Pesticides worry farmers more than pests!

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Cory Davidson
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1 Pesticides and their impact on environment Pesticides worry farmers more than pests! Annually Rs. 25,000-50,000 crore worth of crops is destroyed by pests and insects in India, making the use of pesticides inevitable. But indiscriminate and senseless use of pesticides has killed 2.2 lakh people and has caused diseases in 30 lakh people. A comprehensive management of pests is called for says Mr. P. K. Shetty, Environmental Scientist, National Institute of Advanced Studies, Bangalore. INEP: What is a pesticide? Mr.Shetty: Pests and insects form 71 per cent of the animals in bio-diversity. There are both good and bad insects. Poisonous chemicals are used to keep a check on the quantity of insects. Pesticides are used to increase the yield of the crop by eliminating the disease causing bacterium and also in warehouse and godowns to keep the stored grains free of fungus and other agents of destruction. Insecticides are used in public health programmes and in our homes too to get rid of insects. Indiscriminate use of pesticides can affect our health and the environment. We have to ensure that the use of pesticide is kept to the minimum and that the best quality pesticide is used. The other commonly used insecticide is the organophosphorus. Insecticides with chlorophiriphos, dichlorophos and dimethophos are also used by our farmers. The other compounds used include a carbonate group, organochlorine compounds and synthetic parathrite. INEP: What is biological control of pests? Mr. Shetty: Using natural elements to counter insects is known as biological control of insects. Bio-pesticides are available for controlling harmful insects. The natural enemies of these insects are predators and parasites. There are also some bacteria and viruses that help in controlling pests. INEP: Which are the commonly used pesticides in India? Mr. Shetty:In our country, 181 registered pesticides are used. Different products are used for different purposes. To remove or control diseases we use fungicides. Likewise, we have acaricides, nimaticides, and rodenticides. In our country, the menace of insects is so much that 61% of the pesticides used are insecticides. INEP: Environmentalists say that the use of pesticides has adversely affected both our food and our environment. So what exactly is the role of pesticides? Mr. Shetty: It depends on where the pesticides are used and the quantum of pesticides used. Uncontrolled and unwarranted use of pesticides can adversely affect the environment and health. For instance, indiscriminate use PARISARA SOBAGU 9

of pesticides can even destroy beneficial insects and bacteria resulting in the increase of harmful insects. This will have a direct impact on the ecological balance.

2 of pesticides can even destroy beneficial insects and bacteria resulting in the increase of harmful insects. This will have a direct impact on the ecological balance. Another worry is the entry of these pesticides into our food products. Nowadays pulses, rice, vegetables, milk, eggs, fish and meat show a considerable pesticide content in them. According to a latest reports the use of pesticides has affected more than 30 lakh people all over the world. They have fallen ill. More than 2.2 lakh people have died due to illness caused by pesticides. The chemicals in pesticides results in blindness, cancer, hepatic disorders, nervous disabilities and infertility, to name a few. Also a continuous use of pesticides or insecticides has made the insects and pests develop resistance to them. So, to get rid of these pests and insects the potency of the insecticides has to be increased. As pests become stronger, we are forced us to use stronger chemicals, which destroy our crop and also adversely affect our health. INEP: Do we have any alternatives to chemicals pesticides? Mr. Shetty: We do have organic pesticides. We now have like neem and its products, rotenone, quassia and their by-products. We have bio-pesticides like Bacillus thuringiensis, popularly known as Bt, trichogramma, persirola and NPV. It is opined that use of natural enemies of insects and pests, be they in the form of predator or parasites, as done in organic farming, would reduce the use of chemical pesticides. INEP: Is there a rule to limit the use of pesticides? Mr. Shetty: The use of chemical pesticides becomes a necessity especially in modern agricultural methods. What I am emphasising is that a balance has to be Neem an organic pesticide maintained by using some natural pesticides along with chemical pesticides. INEP: Does the use of pesticides affect other organisms? Mr. Shetty: It does. We have a target organism in mind when we use a chemical pesticide. But in the process we also destroy an organism that is not targeted. INEP: Then, how do we safeguard the untargeted organisms? Mr. Shetty: One method is to limit the use of chemical pesticides keeping in mind the untargeted organisms. We should have knowledge of the insects that are beneficial to the crops. Otherwise we destroy even the good insects with the use of chemical pesticides. INEP: What is bio-magnification? Mr. Shetty: The chemical pesticides we use have long lasting properties. The effect is that they will stay for long periods of time in small quantities in smaller organisms. The strength of the ingested pesticide increases each time the small organisms are consumed by bigger ones. By the time they enter the food chain and reach us the chemical concentration is in substantial quantities. For example, if a small quantity of chemical pesticide gets into algae and that is consumed by small fish, which are consumed by big fish, and we consume 10 PARISARA SOBAGU

