Safe methods for pest control on your farm

Caterpillars on spinach leaf [iStockphoto]

The use of agricultural chemicals to control insect pests and diseases in crops is the most effective method. However, with the increase of lifestyle diseases like cancer linked to the use of agrochemicals on farms, there is a need to explore other safe alternatives. Already, lobby groups have petitioned Parliament to legislate on withdrawal of harmful agricultural chemicals from the market. Should these lobby groups make good their threat, farmers would have to revert to insect and disease control methods that are safe and sustainable.

Sustainable methods

Ideally, agricultural systems should be designed in a way that pests, diseases and weeds do not build up to a level that they cause significant damage to the crop. Approaches such as good agronomic practices, use of resistant varieties, and Integrated Pest Management (IPM) are main preventive measures. Biological control methods and use of natural substances can complement these efforts. Use and safe application of minimal toxic synthetic pesticides should be used as a last resort.

So how do we limit pest build up? Suitable agronomic practices are essential to having healthy crops and preventing the build-up of pest, disease and weed pressure. Practices such as appropriate plant nutrition and soil fertility management based on organic matter forms the basis for healthy crops that are less susceptible to pests, diseases and weeds.

Crop rotation

Crop rotation prevents the carryover of pest, pathogen and weed populations to the following season while intercropping and use of variety mixtures limits the spread of pests and diseases and provides food and shelter for natural enemies of pests. Timely shallow tillage reduces weed populations and at the same time improves nutrient supply to the crop. Appropriate irrigation management avoids water stress (too little or too much) that makes crops susceptible to pests and diseases and reduces proliferation of weeds. Appropriate timing of sowing or planting and of intercultural operations reduce pest pressure.

Growing crops suitable for local conditions and selecting appropriate crop varieties is fundamental as a preventive pest management system. The use of resistant varieties together with rotations of non-susceptible crops can substantially limit pest build-up within a field.

Bio-control

Bio-control makes use of pathogens, insect predators or parasitoids, pheromones and insect traps to keep pest populations low. The total eradication of a pest, which results from use of synthetic pesticides, would reduce the food supply of the pest's natural enemies, undermining a key element in system resilience.

The aim, therefore, should be to manage insect pest populations to the point where natural predation operates in a balanced way and crop losses to pests are kept to an acceptable minimum. The most widely used bio-control methods include conservation and augmentation of natural enemies of pests through flower strips, hedgerows and other natural habitats. Release of predators and parasitoids of pests such as ladybird beetles and predatory mites is also helpful. Use of pheromone dispensers to disrupt the mating of pests and use of traps like sticky coloured boards, pheromone traps and light traps to catch insect pests, are also useful.

Natural pesticides

Various plant extracts and other natural materials can be used to repel pests, reduce their feeding or reproductive activities and reduce proliferation of diseases. Progressive farmers should adopt organic agriculture which is a production system that sustains the health of soils, ecosystems and people. Organic farming makes use of techniques similar to Integrated Pest Management, with the only difference that synthetic chemicals cannot be used as a last resort. Instead, organic farmers can use specific natural substances permitted by organic standards to control pests and diseases if preventive methods are not sufficient.

[The writer is an expert on sustainable agriculture and agricultural solutions]