Plant Description
Dioscorea anthropophagorum A.Chev., also known as the "human-eating yam," is a species of yam native to West Africa. It is a perennial plant that grows up to 3 meters tall, with thin, twining stems that coil around surrounding vegetation. The leaves are heart-shaped and pale green, while the flowers are small and greenish-yellow.
Common Names
Aside from "human-eating yam," Dioscorea anthropophagorum is known by several local names in West Africa, including "amenikpofu" in Ghana, "oro" in Nigeria, and "atoei" in Togo.
Uses
Despite its ominous name, Dioscorea anthropophagorum is not actually known to have consumed any humans. In fact, it is a staple food crop in many West African communities. The tuberous roots of the plant are high in starch and are traditionally cooked, mashed, and eaten as a side dish. The plant is also used in traditional medicine to treat a variety of ailments, including stomach ulcers, diarrhea, and headaches.
General Appearance
When in leaf, Dioscorea anthropophagorum is an attractive plant with heart-shaped foliage and small greenish-yellow flowers. However, it is most notable for its long, coiling stems that can wrap tightly around adjacent foliage and can grow up to 3 meters in length. The tuberous roots of the plant are large and irregularly shaped, with a rough, brown exterior and creamy white flesh inside.
Light Requirements
Dioscorea anthropophagorum A.Chev. requires a lot of sunlight for optimal growth. It flourishes in areas where it can get at least six hours of direct sunlight each day. Therefore, it is essential to grow this plant in an area that experiences maximum sunlight exposure. If grown indoors, the plant should be placed near a well-lit window or under artificial grow lights that emit full-spectrum light.
Temperature Requirements
The plant grows well in tropical to subtropical conditions with temperatures ranging between 20 to 30°C (68 to 86°F). It can withstand temperatures as low as 15 °C (59°F) in winters and up to 40 °C (104°F) in summers. High humidity is preferred, and the plant needs a minimum relative humidity of 60%. The plant is sensitive to frost and cannot tolerate freezing temperatures.
Soil Requirements
The plant grows best in well-drained soil that is rich in organic matter. The soil pH should be neutral to slightly acidic, ranging from 6.0 to 7.0. The plant prefers loamy soil that is moderately moist but not waterlogged. It can tolerate a range of soil textures, including clay, sandy, and loamy soils. However, the optimum soil type is sandy loam with good drainage. The soil should be supplemented with regular applications of organic fertilizers to keep it rich and well-nourished.
Cultivation Methods
The Dioscorea anthropophagorum A.Chev., also known as the human-eating yam, is a plant that is native to West Africa. It is mostly cultivated as an ornamental plant, but it is also grown for its edible tubers.
The plant prefers a sunny location with well-drained soil. It requires warm temperatures and the soil should be kept moist, but not waterlogged. The plant has a climbing habit, so it needs support such as a trellis or poles to climb on.
The ideal time to plant Dioscorea anthropophagorum A.Chev. is during the rainy season, when the soil is moist. The plant is planted through mounds or ridges.
Watering Needs
Dioscorea anthropophagorum A.Chev. needs regular watering to keep the soil moist. However, the plant cannot tolerate waterlogging. Overwatering the plant can result in root rot, which can kill the plant. The plant should be watered at least twice a week during the growing season and reduced during the dormant period.
If the plant is grown in a pot, it requires more frequent watering, as the soil in the pot tends to dry out quickly. The soil should be kept moist but not waterlogged.
Fertilization
Dioscorea anthropophagorum A.Chev. requires regular fertilization to grow well. The plant can be fertilized using a balanced fertilizer once per month during the growing season. Fertilizer should be applied around the base of the plant and mixed with the soil. Fertilizer application should be reduced during the dormant period.
A mixture of organic matter, such as compost, is beneficial in providing the necessary nutrients required by the plant.
Pruning
The Dioscorea anthropophagorum A.Chev. plant requires regular pruning to prevent overgrowth. The pruning is done by trimming off the excess foliage and dead or damaged branches. Pruning helps to encourage new growth and maintains the plant's shape.
