Origin
Euphoria longana Lam., also known as longan, is a small tropical fruit-bearing tree native to Southern China. It belongs to the soapberry family Sapindaceae and is closely related to the lychee and rambutan trees.
Common Names
The longan tree is commonly known as "dragon eye" due to the fruit's white fleshy aril that surrounds a black seed, giving the appearance of an eye inside a dragon's scale. Other names for this plant include "guiyuan" in Chinese, "lam yai" in Thai, "mora" in Spanish, and "alupag" in Filipino.
Uses
The longan fruit is consumed both fresh and dried and is used in traditional Chinese medicine for its purported benefits in easing stress, improving sleep, and enhancing memory. The fruit is rich in vitamin C, potassium, and other antioxidants. In addition to its medicinal properties, the plant is also used for its timber and shade. The bark of the tree is used to make medicines and dyes. The flowers are also used in traditional Chinese medicine to help with insomnia, anxiety, and restlessness.
General Appearance
The longan tree is a slow-growing tropical evergreen that can reach a height of up to 12 meters. It has a symmetrical canopy that provides good shade. The tree produces small, white, fragrant flowers that grow in clusters. The fruit is rounded, about the size of a grape, and has a brown and rough skin. The sweet and juicy white flesh of the fruit is surrounded by a thin and translucent membrane. The seed inside the aril is black and shiny. The leaves of the tree are pinnate and have long leaflets with pointed tips.
Light Requirements
Euphoria longana Lam. thrives in full sun to partial shade. However, to induce proper fruiting, it is advisable to plant them in locations that receive (at least) six hours of direct sun every day.
Temperature Conditions
The plant can grow in a wide range of temperature conditions, from tropical to subtropical regions. However, it grows best in temperatures ranging from 20°C to 30°C. Temperatures below 10°C can cause severe damage to the plant and even death.
Soil Requirements
The ideal soil type for Euphoria longana Lam. is loamy soil, which should be well-draining, fertile, and slightly acidic with a pH range of 5.0 to 6.5. The plant is not picky about the type of soil and can also grow in sandy or clay soil. However, the soil must be nutrient-rich and have good water retention capacity. Too much water stagnation in the soil can lead to root damage and even death of the plant.
Cultivation Methods for Euphoria Longana Lam
For the cultivation of Euphoria longana Lam. or longan fruit, ensure that the plant is grown in tropical and subtropical regions where the temperature ranges between 20°C and 30°C (68°F to 86°F).
For the plant to thrive, it requires fertile, well-draining soil or a sandy loam soil with a pH that ranges from 5.0 to 6.5.
Longan plants establish long taproots that make them tolerant of drought. Therefore, when planting the tree, ensure not to overwater it.
Watering Needs for Euphoria Longana Lam
The longan tree is naturally resistant to drought, but for optimal growth, it requires regular watering. Watering should be done at least once a week, depending on the weather conditions. However, avoid overwatering, as this may lead to root rot.
Established longan trees require moderate watering twice a week.
Fertilization for Euphoria Longana Lam
Fertilization should be done during the first two years of a longan tree’s growth since they require a lot of nutrients. After that, once a year in the spring, apply a balanced fertilizer of NPK 10-10-10 or 15-15-15 to enhance growth and fruit production.
Additionally, incorporating organic matter such as compost into the soil improves fertility and soil structure.
Pruning Euphoria Longana Lam
When pruning the longan tree, begin by removing the dry, damaged, diseased or crossing branches.
Young longan trees require training, which is the initial pruning that involves cutting off branches to force the tree to grow the desired shape.
Longan trees are usually pruned after harvesting to improve sunlight penetration and air circulation.
Pruning should be done when the tree is dormant, which is during the winter season when the leaves drop.
Propagation of Euphoria longana Lam.
Euphoria longana Lam., commonly known as Longan, is propagated through several methods, including seeds, air-layering, grafting.
Propagation through Seeds
The most common method of propagating Euphoria longana Lam. is through seeds. The seeds are collected from mature fruit, cleaned, and sown in well-draining soil. The seedlings emerge after a few weeks, and once they have developed a few true leaves, they can be transplanted to a larger container or directly into the ground.
It is important to note that seed-grown Longan trees may take longer to produce fruits and may not produce fruits identical to their parent trees.
Propagation through Air-Layering
Air-layering is a method of propagating Euphoria longana Lam. that involves creating a small wound on a healthy, mature branch and then wrapping the area with moist sphagnum moss and plastic. New roots will grow from the wounded area, and once they are well-established, the branch can be cut from the parent tree and planted in its new location.
This method is ideal for those who want to propagate Longan from a mature tree with desirable fruit characteristics.
Propagation through Grafting
Grafting involves joining a cutting or scion from a desired Longan tree cultivar onto a rootstock from a different Longan tree. The scion will eventually grow into a new tree, which will produce fruits identical to the desired cultivar. This method is commonly used in commercial Longan production, as it allows for more control over the quality and quantity of fruit produced.
Overall, Euphoria longana Lam. can be propagated through a variety of methods, each with its own advantages and disadvantages. The appropriate propagation method will depend on the grower's goals and resources.
Disease and Pest Management for Euphoria Longana Lam.
Euphoria longana Lam., commonly known as longan, is a tropical fruit tree that is susceptible to several diseases and pests.
Common Diseases
Anthracnose is a common fungal disease that affects longan trees, causing black spots on the fruit's skin. Another fungal disease is powdery mildew, which appears as a white powdery growth on the leaves and fruit of the tree. Root rot is another disease that affects the roots of the longan tree and can cause stunted growth and yellowing of leaves.
Disease Management
To manage anthracnose and powdery mildew, it is important to prune the tree regularly to maintain good air circulation to reduce the humidity and prevent the spread of spores. Applying a fungicide can also help prevent fungal infections. Additionally, ensure that the soil is well-drained to prevent root rot.
Common Pests
Longan trees are also susceptible to several pests, including fruit flies, scale insects, and mealybugs. Fruit flies are attracted to the sweet smell of the fruit and lay eggs on the surface, which results in small larvae inside the fruit. Scale insects and mealybugs feed on the sap of the tree, causing wilting and yellowing of leaves.
Pest Management
To manage pests, it is essential to maintain good sanitation practices. Clear away fallen fruit from the tree and cut back any overgrown vegetation near the tree that could harbor pests. Applying insecticides can also help control pests, but be sure to follow label instructions and safety precautions.
In conclusion, disease and pest management are crucial for the healthy growth and yield of Euphoria longana Lam. Implementing proper management practices can help prevent and control diseases and pests, improving the tree's overall health and productivity.
