Crop Protection Products: Herbicides, Insecticides and Fungicides

Crop protection products are used to limit losses from weeds, insects, diseases and other pests that would otherwise reduce yield or quality. This page explains the main categories of these products and the general principles behind their responsible use in a South African farming context.

The three main categories

Herbicides, used to control weeds that compete with crops for light, water and nutrients. These are often classified as selective, which target specific weed types while leaving the crop largely unaffected, or non-selective, which affect most plant life and are typically used before planting or in non-crop areas.
Insecticides, used to control insect pests that damage crops directly or transmit plant diseases. These vary widely in how they work, from contact products that kill on exposure to systemic products absorbed into the plant.
Fungicides, used to prevent or control fungal diseases, which can spread rapidly in humid conditions and, left unchecked, can destroy a significant portion of a crop.

Modes of action and resistance management

Each crop protection product works through a specific biological mechanism, referred to as its mode of action. Repeated use of products with the same mode of action against the same pest, weed or disease population increases the risk that resistant individuals survive and multiply, eventually making the product ineffective. For this reason, agronomists generally recommend rotating between products with different modes of action rather than relying on a single product season after season.

Integrated pest management

Chemical control is usually most effective and sustainable when combined with other practices, an approach commonly referred to as integrated pest management. This can include:

Crop rotation, which disrupts the life cycles of pests and diseases that build up when the same crop is grown repeatedly on the same land.
Monitoring and thresholds, where fields are scouted regularly and treatment is applied only once pest numbers reach a level likely to cause economic damage, rather than on a fixed calendar.
Biological control, using natural predators or competing organisms to help keep pest populations in check.
Resistant varieties, where available, which reduce the need for chemical intervention against specific diseases or pests.

Registration and labelling

Crop protection products sold in South Africa must be registered, a process intended to confirm that the product works as claimed for the pests and crops listed on the label and that it can be used safely when label instructions are followed. The label specifies the approved crops, target pests, application rate, and importantly, the pre-harvest interval, which is the minimum time that must pass between the last application and harvest. Respecting this interval is central to ensuring that produce entering the market or food chain meets safety expectations.

Safe handling

Because crop protection products are formulated to be biologically active, safe handling practices are important for anyone applying them. General principles include:

Reading the full label before use, including precautions, protective equipment requirements and first aid information.
Using recommended protective equipment, such as gloves and appropriate clothing, during mixing and application.
Storing products securely, away from children, animals and food, and in their original labelled containers.
Disposing of empty containers responsibly, following guidance provided on the label or by the relevant industry disposal programme.

Weather and timing

Wind speed, temperature and the likelihood of rain shortly after application all affect how well a crop protection product performs and how much risk there is of it drifting onto neighbouring land or washing off before it can work. Many product labels specify conditions under which application should be avoided, and following these guidelines reduces both wasted product and unintended environmental impact.