MUSHROOM CULTIVATION TECHNOLOGY IN GHANA
Mary Obodai, Matilda Dzomeku, Deborah Narh Mensah and Richard Takli
Ghana lies in the tropics and is located on the Gulf of Guinea in the Western part of Africa. It lies between latitude 4o and 111/2o North. It is bordered in the North by Burkina Faso, in the West by Cote d’Ivoire and in the East by Togo. It occupies 239,460 square kilometers, and has a population of 27 million.
The use of mushrooms for both consumption and medicinal purposes dates back several centuries in Ghana. Mushrooms are a highly prized delicacy and are collected in forest regions in mid-March and early September. It is part of a normal diet with rural folks who use them in the preparation of soups, stews and as condiments. The collection of edible mushrooms in rural areas and the subsequent sale at urban centres is an old tradition and also found to be a gender-related issue which is generally regarded as work for women and children.
In Ghana, mushroom farming had basically been carried out using the traditional pit method and the termite multiplication methods. The whole concept of intensive mushroom farming began in June 1990 through the collaborative efforts of the Food Research Institute of the Council for Scientific and Industrial Research (CSIR-FRI), Export Promotion Authority and the Ministry of Food and Agriculture. Through this collaboration, the National Mushroom Development Project (NMDP), now known as the Mushroom Unit, was set up.
This report begins with a discussion on the indigenous knowledge of mushroom species and its uses, mushroom cultivation in Ghana, the setting up of the Mushroom Unit, the current situation of mushroom production and concludes with the opportunities for economic development.
2.0 INDIGENOUS KNOWLEDGE OF MUSHROOM SPECIES AND ITS USES IN GHANA.
2.1 Indigenous mushrooms of Ghana
Indigenous and edible mushroom species, which are common in the wet season, form an important part of the diet and are a source of income for many rural and urban Ghanaians. This is evidenced by the presence of stalls selling mushrooms in both rural and urban markets and along major roads. The mushrooms are mainly collected by women and children who, through field experience, can accurately distinguish edible mushrooms (‘mbre’ in Akan) from the poisonous ones (‘saman mbre’). The exact quantities of mushrooms collected each year throughout the country have not been established.
Various surveys carried out in Bia in the Western region of Ghana (2001, 2015), Atiwa forest in Eastern region (2013-2015), Ayum forest in the Brong Ahafo region (2013-2015), Wli Agumatsa Reserve in the Volta region (2014) and Kakum forest in the Central region (2015) unearthed over 300 species of mushrooms. These surveys were carried out under various projects sponsored by UNESCO-Man and the Biosphere, Africa-Brazil Agricultural Innovation Marketplace, Partnership for Enhanced Engagement in Research (PEER-USAID) and the University of Ghana Research Fund.
2.1.1 Major edible mushroom genera of Ghana:
- Termite mushroom - Termitomyces species locally called ‘Twenwodro’, ‘Onu’ or ‘Sibre’ (Figure 1)
- Straw or oil-palm mushrooms - Volvariella species locally known as ‘domo’ (Figure 2)
- Shaggy mane - Coprinus species – ‘locally known as Pinpran’
- Button mushroom – Agaricus bitorquis
- Wood-ear mushrooms - Auricularia species
- Pleurotus species (P. sajor-caju (Figure 3), P. albidus (Figure 4)
- Monkey seat mushrooms - Ganoderma spp.
- Lentinus squarosullus (Figure 5)
- Pleurotus tuber-regium (Figure 6) – A sclerotium forming oyster mushroom (locally known as ‘fuo’), used in the treatment of underweight and convulsion in babies, and also for hypertension and heart pains in adults (Dzomeku, 2009; Sawyerr, 1993)
2.1.2 Medicinal mushrooms of Ghana
Some mushrooms in Ghana used for medicinal purposes are listed below:
- Wood-ear mushrooms ( local name Asuntoku)
Used for treatment of hypertension, rheumatic pains, uterine bleeding and piles, and sores and boils not healing due to old age
- Pleurotus tuber-regium- (known as ‘Fuo’ inAkan, 'Futrufu’ in Ga, 'Era' in Ibo-Nigeria). It is used in addition to melon seeds for treating convulsion, asthma and underweight in children, cures hypertension, chest and heart pains. This is ground and put in warm water and sipped; also ground and smeared on ankles for treatment of gout.
