www.infonet-biovision.org - Zucchini/Courgette

Zucchini/Courgette

Scientific name:

Cucurbita pepo

Order/Family:

Violales: Cucurbitaceae

Importance:

medium

Common names:

ornamental gourd / marrow / zucchini / courgette / gourd / summer squash

Pests and Diseases (clicking takes you to the pest and disease pages):

Anthracnose

Downy mildew

Fruit flies

Powdery mildew

Viruses

more images (click to open)

Distribution of Zucchini/Courgette in Africa

Geographical distribution indicated in red

Index

General Information on Zucchini / Courgette Agronomic Aspects Information on Major Diseases Information on Major Pests Information Source Links

General Information on Zucchini / Courgette

Fruits, leaves and flowers of Zucchini and other Cucurbita species are used as vegetables, and their seeds are consumed roasted as a snack food (CAB 2006). Zucchini has a mild flavour and is very watery. It is often harvested when still very young. At this stage it is also called squash or courgette. Because the fruit has very little flavour of its own it is often used as a base for making savoury dishes. The seeds can be scooped out of and a replaced with a filling - this can then be baked (Plants for a Future 2003). Ornamental gourds are cultivars of C. pepo with small, bitter and inedible fruits in many shapes, sizes and colours (CAB 2006).

Climatic conditions, soil and water management

Zucchini requires a rich, well-drained soil that is able to retain moisture. It grows best in a sunny and sheltered position. Plants are tolerant of light shade. It prefers a pH of 5.5 to 5.9, but tolerates up to 6.8 (Plants for a Future 2003). It responds very well to fairly heavy applications of good compost or well-decomposed manure in the planting hills or ridges. Drought stress quickly reduces fruit setting, so during dry spells irrigation is a must, preferably watering below the leaves or using drip irrigation.

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Agronomic Aspects

Propagation and Planting

Zucchini and squashes are grown from seed. Seeds may be sown in containers and transplanted to the field when they are 10 cm high or have 2 real leaves. Direct seeding of two to three per hill is also commonly practised. Trailing types are planted at distances of 2 to 3 m either way; the seed requirement is 2 to 3 kg/ha. The bushy types are planted closer, for example, plants spaced 60 to 120 cm in rows 1 to 1.5 m apart. The seed requirement for Zucchini is 7 kg/ha. Plant densities vary from 5,000 plants per ha for the long-running trailing forms to 20,000 plants per ha for the bushy types (CAB 2006).

Husbandry

Sole cropping is normally used for commercial production. Zucchini and squashes are also planted in home gardens as fresh vegetables. Cultural practices to improve growth and development include the removal of growing tips to check growth in case of trailing varieties.

Harvesting

Zucchini and other summer squashes, from which the immature fruit is used as a fresh vegetable, develop very rapidly. The first marketable fruits can be harvested 50 to 60 days after planting, or 3 to 6 days after appearance of the female flower. During the harvest season the fruits are harvested two to three times per week. (CAB 2006)

Crop yields for summer squash (immature fruits) are 7 to 12 t/ha. Unless grown for seed, mature fruits are not marketable, so plants are removed when yields become too low. Indicative figures for seed yield of Zucchini and other squashes are 400 to 1500 kg/ha. In seed production, isolation between fields of different Cucurbita species is recommended, not only for reason of purity but also for obtaining maximum yields (pollen of other species may cause reduced fruit set).

Summer squash of good quality (no attacks of fruit flies - little dots on fruits developing into sores full of white larvae) can be kept for up to 14 days when stored at 7 to 10°C and 85 to 95% RH (CAB 2006).

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Information on Major Diseases

Courgettes are affected by similar pests and diseases as other cucurbits; this is plants belonging to the family Cucurbitacea, including melons, squash, pumpkin, and cucumber.

Anthracnose Colletotrichum orbiculare
It is the most destructive disease. It causes defoliation and lesions on the fruits.
What to do:
For more information on Anthracnose click here.

Other fungal diseases, mainly affecting the leaves and stems are:

Powdery mildew (Erysiphe cichoracearum)
Downy mildew (Peronospora cubensis)
Scab (Cladosporium cucumerinum)

For more information on powdery mildew click here.
For more information on downy mildew click here.

