Courgette

Cucurbita pepo

1. Identification and origin

The courgette / zucchini (Cucurbita pepo L.) is an annual horticultural species of the Cucurbitaceae family, native to Central America and Mexico. It includes several varietal groups, such as squashes, courgettes / zucchini and patisson squashes, and is widely cultivated in temperate and Mediterranean regions.

2. Economic importance

The courgette / zucchini is one of the most important fruiting vegetables in intensive horticulture, with high demand for fresh consumption. It is valued for its productivity, short cycle and culinary versatility. It has a strong presence in domestic and export markets, and is also relevant in organic production systems.

3. Botanical characterisation

An annual plant, of trailing or semi-shrubby habit. The leaves are large, palmate, often with pale markings. The flowers are unisexual, large and yellow, with entomophilous pollination. The fruits are modified berries (pepos), harvested immature in the case of the courgette / zucchini. The root system is shallow, with high sensitivity to waterlogging.

4. Soil and climate requirements

It prefers warm, bright climates, with optimum temperatures between 20–30 °C. It is sensitive to cold and frost. It develops best in fertile, well-drained soils, with a pH between 6.0 and 7.5. It requires a good water supply, but without soil saturation.

5. Main pests

• Whitefly (Bemisia tabaci, Trialeurodes vaporariorum): sap sucking and transmission of viruses.
• Aphids (Aphididae): leaf curling and transmission of viruses.
• Mites (Tetranychidae): chlorosis and loss of vigour.
• Cucurbit moth (Diaphania hyalinata, D. nitidalis): borings in leaves and fruits.
• Nematodes (Meloidogyne spp.): root galls and decline of the plant.

6. Main diseases

• Powdery mildew (Podosphaera xanthii, Erysiphe cichoracearum): white mycelium on leaves.
• Downy mildew (Pseudoperonospora cubensis): angular spots and leaf necrosis.
• Watermelon mosaic virus (WMV) and zucchini yellow mosaic virus (ZYMV): mosaics and deformations.
• Crown and root rots (Phytophthora spp., Fusarium spp.): wilting and death of plants.
• Anthracnose (Colletotrichum orbiculare): lesions on leaves and fruits.

7. General crop management

Management includes sowing or planting at the appropriate time, the use of resistant varieties, balanced fertilisation and controlled irrigation. Protection against viruses depends on rigorous monitoring of aphids and whitefly. Ventilation in the greenhouse reduces the risk of powdery mildew and downy mildew. Harvesting should be frequent, when the fruits reach commercial size, to stimulate new fruiting.

Bibliographic references

• EPPO Global Database – Cucurbita pepo.
• CABI Crop Compendium – Cucurbita pepo.
• Robinson, R. W., & Decker‑Walters, D. S. (1997). Cucurbits. CAB International.
• Zitter, T. A. et al. (1996). Compendium of Cucurbit Diseases. APS Press.
• Paris, H. S. et al. (2003). History and taxonomy of summer squash. Annals of Botany.