The pruning is usually done during the dormant period when the plant is not actively growing or during the early growing season before the plant starts flowering.
When pruning, it is essential to use clean pruning shears to reduce the risk of infection. The plant's wounds should be treated with a fungicide to prevent bacterial infections.
Propagation of Dioscorea anthropophagorum A.Chev.
The plant Dioscorea anthropophagorum A.Chev., also known as the cannibal yam, has several propagation methods:
Seed Propagation
The propagation of Dioscorea anthropophagorum A.Chev. through seeds is not commonly used, as the plant usually produces very few seeds that are difficult to germinate. However, if seeds are available, they should be sown in trays or pots with a well-draining soil mix. The seeds should be covered with a thin layer of soil and kept moist but not waterlogged. Germination may take several weeks to several months, and the plants should be kept at temperatures above 20°C (68°F).
Tuber Propagation
The most common propagation method for Dioscorea anthropophagorum A.Chev. is through the use of tubers. The tubers should be taken from healthy mature plants during the dormant season, usually from November to February. They should be stored in a cool and dry place until planting.
The tubers should be planted horizontally, about 20 cm (8 inches) deep, in well-draining soil with a pH between 5.5 to 7.0. The planting site should be in a location that receives partial shade to full sun. The spacing between plants should be at least 1 meter (3 feet) to allow enough space for the plant to spread and grow.
Plant Division
Another way to propagate Dioscorea anthropophagorum A.Chev. is through plant division. This method involves separating the plant into smaller sections, each with its tuber and roots. This process should be done during the dormant season, and care should be taken not to damage the tuber or roots during the separation process.
The separated sections should be planted as described in the tuber propagation section, with proper spacing and soil requirements.
Disease and Pest Management for Dioscorea anthropophagorum A.Chev.
Dioscorea anthropophagorum A.Chev., commonly known as the "Man-Eating Yam," is a plant that is primarily grown for its edible tubers. Like any other crop, it is susceptible to diseases and pests which can reduce its yield and eventually lead to crop failure. Proper disease and pest management strategies are therefore necessary to ensure a healthy and productive crop.
Common Diseases
The common diseases that affect Dioscorea anthropophagorum A.Chev. include:
- Yam Anthracnose: This fungal disease is caused by the pathogen Colletotrichum gloeosporioides and can result in the rotting of the yam tuber. Symptoms include brown to black circular lesions on the yam skin and the presence of black spores on the lesions.
- Rhizoctonia Root Rot: This disease is caused by the fungus Rhizoctonia solani and affects the roots and stems of the plant. Symptoms include stunted growth, yellowing of the leaves, and the presence of brown cankers on the stems.
- Xanthomonas Leaf Spot: This bacterial disease is caused by Xanthomonas campestris and can affect the leaves and stems of the plant. Symptoms include circular water-soaked spots on the leaves which later turn yellow and eventually brown, leading to defoliation.
Pest Management
The common pests that affect Dioscorea anthropophagorum A.Chev. include:
- Yam Beetle: This beetle (Heteroligus meles) feeds on the leaves of the plant, causing defoliation. A severe infestation can lead to reduced yield and stunted growth. Handpicking of the beetles is an effective management strategy.
- Yam Mite: This mite (Oligonychus gossypii) feeds on the leaves of the plant, causing yellowing and defoliation. Introducing natural predators such as ladybugs and lacewings can help control the population of yam mites.
- Yam Tubers Fly: This pest (Hylemya spp.) lays its eggs on the yam tubers, and its larvae feed on the flesh of the tuber, causing rotting and reduced yield. The use of insecticides or the use of mesh bags to cover the tubers can help prevent infestation.
To prevent and manage diseases, a combination of cultural, physical, and chemical control methods can be employed. These include crop rotation, avoiding waterlogged soil, removing infected plant parts, the use of fungicides or bactericides, and ensuring proper sanitation. It is important to identify the disease or pest correctly to ensure proper management.
Overall, proper disease and pest management is crucial in ensuring a healthy and productive crop of Dioscorea anthropophagorum A.Chev.
