ECO- FRIENDLY USES OF PLANTS AND THEIR PRODUCTS
Today the modern lifestyle is techno savvy and the youth, in general, is moving away from nature. Despite the fact that we have all latest gazettes and other utilities, even then we cannot escape from the fury of nature; as we are also the part and parcel of mother nature. Nature has given us its products in the form of plants; and from the plants, we can get medicines, food, flavor, textile, cosmetics, colors, pesticides, etc. Plant products are highly eco-friendly and safer to use, easily and highly degradable. They do not leave any harmful residues in the soil or water. Earlier there were many plants/ herbs whose bioproducts were used for the control of insect pests on crops. Also, a lot of herbs were used as air purifier / as medicines against many diseases. But presently either for the sake of easiness or to have instant results, synthetic forms of pesticides are being used which have cascading impacts on us either directly or indirectly. To reverse these impacts there is a need to promote the use of plants or their products to save the humanity. Plants are a rich source of organic chemicals which have a diverse array of chemicals to fend- off insect pests, purify the air and act as medicines. Plants have evolved for over 400 million years and to defend themselves from insect attacks they have developed inbuilt protection mechanisms of repellents and insecticidal effects. The use of plant extracts has been mentioned even in the Bible. Massive use of these insecticides has had a long and difficult road because the earliest data gathering done by researchers among farmers and natives revealed a lot of practices based on superstitions, which, when tested by scientific methods were not found to be effective. After the Second World War few plants and plant extracts that had shown promising effects were widespread in use, were later on replaced by synthetic insecticides. When synthetic insecticides came into existence in 1940’s some people thought that botanical insecticides would disappear forever, but problems like environmental contamination, residues in food & feed and pest resistance brought them back to the fore. There is no doubt about that botanical insecticides are an interesting alternative to the synthetic insecticides for insect pest control. Out of the more than 2, 50,000 plant species evaluated for their insecticidal properties only a few plants had this value. This means the potential for their use as pesticides is immense. In fact, plants like neem (Azadirachta indica J.), have shown excellent results, and in the market, there are already commercial products prepared from these plants. But one should not be complacent that success is at hand and botanical insecticides will replace the synthetic insecticides. They are the alternatives that can be included in Integrated Pest Management (IPM) programs.
The plant-based insecticides repel, deter feeding & oviposition, disrupt behavior & physiology of insects. The ecological and environmental problems created by synthetic pesticides have made us turn towards botanical insecticides once again. Different groups of plant metabolites possessing pesticidal bioactivity are: terpenoids from limonoids and pyrethrum ; alkaloids from anabasine and nicotine ; phenolics from rotenone and Karanj; non-protein amino acids from Allin and canavanine ; Some important plants which have insecticidal values belong to the families such as Apocynaceae, Asteraceae, Euphorbiaceae, Fabaceae, Meliaceae, Leguminaceae, Myrtaceae, Ranunculaceae, Rutaceae , Rosaceae, etc. The important insecticides which have been extracted from plants are: Pyrethrum from Chrysanthemum; Pyrethrins from Cinerariaefolium; Rotenone from Derris; Sabadilla from Schoenocaulon Officinale, Veratrum album; Nicotine from Nicotiana species also from Duboisia Anabasis, Asclepias Equisetum, and Lycopodium; Azadirachtin from Azadirachta indica & Melia azedarach. Neem, Chinaberry, Karanja have some phytochemicals which affect the behavior and physiology of the insects. Pyrethrum, nicotine and related alkaloids; rotenone and related alkaloids, quassia, unsaturated isobutyl amide, acetogenins, citrus limonoids and essential oils have insecticidal phytochemicals. Some plants have various chemicals which act as juvenile hormone mimics, juvenile hormone antagonists, molting hormone mimics, chitin synthesis inhibitor and molting hormone antagonists. The plant products such as pyrethrum, pyrethrins, rotenone, ryanodine, nicotine, Neem seed kernel Extracts or neem oil, Karanja oil, lemon grass oil, Tulsi oil, garlic oil, turmeric oil, etc. have insecticidal values which in one or the other way are used against harmful insects on crops, stored grain pests , household pests such as mosquitoes, flies, cockroaches, house crickets and cloth moths. The plant-based insecticides are safer to human beings, animals, and birds. They are highly biodegradable and do not contaminate the environment. The usable forms from these plants can be easily extracted through aqueous or organic solvents. The essential oils can also be easily extracted various methods. Some products of these plants like neem seed kernel extract, neem oil, garlic oil, etc. are ready to use and available in the market.
In addition to the above-mentioned plants, there are other ones such as Aloe vera, Ficus, Ivy, Spider plant, Snake plant and Peace Lilies that act as an air purifier, can easily be grown in earthen pots inside the house. The medicinal plants like Tulsi (effective against cold and cough); Marua (good for bad breath and mouth ulcers); Aloe vera (effective against stomach problems and skin diseases). Kari Patta (helps in digestion) and mint (a good appetizer) can be easily grown in pots/kitchen garden for their daily use.
Professor and Additional Dean
Faculty of Agricultural Sciences