Green pesticides as a constituent of sustainable agriculture

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PAKISTAN BEING tropical country has diverse range of climatic conditions and its agriculture suffers severe losses due to pests. Pesticide production in the world shows a sudden escalating trend because of severe problems which are arising from the use of synthetic pesticides. Pakistani farmers need an effective tool against pests. In 1980s, the estimation of world pesticide production was about US$ 11600 million of which 14 percent spoke to herbicides, 34.7 percent insecticides, 18.8 percent fungicides and bactericides, and 5.5 percent some different pesticides, recently use of pesticides has expanded regarding amount add up to US$ 31191 million, of which the herbicides contributed 48 percent, insecticide 25 percent, fungicides and bactericides 24 percent and other shared 3 percent total pesticides cost around the world.

In Pakistan, 88.3% pesticides are utilizing as a part of Punjab, 8.2% in Sindh, 2.8% in Khyber Pakhtunkhwa and 0.7% in Baluchistan. Overall 90% herbicide and insecticides, 7% fungicides, and 0.2% acaricides and fumigants are being used as pesticides in Pakistan. The use of eco-friendly approaches is gaining importance but the small farmers in Pakistan are not completely aware of eco-friendly approaches to control the pests. Although, Pakistan has a valuable resources of plants that could be used as green pesticides, research on Green Pesticides has not gained ground. Green pesticides are good replacement to chemical synthetic pesticides.

Green pesticides are pest control elements that are less harmful compared to Chemical Pesticides and that can be just as effective as chemical pesticides. In this age overuse of pesticides caused the environmental problems, has been the matter of deep thinking for both public and scientists. There is demand to find the highly biodegradable pesticides to solve the problem of long term toxicity to mammals and environmental problems. There is need one must study the environmental friendly pesticides and develop techniques that can be used to reduce pesticide use while maintaining crop yields. In short terms we can say “The greenest solution to pest problems is natural control”.

Pesticides can easily be replaced by natural products as an excellent alternative to synthetic means of pest control to reduce negative impacts to the environment and human health. Moving towards green chemistry is a new crop protection tool with novel mode of action and makes commercialization of natural products as green pesticides a profitable and interesting act that is commanding attention.

Green pesticides concept refers to all types of natural and beneficial pest control techniques that can contribute to reduce the pest population and deals with food security. These approaches are eco-friendly and safe to use. As compared to chemical pesticides they are more compatible with the environmental components. Present concept of green pesticides comprises of substances such as plant extracts, pheromones, hormones and toxins from natural origin and also includes many aspects of insect control such as plant derived pesticides, pheromones and secondary metabolites from microorganisms.

Scientists are moving more and more towards natural means of fighting with insect. People have extracted compounds from plant origin to use as botanical (green) pesticides for hundreds of years. There is evidence dating back to 400 B.C. that compounds harvested from botanical species were used to control insect pests.

Biodegradable and target specific neem derived green pesticides have been used traditionally for many years. Neem oil is a natural mean of insect control as a repellent and insecticide that is effective on thousands of insect pests. It has two big advantages over synthetic pesticides first insect cant develop resistance to it; secondly it is not harmful to beneficial such as ladybugs. Neem extract has very low toxicity on humans and mammals. Neem seeds are rich source of neem oil and can be easily purchased in most countries. One once of neem oil mix with a gallon of water and one teaspoon of dish-washing liquid, after preparing the solution sprays on plants. It is very effective against insect control. The neem tree is the source of hundreds of products, including pesticides made from the extracts of the bark, leaves and seeds.

Azadirachtin is the primary insecti¬cidal extract in neem. Azadirachtin is act as an insect repellant, an anti-feedant and growth regula¬tor. Neem extract can act as a systemic insecticide i.e. upon application to the soil; the active ingredients are absorbed into the plant and transported towards leaves and growing tips. Neem pesticides are effective against many caterpillars, flies, whitefly, and scales can easily be control by neem extract. Neem extracts degraded within 3-4 days in the soil. Neem seed kernel extract can be prepared as: Take 3 to 7 kg of neem seed and gently ground it. The ground powder will be taken in the muslin cloth and tied to get a pouch; it is allowed to soak in 50 to 100 L of water for overnight. The pouch is squeezed for four to five times to get the extract into the water. To get milky neem seed kernel extract 50 to 100 gm of detergent is added to the solution. Keep in mind spray the extract after 3.30 p.m. to get effective results.

Tobacco was used as an insecticide to control plant pests and effective about thousands of years. The stem and leaves of tobacco plant are used as insecticides. Nicotine is present in tobacco in the form of toxic substances. Nicotine spray was traditionally used to control the range of pests including whiteflies, leaf aphids, thrips and leaf miners. Homemade “tobacco juice” is short-lived and much milder nicotine containing solution used to kill pest. Commercial products that contain various plant extracts such as garlic, neem and allelopathic crops extract allowed for use on some crops and plants. Tobacco juice extract can be prepared as: take 250 g tobacco biomass after collecting boil it in 4 liters of water for half hour. Add 30 g soap and mix well. Dilute 1 part extract with 4 parts of water and use as spray. Adding a little lime powder increase the efficacy of the extract.

Green pesticides are less toxic than synthetic pesticide. They generally affect only the target pest and are closely related organisms compared to synthetic pesticides that are not target oriented may affect many organisms such as birds, insects, and mammals. Small quantities of green pesticides are effective and often decompose quickly, thereby avoiding the pollution problems caused by synthetic insecticide. Green pesticides used as a component of Integrated Pest Management (IPM) programs and can greatly decrease the use of synthetic insecticide, while crop yields remain high.

Green pesticides must be handled with proper care, use as you required. After handling it always wash your hand, foods on which these are used always wash before eating or selling. A green pesticide also works according to the conditions not in all conditions. Due to little scientific research their effectiveness and modes of action are not understood properly. Further studies are required to explore this natural approach against any type of pest and one should show interest in this direction. At present day, scientists are encouraged to carry out research on green pesticides and develop low cost production technology for farmer and farmers are also showing greater interest in the use of green pesticides.


Published in: Volume 06 Issue 33

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