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Pesticides are harmful agents used to kill animals, fungi, or plants that harm crops or decorative plants economically or provide a health risk to domestic animals or humans. They disrupt the pest organism's normal metabolic activities. Herbicides, insecticides, and fungicides are examples of pesticides. Pesticides offer advantages and disadvantages, such as possible harm to humans and other creatures.
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| Table of Content |
Key Terms: Insect growth regulator, Pests control, Haloalkanes, Haloarenes, Target Group Pesticides
What are Pesticides?
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Pesticide is a substance or mixture of chemicals that either kill a pest or prevents or reduce the damage that a pest can inflict. Insects, mice, and other animals, as well as undesired plants (weeds), fungi, germs, and viruses, can all be pests.
Pesticides can also be used to regulate a plant's growth, defoliate a plant's leaves prematurely, or function as a drying agent (desiccant). Pesticides are chemicals, although they can also be made from natural things like animals, plants, bacteria, and other microorganisms.
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Pesticides Application Effects
Insects, rodents, fungi, slugs & snails, bird mites, and weeds are examples of pests. Pesticides have been described in a variety of ways. Insecticides, fungicides, larvicides, rodenticides, molluscicides, and other pesticides are among them.
Herbicides are used to kill weeds and other undesired plants, insecticides are used to control a wide range of insects, fungicides are used to prevent mold and mildew growth, disinfectants are used to prevent the spread of bacteria, and compounds are used to control mice & rats. People are exposed to low quantities of pesticide residues in their foods due to the widespread use of agricultural pesticides in food production.
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Types of Pesticides
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Active components in pesticides are classified according to the pests they control or how they operate. Following are the types of pesticides and they are divided into categories based on the pests they kill.
- Target Group Pesticides
- Chemical Structure
- Mode of Action
- Formulation
Types of Pesticides
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Target Group Pesticides
The following pesticides are part of target group pesticides.
- Insecticides
- Fungicides
- Herbicides
- Larvicides
- Rodenticides
- Algaecides
- Molluscicides
Chemical Structure of Pesticides
According to chemical structure pesticides are classified into the following groups.
| Structure | Example |
|---|---|
| Chlorinated Hydrocarbon | Kelthane |
| Carbamate | Sevin |
| Organophosphates | Basudin |
| Pyrethroids | Decis |
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Mode of Action of Pesticides
To understand the mode of action type pesticides, go through the following table.
| Direct Application | They are dusted or sprayed like pests |
| Fumigants | These are the harmful chemical gases that kill insects |
| Selective Herbicides | They destroys small seeds & weeds but not the plant. |
| Control as plant food | They kill those pests that are inhaled while eating |
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Formulation of Pesticides
Following is the basis of pesticides formulation:
| Parameters | Description |
|---|---|
| Dust | They are dry small particles |
| Granular | They are large dry particles |
| Wettable Powders | To make a steady suspension or solution |
| Dry bait pesticides | They're combined with pest food to make dry pellets that pests will consume. |
| Emulsifiable Concentrate | To make an emulsifier by dissolving a pesticide in an organic solvent. |
| Pheromones | are active compounds that restrict the growth of certain insects by interfering with their mating behaviour. |
| Wood Preservatives | To make wood more fungal and insect resistant |
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Benefits of Pesticides
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Following are the benefits of pesticides.
- Crop yields & Crop/livestock quality have improved.
- It extends the shelf life of stored food
- They are employed in the preservation and protection of the environment.
- The lives of animals have been saved, and sickness has been decreased.
- It can help to prevent deforestation, soil erosion, and natural resource conservation.
- Drivers have an unrestricted view & Wooden constructions are safeguarded.
- Hazards from trees, brush, and leaves are avoided.
- Human lives have been saved, and sickness has been decreased.
- Malaria is one of the diseases that has been managed, and millions of lives have been saved or improved as a result of DDT alone.
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Harmful Effects of Pesticides
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The following are the effects of pesticides.
