Classification of pesticides

According to the World Health Organization (WHO), pesticides are chemical compounds that are used to kill pests, including insects, rodents, fungi and unwanted plants (weeds). Pesticides can be classified or grouped in many different ways some of which are outlined below. 

CLASSIFICATION OF PESTICIDES BASED ON;

1. TARGET ORGANISM

Pesticides can be grouped based on the different types of organisms that they control. This class of pesticides include;

• Insecticides - These are pesticides that specifically target and kill insects. They include ovicides and larvicides used against insect eggs and larvae, respectively. Examples of insecticides include parathion, malathion, diazinon, methyl parathion etc.

• Fungicides - Fungicides are biocidal chemical compounds or biological organisms used to kill parasitic fungi or their spores. Examples of fungicides include carbendazim, mencozeb, merpan, hexanconazole etc.

• Bactericides - These are substances that kill bacteria. Bactericides are disinfectants, antiseptics or antibiotics. Examples of bactericidal are daptomycin, fluorquinolones, metronidazole, nitrofurantoin, contrimoxazole etc.

• Herbicides - These are substances that are toxic to plants and used to destroy unwanted vegetation. Selective herbicides kill certain targets while leaving the desired crop relatively unharmed. Examples of herbicides include Dicamba, Glufosinate ammonium, atrazine, simazine etc.

 2. CHEMICAL STRUCTURE (SOURCE)

Pesticides are also classified based on their source or chemical structure. This class of pesticides include;

• Synthetic Pesticides - These are pesticides manufactured by man. They do not occur in nature. Examples of synthetic pesticides are organochlorines (toxaphene, dieldrin, aldrin), organophosphates (Diazinon, glyphosphate, malathion), Carbamates (Carbofuran, aldicarb, carbaryl) and pyrethroids (fenpropanthrin, deltamethrin, cypermethrin).

• Organic Pesticides - These refers to pesticides produced from animal or plant parts. Organic pesticides are made from naturally occurring substances or self-made mixtures made from organic soaps and/or ethanol. Examples are pyrethrin, lime sulfur, sabadilla, garlic, onions, tobacco water, rotenone etc.

 3. PHYSICAL STATE

Pesticides can also be classified based on their physical state or how they are formulated. Pesticides are formulated (prepared) in liquid, solid and gaseous forms. This class of pesticides is comprised of;

• Liquid Pesticides - These include suspensions (flowables), solutions, emulsifiable concentrates, microencapsulated suspensions and aerosols.

• Solid Pesticides - Includes dusts, particulates, granular, pellets, soluble granules, soluble powders, baits, tablets, dry flowables and wettable powders.

• Gaseous Pesticides - These are typically fumigants.

 4. TARGET RANGE

Pesticides can also be classified based on the range of pests they are capable of targeting. This class of pesticides include;

• Broad Spectrum Pesticides - These are chemicals that kill a wide range of pests. They are also called non-selective pesticides and they target entire groups or species of organisms. Examples include organophosphate, carbamate, acetamiprid, pyrethroid and neonicotinoid insecticides.

• Selective Pesticides - These are chemicals that kill only a specific pest or group of pests. These pesticides have a minimal impact on organisms that are not targeted by the pesticide. Examples include Primicarb, Bt, NPV and Indoxacarb.