- Daldinea concentrica –Used for the treatment of hernia
- Ntrotrowa- Used for the treatment of hernia
- Oil-palm mushrooms: Promotes body resistance against infectious diseases, accelerates healing of wounds and reduces blood serum cholesterol
3.0 MUSHROOM CULTIVATION
Traditionally, wild mushrooms such as the termite mushrooms – Termitomyces spp., oil-palm mushroom - Volvariella spp., wood-ear - Auricularia spp. etc. are collected in the forest regions. There are, however, some traditional methods for their cultivation. These consist of the pit method for the production of the oil-palm or straw mushrooms, and the termite multiplication method for production of the termite mushrooms (Termitomyces spp.).
3.1 Oil palm mushroom (Volvariella volvacea)
3.1.1 The Pit-method
The oil palm or straw mushroom occurs naturally on felled and rotten oil palm trunks (Elaeis guineenis) which has been tapped for palm wine (toddy). They are also found on fermenting cocoa wastes in cocoa growing areas and on dead logs, and sawdust of some forest tree species, such as silk cotton tree (Ceiba petandra), ‘wawa’ (Triplohiton scleroxylon) and ‘kyenkyen’ (Antiaris africana). Traditionally, the oil palm mushroom has been cultivated in some forest areas on cassava, cocoyam and yam peelings, or on oil palm and cocoa wastes.
A pit of about 21cm by 5cm is dug and lined with fresh banana leaves. Heaps of cassava, cocoyam, and yam peelings are put into the pit. A fresh fruiting body of the oil-palm mushroom is mashed and the brown suspension of spores sprinkled all over the surface of the materials. The heap is then covered with more fresh leaves to retain moisture and avoid the direct sunlight.
Mushrooms begin to appear after three to four weeks, especially during the wet season, and are ready for harvesting at the button or egg stage. Fresh materials are added to the heap from time to time to prolong the period of production. In cocoa growing areas, beds of cocoa husk are moistened with palm wine and covered with fresh banana leaves to produce the oil palm mushroom.
3.2 The Termite Mushroom (Termitomyces species)
Several species of Termitomyces, locally regarded as the ‘King of the mushrooms’ occur on termite hills or mounds constructed by specific mushroom-growing termites. In the eastern region farmers cultivate it artificially. They put bundles of dried banana leaves and twigs on top of a termite mound which produces the mushroom and allow the termite to invade them. These ‘infested’ banana leaves are then transferred to other sites on the farm to allow the termites to build their mounds. It takes two years for the first production of these mushrooms. Subsequently it produces termite mushrooms every year around the same time.
These mushrooms are mostly eaten fresh and the surplus preserved by smoke drying over a fireplace, or sun-dried for future use. The two methods listed above give very low and unstable yields. In June 1990, the National Mushroom Development Project was set up to systematically develop and promote mushrooms as a non-traditional export crop. This project was made by the Research and the Production Units. In 1998, these two Units were taken up by the Mushroom Unit currently housed in the CSIR-Food Research Institute.
4.0 THE MUSHROOM UNIT
The present mandate of the Mushroom Unit is as follows:
- To research into all areas of mushroom growing technology, mushroom biotechnology, and environmental applications.
- To collect and maintain pure cultures of indigenous and exotic mushrooms in the National Mycelium Bank.
- To investigate efficient methods for processing and preserving mushrooms of both local and exotic strains.
- To produce and supply improved mushroom spawn to growers for commercial cultivation.
- To produce spawned compost bags
- To carry out training programmes.
- To provide extension services for farmers.
