Bergamot

Description

Bergamot, Citrus bergamia, is an evergreen tree grown for its fruit, flowers and leaves, which are used primarily for the extraction of its lemon scented oil. Bergamot is an erect, branching tree with oval leaves that are alternately arranged. The tree produces clusters of white flowers and a fruit that resembles a pear-shaped orange. The fruit is green and turns yellow when ripe. Bergamot trees can reach up to 4 m (13.1 ft) in height and will remain productive for up to 60 years if managed well. Bergamot may also be referred to as bergamot orange or sour orange, and its origin is unknown, although it is almost exclusively grown in the coastal plains of southern Italy.

Crop Details

Scientific Name: Citrus bergamia

Other Common Names: Bergamotto (Italian), bergamote (French), bergamotte (German), bergamot (Turkish), бергамот (bergamot) (Russian)




Uses & Benefits

 

Bergamot’s essential oil is known for its ability to effectively combat stress, anxiety, depression, improve digestion, relieve pain and heal wounds. 

On the skincare front, the oil's antibacterial and anti-inflammatory attributes make it a valuable asset against conditions like acne, eczema, and psoriasis. 

Bergamot's distinctive citrus flavor is a staple in Earl Grey tea and culinary applications.

The oil produced by the flowers, leaves and rind of the fruit is used in eau de toilette, cologne and soap. The bitter fruit is used to make marmalade and to flavor liqueurs.




Varities of Bergamot

Bergamot, when referred to in the context of plants, often relates to two main types: Monarda didyma (Bee Balm) and Citrus bergamia (Bergamot Orange). Here are common varieties of both:

Monarda didyma (Bee Balm)

Jacob Cline: This variety features bright red, tubular flowers and stands out for its excellent mildew resistance. It's a favorite among gardeners and attracts pollinators like bees and hummingbirds.

Prairie Night: Known for its deep purple or nearly black flowers, Prairie Night is a striking addition to any garden. It also has a strong, pleasant aroma.

Raspberry Wine: With its vibrant, raspberry-colored blooms, this cultivar adds a burst of color to gardens. Its scent is reminiscent of raspberries, and it attracts pollinators.

Balmy™ Series: This series includes various colors like pink, purple, and lavender. The compact size of these plants makes them ideal for small gardens or containers.

Citrus bergamia (Bergamot Orange)

Castagnaro: A popular Italian variety, 'Castagnaro' is known for its high-quality fruit and aromatic peel. It's primarily used in the production of Bergamot essential oil.

Calabrese: Grown in the Calabria region of Italy, this variety is highly prized for its fragrant and flavorful fruit, making it a key ingredient in Earl Grey tea.

Meyer Lemon Bergamot: This hybrid variety combines the traits of the Meyer lemon and bergamot. It offers sweeter and less acidic fruit with the signature bergamot aroma.

Djerba Bergamot: Grown on the Tunisian island of Djerba, this bergamot variety is known for its sweet and aromatic peel, which is used in perfumery and culinary applications.




Propagation

 

Basic requirements

Bergamot oranges grow best in regions with a pronounced change in season. They will grow best at temperatures between 12.8 and 37.8°C (55–100°F) during the growing season and 1.7 to 10°C (35–50°F) during dormancy. Mature trees can survive short periods of freezing, whereas young trees will be killed. Trees should be protected from frosts and freezing conditions to prevent damage. 

The trees will also tolerate drought conditions but perform poorly in water-logged soil. Trees will grow best when planted in a well-draining sandy loam with a pH between 6.0 and 7.5. The soil must be deep enough to permit adequate root development. Trees require full sun and should be protected from wind, which can cause damage to the trees.

Propagation

Bergamot seedlings are usually produced by grafting or budding to an appropriate rootstock, as seeds will not produce fruit true to type. Grafting is the process by which a scion from one plant is joined to the rootstock of another to produce a new tree. Budding is a special type of grafting where the scion that is joined to the rootstock consists of a single bud. Budding is commonly used in citrus propagation as it is the easier of the two processes and works very well.

Budding

Budding should be carried out when seedling stems have reached roughly the diameter of a pencil (6–9 mm/0.25–0.36 in) and at a time when the bark of the rootstock tree is slipping (this is the term used to describe a period of active growth when the bark can be easily peeled from the plant). 

Twigs (budwood) should be collected from the previous growth flush or the current flush so long as the twig has begun to harden. The twigs should have well developed buds and should be as close as possible to the diameter of the rootstock onto which they will be joined. It is extremely important to only collect budwood from disease-free trees. The use of diseased budwood can cause the spread of many serious citrus diseases, which can kill trees. 

The budwood to be used for propagation should be trimmed to create budsticks that are 20–25 cm (8–10 in) by removing any unwanted wood and leaves. These budsticks can be stored for 2–3 months under the correct conditions but it is best to use them as soon as possible after cutting. The simplest way to join the budwood to the rootstock is by T-budding. The area to be joined should be pruned to remove any thorns or twigs and the cut should be approximately 15 cm (6 in) from the ground. Using a sharp knife, a 2.5–3.8 cm (1–1.5 in) vertical cut should be made in the stem of the rootstock, through the bark. 

A horizontal cut should be made at either the top or the bottom of the vertical cut to produce a “T-shape” The horizontal cut should be made at a slightly upward-pointing angle and should reach through the bark. Remove a bud from a budstick by slicing a thin, shield-shaped piece of bark and wood from the stem, beginning about 1.25 cm (0.5 in) above the bud. This piece should measure 1.9–2.5 cm (0.75–1.0 in) in length. Immediately insert the piece of bud into the cut on the rootstock by sliding it under the opened bark so that the cut surface lies flat against the wood of the rootstock plant. Finish the join by wrapping the bud with budding tape. When the union is made and the tape is removed, the bud is forced to grow by cutting the rootstock stem above the join, about 2/3 of the way through the stem. This cut should be made 2.5–3.9 cm (1.0–1.5 in) on the same side as the join. The top of the seedling should then be pushed over towards the ground. This process, known as "lopping,” allows all of the nutrients to be diverted to the bud Once the bud begins to grow and reaches several inches in length, the lop can be removed completely from the seedling.

