African Organic Agriculture Training Manual: Citrus Crop Management
Citrus is widely cultivated in tropical as well as subtropical African countries. While fresh fruit for the market is produced preferably in subtropical climates (e.g. South Africa) and Mediterranean climates (e.g. Tunisia, Egypt, Morocco, Libya), citrus for juice is predominant in tropical climates because of the possibility for higher sugar content. The most important species of citrus fruits are sweet oranges (Citrus sinensis), limes (C. aurantifolia), grapefruits (C. paradisi), lemons (C. limon) and mandarins (C. reticulata), often called tangerines. This chapter focuses on the management of sweet oranges (Citrus sinensis) only.
Common challenges related to citrus production in sub-Saharan Africa
- Inferior varieties - Most farmers rely on local varieties that are sometimes very susceptible to infections and low yields. New seedlings are generally raised directly from seeds, hence propagating the low yielding traits of the mother plants. Improved varieties are not easily accessible to farmers due to the limited availability of plant nurseries. As most improved varieties can only be propagated vegetatively by budding or grafting, farmers who lack this knowledge cannot do it themselves.
- Poor yields - Due to drought and poor management, poor yields often result. Most citrus production is done on small gardens mainly for the domestic market. The crops are not irrigated and in most cases suffer from drought stress, delayed flowering, affecting potential yields.
- Pests and diseases - Citrus is attacked by many diseases that cause serious losses (e.g. greening disease, anthracnose, damping off, phaeoramlaria leaf and fruit spot). Citrus is also very liable to infestation by pests like aphids, scales and white flies, some of which are vectors of the citrus tristeza virus or the greening disease.
- High postharvest losses - Harvesting of immature and overmature fruit, mechanical damage during harvest, transport and distribution, water loss (wilting) due to a poor handling system, and decay either due to blue or green mould and insect damage due to the Mediterranean fruit fly result in high postharvest losses.
To meet the above mentioned challenges and make citrus production more sustainable and profitable, interventions are needed. This chapter introduces organic approaches, which can be adapted to local conditions and can help address some citrus production challenges.
Learning targets for farmers:
- Realise the importance of appropriate soil management for short- and longterm productivity
- Understand the relevance of habitat diversification in and around the orchards to promote natural enemies for effective management of most pests
- Recognise the importance of proper crop management and regular monitoring for effective pest and disease management
- Note the value of appropriate irrigation for crop growth and fruit development
- Develop awareness for timely harvesting and proper postharvest handling for high fruit quality