Overview
Crotalaria incana L. subsp. incana, also known as gray rattlebox, is a member of the legume family Fabaceae. This plant is native to tropical and sub-tropical regions of Africa, but it has also been introduced to other areas around the world as an ornamental plant.
Common Names
Along with gray rattlebox, Crotalaria incana is also commonly referred to as silverleaf rattlepod or hairy crotalaria. These common names are attributed to the plant's appearance and sound made when the seeds rattle within its pods.
Appearance
Gray rattlebox is an annual or perennial herb that can grow up to 1 meter tall. It has an upright growth habit with branches that are covered in short gray hairs. The leaves are alternate and ovate in shape, with a grey-green color on the upper side and a lighter shade on the underside. The flowers are yellow and grow in clusters. The fruit of the plant is a long narrow pod that contains small black seeds.
Uses
Crotalaria incana has been used for various purposes in traditional medicine. The plant contains alkaloids that are known to have insecticidal and anthelmintic properties. It has been used to treat various ailments such as fever, malaria, rabies, and snake bites. However, the plant is also known to be poisonous to livestock such as cattle and sheep. Due to its toxicity, it is not recommended for use in modern medicine.
Gray rattlebox is also used as a cover crop due to its ability to fix nitrogen in the soil. It is commonly used as a green manure crop in agriculture to increase soil fertility and improve crop yields.
Light requirements
Crotalaria incana L. subsp. incana grows best in full sun but can also tolerate partial shade. It requires at least 6 hours of sunlight per day to thrive.
Temperature requirements
This plant species prefers warm temperatures ranging between 20°C to 35°C (68°F to 95°F) during the day and nighttime temperatures not lower than 15°C (59°F). It is sensitive to frost and cannot withstand temperatures below 10°C (50°F).
Soil requirements
Crotalaria incana L. subsp. incana prefers well-drained, light, and sandy soils. It can also grow in soils with low to moderate fertility but is intolerant of waterlogged or poorly drained soils. The ideal soil pH range for this plant is between 5.5 to 7.5.
It is important to note that the plant is also well adapted to grow in a wide variety of soil types, including acidic, neutral, and alkaline soils, as well as in soils that are rich in organic matter. However, it is essential to ensure that the soil is not too heavy or compact as it can lead to root rot and other soil-borne diseases.
Cultivation Methods for Crotalaria Incana L. Subsp. Incana
Crotalaria incana L. subsp. incana is a hardy plant that can grow in a wide range of conditions. It is commonly grown from seed, which should be planted in soil that is well-draining and nutrient-rich. The seeds should be planted at a depth of 1 to 2 centimeters and spaced at least 10 centimeters apart. The best time to plant is in the warmer months when the soil has warmed up, and the risk of frost has passed.
Watering Needs for Crotalaria Incana L. Subsp. Incana
Crotalaria incana L. subsp. incana needs to be watered regularly but should not be overwatered. The frequency of watering will depend on the climate, soil type, and stage of growth. In general, the plant should be watered deeply once a week during periods of low rainfall. If possible, watering should be done in the morning to allow the foliage to dry out during the day and prevent the growth of fungal diseases.
Fertilization for Crotalaria Incana L. Subsp. Incana
Crotalaria incana L. subsp. incana does not require heavy fertilization and prefers a slightly acidic soil pH of 5.5 to 6.5. A balanced fertilizer should be applied once a month during the growing season. When applying fertilizer, care should be taken not to apply too much, as this can cause excessive foliage growth at the expense of flowering.
Pruning for Crotalaria Incana L. Subsp. Incana
Crotalaria incana L. subsp. incana does not require pruning, but it can be beneficial to remove spent blooms as this can encourage the plant to produce more flowers. If the plant becomes too leggy or overgrown, it can be pruned back in early spring before new growth begins. Care should be taken not to prune too heavily, as this can reduce the overall size and flowering of the plant in the following season.
Propagation of Crotalaria incana L. subsp. incana
Crotalaria incana L. subsp. incana can be propagated either by seeds or by vegetative methods such as stem cuttings and layering.
Propagation by Seeds
Seeds of Crotalaria incana L. subsp. incana can be sown directly into the prepared soil or in a seed tray. The optimum time period for sowing the seeds is in spring or summer when the temperature is warm and the soil is moist. The seeds can be sown at a depth of 1-2 cm in well-drained, loamy soil. Germination usually occurs within 10-15 days under suitable conditions.
Propagation by Stem Cuttings
Crotalaria incana L. subsp. incana can be propagated by stem cuttings taken from healthy and mature plants during their growing season. The cuttings should be about 10-15 cm long and should contain at least two nodes or leaves. The lower leaves should be removed and the cuttings should be dipped in rooting hormone powder before planting them in a well-drained, sterile potting mix. The soil should be kept moist, and the cuttings should be placed in a shaded area to prevent water loss through transpiration. Roots will start forming in 2-4 weeks.
Propagation by Layering
Layering is another vegetative method of propagating Crotalaria incana L. subsp. incana. In this method, a low-lying branch of the parent plant is bent downwards and covered with soil, leaving the top portion of the branch exposed. The portion that is buried underground will eventually develop roots. Once the roots have formed, the new plant can be detached from the parent plant and transplanted elsewhere. This method is advantageous since the new plant will have the exact genetic makeup of the parent plant.
Disease Management
Crotalaria incana L. subsp. incana can be susceptible to a range of fungal and bacterial diseases, which can cause leaf spots, stem cankers, root rots, and wilting. Good cultural practices such as sanitation, proper irrigation, and adequate spacing can help prevent disease. Fungicides and bactericides can be applied as a preventative measure, but should be used sparingly and carefully to avoid environmental damage.
Common Diseases
One common disease that can affect Crotalaria incana L. subsp. incana is anthracnose, which is caused by the fungus Colletotrichum gloeosporioides. Symptoms include sunken lesions on leaves and stems, as well as yellowing and defoliation. Another disease to watch out for is Fusarium wilt, which is caused by the soilborne fungus Fusarium oxysporum. This disease can cause yellowing, wilting, and death of the plant.
Pest Management
Crotalaria incana L. subsp. incana can also be susceptible to a variety of insect pests, including aphids, spider mites, and whiteflies. These pests can cause damage to leaves, flowers, and seed pods, as well as transmit viruses. Integrated pest management (IPM) strategies should be used to manage these pests, including cultural controls such as pruning and removal of infested plant parts, biological controls such as the use of natural enemies, and carefully selected insecticides as a last resort.
Common Pests
One common pest that can affect Crotalaria incana L. subsp. incana is the root-knot nematode, Meloidogyne incognita. This pest can cause stunted growth, yellowing, and wilting. Another pest to watch out for is the soybean looper, a type of caterpillar that can cause defoliation and damage to seed pods.
