Native Knowledge: Organic Pest Management in Nepal
Recently, haphazard use of pesticides and insecticides has caused major environmental problems, ultimately affecting human health. Application of eco-friendly, indigenous technical knowledge can be one of the best options to enhance the crop production system in an organic way (native knowledge referring to the understanding, skills, practices, and philosophies developed by societies with long histories of interaction within their natural milieu). Some of the major documented indigenous technical knowledge applied to control insect pest management in Nepal are highlighted below:
Cultivation practices — like jarring plant parts to kill insects and removing the infected plant parts — are followed to control pests and diseases. Application of indigenous instruments, like hasiya, foruwa, halo, etc., during the crop harvest operation and field preparation also help kill major insects and pests. In the case of specific pest attacks, like the rice moth which creates clusters of rice on paddy, pests are combed out with sticks. Another interesting native technique to control pests is the spreading of cooked rice around the field to attract birds to kill caterpillars. Some traditional techniques of biological control include putting scarecrows in a field to control from birds, using cats to control rat infestations, and having mongooses present to control insects/pests in paddy fields.
Sap sucking insects: Traditional practices like planting marigold species as a border crop can control sap sucking insects like aphids, white flies, and bugs. Limonene is the leading agent released by marigolds, which results in a reduction of the pest population. Native practices like applying a mixture of chili powder and water — or chinaberry (Melia azedarach) leaves and water — can help reduce the presence of aphids.
Aphid, Caterpillar, Beetle: Applying a combination of Jholmol (1:7 ratio of Jholmol and water) and diluted cow urine is another indigenous 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, locally sourced plants with insecticidal or insect repellent properties like Artemisia vulgaris (common name: titeypati), Azadiracta indica (local name: neem), Papaya leaves, Ocimim sanctum (tulsii), Chili powder, 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.
Shoot Borer: Protection from stem borer (chillozonellis) attacks can be achieved by pinching the rice seedling before sowing and mixed cropping onion and sugarcane and spreading grounded pulp of the khaira leaf on the wheat crop; the scent of the pulp is sufficient to kill the pests. In the case of paddy, the pulp is introduced into the paddy field through the irrigation channel.
Leaf roller: Mixtures of 1kg turmeric powder with 3-4 liters of cow urine and 15-20 liters of soap water (4gm of soap/ liter) are applied on paddy field to control leaf roller. Application of neem water is another traditional practice to control leaf roller.
Storage pest insects: Grain storage with ash or neem and mixtures of vegetables seed with ground bojho to prevent from storage pest attack are common traditional practices to control storage pests. Trial for storage pest control with the application of Acorus calamus (local name: bojho) seem to turn out well, and research in Entomology Department of Nepal Agriculture Research Council (NARC) was successful.
Native technical knowledge can significantly contribute to sustainable crop production, but this knowledge is often forgotten and neglected. There is an ongoing need for documentation, scientific validation, and certification of native knowledge and practices clarifying its role to increase land productivity and sustainability.