General Information
Vigna parkeri Baker subsp. maranguensis (Taub.) Verdc., also known as the Marangu bean, is a type of plant belonging to the Leguminosae family. This plant is native to the African region particularly in Mount Kilimanjaro, Tanzania, Kenya, and Uganda. The plant is an annual herb that bears edible pods.
Description
The plant's stem stands erect and grows up to 30 centimeters in length, with a slender, sparsely pubescent, and cylindrical shape. The leaves are trifoliate, alternate, and measure 5-15 centimeters long. The leaflets are ovate with a pointed apex and slightly toothed margins. The flowers are borne in racemes measuring 5-12 centimeters, with a single purplish-blue flower measuring about 1 centimeter in length. The fruits are linear, slightly curved, and measure 5-10 centimeters long, with 8-12 seeds per pod.
Common Names
The plant is commonly referred to as Marangu bean, Marangu mung bean, and Marangu cowpea.
Uses
The Marangu bean is highly valued as a food crop due to its unique nutty flavor and high protein content. The beans can be cooked fresh or dried and stored for later use. In addition, the plant is commonly used as a cover crop to improve soil fertility through nitrogen fixation. Traditional medicine practitioners also use the plant to manage various ailments such as diarrhea, dysentery, and diabetes.
Growth Conditions for Vigna parkeri Baker subsp. maranguensis (Taub.) Verdc.
Light requirements: Vigna parkeri Baker subsp. maranguensis typically grows well in areas with partial or full sun exposure. The plant requires adequate sunlight for photosynthesis, which is necessary for growth and development. Too much shade can stunt growth, decrease flowering, and reduce yield.
Temperature requirements: The plant grows best in warm temperatures ranging from 25°C to 32°C. It is sensitive to frost and cannot tolerate low temperatures. The optimum temperature range for Vigna parkeri Baker subsp. maranguensis is between 28°C to 30°C. Temperatures lower than 15°C can cause stunted growth, leaf yellowing, and death of the plant.
Soil requirements: The plant thrives in well-drained, sandy or loamy soils with a pH range of 6.0 to 7.0. The soil should be rich in organic matter and have good water retention capacity. The root system of Vigna parkeri Baker subsp. maranguensis is shallow, and the plant cannot handle waterlogged or compacted soils. It is also essential to maintain adequate soil moisture levels for optimal growth and yield.
By adequately providing light, temperature, and soil requirements, Vigna parkeri Baker subsp. maranguensis can grow vigorously and produce a bountiful harvest.
Cultivation of Vigna parkeri Baker subsp. maranguensis
Vigna parkeri Baker subsp. maranguensis is a plant that can be grown in a variety of environments, including both outdoor gardens and indoor containers. This plant thrives in soil that is well-drained and fertile, and it prefers a neutral pH level.
Watering Needs for Vigna parkeri Baker subsp. maranguensis
Vigna parkeri Baker subsp. maranguensis requires frequent watering to develop healthy roots and foliage. Water the soil regularly, making sure to keep the soil evenly moist. Use a watering can or hose to deliver water directly to the soil, avoiding the foliage as much as possible. Be sure not to overwater, as this can lead to root rot.
Fertilization of Vigna parkeri Baker subsp. maranguensis
Vigna parkeri Baker subsp. maranguensis requires regular fertilization to promote healthy growth. Use a balanced, water-soluble fertilizer that is high in nitrogen, phosphorus, and potassium. Apply the fertilizer every two weeks during the growing season, following the instructions on the product packaging. Be cautious not to over-fertilize, as this can damage the plant.
Pruning of Vigna parkeri Baker subsp. maranguensis
Pruning is a valuable technique for maintaining the shape and health of Vigna parkeri Baker subsp. maranguensis. During the growing season, remove any dead or damaged leaves, stems, or flowers as soon as possible. Trim back leggy or overgrown stems to encourage bushy, healthy growth. Prune once a year in the early spring to remove any dead or diseased branches and to shape the plant for optimal growth.
Propagation of Vigna parkeri Baker subsp. maranguensis (Taub.) Verdc.
Vigna parkeri Baker subsp. maranguensis (Taub.) Verdc. can be propagated through various methods. The plant can be propagated through seeds, cuttings, and division.
