Overview:
Manihot tristis Muell. Arg. is a species of flowering plant that belongs to the Euphorbiaceae family. It is an evergreen shrub that is primarily found in tropical regions such as Central and South America.
Common names:
The common names of Manihot tristis Muell. Arg. include 'Bitter Manioc', 'Wild Manioc', and 'Wild Cassava'.
Appearance:
The plant grows up to a height of 3m and has a sprawling habit. It has a woody stem, more like a trunk, that branches off from the base, and may be dark grey, dark brown, or black in color. Its leaves are dark green, shiny, and deeply lobed, similar to the shape of a hand. It blooms small greenish-yellow flowers that are clustered in short spikes, and has roundish, smooth fruits that are about 1cm in diameter.
Uses:
The roots of Manihot tristis Muell. Arg. are utilized for preparing a poison that is used for fishing. The plant also contains a toxic substance that has been used to make arrow poisons by indigenous people. However, the toxic substances present in the plant may be dangerous and therefore should not be consumed. In addition to that, the plant has high ornamental value and can be grown in gardens and landscapes.
Light Requirements
Manihot tristis Muell. Arg. prefers full sunlight for its healthy growth. It cannot tolerate low light conditions and requires at least 6 hours of direct sunlight each day.
Temperature Requirements
The plant thrives in warm temperatures between 20 to 32 degrees Celsius. It cannot survive in harsh winter conditions and frost. A tropical climate with high humidity is favorable for its growth.
Soil Requirements
Manihot tristis Muell. Arg. requires well-draining, deep, fertile soil with a pH range of 5.5-6.5. The soil must be rich in organic matter and provide an adequate supply of nutrients for the plant's growth. It can also grow in sandy or clay soils but requires regular watering and fertilization to maintain its growth.
Cultivation of Manihot tristis Muell. Arg.
Manihot tristis Muell. Arg. is a hardy plant that grows well in warm tropical climates. As such, it is important to plant it in an area that receives full sun exposure. The plant prefers well-draining soil that is rich in organic matter, with a pH of 5.5 to 6.5. It is important to clear any weeds or debris from the planting area, as the plant is susceptible to competition from other plants.
Watering Needs of Manihot tristis Muell. Arg.
Manihot tristis Muell. Arg. requires regular watering to thrive. The plant should be watered thoroughly, but not excessively. Overwatering can lead to root rot and other fungal diseases. The best way to determine when to water the plant is to check the soil moisture by digging a small hole near the plant's roots. If the soil is dry, it is time to water the plant.
Fertilization of Manihot tristis Muell. Arg.
To ensure the proper growth and development of Manihot tristis Muell. Arg., it is important to fertilize it regularly. A balanced fertilizer that contains equal amounts of nitrogen, phosphorus, and potassium is recommended. The fertilizer should be applied every three to four months during the growing season.
Pruning Manihot tristis Muell. Arg.
Pruning is not necessary for Manihot tristis Muell. Arg., as it tends to grow in a bushy, self-supporting shape. However, if pruning is desired, it is best to do it during the dormant period, which is typically in the winter. Only prune away dead, diseased, or damaged branches, being careful not to prune away too much of the plant to avoid stunting its growth.
Propagation methods
The plant Manihot tristis Muell. Arg., also known as the sad cassava, can be propagated through different methods:
Seeds
Seeds can be obtained from the plant's fruits. The seeds must be sown freshly and not allowed to dry out. They can be planted directly into a well-draining soil mix and kept moist. Germination usually occurs within 2-4 weeks.
Cuttings
The sad cassava can be propagated through stem cuttings. Cuttings must be taken from young stems or shoots in the active growing season. The cuttings should be made just below a node with at least two leaves on the stem. They should be dipped in rooting hormone, planted in a well-draining potting mix, and kept moist. Within 3-4 weeks, roots should start to appear, and new growth should emerge within 4-6 weeks.
Air-layering
Air-layering can also be done to propagate Manihot tristis Muell. Arg. This involves wounding the stem and wrapping it with moist sphagnum moss and plastic wrap. Once roots have formed within the moss, the stem can be cut off and planted in a well-draining soil mix.
It is important to note that the sad cassava can be toxic if not properly prepared. The plant must be cooked thoroughly before consumption to remove cyanide compounds.
Disease and Pest Management for Manihot tristis Muell. Arg.
Manihot tristis Muell. Arg. is susceptible to various diseases and pests that can greatly affect its growth, yield, and overall health. Awareness of these common problems is essential in managing them properly and preventing their recurrence. Here are some of the most common diseases and pests that might affect the plant, along with suggested ways to manage them effectively:
Common Diseases
Cassava Mosaic Virus (CMV) - This is a plant virus that causes stunted growth, yellowing of leaves, and reduced yield of the plant. The virus is transmitted by whiteflies and can spread rapidly within the cassava field. To manage this, plant virus-free cuttings, weed regularly, and remove infected plants immediately. Use insecticides to control whiteflies if necessary.
Anthracnose - This is a fungal disease that affects the leaves, stems, and roots of the plant. It causes yellowing, wilting, and premature dropping of leaves. To manage this, prune the affected parts, provide good drainage and air circulation, avoid overhead watering, and apply fungicides as necessary.
Bacterial Blight - This is a bacterial disease that causes water-soaked lesions on leaves, stems, and roots of the plant. It can lead to severe rotting and death of the plant if left untreated. To manage this, remove and destroy infected plants, avoid overhead watering, and apply copper-based bactericides as necessary.
Common Pests
Cassava Green Mite - This is a small pest that causes yellowing and mottling of leaves, leading to premature dropping. It can also stunt the growth and reduce yield of the plant. To manage this, use natural predators such as ladybugs, remove and destroy infected plants, and apply acaricides as necessary.
Cassava Mealybug - This is a small insect that sucks the sap of the plant, causing yellowing and wilting of leaves. It can also promote the growth of black sooty mold on the leaves. To manage this, use natural predators such as wasps, remove and destroy infected plants, and apply insecticides as necessary.
Termites - This is a group of insects that feed on the roots and stems of the plant, causing wilting and death. They can also create tunneling on the stem, weakening the plant's support. To manage this, use natural predators such as birds, apply termite-resistant mulches, remove and destroy infected plants, and apply insecticides as necessary.
Overall, the key to effective disease and pest management in Manihot tristis Muell. Arg. is early detection, prompt action, and preventive measures. By following the suggested management strategies, growers can keep their plants healthy, vigorous, and productive.
