in water overnight and piled into heaps of three or four layers, with spawn broadcast between the layers. The heap is compacted until it is 30 to 60 cm thick. Thickness varies according to growing season: during warm weather, the height of the bed should not exceed 50 cm so that the bed will not overheat and kill the spawn. The latter method has the advantage of raising the temperature of the heap. Each bed is covered with paddy straw or plastic sheet for humidity control. Use of newly harvested but dried straw, high quality spawn and good cultural management of the bed to avoid pests and diseases are important considerations for obtaining higher yields.

 

3.       Nonpasteurized Indoor or Outdoor Molded Beds: -

In this method wooden frames of various sizes are used. The usual size is  30 cm wide and 30 cm high and the length of the frame varies according to the amount of substrate available. The frame is open at the top and bottom. A growing house made of used to control humidity and heat, and to protect the beds from sunlight. Materials used are simple and include: (i) Chopped paddy straw (ii) Cotton waste (iii) Wooden frame 30x30x50 cm (iv) Water for soaking straw and cotton and (v) Growing house or a dark room.

The straw and the cotton waste are soaked separately. The soaked straw, after complete draining, is placed in the wooden frame on a wooden platform and compacted by trampling. The soaked cotton waste is spread around the edge of the wooden frame in a strip about 8 to 10 cm wide. Spawn is broadcasted on the cotton. More soaked straw is packed into the wooden frame, and trampled as before. The process is repeated three times, spreading cotton waste over the top layer each time.

The wooden frame is removed and the prepared small beds are carried to a growing house on the wooden platform. The temperature should be about 32 to 350C. The moisture content of the beds is checked daily. The beds must not become soggy and anaerobic. Prepared beds may be established outdoors where there are covered with plastic sheets. Mushroom appear in 5 days and are ready for harvest in 7 days.

 4.       Indoor Beds (pasteurized)

A semi-industrialized method production, which requires pasteurization of the growing substrate directly inside the mushroom houses, requires indoor beds. Materials used in indoor cultivation are : Cotton waste or chopped paddy straw, wooden frames about 92 cm x 28 cm (for composting) (sides only-no top or bottom), Water, CaCO3 (calcium carbonate) 2% w/w of substrate rice bran, and supplements : chicken manure (5% w/w) or sewage sludge (5% to 10% w/w) or NPK chemical fertilizer (1% w/w). For preparation of compost, a wooden frame is placed on the ground and the cotton waste or paddy straw raw materials are packed inside. Limestone, fertilizer, and water are mixed with the material as it is packed. The materials are tramped as they are added, to help with mixing and absorption of the water. When the frame has been completely filled, it is pulled up to a height of about 15 to 20 cm and another layer of compost is added in top of the first layer. A finished pile of compost usually consists of four to six layers and is about 70 to 90 cm in height. 

The pile is covered with a plastic sheet and allowed to ferment. After two days, the fermented compost is turned by hand or thoroughly mixed by a mechanical mixer. The rice bran (2% of the dry weight of the compost) is added at this point. Water is also added, if necessary. The mixed compost is re-piled and covered with the plastic sheet. Fermentation continues for another two days.

A suitable size of bed is about 0.4 m2.  The layer of compost should be about 10 cm thick and should consist of about 8 kg (dry weight) or 26 to 28 kg (wet weight) of compost materials. Live steam (pressurized and over 1000C) is introduced into the mushroom house for Pasteurization. The air temperature about 60 to 600C is maintained for another 2 hours. The temperature is then gradually lowered to about 520C by a gentle stream of fresh air. The temperature during the next 8 hours is maintained at 50 to 520C  by a continuous fresh air supply. The steam valves are then closed and the temperature is allowed to drop gradually to 34 to 360C . This can take 12 to 16 hours, depending on the outside temperature. The beds now become ready for spawning.

For Spawning, the air temperature is cooled to 350C and the bed temperature to about 36 to 380C. The amount of spawn to be used is calculated at 1.4% (dry weight) or 0.4% (wet weight) of the compost. Pure culture spawn is removed from the bottles and placed on a tray for easy handling. The spawn is broken into pieces about the size of peanuts. The pieces are inserted into holes in the compost at a depth of about 2 to 2.5 cm spaced 12 to 15 cm apart. The spawn is covered with the displaced compost and the beds are covered with a plastic sheet. The temperature of the mushroom house is maintained at 32 to 340C during the spawn running period. Full growth may take only 3 to 4 days, depending on the compost quality and the temperature.

 During the 3-day period of spawn run, no water or light is needed. Only a limited amount of fresh air is required during this period. Three days later fluorescence light and additional ventilation are provided. On fifth day after spawning, mushroom primordia usually appear on the surface of the beds. Four to five days later, the first flush of mushroom is ready for harvest.h

  Harvesting: -

The first crop of mushroom is usually harvested 10 days after planting the spawn. The first flush normally provides three or four successive days of harvesting and produces 85 to 90 % of the expected yield. During the next 3 to 5 days (the rest period), additional water may be added to the substrate. Stable conditions must be maintained in the growing room during the period. Spraying with superfine mist will maintain the desired humidity in the growing rooms and protect the substrate form excessive drying. The temperature can be maintained at the appropriate level by opening or closing the ventilators. The second flush may be also provide 2 or 3 days of harvesting, but the yield is lower (10 to 15%of the total yield). Volvariella is best harvested at the button (egg-shaped) stage when the volva or the universal veil has not broken. A yield for outdoor beds ranges form 10 to 12% B.E. while indoor beds of cotton waste may yield as high as 50% B.E.


Ag.
Technologies
(Mushroom Cultivation)

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