Carob tree

Ceratonia siliqua

1. Identification and origin

Ceratonia siliqua L. is a perennial tree species of the Fabaceae family, known as the carob tree. It is native to the Mediterranean region, where it is widely naturalised. The tree is adapted to dry and poor environments, being traditionally cultivated in Mediterranean countries for the production of pods (carob) and seeds.

2. Economic importance

The carob tree has great economic importance in arid and semi-arid regions, due to its hardiness and low maintenance cost. The pods are used in the food industry (carob flour, syrups, cocoa substitutes), pharmaceutical and cosmetic industries. The seeds provide carob gum (LBG – locust bean gum), a thickener of high commercial value. The crop has gained relevance in international markets due to the growing demand for natural and gluten-free products.

3. Botanical characterisation

Perennial tree, of medium size, with a dense and rounded crown. The leaves are compound, coriaceous and persistent. The flowers are small, reddish-green, arranged in axillary inflorescences, and may be male, female or hermaphrodite. The fruit is an elongated pod, fleshy and rich in sugars, which turns dark brown at maturity. Reproduction can be done by seed or by grafting, the latter being preferred for production uniformity.

4. Soil and climate requirements

It adapts to Mediterranean climates, with hot and dry summers and mild winters. It tolerates high temperatures and long periods of drought. It prefers deep, well-drained soils, of medium to light texture, with a pH between 6.0–8.0. It is sensitive to waterlogging and intense frosts, especially in young plants. Production is favoured by good sun exposure.

5. Main pests

• Scale insects (Coccoidea): sap sucking and honeydew production.
• Aphids (Aphididae): deformations and transmission of viral diseases.
• Carob moth: Apomyelois ceratoniae causes damage to the pods.
• Fruit fly: Ceratitis capitata can attack ripe fruits.
• Mites (Tetranychidae): silvering and reduction of the photosynthetic area.

6. Main diseases

• Root rots: Phytophthora spp. associated with poorly drained soils.
• Cankers and necroses: caused by opportunistic fungi in weakened trees.
• Anthracnose: Colletotrichum spp. causes foliar spots and necroses.
• Sooty mould: development of saprophytic fungi on insect honeydew.
• Occasional viral diseases: mosaic and chlorosis symptoms.

7. General crop management

It includes the use of quality seedlings or grafted plants, planting in well-drained soils, weed control and monitoring of pests and diseases. Formation and cleaning pruning improves ventilation and reduces sanitary problems. Supplementary irrigation, when available, increases productivity, especially in dry years. Harvesting must be carried out when the pods reach a uniform brown colour and an adequate sugar content.

Bibliographic references

• EPPO Global Database – Ceratonia siliqua.
• CABI – Crop Factsheets – Ceratonia siliqua.
• Batlle, I., & Tous, J. (1997). Carob tree. Ceratonia siliqua L. International Plant Genetic Resources Institute.
• Tous, J., & Batlle, I. (1990). The carob tree: botany, horticulture and genetic resources. FAO.
• FAO – Technical documents on Mediterranean fruit trees.
• Yousif, A. K. et al. (2014). Carob: botany, production and uses. Journal of Food Science and Technology.