Pesticide is defined as any substance or 'mixture of substances, intended for preventing, destroying or controlling any pest including vectors of human or animal diseases, unwanted species of plants and animals. Pesticides are classified according to their use and kinds of applications as insecticides, fungicides, herbicides and, other pesticides. Insecticides account for the major share of pesticides consumption in India that includes both preventive treatments, which are applied before infestation levels are known, and intervention treatments, which are based on monitored infestation levels and expected crop damages. The use of pesticides in Indian agriculture was negligible in early 1950s with only 100 tonnes of pesticides being consumed at the beginning of the First Five Year Plan. Consumption of pesticides (technical grade material) stood at 55.54 thousand tonnes in 2010-11. However, there are vast inter-State differences in the level of consumption of pesticides.
Effects of Pesticides
In recent times (particularly during the last two decades), increasing attention has been drawn to the health hazards and environmental problems that are caused by the unabated use of pesticides. Health hazards are both direct and indirect.
Another problem with the use of pesticides is that the targeted pests develop resistance towards them. As a result, higher and higher doses of more and more toxic chemicals have to be applied. Use of fertilizers and pesticides brings about physiological changes in plants leading to multiplication and proliferation of several pests. It is also important to note that pesticides application needs a scientific approach and Integrated Pest Management On account of the above reasons, what is now advocated is not just pest extermination but economical utilisation of pesticidal chemicals with least ecological damages. The main facets of the plant protection system currently in use are the following three - pest and disease control through Integrated Pest Management (IPM) schemes, locust surveillance and control, and plant and seed quarantine. Integrated Pest Management includes pest monitoring, promotion of biological control of pests, organising demonstration, training and awareness of IPM technology. The IPM technology encourages the use of safer pesticides including botanicals (neem based) and bio-pesticides.
What are common pesticides used in India?
The pesticides used in India can be classified into five on the basis of chemical nature.
1. Organochlorides:- These are organic compounds with many atoms of chlorine per molecule. DDT, BHC, ALDRIN, DIELDRIN and ENDRIN are chlorine pesticides. DDT is the oldest and most popular synthetic pesticide. BHC alone represents 50% of the total pesticide volume of pesticide. Aldrin is used in the foundation/base of buildings to prevent attack by termites. All these chemicals are lipophillc and get bio-accumulated in the fatty tissue of animals.
2. Organophosphates:- MALATHIION (Flit) used in anti-malarial programmes and PARATHION are esters of organic compounds with phosphoric acid. Fenitrethion, Malathion and parathion are very effective on the nervous system.
3. Carbamates:- These are compounds having a chemical structure similar to acetylcholine. Carbofuran (furadon), propoxur (baygon) are carbamate pesticides.
4. Pyrethroids:- These are synthetic products from pyrethin, a plant chemical extracted from chrysanthemum cinerarifolium.
5. Triazines:- These are compound like simazine, altrazine derived from urea. They are effective weedicides (herbicides) used against the weeds of tea, tobacco and cotton.
Use of pesticides increased substantially in India after the success of Green Revolution. Although the use of pesticides protected the crops in Indian but it caused environment degradation and danger to the human being and animals as well.