Description of Manihot esculenta Crantz
Manihot esculenta Crantz is a tropical plant that belongs to the Euphorbiaceae family. It is commonly known as cassava and is native to South America. Cassava became an essential food crop in Africa after its introduction and is now grown in other parts of the world, including Asia, the Caribbean, and Central America.
Common names of Manihot esculenta Crantz
Cassava is known by several names across different regions of the world. In Africa, it is referred to as yucca, manioc, or tapioca. In some parts of Asia, the plant is called kamoteng kahoy or balinghoy, and in Central and South America, it is known as mandioca or yuca.
Uses of Manihot esculenta Crantz
Cassava is primarily cultivated for its starchy roots, which are a significant source of carbohydrates. The roots can be cooked, fried, boiled, or roasted and are a staple food in many regions of the world. Besides its use as a food crop, cassava is also used in the production of several commercial products such as animal feed, biofuels, and starch. The leaves of the cassava plant can also be consumed as a vegetable and are rich in protein and vitamins.
General Appearance of Manihot esculenta Crantz
The cassava plant can grow up to 2-4 meters tall, with deep green, palmate leaves that are typically five to seven lobed. The leaves have a rough, textured surface and can be up to 30 centimeters long. The plant produces long, tuberous roots that can be up to 1 meter in length and weigh up to several kilograms. The roots have a tough, brown exterior and a white, starchy interior.
Light Requirements
Manihot esculenta Crantz, commonly known as cassava, requires full sun exposure to grow well. The plant needs a minimum of six hours of direct sunlight to thrive. Lack of adequate sunlight can lead to stunted growth, poor yields, and increased susceptibility to diseases and pests.
Temperature Requirements
Manihot esculenta Crantz grows best in areas with a tropical climate. The ideal temperature range for cassava cultivation is between 25°C to 35°C. The plant cannot tolerate frost or temperatures below 16°C, which can cause significant damage to the foliage and root system.
Soil Requirements
The plant prefers well-draining soils with a pH range of 5.5 to 7.0. Heavy clay soils with poor drainage can lead to root rot and stunted growth. Cassava grows well in sandy or loamy soils that are rich in organic matter and nutrients. Soil fertility is essential for the optimal growth and development of Manihot esculenta Crantz.
Cultivation Methods
The most common method of cultivating Manihot esculenta Crantz is through stem cuttings. Cuttings of around 20-25 cm are planted into well-prepared soil, which should be free of weeds and pests. The ideal time to plant cuttings is during the rainy season, as the soil moisture aids in the plants' growth and establishment. It is essential to plant the cuttings at a depth of 7-10 cm into the soil. The soil should also be kept moist during the initial stages of rooting, which takes around 2-3 weeks.
Watering Needs
Manihot esculenta Crantz requires a consistent source of water to thrive. Watering requirements vary depending on the soil type, temperature, and humidity. During the vegetative growth stage, it is recommended to water the plants once weekly, and as the roots mature, the frequency can be reduced to fortnightly. During the dry season or periods of water scarcity, it is essential to irrigate the plants frequently.
Fertilization
Proper nutrition is essential for crops' growth, and Manihot esculenta Crantz is no exception. Applying organic fertilizers such as animal and plant manure promote crop growth and health. The ideal time to apply fertilizer is during land preparation and before planting. Nitrogen application is crucial during the vegetative stage. Calcium phosphorus and potassium fertilizers are essential during the root development phase. Fertilizer application should be reduced during the flowering and fruiting stages.
Pruning
Pruning is essential to maintain the plant's shape and stimulate growth. The ideal time for pruning is after harvesting the tubers. It is essential to remove all diseased, damaged, and broken stems and leaves from the plant to reduce disease spread. Pruning also controls the height and promotes bushy growth. Manihot esculenta Crantz is susceptible to pests and diseases, and pruning and regular crop rotation reduce these problems.
Propagation of Manihot esculenta Crantz
Manihot esculenta Crantz, commonly known as cassava, is propagated using stem cuttings. This plant is typically propagated asexually and has no known sexual reproduction process.
