Tomato plant

Solanum lycopersicum

1. Identification and origin

The tomato plant (Solanum lycopersicum L.) is an annual or short-cycle perennial herbaceous species belonging to the Solanaceae family. It originates from the Andean region of South America, having been domesticated in Mexico and spread to Europe in the 16th century. It is currently one of the most widely cultivated vegetables in the world, both in open field and in greenhouse.

2. Economic importance

The tomato is a crop of high economic and food relevance, used fresh or processed (pulp, concentrate, sauce, juice, dehydrated). In Portugal, it has a strong presence in Ribatejo, Oeste and Alentejo, mainly for industry. Its economic value results from the high demand, diversity of varieties and importance in the agri-food chain.

3. Botanical characterisation

The tomato plant has a variable growth habit (indeterminate or determinate), with a herbaceous and pubescent stem. The leaves are compound, alternate, with a characteristic odour. The flowers are yellow, hermaphrodite, grouped in clusters. The fruit is a fleshy berry, variable in shape and colour (red, yellow, orange, green). The root system is deep and branched, sensitive to waterlogging and salinity.

4. Soil and climate requirements

The tomato plant adapts to hot and temperate climates, with optimal temperatures between 20 and 28 °C. It is sensitive to frost, excessive humidity and sudden thermal variations. It prefers well-drained soils of medium texture, rich in organic matter, with a pH between 6.0 and 7.0. The crop requires good light and regular irrigation, avoiding waterlogging. In greenhouse, it requires adequate ventilation to reduce fungal diseases.

5. Main pests

• Whitefly (Bemisia tabaci, Trialeurodes vaporariorum) — sap sucking and transmission of viral diseases
• Tuta (Tuta absoluta) — mines in leaves, stems and fruits
• Aphids (Myzus persicae, Aphis gossypii) — sap sucking and transmission of viruses
• Mites (Tetranychus urticae) — leaf discolouration and necrosis
• Nematodes (Meloidogyne spp.) — root galls and reduction in vigour
• Tomato fruitworm (Helicoverpa armigera) — perforations in leaves, flowers and fruits
• Beet armyworm (Spodoptera exigua) — defoliation and damage to young fruits

6. Main diseases

• Late blight (Phytophthora infestans) — leaf spots and fruit rot
• Powdery mildew (Oidium neolycopersici) — white coating and reduction of photosynthesis
• Early blight (Alternaria solani) — concentric spots on leaves and fruits
• Fusarium wilt (Fusarium oxysporum f. sp. lycopersici) — vascular wilt
• Verticillium wilt (Verticillium dahliae) — wilting and decline
• Tomato mosaic virus (ToMV) — mosaics and deformations
• Tomato spotted wilt virus (TSWV) — severe necrosis and deformations

7. General crop management

Management of the tomato plant is based on the choice of varieties adapted to the production system (field or greenhouse) and resistant to diseases. Crop rotation is essential to reduce pressure from soil fungi and nematodes. Ventilation and humidity control are decisive in greenhouse. Monitoring of Tuta absoluta, whitefly and aphids is critical due to the risk of viral diseases. Fertilisation must be balanced, with attention to calcium to prevent blossom end rot. Harvesting is carried out according to the destination (fresh or industry), ensuring proper ripening.

Bibliographic references

• EPPO Global Database – Solanum lycopersicum
• CABI – Crop Protection Compendium – Solanum lycopersicum
• Jones, J. B., et al. (2014). Compendium of Tomato Diseases and Pests. APS Press.
• Hanssen, I. M., & Lapidot, M. (2012). Tomato virus diseases. Advances in Virus Research, 84, 343–404.
• Bai, Y., & Lindhout, P. (2007). Domestication and breeding of tomatoes: what have we gained and what can we gain in the future? Annals of Botany, 100, 1085–1094.