those fish, the chemical content of those pesticides will have magnified into huge proportions. This is known as bio-magnification. INEP: We hear a lot about comprehensive or holistic pest management.

3 those fish, the chemical content of those pesticides will have magnified into huge proportions. This is known as bio-magnification. INEP: We hear a lot about comprehensive or holistic pest management. Please explain. Mr. Shetty: When we use a pesticide, we should ensure that it is not just a chemical pesticide but a judicious mix of all types of pesticides. We should also use other cultures like organic and herbal pesticides. Some pests should be eliminated mechanically. Weeds should be removed manually. We should use chemical pesticides only when it is absolutely necessary. We should take care that the crop and the environment are not affected by the use of pesticides. Such judicious management of the use of pesticides is known as comprehensive pest management. INEP: Can the use of pesticide be limited if we use a genetically modified species? Mr. Shetty: Arguments for and against whether the genetically modified crops are pest-resistant, and whether the use of pesticides can be reduced are still on. For example, the use of Bt, a bacterial gene, for pest resistance in cotton has proved that it can resist an attack from a pest called helicoverpa. It has been proved so scientifically but only in laboratory conditions. But the debate is still on about its behaviour in field conditions and whether our farmers will accept it. INEP: What is the quantum of loss due to insects and pests? Mr. Shetty: According to one estimate every year in India Rs.20, 000 to 50,000 crore worth of crop loss is reported due to insects. This figure will increase if we do not control insects with the use of pesticides, both chemical and organic. INEP: Were we using pesticides earlier? Mr. Shetty: Man has been using pesticides ever since he began to grow crops. There is documented evidence about the use of sulphur to contain the attack of pests and insects by a Sumerian tribe in Greece around 2500 B.C. We have records and documents showing the use of organic pesticides. In 900 A.D. the Chinese used red ants to control insects affecting the citrus groves. In 1763, nicotine was used as a botanical pesticide. In 1865 Paris green was successfully used to contain insects. After 1940 a variety of pesticides have become common. Now more than worrying about the insects, farmers are worried about the insecticides that destroy them. INEP: These are all records about countries abroad. What about our country? What have been their uses in India? Mr. Shetty: Right from the beginning, we have been using organic methods in agriculture. So neem and its products and other herbal pesticides have been used to withstand and avoid the onslaught of insects. After the green revolution, that is, after 1960, we have been using inorganic chemical pesticides. INEP: Can we completely do away with pesticides? Helicoverpa PARISARA SOBAGU 11

Mr. Shetty: In the modern method of agriculture, especially for growing high yielding hybrid varieties, the use of chemical pesticides has become inevitable.