Planting seedlings

Bergamot trees can be purchased as seedlings that have already been grafted and only require planting in the garden or orchard. The best time to plant citrus trees is in the spring, after all the danger of frost has passed in your area. Standard sized trees should be spaced 3.7–7.6 m (12–25 ft) apart in an area that receives full sunlight but is protected from strong winds, which can damage the trees. Planting against a south facing wall will help protect the tree in cooler climates.

General care and maintenance

Newly planted trees require proper irrigation to ensure they become established. During the first year, water should be applied at the base of the trunk so that the root ball is kept moist to allow the roots to establish themselves in the soil. Newly planted trees should be provided with water every 3–7 days. The soil should be moist, but not wet. Trees planted in sandy soils will require water more frequently. Young trees will also require a light application of fertilizer every month in the first year.

Harvesting

Harvesting bergamot, whether it's Monarda didyma (Bee Balm) or Citrus bergamia (Bergamot Orange), involves careful timing and consideration of the specific plant type. For Monarda didyma, which is often grown for its striking flowers and aromatic leaves, the best time to harvest is when the blooms are in full glory. To maintain the plant's health and encourage continuous flowering, it's advisable to trim the flowering stems, cutting them just above a pair of leaves while ensuring not to remove more than one-third of the plant's height at a time. On the other hand, Citrus bergamia, primarily cultivated for its fragrant peel, is harvested during the winter months when the fruit is ripe. The fruit should be gently hand-picked to avoid damage to the tree and then carefully peel the bergamot, capturing the valuable essential oils. Proper harvesting methods are essential to maintaining the quality and utility of the harvested material.




References

CABI Crop Protection Compendium. (2008). Citrus bergamaia datasheet. Available at: http://www.cabi.org/cpc/datasheet/13437. [Accessed 06 November 14]. Paid subscription required.

Orwa, C., Muta, A,, Kindt, R., Jamnads, R. & Simons, A. (2009). Agroforestree Database: a tree reference and selection guide. Citus bergamia. Available at: http://www.worldagroforestry.org/treedb2/AFTPDFS/Citrus_bergamia.pdf. [Accessed 06 November 14]. Free to access.

Timmer, L. W., Garnsey, S. M. & Graham, J. H. (2000). Compendium of Citrus Diseases. American Phytopathological Society Press. Available at: http://www.apsnet.org/apsstore/shopapspress/Pages/42481.aspx. Available for purchase from APS Press.




Common Pests and Diseases

Diseases

Category : Fungal

Alternaria brown spot Alternaria spp.

Symptoms
Infected fruit change color prematurely; brown or black lesions on young twigs, leaves and fruit; diseased fruit may fall from tree.
Cause
Fungi
Comments
Avoid overhead irrigation and excessive application of nitrogen.
Management
Plants that are stressed are more susceptible to the disease, ensure plants are provided with water and fertilizer; delaying harvest until diseased fruit has dropped from tree can reduce the number of fruit lost to the disease post harvest; preharvest treatment with fungicide is often ineffective.

Black spot Guignardia citricarpa

Symptoms
Small brown or black spot and speckles on rinds of fruit; premature fruit drop; reduced fruit yield; symptoms are often more apparent on the side of trees which receive most sunlight; infected leaves generally show no symptoms.
Cause
Fungus
Comments
Widespread in areas of the Southern hemisphere with summer rainfall; fungus survives in decomposing leaves on/in soil around infected trees; spores can be spread by wind and water splash.
Management
Remove leaf litter from around trees to reduce inoculum; keep trees well irrigated during dry periods to reduce leaf fall; apply copper containing fungicides where appropriate.

Powdery mildew Oidium tingitaninium
Oidium citri

Symptoms
White powdery patches on upper surface of young leaves and possibly stems and young fruit; newly emerging leaves and shoots may be discolored; severe infestation can cause leaves to drop from plant, twigs to die back and premature dropping of fruit.
Cause
Fungus
Comments
Emergence of disease is favored by cool, damp weather conditions; very common in Asian countries.
Management
Disease can be controlled by timely applications of fungicide to protect new growth flushes; systemic fungicides give longer periods of protection.

Pseudocercospora leaf and fruit spot Pseudocercospora angolensis

Symptoms
Lesions with gray centers and chlorotic halos on leaves; holes in leaves where lesions have dropped out; lesions may coalesce to produce chlorotic patches on leaves; raised tumor-like growths on young fruit; circular or irregularly shaped flat lesions on mature fruit.
Cause
Fungus
Comments
Can be devastating to citrus trees.
Management
Control relies on the use of copper fungicides.

Category : Bacterial, Fungal

Canker Xanthomonas axonopodis

Symptoms
Slightly raised blisters on leaves with surrounding tissue turning yellow; lesion turn tan brown in color and develop a water soaked margin with white halo; centers of lesions become raised and develop a corky texture; lesions on stems and twigs are raised, corky and dark brown to black in clor with an oily or water soaked margin; raised blister-like lesions develop on fruit; fruit lesions turn dark brown or black and are sunken; fruit drops from tree prematurely.
Cause
Bacterium
Comments
Serious disease in humid tropical and subtropical areas; disease spreads rapidly over short distances.
Management
Control of the disease is reliant on timely sprays of copper containing fungicides and the provision of windbreaks to reduce spread of inoculum from infected trees.
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