Zucchini yellow mosaic potyvirus on Cucurbita pepo. ZYMV provokes in cucurbit crops very severe symptoms of stunting, yellowing, necrosis (occasionally), mosaic, leaf deformations, fruit discolorations and deformations.

Virus diseases
Many important virus diseases affect cucurbits. These include

Cucumber mosaic cucumovirus (CMV)
Watermelon mosaic 2 potyvirus (WMV-2)
Watermelon mosaic 1 potyvirus
Zucchini yellow mosaic potyvirus (ZYMV)
Squash leaf curl bigeminivirus (SLCV).

For more information on these diseases refer to datasheet on cucumber (click here).

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Information on Major Pests

Fruit fly maggots in water melon fruit

Fruit flies
Fruit flies are the most serious insect pests on zucchini/squash with the ability to totally wipe out any marketable fruit.
What to do:

Frequent applications of neem can keep fruit fly attack to a minimum.

For more information on neem click here.
For more information on fruit flies click here.

The leaf-feeding Epilachna beetles are a serious problem for Cucurbita growers.
Aphids and various leaf beetles can also cause problems on courgetes.
For more information on aphids and their control click here
For more information on pests attacking cucurbits refer to page on cucumber (click here).

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Information Source Links

AIC, Nairobi (2003). Fruits and Vegetables Technical Handbook
AVRDC International Cooperators' Factsheet on Cucurbits www.avrdc.org/LC/cucurbits/publications.html
Beije, C.M., Kanyangia,S.T., Muriuki, S.J.N., Otieno, E.A., Seif, A.A., Whittle, A.M. (1984). Horticultural Crops Protection Handbook. National Horticultural Research Station, Thika. KEN/75/028 and KEN/80/017/
Blay, E., Cudjoe, A. R., Braun M. (eds) (2000). Handbook of crop protection recommendations in Ghana: An IPM approach. Vol 2; vegetables. Plant Protection & Regulatory Services Directorate (PPRSD) and the Integrated Crop Protection Project, German Development Cooperation (GTZ).
Bohlen, E. (1973). Crop pest in Tanzania and their control. Federal Agency for Economic Cooperation (BFE). Veralgh Paul Parey. ISBN 3-489-64826-9.
EcoPort. The consilience engine. www.ecoport.org
Ekesi, S., Billah M. K. (eds) (2006. A field guide to the management of economically important tephritid fruit flies in Africa. ICIPE. ISBN: 92-9064-179-7.
Ministry of Agriculture and Rural Development (Kenya) (MoARD) & Japan International Cooperation Agency (JICA) (2000). Local and Export Vegetables Growing Manual. Reprinted by Agricultural Information Resource Centre, Nairobi, Kenya. 274 pp.
Ostermann, H. and Dreyer, M. (1995). Vegetables and grain legumes. In: The Neem tree Azadirachta indica A. Juss. and other meliaceous plants sources of unique natural products for integrated pest management, industry and other purposes? Edited by H. Schmutterer in collaboration with K. R. S. Ascher, M. B. Isman, M. Jacobson, C. M. Ketkar, W. Kraus, H. Rembolt, and R.C. Saxena. VCH. pp. 392-403. ISBN: 3-527-30054-6
Park SoDeuk, Kwon TaeYong, Lim Yang Sook, Jung KiChae, Choi BooSull (1996). Disease survey in melon, watermelon, and cucumber with different successive cropping periods under vinylhouse conditions. Korean Journal of Plant Pathology, 12(4):428-431.
Plants for a Future (2003). Edible, medicinal and useful plants for a healthier world. http://www.pfaf.org/database/plants.php?Cucurbita+pepo
Sherf, A.F., Macnab, A.A. (1986). Vegetable Diseases and Their Control. 2nd. Edition. John Wiley & Sons Inc. USA. ISBN: 0-471-05860-2
University of Georgia: College of Agricultural and Environmental Sciences, Department of Horticulture Vegetable Crops: Pumpkin. http://www.uga.edu/vegetable/pumpkin.html

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