Pesticides are toxic compounds that are used to eradicate, kill, and control pests that are hazardous to seeds, plants, trees, birds, animals, people's health, and building sites. Pesticide is defined as any organic, vegetation, biological, or chemical material that is used to protect plants, agricultural products, forest and forest products, living things, livestock, human health, storage, packaging, and construction projects from any harmful disease, insect, mite, nematode, weed grass, and rodents. This definition is based on the Pesticide Management Act 2076 (B.S.).
In 1952 AD, DDT was initially brought into Nepal in order to combat malaria. In our nation, 396 grams of pesticides are now used per acre on average. Approximately 80% of pesticides that are applied end up incorporated into the soil, where they take a while to dissipate. This leads to the destruction of soil microorganisms and increases the likelihood of contaminating surface and subsurface water sources.
Types of Pesticides
The pesticides are divided into the following classes according to their method of action, impact on the environment, and pests they target:.
On the Basis of Effect on the Environment
Based on their impact on the ecosystem, pesticides may be classified into two categories:
- Non-persistent or environmentally biodegradable
Biodegradable pesticides are those that microorganisms and other living things can easily break down into harmless molecules when exposed to water, air, light, or heat. Malathion, dimethoate (Nugor, Rugor, Dimet), etc. are a few examples.
- Persistent or not biodegradable in the environment
These pesticides are long-lasting in our food chain and do not break down readily in the environment. Most nations have outlawed this kind of insecticide. The use, import, and export of these chemicals are prohibited in Nepal as well. Take DDT, Aldrin, and so forth.
On the Basis of the Pests They Affect
- Insecticides
Insecticides such as malathion, cypermethrin, fenvalerate, nitenpyram, etc. are used to eradicate and manage dangerous insects.
- Fungicides
They are employed to combat fungus and the illnesses they can cause. Dimethomorph, Sectin, Mancozeb, Carbendazim, etc. are a few examples.
- Herbicides:
In our agricultural lands, they are employed to eradicate or manage invasive herbs and plants. For instance: atrazine, butachlor, isoproturon, etc.
- Rodenticides
Rodenticides are insecticides that are used to kill rats and other rodents, including mice, squirrels, hamsters, porcupines, etc. For instance, bromadiolone, coumatetralyl, and zinc phosphide.
- Miticides
They are used to kill mites. For example: bifenazate, fenazaquin, propargite, fenpyroximate, etc.
On the Basis of Mode of Action
- Contact Pesticides
When these insecticides come into direct contact with their bodies, they destroy pests like as aphids (lahi), larvae, thrips, white house flies, etc. Some examples of contact insecticides are malathion and chlorpyrifos.
- Internal Pesticides
The poisoning impact of these insecticides kills the pests when they eat the leaves, flowers, and fruits of the plants. This category includes pesticides such as fenvalerate, malathion, and cyclomethrin.
- Systemic Pesticides
Plant components that absorb pesticides, such as roots, leaves, etc., turn the plant into a poison. Thus, insects are likewise destroyed when they consume the plant material or drink its juice. Systemic pesticides include those that kill aphids, larvae, thrips, white house flies, leaf miners, stem borer, etc. Examples of such pesticides are thiamethoxam and dinotefuran.
- Fumigants Pesticides
When these insecticides come into contact with the air, they release toxic gases or fumes that kill the bugs. Typically, these insecticides are used to eradicate pests while agricultural products are being stored. Methyl bromide and aluminum phosphide are two examples.
Safety Precautions in the Use and Storage of Pesticides
The following precautions must be followed strictly during the storage and use of chemical pesticides:
- Only pesticides that have received approval under the "Pesticides Management Act, 2076" are legal for use, production, trade, or importation.
- Only agricultural professionals should recommend the purchase of pesticides. Similar to this, any leftover pesticides need to be handled and kept in a secure location after usage.
- Pesticide labels need to be legible and complete.
- It is not advisable to keep pesticides close to food storage areas or in areas that are easily accessible to youngsters.
- The insecticides need to be kept in a leak-proof, airtight container.
- Users should read and completely adhere to the directions provided on the label, as even a slight error or act of carelessness can result in an accident and damage.
- Use only less toxic but still effective insecticides. Additionally, full-body protection suits are worn when operating them. Gloves should be used in addition to masks for the mouth and nose, goggles for the eyes, and masks for the nose.
- Pesticide-spraying tools need to be cleaned right away after use and kept in a secure location. They must not, however, be cleaned in close proximity to water sources.
- As soon as we finish using the insecticides, we ought to wash our hands and take a bath.
- We ought to do all in our power to implement the integrated pest control strategy.
- After applying pesticides, produce, fruits, and vegetables shouldn't be sold or eaten right away.
- Only the crop protection officer may authorize the purchase of the most hazardous pesticides categorized as Group IB pesticides.
- The saying "all pesticides are poisons; they are not medicines" is one we should remember.