IMPACTS OF PESTICIDE USE IN AGRICULTURE
Megha C M
Guest lecturer-Dept of Zoology
Mob. No: 9611297351
Environment safety and food security are the major concern in frequently growing human population all over the world. Pest cause a serious damage in agriculture in terms of yield and high price if chemicals that cost much rupees annually and increase the agricultural production budget. The wide spread application of chemical pesticides has been preferred due to benefits they provide in agriculture, particularly by protecting crops from pest damage. On the other hand pesticides passes a serious danger to human health and environment .farmers and specially those directly involve in handling of pesticides are at high risk of exposure to pesticides when mixing and applying pesticides or working in treated field and form residues on food and drinking water . in many cases farmers face great risk of exposure due to use of toxic chemicals that are banned, incorrect application of chemicals ,purely techniques ,poorly maintained or totally inappropriate spraying equipment, inadequate storage particles and often reuse of old pesticides containers for food ,poor use of personal protection equipment’s. Various human health related concerns are associated with pesticides, ranging from short term impact such as head ache and nausea to chronic impacts, such as various cancers, birth defects, infertility and endocrine disruption. Children are more endangered by short term and chronic exposure to pesticides. Excessive use of pesticides may lead to destruction of biodiversity, secondary pest outbreaks, destruction of non target species, soil, water and air contamination. The purpose is to discuss hazardous effects of chemical pesticides on human health and environment.
Pesticide Impact on Insect Natural enemies.
Predators are organisms that live by preying on other organisms and play a very crucial role in keeping pest population under control. Predators can be exposed to insecticides under the following circumstances, by direct contact with the spray droplets by uptake of residues when contact with the contaminated surfaces, acaricides and insecticides have negative effects to varying degrees of all stages. From toxicity of five insecticides(tubufenozide, flufenoxuron) on predator mites. The toxicity effects on reproduction and survival of adult stages. Pesticides affect predator behaviour and their life history parameters including growth rate and development.
Insecticides such as indoxacrab, thiamethoxum.
Pesticide impact on pollinator:
Using pesticides in agriculture could causes direct loss of insect pollinators and indirect loss of crabs because of lack of adequate population of pollinators. Bees are the prominent and economically most important group of pollinators world wide. 35% of world good crops depends on pollinators pesticide risk is not limited to its acute toxicity and level at which it becomes lethal to an individual insect. There is a high level of mortality due to homing failure, besides bees many other pollinators such as butterfly, ladybugs and lacewings, dragonflies and houseflies are under exposure. A number of these species are facing severe declines similar to or worse than those faced by honeybees.
Pesticide impact on human health:
Pesticide cause a acute and chronic poisoning with effects of varying hazard on human health, from mild effects to death. Exposure to pesticides normally occur while spraying the solution loading in spray tank and while applying the pesticide, pesticides such as Atrazine,chloropyrifos,malathion causes immune effect caused by some pesticides ,carbonyl, endosulfan ,methachor causes cancer (bone,leukemia,prostate cancer, breast cancer etc) Atrazine causes birth defects and fetal growth. Organophosphate causes respiratory problems and DDT causes metabolic disorders.
Pesticide impact on aquatic systems:
Aquatic environments are exposed directly and indirectly to pesticide through overspray, runoff or spraydrift ,affecting aquatic plants and micro invertebrates and vertebrates such as fish and amphibians. The impact of pesticides on aquatic environment is influenced by their water solubility and uptake ability within an organism for example , an herbicide clomazone is compared the toxicities of two herbicides griazine compounds on freshwater algal community above 0.05mg/L algal growth rate will be completely inhibited by endosulphan the Anabena growth rate will be completely stops.
Pesticide impact on soil environment:
Adverse effects of pesticides on soil microorganism ,soil enzymes functional diversity pesticides causes direct toxic or chemical effects on microbial communities the persistence concentration and toxicity of pesticides affects the soil micro organisms cause due throwing of pesticides on soil in water ecosystem and sprayed on plants. The pesticide triflutin or oryzalin inhibit growth of symbiotic fungi that helps in nutrient uptake it effects the earthworm at cellular level causes DNA damage, glycophosphate affect feeding activity and viability of earthworms.
pesticides have now become an essential part of agricultural production , many pesticides are not easily degradable they persist in soil, laech ground water and surface water contaminate wider environment. The above discussion clearly highlights the hazards concerns of indiscriminate use of pesticide results in environment negative effects in environmental components and human health , adverse effects are increase in resistant pest population, decline on beneficial organisms contamination of aquatic forms. This is the time that necessitates the proper use of pesticides to protect our environment and eventually health hazards associates with it. To reduce intensive use of practices and search for effective bio pesticides or biological agents to control agricultural pests in order to reduce to chemical pesticides.