The traditional system of agriculture in Nepal was organic but with the change in time, the practices changed more towards inorganic which is a direct threat to agriculture productivity, environmental quality and human health. Pest management in organic farming is mainly achieved by using different cropping techniques, biological control and natural pesticides (mainly extracted from plant or animal origins). Some of the major indigenous technical knowledge applied to control insect pest management in Nepal are highlighted below:
Cultural practices like ploughing, hoeing and basin preparation influence directly, the survival of soil inhabiting pests. Application of indigenous instruments, like hasiya, foruwa, halo, etc., during the crop harvest operation and field preparation also help tokill major insects and pests. These agricultural operations expose soil inhabiting insect, pests and other arthropods and nematodes to harsh weather and to natural predators. Insects are most vulnerable when in the pupal stage and most insect-pests pupate in the soil which furnishes a protective habitat. Birds like the king crow, the myna, the starling, etc. pick up the exposed pupae following these cultural operations.
Cow-dung and clay mixture :
Cowdung and cow urine possess complex degrading substances and may possess anti-bacterial properties and also addition of clay results in better adhesion of other constituents to the treated surface. Sealing of wounds/cut prevents access of pathogens to the otherwise exposed surface. To some extent, the already present pathogen is also dead by using the applied paste. Pruned ends of twigs and cuts are also favourable spots for the settlement and establishment of woolly (apple) aphid on apple trees. Covering such sites with the cowdung paste hastens healing and prevents aphid settlement.
Whitefly and nematodes :
The marigold is the most well-known plant for repelling insects. The flower produce limonene which repel whiteflies away from tomato and kill bad nematodes.
Aphid, Caterpillar, Beetle :
Application of Jholmol (1:7 ratio of Jholmol and water) and diluted cow urine is another traditional practice to control pests like aphids, caterpillars, and beetles. Jholmol works both as a growth promoter and insect repellent. It can be prepared by mixing cow urine, some locally sourced plants with insecticidal or insect repellent properties like titepati, neem, Papaya leaves, tulsii, etc. A diluted form of Jholmol i.e. 1:7 (Jholmol : water) is applied on the plant parts. It is one of the best traditional practices of pest management and is an eco-friendly and sustainable way to reduce pest population, controlling a broad range of pests.
Use of wood ash on and around vegetable crops :
It is a common practice to sprinkle wood ash on vegetable crops, especially growing in kitchen garden and to spread it around plants to ward off pests and to enhance nutrient status of the soil. To achieve this a thick layer of ash is spread on the soil around plants and it is also sprinkled on foliage to protect it against a variety of pests. This is because it is a source of phosphorus for plants and it also acts as a physical poison usually causing abrasion of epicuticular waxes and thus exposing pests to death through desiccation. The treated foliage further becomes unpalatable for foliage feeders like cutworms, caterpillars, grasshoppers, etc.
Use of scare crow to scare birds and animals :
Scare crow are used to scare the birds and animals that destroy the crops. These are specially kept in cereal crop field like rice, wheat and maize or vegetable and fruit fields.
Traditionally Neem oil and their leaves have been used to protect stored grains and legumes. Neem leaves are mixed with the grain in storage or the grain is stored in jute bags treated with neem oil or other neem extract. These methods can protect food and seed stores from insect pest for several months. Spraying neem seed kernel extract twice to control pod borer at flowering and fruiting stage.
There is an abundant traditional knowledge and practices of plant protection among rural farmers, which need to be tapped for present and future agriculture. As the world is moving towards “Go green” slogan, encouraging and educating the farming community to adopt eco-friendly pest management strategies to pause environment being polluted by synthetic insecticides is a need of the hour to mend Nepalese farming.