Basil

Ocimum basilicum

1. Identification and origin

Basil (Ocimum basilicum L.), belonging to the Lamiaceae family, is an aromatic plant native to the tropical regions of Asia, especially India and Southeast Asia. The species spread along trade routes to the Middle East, Africa and Europe, becoming one of the most widely used culinary herbs in the world. There are numerous cultivars and varieties, differentiated by aroma, colour, size and essential oil composition.

2. Economic importance

Basil is widely used as a fresh or dried aromatic herb, essential in Mediterranean, Asian and Latin American cuisine. It is also important in the essential oil, cosmetics, perfumery and phytotherapy industries. The essential oil is rich in compounds such as linalool, eugenol and methyl chavicol, depending on the chemotype. The main producers include India, Egypt, the United States, Italy and France.

3. Botanical characterisation

An annual herbaceous plant (or perennial in tropical climates), 30–80 cm tall. The leaves are opposite, ovate, with entire or slightly serrated margins, very aromatic. The flowers are small, white or pinkish, grouped in terminal inflorescences. The fruit is a set of four small, dark nutlets. The root system is fasciculate and shallow. The morphology varies widely among cultivars (green, purple, curly, broad, small leaves).

4. Soil and climate requirements

Basil prefers warm climates, with temperatures between 20–30 °C, being sensitive to cold and frost. It develops best in light, fertile, well-drained soils, rich in organic matter, with a pH between 6.0 and 7.5. It requires good light and regular irrigation, avoiding waterlogging. Early flowering reduces leaf quality, and it is common to remove the inflorescences to prolong production.

5. Main pests

• Whitefly (Bemisia tabaci, Trialeurodes vaporariorum): Honeydew, sooty mould and transmission of viral diseases.
• Aphids (Aphis gossypii, Myzus persicae): Sap sucking and leaf deformations.
• Thrips (Thrips tabaci, Frankliniella occidentalis): Damage to young leaves and virus transmission.
• Mites (Tetranychus urticae): Chlorosis and fine webbing in dry conditions.
• Caterpillars (Noctuidae): Defoliation and damage to shoots.
• Nematodes (Meloidogyne spp.): Root galls and reduced vigour.

6. Main diseases

• Basil downy mildew (Peronospora belbahrii): One of the most serious diseases, causing yellow spots and necrosis.
• Powdery mildew (Erysiphe spp.): White coating and reduced photosynthesis.
• Root rots (Pythium spp., Rhizoctonia solani): Wilting and death of seedlings.
• Leaf spot (Cercospora spp.): Circular lesions and leaf drop.
• Viruses (CMV, TuMV): Mosaics, deformations and reduced production.

7. General crop management

Includes the choice of cultivars adapted to the local climate, sowing in well-drained soils, regular irrigation without waterlogging, weed control, monitoring of whitefly, thrips and downy mildew, and the removal of flowers to prolong vegetative production. Harvesting should preferably be carried out in the morning, when the essential oil content is highest.

Bibliographic references

• EPPO Global Database. Ocimum basilicum – pests and diseases.
• CABI Invasive Species Compendium. Ocimum basilicum – datasheets.
• Simon, J. E., Morales, M. R., Phippen, W. B., Vieira, R. F., & Hao, Z. (1999). Basil: A source of aroma compounds and essential oils. In: Janick, J. (Ed.), Perspectives on New Crops and New Uses. ASHS Press.
• Grayer, R. J., & Kite, G. C. (2004). The diversity of Ocimum. In: Hiltunen, R., & Holm, Y. (Eds.), Basil: The Genus Ocimum. CRC Press.
• Vieira, R. F., & Simon, J. E. (2006). Chemical characterization of basil cultivars. Journal of Agricultural and Food Chemistry.