- It can have acute, or short-term, negative health impacts, as well as chronic, or long-term, negative health effects that can develop months or years after exposure. Stinging eyes, rashes, blisters, blindness, nausea, dizziness, diarrhoea, and death are examples of acute health impacts.
- It has the potential to contaminate soil, water, turf, and other plants. It can be hazardous to birds, fish, helpful insects, and non-target plants in addition to harming insects and weeds.
- They impair soil quality, which in turn degrades food quality and yield. Chemical pesticides pollute and reduce the nutritional value of food.
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Things to Remember
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- They're employed to keep organisms that are dangerous or detrimental to their surroundings under control.
- The persistent ones, on the other hand, can take months or even years to break down.
- They are compounds that aid in the repelling or control of hazardous organisms to plants.
- Pesticides originating from natural elements such as animals, plants, microbes, and minerals are known as biopesticides.
- Crop protection enables farmers to protect their crops while also providing a high yield to the general public.
- Agricultural crops can be destroyed by a wide range of pests, resulting in significant financial loss.
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Sample Questions
Ques. Is it okay to use pesticides after they have dried? (2 Marks)
Ans. After they dry, pesticides used for lawn care are perfectly harmless. Some pesticides require additional precautions, including removing sensitive items from your property, avoiding regions near the ignition, applying in well-ventilated places, and ensuring that the pesticide does not saturate the area.
Ques. What are pesticides? Which of the five types of pesticides are there? (2 Marks)
Ans. A pesticide is any substance that is used to kill, repel, or control pests in plants or animals. The types of pesticides are as follows.
- Insecticides
- Herbicides
- Rodenticides
- Fungicides
- Molluscicides
Ques. Why are pesticides harmful? (3 Marks)
Ans. Pesticides are deposited in the gut, where they poison your body slowly but certainly. They have been linked to cancer, Alzheimer's disease, ADHD, and even birth deformities in numerous studies. They can also cause harm to the neurological, reproductive, and endocrine systems.
Over time, the substances might bioaccumulate in the body. Birth deformities, cancers, genetic abnormalities, blood and nerve diseases, endocrine disturbance, unconsciousness, and death are all possible side effects of exposure. Pesticides have been linked to developmental impacts.
Ques. How pesticides are used? (3 Marks)
Ans. Pesticides are chemical compounds used to kill pests such as insects, rodents, fungi, and invasive plants (weeds). They're employed in public health to kill disease vectors like mosquitoes, as well as in agriculture to kill pests that harm crops.
Mosquitoes, ticks, rats, and mice are among the pests and disease carriers that pesticides are used to suppress. In agriculture, pesticides are used to manage weeds, insect infestations, and illnesses. Pesticides come in a variety of forms, each of which is designed to combat certain pests.
Ques. What are the pesticides drawbacks? (3 Marks)
Ans. The consequences of widespread pesticide use are significant. It includes contamination and mortality of domestic animals, the loss of natural insect antagonists, pesticide resistance, honeybee decline, which affects pollination, fish and bird death, and groundwater contamination.
Furthermore, certain pesticides produce immunotoxicity in humans, which can lead to carcinogenesis, immunosuppression, hypersensitivity (allergies), autoimmune disorders, and inflammation; children may be especially susceptible to pesticide toxicity.
Ques. What are the advantages of using pesticides? (3 Marks)
Ans. Pesticides have the primary benefit of assisting farmers in keeping insects and other pests from harming crops. The following are the benefits of pesticides.
- Controlling organisms that harm other human activities and structures is beneficial.
- Control of pests and disease vectors in plants.
- Control of disease vectors and nuisance organisms in humans and animals.
Ques. What is DDT? (3 Marks)
Ans. DDT, or dichloro-diphenyl-trichloroethane, was the first modern synthetic insecticide to be produced in the 1940s. It was first employed successfully in both military and civilian populations to battle malaria, typhus, and other insect-borne human diseases.
Swiss chemist named Paul Hermann Müller created Dichloro-Diphenyl-Trichloroethane (DDT). An organochlorine is a colourless, tasteless, and practically odourless crystalline chemical compound. Originally designed as an insecticide, it became notorious for its harmful effects on the environment.
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