Pesticides

Pesticides are substances that are used to control pests. Pesticides can be chemical such as carbanate or biological like bacteria or viruses that deter or kill pests. It may include insecticides to kill insects, herbicides for weed control, fungicides to control fungi, and rodenticides to kill rodents. Pesticides are used to target pests that are considered to be harmful like insects, weeds, microbes, etc. However, along with the benefits pesticides can cause harmful effects too including harm to the nontarget species, environmental degradation, a potential risk to human health, and loss of biodiversity.

Definition of Pesticides

Pesticides are chemical substances that are used for preventing, destroying, or controlling any pest. They include insecticides, herbicides, ungicides, etc.

What are Pesticides?

According to The Food and Agriculture Organization (FAO), a pesticide is defined as any substance or mixture of substances intended for preventing, destroying, or controlling any pest, including vectors of human or animal disease, unwanted species of plants or animals, causing harm during or otherwise interfering with the production, processing, storage, transport, or marketing of food, agricultural commodities, wood, and wood products or animal feedstuffs, or substances that may be administered to animals for the control of insects, arachnids, or other pests in or on their bodies.

They include herbicides, insecticides, fungicides, and other substances used in agriculture and pest management. Herbicides target unwanted plants, insecticides control insect infestations, and fungicides control fungal infections. Pesticides are used in public health to control disease vectors like mosquitoes, and reduce the spread of illnesses. However, prolonged exposure or misuse of pesticides can result in risk to human health, harm to non-target species and biodiversity loss.

Types of Pesticides

Pesticides can be classified on the different criteria that is as follows:

• On the basis of the type of pest it kills. For example herbicides, insecticides, fungicides, and rodenticides.
• On the basis of chemical structure. For example organic, inorganic, synthetic, or biological (biopesticide)
• On the basis of biodegradablity. For example Biodegradable and Non biodegradable or persistent.
• On the basis of physical state. For example gaseous that is fumigant.

On the Basis of the Type of Pest it Kills

On the basis of the type of pest it kills, it can be classified as:

• Herbicides: Target unwanted plants (weeds).
• Insecticides: Aimed at controlling and eliminating insects.
• Fungicides: Combat fungal infections in plants.
• Rodenticides: Used to control rodents.
• Pediculicides: Specifically designed to eliminate lice.
• Larvicides: Used to destroy larvae

On the Basis of Chemical Structure

On the basis of chemical structure pesticide can be classified as:

• Organic Pesticides: Derived from living organisms or natural substances.
• Inorganic Pesticides: Chemical compounds containing metals or minerals.
• Synthetic Pesticides: Chemically manufactured substances.
• Biopesticides: Derived from living organisms, including bacteria, fungi, and botanical extracts.

Other chemically-related Pesticides

Other chemically-related pesticides includes:

1. Organophosphates: It is widely used in the agriculture and target a broad range of insects. It kills the insects by disrupting their nervous system by inhibiting neurotransmitter acetylcholinesterase.
2. Pyrethroids: It effects the nervous system of insects. It attracts the insects as it mimic the natural pyrethrins found in chrysanthemum flowers.
3. Neonicotinoids: It is used in agriulture to control the pest population. It affects the nervous system of insects by acting on insect nicotinic acetylcholine receptors.
4. Carbamates: It is used as insecticides and fungicides in agriculture. It inhibit acetylcholinesterase, similar to organophosphates.
5. Triazines: It is used as herbicides for weed control in crops. It inhibit photosynthesis in plants by disrupting electron transport.
6. Benzimidazoles: It is used as fungicides used in agriculture and horticulture to control fungal diseases. It disrupt fungal cell division by interfering with microtubule formation.

On the Basis of Biodegradability

On the basis of biodegradablity the pesticides can be divided as:

• Biodegradable: These pesticides can be broken down by the microbes and other living organism into harmless compounds.
• Non-Biodegradable: These pesticides can not be broken down easily by the microorganisms. They remain in the envrionment and it take years to break them.

On the Basis of Physical State

On the basis of physical state for example in the gaseous Pesticides like Fumigants. It is applied in the form of gas to control pests.

Examples of Pesticides

Various examples of pesticides include fungicides, herbicides, and insecticides.

• Insecticides: Heptachlor, Aldrin, BHC, DDT, Endrin, Chlordane, Parathion.
• Herbicide: Atrizine, Simazine, Propazine, Diuron.
• Fungicide: Maneb, Ferbam, Ceresin, Copper sulphate.

Uses of Pesticides

Uses of pesticides includes the following:

• Pesticides are used in agriculture to protect crops from pests such as insects, fungi, and weeds.
• The use of the pesticide increases the yield and improves the quality of the crop.
• Pesticides are used to manage and control the disease-carrying vectors, such as mosquitoes and ticks and help to preven the diseases like malaria.
• Herbicides are commonly used in ponds and lakes to control algae and plants that interfere with swimming and fishing.
• Pesticides are used to protect livestock from parasites and insects that can harm or transmit diseases to animals.
• They are used to protect the stores grains and other food products from infestations by insects and rodents.
• Herbicides are used to control or eliminate unwanted plants or weeds in agriculture fields.
• These are used to control invasive species that can have negative impact on the ecosystems by outcompeting native species.
• They can also kill bees, wasps or ants that can cause allergic reactions.