4 Mr. Shetty: In the modern method of agriculture, especially for growing high yielding hybrid varieties, the use of chemical pesticides has become inevitable. If we want to reach a stage of saying no to pesticides, we have to be choosy about the crop we grow. We need a system where we can control the use of pesticides. We have to incorporate a holistic management of the use of pesticides. If possible, we have to adopt organic methods of farming. and using gloves. In several countries they have masks, while some use respirators and others protective clothing. In our country we have to use all these. We have to keep children away during the spraying of pesticides. Before spraying, we have to check the direction in which the wind is blowing. A week prior to harvesting no insecticide should be used, as the insecticides reach the market along with the vegetable produce and ultimately the humans. INEP: Can you please tell us the overall impact of pesticides on the environment? Mr. Shetty: The use of chemical pesticides adversely affects our health. It affects bio-diversity. It kills the nontargeted organism when we use pesticides on the target organism. An indiscriminate use of pesticides and senseless application increases the dangers of the use of pesticides. INEP: Can you name some insects and beetles that affect our crops? Mr. Shetty: Helicoverpa is one that is commonly seen affecting the cotton crop. Helicoverpa is a broad spectrum insect, which affects several crops and in larger quantities. It has the capacity to eat not just one, but several crops and in larger quantities. Paddy is affected by the brown plant hopper, a major destroyer. In vegetables we have the diamondback moth which is a major pest. INEP: What are the precautions one has to take while using pesticides? Mr. Shetty: One has to take precautions, like covering up one s face Diamondback INEP: What is the ideal time to use pesticides? Mr. Shetty: Generally the morning and evening times are the best to use pesticides. At other times one sweats more profusely than, and hence along with the sweat the pesticide may get underneath the skin. So we have to use pesticides when we sweat the least. INEP: We have to wash vegetables and fruits before we consume them. It is good, healthy habit. Mr. Shetty: People feel that pesticides can be present only on the outer skin of the vegetables. There are some chemicals that stay inside the vegetables. We cannot do without vegetables and fruits. So we have to wash them well at least to eliminate some amount of pesticides. Further, when vegetables are boiled it reduces the impact of pesticides. Some of the organochlorine compounds accumulate in fat-rich organs and it is difficult to reduce or eliminate them. But all these elements are likely to get into human bodies. If more care is taken and vegetables and fruits are washed well with clean water we can reduce the amount of pesticides that we consume. Student: What are the ill effects of the use of chemical pesticides on food? Mr. Shetty: Chemical pesticides are used to increase the yield of the crop, the size of the crop and to prevent 12 PARISARA SOBAGU

5 insects, beetles and other pests which cause diseases to plants. It is natural that some portion of these gets into the food product and then into our body, be it vegetables, fruits, paddy, wheat or anything. Some portion gets washed away when we wash them with water but some other elements that are inside the food product reach our body or system. Once inside the body it can cause various diseases like cancer, nervous disorders, hepatic disorders etc. Student: Why do we use pesticides? Mr. Shetty: Chemical pesticides, organic pesticides or herbal pesticides are all used to protect plants from insects or pests and disease-causing organisms. These are also used to increase the yield of the crop. Student: Which are the most popular pesticides used now and what are the reasons for banning a few among them? Mr. Shetty: Most of the pesticides used nowadays are oxygano-chlorine compounds. These have devastating effects on humans and environment. This is a long lasting pesticide. Along with the food, these organochlorine compounds be it DDT, BSE get into our body and produce adverse effects. This is proved by scientific experiments. Some studies say that traces of these dangerous elements are available in breast milk too. Hence these compounds have been banned in India and several other countries because they are very dangerous to bio-diversity and also humans. Student: What is DDT? Mr. Shetty: DDT is an organo-chlorine insecticide. DDT means Dichloro-Diphenyl-Trichloroethane. Reports suggest that this is harmful to the environment and humans. This is a very powerful and poisonous pesticide. It is also a long lasting one. At one time it was used to contain the spread of malaria. We can imagine how powerful a chemical it is. This is also known as a broad spectrum insecticide. It is used to control a variety of insects. Considering the ill effects that this had been causing the use of DDT has been drastically reduced. Protective gear is essential while using pesticides PARISARA SOBAGU 13

Chapter 23 Pest Management

Chapter 23 Pest Management Overview of Chapter 23 What is a Pesticide? Benefits and Problems With Pesticides Risks of Pesticides to Human Health Alternatives to Pesticides Laws Controlling Pesticides Use