Plant protection substances/active ingredients
Rising awareness for natural pesticides
The use of synthetic substances potentially poses problems for the environment, biodiversity, human health, and other areas. This is why the use of synthetic substances is not allowed for plant protection in certified organic farming. Awareness is increasing among farmers and consumers in Africa on the advantages of natural pesticides for human health (e. g. lower health risks during application of pesticides, lower or no residues in food), soils (promotion of natural soil fertility and biodiversity (less negative impacts on beneficial insects).
Smallholder farmers can grow or produce the raw materials required to prepare some of the biopesticides which are important for their farming. When they can produce these, the farmers will have ready access to these plant protectants and reduce the cost of plant protection. Some of the plants used to prepare concoctions have repellent properties and can protect crops in-situ when growing.
Challenges related to natural pesticides
Organic farmers rely on natural agents to control pests and diseases when the preventive measures for plant protection prove not sufficient. However, reliance on biopesticides is usually linked to some challenges as follows:
Unsatisfactory effectiveness of farm-made products: Some African farmers apply some natural home-made products from local sources. However, some of these products may not prove effective enough for controlling the prevailing pests and diseases. As a result, confidence in the effectiveness of natural inputs is commonly rather low among farmers. Home-made products are fine to strengthen the plants against pest and disease attacks (Step 2 – see page 7). But when they are used as ‘pesticides’ (Step 3 – see page 7), farmers who export their products to Europe may get in conflict with the EU organic legislation and risk decertification.
Limited availability of raw materials locally: Some effective raw materials may not be readily available locally, e. g. the neem tree is not naturally found everywhere, hence, unless deliberately planted, its use can be limited. In such cases, farmers are encouraged to explore other locally available materials, or plant those not readily available in their area.
Limited availability of commercial products: Commercial plant protection products can be expected to be more effective if used correctly. But in most African countries, the availability of commercial plant protection products for organic/ecological agriculture is very limited with regard to the variety of product categories, the variety of products within the categories, and the quantities. Particularly biopesticides with a narrow spectrum of action with complex production processes are hardly available in Africa so far, and would probably be too expensive for many farmers.
Unrealistic promises on the effectiveness of commercial products: Producers and distributors have a vital interest to encourage farmers to buy their products. For this purpose, they may exaggerate the effectiveness and cost/ benefit-ratio of their products. To minimise negative effects for the farmers, independent advice to all farmers is essential to counterbalance potentially exaggerated information by some commercial local and international input companies.
Little knowledge on permitted biopesticides: Knowledge about which plant protection products and active ingredients are permitted for use in organic agriculture is limited. There are many factors which come into play when considering which inputs to use. They include, type of crop, national regulatory standards (if the crops being grown are for marketing as certified organic), standards and regulations in destination export markets, other standards which may apply for the farmer’s case, availability, cost, and others.
Substances with a broad spectrum of action versus substances with a narrow spectrum of action: From an agro-ecological perspective, first priority should be given to pesticides with a narrow spectrum of action, which results in minimal damage to beneficial organisms. A typical example is Bacillus thuringiensis (Bt). Plant extracts typically have a broader spectrum of action and are thus more likely to affect non-target organisms including beneficial organisms which are friendly to the farmer in keeping the pests under control. From an economic view, farm-based pesticide production would be advantageous for the farmers. However, we consider that in the case of pesticides, priority should be given to ecological considerations. Reversing the priorities might end up using a neem product (because it is local) instead of a potassium soap, even if the soap would be preferable from an ecological point of view. It is important that farmers are made aware of these considerations so as to make informed choices and actions.