Harmful Effects of Pesticides

Pesticides are chemical or biological substances used to control or eliminate pests. The excess use of the pesticide can cause various harmful effects like:

• Pesticides can contaminate soil, water, and air, leading to environmental pollution.
• It may harm non-target organisms like birds, bees, that can disturb the ecosystem balance and biodiversity.
• It can leach into groundwater, contaminating drinking water sources.
• Some pesticides, particularly neonicotinoids, are associated with declines in pollinator populations, such as bees, butterflies.
• Pesticides have negative effect on the endocrine system in humans and wildlife, that can cause reproductive and developmental issues.
• Pesticides can remain in the envrionment for a long period of time and have a negative impact on ecosystem.
• Pesticides can bioaccumulate in the tissues of organisms, moving up the food chain and can reach upto a level that is harmful to predators, including humans.
• Farmers and labourers involved in the application of pesticides face occupational hazards, including acute poisoning and long-term health effects.
• Over time, target pests can develop resistance to pesticides making them less effective.

Pesticide Control

Pesticide control means the management and regulation of the use of pesticides to ensure their safe and effective application while minimizing potential harm to human health, the environment, and non-target organisms. There are in total 292 pesticides registered in India and are registered with Directorate of Plant Protection, Quarantine & Storage under the Ministry of Agriculture & Farmers Welfare. In India pesticides control involves a combination of regulatory measures, monitoring, and awareness programs. Some of the steps that have been taken for pesticides control are as follows:

• The Insecticides Act, 1968 and Insecticides Rules, 1971 regulate the import, registration process, manufacture, sale, transport, distribution and use of insecticides (pesticides).
• All pesticides have to undergo the registration process with the Central Insecticides Board & Registration Committee (CIB & RC) before they can be made available for use or sale.
• On the packaging the labels are used that provides information related to the usage, precautions to be taken and disposal method.
• Central Insecticides Board & Registration Committee (CIB & RC) scrutinizes and periodically reviews all pesticides and their usage. In cases where pesticides are found to be harmful or have adverse effects, the authorities may impose bans or restrictions on their use.
• The FSSAI regularly check the pesticides residue in the food products.
• The government promotes Integrated Pest Management (IPM) that encourages the use of biological control, cultural practices, and resistant crop varieties in addition to judicious pesticide use.

Biological Pesticides

Biological pesticides, also known as biopesticides, are pesticides derived from natural materials such as animals, plants, bacteria, and certain minerals. Biopesticides are used for controlling pests in agriculture, forestry, and public health. There are three main type of biopesticides: Predatory or Parasitic Organisms pesticides (derived from beneficial insects or other organisms), Microbial pesticides (derived from microbes), and Plant-incorporated protectants (derived from plants). The commonly used biopesticides are living organisms, which are pathogenic for the pest of interest such as biofungicides (Trichoderma), bioherbicides (Phytophthora), and bioinsecticides (Bacillus thuringiensis). 

Biopesticides work through various mechanisms, such as predation, parasitism, competition, antibiosis, or interference with the pest’s reproductive cycle. They are target specific and having minimal impact on non-target organisms. They leave little to no residue on crop and have lower toxicity to humans, animals, and beneficial insects. They are useful in sustainable agriculture and organic farming.

FAQs on Pesticides

1. What are Examples of Pesticides?

Examples of pesticides are insecticides, fungicides, herbicides that are – Glyphosate, Acephate, Deet, Propoxur, Metaldehyde, Boric Acid, Diazinon, Dursban, DDT, Malathion, etc.

2. How do Pesticides Kill Insects?

Pesticides such as insecticides act in the nervous system of the insects, inhibit their biochemical processes or interfer with their ability to feed and reproduce. The mechanism of action depend on the type of pesticide and its mode of action.

3. Are Pesticides Harmful to Humans?

Yes, the pesticides can be harmful to humans by exposure through ingestion, inhalation, or skin contact. They can cause short term harm including stinging eyes, rashes, blisters, blindness, nausea, dizziness, diarrhea and death. Long term effects can include damage to the kidney, lungs or brain and can cause cancer.

4. What is a Pesticide Used For?

Pesticides are used to control and manage the pests such as insects, fungi, rodents and weeds. They are used in agriculture fields to protect crops and in public health to control vectors borne diseases like malaria.

5. What are Basic Pesticides?

Pesticdes include insecticides for controlling insects, herbicides for managing weeds, fungicides for combating fungal diseases, and rodenticides for addressing rodent infestations.