4.1 Current production methods
With the establishment of this Unit, two main methods of production are currently being used in Ghana. These are the plastic bag and the low-bed methods introduced from Taiwan and modified to suit Ghanaian conditions. The main agricultural wastes used in the plastic bag method are sawdust (Triplochiton scleroxylon, or a mixture of Chlorophora excelsa and Terminalia ivorensis), grass (JUNCAO), cassava by-products (sticks and peels), yam waste and rice straw. With these methods there is an all year round production of some mushrooms (oyster, wood-ear, monkey seat and P. tuber-regium) and they offer better, stable and higher yields. Currently, over twenty tons of oyster mushrooms are produced daily depending on the season. There is, however, a potential to produce between 25 tons of fresh mushrooms each day. The two methods are explained below:
4.1.1 Plastic bag method
This method is used in the production of the oyster, wood-ear and monkey seat mushrooms. The main material used as substrate is sawdust compost prepared from either Triplochiton scleroxylon, or a mixture of Chlorophora excelsa and Terminalia ivorensis.
Fresh sawdust from either of these woods is initially mixed with 10% rice bran and 1% quicklime on a weight to weight basis and brought to a moisture content of 70% by adding water (using the squeeze test). It is then heaped on a cemented platform, and allowed to decompose for 21-28 days in the case of Triplochiton scleroxylon sawdust (Obodai et al., 2007; Obodai & Johnson, 2002; Obodai, 1992), and 60 days for the mixture of Chlorophora excelsa and Terminalia ivorensis (Obodai & Sawyerr, 1995). During decomposition, the heap is turned every 4-5 days to allow for aeration and uniform composting. After composting, the substrate is bagged in heat resistant polypropylene or high density polythene bags dimensions (33 x 17cm) to a wet weight of about one kilogram. Each bag is fitted with a plastic neck of 2.5cm diameter ‘PVC’ pipe or cut bamboo and closed with a cap (Auetragul, 1984).
The bagged substance is then sterilised by steaming in a 200-litre oil barrel drum with a perforated lid at 100 °C for 2-3 hours. After allowing to cool, they are then sent to the inoculating room where each bag is spawned with 3-5g good quality sorghum grain spawn. The spawned bags are then sent to a semi-dark incubating room where the temperature is maintained between 26 and 30 °C for complete mycelia colonisation of the substrate. The mycelium permeates and degrades the substrates and virtually knits the substrate together. Most of the Pleurotus species under cultivation require between 30 to 33 days for complete colonisation, whilst P. cystidiosus and Auricularia species require between 45 to 65 days. After the mycelia have fully colonised the substrate, they are allowed to ‘thicken’ (form pinheads) for about a week and then the bags are sent to the cropping house for cropping and harvesting. In the case of Auricularia species, 12 diagonal slits of 4 cm are made around the bag, which are left in the incubation room for 14 days before they are sent to the cropping house.
The cropping house is a wooden framed structure, covered on the outside with local sedge or woven mats, and roofed with thatch to allow for aeration and water retention. Inside the cropping house are wooden or bamboo racks on which the bags are arranged horizontally on top of each other. The surface of the bags are exposed by cutting off the neck. To obtain good flushes, a high relative humidity of 85-95%, and temperature between 24 and 28 °C is kept in the cropping house. This is maintained by watering regularly with at least four buckets of water twice a day in the wet season, and three to four times in the dry season. When these bags are opened, it takes 5 to 7 days for the pinheads to appear and 36 to 48 hours for the mushrooms to be ready for harvesting. The fruit body yield per compost bag is between 200 to 300 grams every cycle of two months, depending on environmental conditions. A cropping house of size 4 x 6 x 2.4m can contain 2,000 - 2,500 bags, and a size of 6 x 8 x 2.4 contains 5,000 - 6,000 bags.
4.1.2 Low bed method
This method is used in the cultivation of the oil-palm mushroom (Volvariella spp.). The substrates used in this method include rice straw, maize stover, sorghum stover, cotton waste, banana leaves and pseudostem, oil palm pericarp fibre and empty bunches, peelings from root tubers such as cassava, cocoyam and yam.
A bed is made with the help of a wooden trapezoid mould frame with both ends opened. The dimensions are base 35 cm, top 30 cm, the height 35 cm and the length 91 cm or more. Dry bedding materials such as rice straw, maize stover, etc. are soaked overnight. Some materials such as cotton waste are soaked, shredded and used immediately. The wooden mould is placed on the ground (cemented floor or soil which has being initially treated against termites if there are any) with the base downwards. The soaked materials are put into the mould, up to one-third the height and compacted.
