Mushroom

DESCRIPTION

Mushroom (Agaricus bisporus) belongs to the fungi family. They belong to the class of Basidiomycetes and order Agaricales. Mushrooms are spore-producing organisms which they use in reproduction.

This reproductive structure, known as sporocarp, produces spores- which under favorable conditions germinate to form a mass of branched hyphae. These hyphae form from the underground part of the mushroom, known as the mycelia.

The other parts of the mushroom include the stem; which is the axis supporting the mushroom cap and the cap, which is the visible upper part of the plant and comes in different colors and shape.  

Mushrooms do not possess chlorophyll like green plants for manufacturing their food but for their growth and development, they depend on organic foods or decaying materials for nutrient.  These nutrients are usually provided by a mushroom-growing medium called substrates of compost.

In Nigeria, edible mushroom popularly known as “ogiri agbe” in Yoruba and “Ero” by the Igbos are sourced from the wild due to inchoate mushroom farming culture. They are gathered wild by women and children who through their expertise are able to distinguish the edible from the poisonous ones.

There are over two thousand types of mushrooms, but only 2.5-5 % are edible. The rest are highly poisonous and can masquerade as the edible ones.

About twenty-five, edible mushroom species of good repute whose knowledge were handed down generational lines via oral communication have been identified in Nigeria.

ORIGIN

Mycophagy, the act of consuming mushrooms, dates back to several hundred years BC in China. This is the first reliable evidence of mushroom consumption, although edible mushroom species have been discovered in archaeological sites which existed 13,000 years ago in Chile. Edible fungi were also collected from forests in ancient Greek and Roman times and highly valued. The Chinese have valued and used mushrooms for medicinal purposes as well as for food for centuries even till date making them the leading exporter of cultivated mushrooms.   

CULTIVATED VARIETIES

There are many types of mushrooms and they can be categorized into four groups: Saprotrophic, Mycorrhizal, Parasitic and Endophytic. There exist about 25 genera under which different species of mushrooms can be classified. Below are the descriptions of a few of the edible and cultivable species:

Portobello (Agaricus brunnescens syn. A. bisporus): Agaricus bisporus is an edible mushroom native to grasslands in Europe and North America. It belongs to the Agaricaceae family. It has two colors i.e. white and brown, both of which have their individual names. It is a very popular variety of mushroom which is mostly seen in the supermarkets.  The annual world production of this species is about one million ton. It is also called button mushroom, white button mushroom, and supermarket mushroom.

Oyster mushroom (Pleurotus ostreatus): this belongs to the Tricholomataceae family. The mushroom has a fan or oyster-shaped cap spanning 5–25 cm. Its color varies from light tan/gray to dark-brown. More than 20, 000 tons of this species are produced annually. It is grown on logs and very easy to cultivate.

Himematsutake (Agaricus blazei): it belongs to the Agaricaceae family.  It has a slippery texture with a sweet almond taste. It is highly expensive and very popular in Japan where it has spawned a $600 million industry since 1995. It is also called Almond Portobello.

The Lingzhi mushroom/ Reishi (Ganoderma lucidum):

Reishi mushroom is a fungus that has been described as being “tough” and “woody” with a bitter taste. The fruiting body (above-ground part) and mycelium (filaments connecting a group of mushrooms) are used as medicine.

Termitomyces species is a well-known edible mushroom in Nigeria. These mushrooms make their appearance after heavy rains and grow in contact with termite nests in forest soil. They usually appear between the months of April through October.

Nameko (Pholiota nameko): this is also called the slimy mushroom. It belongs to the Strophariaceae family. It is a Japanese mushroom produced at 15,000 tons a year.

Enoki (Flammulina velutipes): this belongs to the Tricholomataceae family. It is Dainty and Q-Tip shaped. It has long been known and cultivated in Japan. World production is estimated to be 40, 000 tons per year. It is also called winter or velvet stem mushroom.

Morels (Morchella sp.): it belongs to the Morchellaceae family.  It is spongy looking and hollow. It is not as common as the portobello, but similar in texture, flavor, and heartiness, the wine cap is a beautiful brownish mushroom with a bright white stalk. It is also called Land fish mushrooms.

Other edible species are: Lentinus squarrosulus, Auricularia auricula, Lepiota sp, Volvariella esculenta, Lycoperdon spp among others.

CULTIVATION

Farm layout

The land requirement for mushroom production could be as low as one plot of land. On a low investment level, mushroom houses are just built on arable land while on a high investment level; houses with smooth cemented floors are used. This cement floors are slightly slanted to allow easy cleaning and water draining. Also, if there are any existing structures such as chicken houses, slaughterhouse, and old milk factories, etc. they can be used to reduce cost of rebuilding. Some criteria to be considered before choosing a mushroom farm site include:

The climatic condition of the area;

– Temperature

The optimal temperature for growing mushroom is about 25°C.The ambient temperature has to fit the chosen mushroom strain. If the temperature in the mushroom house is too high opening the doors and windows at night will also help keep the temperature down, misting will also be necessary.

– Light

Required light (color and intensity) depends on the strains. When the small mushrooms emerge and you notice that the stems are long and the caps small, the aeration and light requirements were not met. Note that; Oyster mushrooms are very sensitive to insufficient aeration and light.

– Humidity

Good control of the humidity during cropping is very important for all types of mushroom. Keep the humidity high (80 – 90%) by spraying water several times per day.

2. Farm Hygiene

Since chemical control of pests and diseases is not possible in small-scale mushroom cultivation, the only preventive measure is hygiene. Hygiene is vital on a mushroom farm especially for those farmers who will produce their own substrate.  Therefore checking a suitable site for a mushroom farm is very important. The surroundings of a farm should be clean and free from possible contamination from insects, moulds, infected soil, etc. building a new mushroom farm close to other mushroom farms should be avoided and used substrate should be disposed or used as manure as soon as possible.

3. Species

Choose a species that fruits at temperatures near your outdoor temperatures. This limits investments in climate control and reduces energy costs. The only mushrooms currently being cultivated at temperatures around or just below 30°C are: Oyster mushrooms (Pleurotus ostreatus), Volvariella volvacea, Agaricus bitorquis, and Wood ear mushrooms (Auricularia polytricha).

4. Aeration/ventilation

The mushroom house needs openings that will provide light and ventilation.

To find out details of mushroom production click here

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REFERENCES

• Bram van Nieuwenhuizen., Peter Oei (2005). Small-scale Mushroom Cultivation. Digigrafi, Wageningen, the Netherlands. https://journeytoforever.org/farm_library/AD40.pdf
• Cultivation of Edible Mushrooms
• https://www.botany.hawaii.edu/faculty/wong/BOT135/Lect020.htm
• Mushroom cultivation https://nstfdc.nic.in/userfiles/mushroomcultiv.pdf
• Six steps to mushroom farming: https://mushroominfo.com/growing-mushrooms/six-steps-to-mushroom-farming/#sthash.M0yqveqe.dpuf
• https://www.mushroomidea.co.uk/

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