Seed propagation
Seed propagation is the most common method used for Vigna parkeri Baker subsp. maranguensis (Taub.) Verdc. To propagate the plant using seeds, collect the ripe pods from the parent plant and allow them to dry. Break open the dry pods and collect the seeds. Soak the seeds in water for at least 12 hours to soften the coat before planting them in a well-drained potting mix. Keep the soil moist, and the seeds will germinate in around two weeks.
Cutting propagation
Cuttings can also be used to propagate Vigna parkeri Baker subsp. maranguensis (Taub.) Verdc. To propagate the plant using cuttings, take a 3-4 inches semi-hardwood cutting from the parent plant, removing all the leaves except the top two. Dip the cut end in rooting hormone and plant it in a well-draining potting mix. Place the cutting under a shade for at least a week to allow it to establish before transferring it to a sunny spot.
Division propagation
Division is another method of propagating Vigna parkeri Baker subsp. maranguensis (Taub.) Verdc. In this method, the parent plant is dug out of the ground, and the rhizomes are separated carefully. Replant the rhizomes in a new pot or location, and ensure to keep the soil moist until new growth appears.
Disease Management
Vigna parkeri Baker subsp. maranguensis (Taub.) Verdc. is susceptible to several plant diseases, including:
- Anthracnose: This disease is caused by the fungus Colletotrichum lindemuthianum and affects various parts of the plant, including leaves, stems, pods, and seeds. Symptoms include circular or irregular-shaped lesions on the leaves, stems, and pods, which can spread quickly and cause defoliation and pod rot. To manage Anthracnose, practice crop rotation, plant resistant varieties, apply fungicides, and remove infected plant debris.
- Bacterial blight: Caused by the bacterium Xanthomonas axonopodis pv. vignicola, this disease affects leaves and stems and is characterized by translucent or water-soaked spots on the leaves, which later turn brown and necrotic. The affected plants may also show stunted growth and wilting. To manage bacterial blight, use disease-free seed, practice crop rotation, avoid overhead irrigation, prune infected leaves and stems, and apply copper-based fungicides.
- Fusarium wilt: This fungal disease is caused by Fusarium oxysporum and affects the vascular system of the plant, causing wilting and yellowing of the leaves and stunted growth. Infected plants may also show vascular discoloration and, in severe cases, death. To manage Fusarium wilt, use disease-free seed, practice crop rotation, and apply fungicides containing thiophanate-methyl or azoxystrobin.
- Mosaic virus: The mosaic virus is caused by various viruses and is characterized by mottled or streaky discoloration and deformation of the leaves. Infected plants may also show stunted growth, reduced yield, and poor quality of the seeds. To manage mosaic virus, use disease-free seed, eliminate weeds and other host plants, avoid mechanical transmission, and remove and destroy infected plants.
Pest Management
Vigna parkeri Baker subsp. maranguensis (Taub.) Verdc. is also vulnerable to several insect pests, including:
- Aphids: Aphids are small, soft-bodied insects that suck sap from the leaves and stems of the plant, causing stunted growth, wilting, and leaf curling. To manage aphids, encourage natural predators like ladybugs, lacewings, and parasitic wasps, use insecticidal soap or neem oil, and practice crop rotation.
- Bean Seed Beetle: This pest damages the seeds of the plant and reduces seed quality. The adult beetle feeds on the seed coat, while the larvae feed on the endosperm. To manage bean seed beetle, use disease-free seed, store seed properly, and apply insecticides containing spinosad or carbaryl.
- Leafminer: Leafminers are larvae of flies that burrow through the leaves, causing tunnels and blisters. This damage weakens the plant and makes it more susceptible to disease. To manage leafminers, practice crop rotation, remove and destroy infested leaves, and apply insecticides containing spinosad or pyrethrin.
- Spider Mites: Spider mites are tiny arachnids that feed on the plant sap and cause stippling and yellowing of the leaves. Severe infestations can cause leaf drop and poor plant growth. To manage spider mites, increase humidity levels, remove and destroy infested leaves, and apply insecticides containing neem oil or insecticidal soap.