The mushroom spawn (with the chlamydospores formed) is dispersed into pieces by shaking the bottle. This is then sprinkled on top of the materials, along the periphery inside of the mould as the first layer. Two more layers are made in the same manner. With the top-most layer the entire surface is inoculated with the spawn. The wooden mould is then removed and used to make more beds spaced about 10-15 cm. In between the beds, a layer of composted sawdust of Triplochiton scleroxylon is placed. At least five beds are made in a row parallel to each other. The beds are then covered with transparent plastic sheets and woven mats placed on top of them to prevent the beds from drying up by sunlight or wind. The beds are left for one week, after which the polythene and woven mats which had been used to cover them are raised off the beds to a height of 15 cm. This is to allow for aeration, and also to allow enough space for the growing mushrooms.
Mushroom pinheads appear 3-5 days later on the beds as well as the ground, and button to egg-stage mushrooms are picked 48 hours later. The average yield per bed varies between 1.2 to 2 kilograms. With the low bed method of production of the oil palm mushroom, several kilograms of these mushrooms can be produced daily.
5.0 OPPORTUNITIES FOR ECONOMIC DEVELOPMENT
- Mushroom farming is a very profitable venture. With the introduced methods of production an all-year round availability of fresh mushroom is now possible.
- Locally available natural resources, agricultural wastes, forest by-products which hitherto were an environmental nuisance causing all forms of air pollution can now be converted into substrates for the production of nutritious and medicinal mushrooms, thus making good use of these leftovers.
- Through organised courses, over 3,000 unemployed youth, pensioners, housewives and people from all walks of life have been trained. Participants are not only from Ghana, but also from neighbouring countries such as Togo, Nigeria, Liberia and Cote d’Ivoire. To date, over 250 compost bag producing centres have been set up in the Greater Accra, Volta, Brong Ahafo, Eastern, Ashanti and western regions of Ghana, with current monthly total production capacity of between 45,000-50,000 bags. This has created jobs for the youth and pensioners etc. It also continues to provide extra income for farmers, during their off season.
- The daily diet of many Ghanaians have been enriched through increased consumption of medicinal and nutritious mushroom
- The health of many Ghanaians have been improved
- Two mushroom Associations have been formed namely: Mushroom Growers and Exporters Association of Ghana and Mushroom Cluster Groups. Both groups have branches nationwide
- Adding value to mushrooms such as mushroom powder, mushroom pepper sauce (locally known as shitↄ), mushroom drinks and canned mushroom is now on the increase
In conclusion, mushroom cultivation has come a long way from the natural low yield or inefficient seasonal gathering to the advanced stages of using pure spawn on more advance methods for a stable and all year round production of various mushrooms. The opportunities this has offered for the economic development in Ghana include the profitable use of wastes and consequent environmental protection, job opportunities and income generation for the average Ghanaian. Nutritional and medicinal benefits from its consumption will soon be a source of foreign exchange earning to the country as a whole.
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Dzomeku, Matilda (2009). Studies on occurrence, ethnomycology and cultivation of Pleurotus tuber-regium (Fr.) Sing. Kumasi, Ghana: Kwame Nkrumah University of Science and Technology, M.Phil. Thesis.
Obodai, M., Dzomeku, M., Awotwe, B., Takli, R.K. & Narh, D. (2007) Manual on mushroom cultivation technology in Ghana.
Obodai, M & Apertogbor, M. (2001). An ethnobotanical study of mushroom germplasm and its domestication in the Bia Biosphere Reserve. FRI-Man and the Biosphere (MAB) report.
Obodai, M. Sawyerr L.C. (1995). Effect of composting of mixed redwood sawdust on fruitboby yield of two Pleurotus eous varieties: Technical report.
Obodai, M. (1992). Comparative studies on the utilisation of agricultural waste by some mushrooms (Pleurotus and Volvariella spp.) M.Phil. thesis, University of Ghana.
Sawyerr, L.C. (1993). Sclerotium formation on sawdust compost by Pleurotus tuber- regium, a medicinal Ghanaian mushroom. Presented at the First International Conference on Mushroom Biology and Mushroom Products, Hong Kong.
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