Preparing Cassava Stem Cuttings
To propagate cassava, select mature stems from the plant with a diameter of at least 2cm. Cut the stem into sections that are 15 to 20cm long.
Make sure each section has at least three to four nodes and leaves. Remove all the lower leaves of the stem except for the top three to four leaves.
Planting Cassava Stem Cuttings
To plant the cassava stem cuttings, prepare the soil area by adding compost or manure to enrich it. Dig planting holes with a depth of about 20cm and a width of 10cm.
Insert the stem cuttings into the planting hole upright, spacing them 1 to 1.2 meters apart. Cover the stem cuttings with soil up to the level of the upper leaves, press the soil lightly, and water.
Cassava Propagation through Mini-cuttings
Cassava can also be propagated through mini-cuttings. The process involves using small lengths of stem cuttings that are 10-15cm long with two or three buds.
The mini-cuttings are planted into the nursery in a medium containing soil, compost, and sand. They require optimum levels of warmth and humidity to sprout.
After four weeks, the mini-cuttings will have sprouted enough roots and are transplanted to the field or garden.
Propagation through stem cuttings and mini-cuttings is an efficient way of increasing cassava production and ensuring healthy harvests.
Disease and Pest Management for Manihot esculenta Crantz Plant
Manihot esculenta Crantz, commonly known as cassava, is a staple food crop especially in the tropics. However, the plant is vulnerable to various diseases and pests that can cause significant losses to the growers. Disease and pest management are essential to ensure optimal yields from cassava crops.
Common Diseases
Cassava is susceptible to various diseases, including:
- Cassava Mosaic Disease (CMD): This is the most prevalent and devastating disease in cassava. It is caused by a virus transmitted by whiteflies. Infected plants usually show stunted growth, distorted leaves, and reduced yield. CMD can be managed through the use of CMD-resistant varieties, crop rotation, and proper sanitation practices.
- Cassava Bacterial Blight (CBB): CBB is caused by bacteria that affect the leaves, stems, and roots of the cassava plant. The symptoms include wilting, yellowing, and premature leaf fall leading to reduced yields. Control measures for CBB include field sanitation, planting of resistant varieties, and copper-based fungicides.
- Cassava Anthracnose Disease (CAD): This fungal disease affects the leaves, stems, and roots of the plant. The symptoms include circular black spots on leaves that spread, leading to the death of the plant. The disease can be controlled through field sanitation, planting of resistant varieties, and approved fungicides.
Common Pests
Cassava is also vulnerable to various pests that can cause significant damage to the crops. These include:
- Cassava Green Mite (CGM): CGMs feed on the leaves of the cassava plant resulting in yellowing and wilting. The pests can be managed through the use of pesticides, natural predators like lacewing, and proper field hygiene.
- Mealybugs: Mealybugs are another pest that attacks cassava by piercing and sucking the sap from the plant. They cause reduced growth rate and yellowing of the leaves. Electrical conductivity spraying, use of approved pesticides, and proper pruning are effective control measures against mealybugs.
- Cassava Whitefly: The whitefly is the vector of cassava mosaic disease. Controlling the whitefly population is crucial in CMD management. Recommended control options include cultural control, use of yellow sticky traps, and the application of systemic insecticides.
Management Strategies
Adopting environmentally friendly and sustainable management strategies is crucial in maintaining cassava productivity while minimizing damage to the ecosystem. Some of the recommended management practices include:
- Using healthy planting materials to avoid the introduction of diseases and pests.
- Regularly monitoring cassava fields for diseases and pests and taking immediate control measures upon detection.
- Rotating cassava crops with non-host plants to manage pest and disease build-up in the soil.
- Practicing good field hygiene, such as removing and destroying infected plant residues.
- Planting cassava varieties that are resistant to pests and diseases where possible.
- Limiting the use of synthetic chemicals by adopting cultural, biological control and organic options.
Timely and appropriate disease and pest management are crucial in maintaining optimal cassava yields. Proper field hygiene, use of resistant varieties, chemical-free pesticidal options, and implementation of sustainable management practices are crucial in this regard.
