Origin
Digitaria insularis, also known as sourgrass or smooth fingergrass, is a species of grass native to tropical and subtropical regions of the Americas, specifically South America, Central America, and the Caribbean.
Common Names
Digitaria insularis is commonly known as sourgrass in English and capim-amargoso in Portuguese. It is also referred to by other local names depending on the region, including capim-de-leite, capim-papuã, and llerva loba.
Uses
Digitaria insularis has several uses in traditional medicine. It has been used in Brazil to treat kidney and bladder stones, liver diseases, and rheumatism. Additionally, it is used as an antidiarrheal, anti-inflammatory, and antipyretic.
The plant is also utilized in agriculture as a forage plant for livestock due to its high nutritional content. It is considered a weed in many areas where it grows, but it also has the ability to restore soil fertility and prevent erosion.
General Appearance
Digitaria insularis is a cool-season perennial grass that can grow up to 6 feet (2 meters) tall under optimal conditions. The plant has broad, linear leaves that can grow up to 5 inches (13 centimeters) long. The leaves are smooth, hairless, and have a bluish-green tint.
The inflorescence is composed of panicles that can emerge from the axils of the leaves and extend up to 2 feet (60 centimeters) long. The panicles are open, spreading, and have numerous small spikelets that contain the plant's seeds.
Digitaria insularis prefers warm and humid climates and thrives in moist or wet soil. It is a highly adaptable plant that can tolerate a wide range of environmental conditions, including drought and low temperatures.
Light Conditions
Digitaria insularis is a plant that prefers full sunlight to grow best. It can tolerate partial shade, but it might not grow as vigorously. Therefore, it is recommended to grow this plant outdoors in an open and well-lit area.
Temperature Requirements
This plant is native to tropical and subtropical regions of the Americas, where temperatures are warm throughout the year. Therefore, it prefers warm temperatures between 20°C to 35°C for optimal growth. Temperatures below 10°C can lead to slow growth or even death of the plant. Hence, it is suited for cultivation in warm and humid regions.
Soil Requirements
Digitaria insularis can grow in different types of soils, including sand, loam, and clay, but it grows best in well-draining rich soil. The ideal pH range for the plant is between 5.5 and 7.5. The plant is drought-tolerant, but it grows best in evenly moist soil.
Cultivation
Digitaria insularis (L.) Mez ex Ekman, commonly known as sourgrass, is a tropical grass that can grow up to 60cm in height. It is relatively easy to cultivate and can be planted in most soils.
The best time to plant Digitaria insularis is during spring or summer when the temperature is above 18°C. It can be grown from seeds or propagated through cuttings.
When planting, ensure that the soil is well-drained and loosened to facilitate root development. You can plant the seeds to a depth of between 5mm to 10mm. Water the seeds immediately after planting, and keep the soil moist until the seeds germinate, which may take between 7 to 21 days.
Watering Needs
Digitaria insularis requires regular watering to remain healthy and lush. It can withstand periods of drought but is sensitive to waterlogging.
During the summer or dry periods, water deeply and less frequently to encourage the roots to grow deeper. In periods of rainfall, reduce watering frequency to avoid waterlogging.
Avoid watering during the afternoon when the sun is at its peak to prevent the leaves from burning. Instead, water early in the morning or late in the afternoon when the temperature has cooled down.
Fertilization
Fertilization is not necessary for Digitaria insularis, but it can benefit from occasional feeding, especially when grown in poor soils.
You can use an all-purpose fertilizer once every four months to replenish the nutrients in the soil. Apply the fertilizer according to the recommended dosage and water the plant immediately after application to prevent root burn.
Avoid overfeeding the grass as it can cause rapid growth, which may make it more susceptible to pests and diseases.
Pruning
Digitaria insularis does not require frequent pruning, but you can trim it once every few months to maintain its shape and remove dead or damaged leaves.
When pruning, use sharp and clean tools to prevent damaging the plant. Cut the blades to a height of between 10cm to 15cm from the ground and ensure that the stems are not exposed as this may invite pest infestations.
You can dispose of the pruned leaves in a compost bin to make organic manure for your garden.
Propagation of Digitaria insularis (L.) Mez ex Ekman
Digitaria insularis can be propagated through seeds, vegetative means such as rhizomes, stolons or stem cuttings, and tissue culture.
Seed Propagation
Seeds of Digitaria insularis can be sown directly into the soil or started indoors first. The best time for sowing is in spring after the last frost. The seeds should be sown at a depth of 1 to 2 cm and spaced 30 to 60 cm apart. For indoor starting, seeds can be soaked overnight and then sown into pots or flats filled with seed starting mix. Once the seedlings have reached a height of 5 to 6 cm, they can be transplanted outdoors.
Vegetative Propagation
Digitaria insularis can also be propagated vegetatively. This method involves taking cuttings from the plant and rooting them in soil or water. Rhizomes and stolons can also be transplanted to establish new plants. This method is best done in the spring or early summer.
Tissue Culture
Tissue culture is a process by which small pieces of the plant are grown in a sterile medium under strict environmental conditions to produce new plants. This method is often used by researchers to produce large numbers of disease-free plants. It can also be used to produce plants with desired traits.
Disease and Pest Management for Digitaria insularis (L.) Mez ex Ekman
Digitaria insularis, commonly known as sourgrass or hairy crabgrass, is a troublesome weed that can cause significant damage to crops if not properly managed. Here are some common diseases and pests that may affect the plant and ways to manage them:
Diseases
Fungal Leaf Spots: These spots are caused by fungi and appear as small, dark lesions on the leaves of the plant. To manage fungal leaf spots, remove infected leaves immediately and spray the remaining plant with a fungicide.
Root Rot: Root rot is caused by waterlogging or poor drainage in the soil and can cause the plant's roots to decay. To prevent root rot, make sure to plant the digitaria insularis in well-draining soil and avoid overwatering.
Pests
Aphids: Aphids are small, soft-bodied insects that suck the sap from the stem and leaves, causing them to become distorted and yellow. To manage aphids, spray the plant with a strong blast of water or use an insecticidal soap.
Cutworms: Cutworms are the larvae of several species of moths and can cause significant damage to the plant's stems by cutting them off at the base. To manage cutworms, remove any weeds or debris around the base of the plant that may be providing a hiding place for the pests. You can also use Bacillus thuringiensis (Bt) as a biological control.
Spider Mites: Spider mites are tiny, spider-like insects that suck the sap from the leaves, causing them to appear speckled and eventually turn brown. To manage spider mites, spray the plant with a strong blast of water or use a miticide.
In conclusion, managing diseases and pests is an essential part of growing a healthy and productive Digitaria insularis. Proper precautions, such as proper drainage and planting in well-draining soil, timely removal of infected plant parts, and appropriate use of insecticides and biological controls, will help to ensure healthy growth and good crop yield.
