Could you inform me about the other biocides?

Herbicides are used to destroy the weeds without doing any harm to crop. These are mostly used in agriculture.

The major herbicides used today include 2,4-D, atrazine, dicamba, clopyralid, glufosinate ammonium, glyphossate, imazapic, linuron, metoalachlor, triclopyr, picloram and paraquat

Nematicide is a pesticide used to kill the parasitic roundworms. A mixture of neem cake is reported to be an effective nematicide. Several compounds from carbamates, oxime carbamates, organophosphorus, organophosphate and phosphonothioate are used as nematicides.

Miticides or acaricides are the pesticides used to destroy and eradicate mites. Carbamate, organochlorine, permethrin and organophosphate miticides are the common ones.

Molluscicides are called snail baits and are pesticides against all sorts of snails that can damage the crops in agriculture or in garden. Iron III phosphate, aluminium sulphate, metaldehyde and acetyl cholinesterase inhibitors are the commonly used molluscicides and the last one is highly toxic to animals and human beings.

Rodenticides are poisons used to kill rodents such as rat and mouse. Rodenticides are tasteless, odourless, and lethal and have delayed poisonous effect. Rodents, normally, eat little, wait and if they do not become sick, they eat further.

The important rodenticides include:

• Anticoagulants, for example 4-hydroxycumarin
• Metal phosphides, for example zinc phosphide
• Arsenic
• Bromethalin
• Chloralose
• Crimidine
• 4-amine
• Phosacetim
• Fluoroacetamise
• Endrin
• 1, 3-Difluoro-2-propanol
• Pyrinuron
• Thallium
• Tetramethylene disulfotetramine
• Sodium fluoroacetate
• Scilliroside
• Zyklon B (hydrogen cyanide)

All are poisons and should be handled carefully.

Could you tell me about insecticides?

Chemical substances which are capable of killing almost all forms of living organisms in the fields of agriculture, forestry and household are biocides. These can be insecticides, fungicides, herbicides, nematicides, miticides, molluscicides, and rodenticides.

Insecticides are used against insects, their eggs and larvae found in agriculture, industry and household. Even though the insecticides have contributed towards agricultural revolution in the 20th century, these have altered our ecosystem and poisonous insecticide residues persist in food and drinking water. A balance between agricultural use and environmental health issues is very difficult to maintain. We must try it always with new ideas and more research.

There are various kinds of insecticides and they include:

• Organochlorines: DDT, aldrin, chlordane, endosulfan. endrin, dieldrin, heptachlor, lindane, pentachlorophenol and hexachlorobenzene. Mustard gas is used in the war as chemical weapon.

• Organophosphates: azinphos-methyl, chlorethoxyfos, dichlorvos, fenthion, malathion, mevinphos, parathion, parathionmethyl and tribuvos.

• Carbamates: used as insecticides, fungicides and herbicides in agriculture. Used against mosquitoes inside the buildings. These are aldicarb, carbofuran, carbaryl, methomyl and methyl carbamates.

• Pyrethroids: These are natural insecticides developed from the plant product (dried flowers) called pyrethrum. Permethrin, remethrin, cypermethrin, bifenthrin, tetramethrin, transfluthrin and many more belongs to this group and these are produced by adding chlorine, bromine, nitro group or others.

• Neonicotinoids: these are the synthetic analogue of natural nicotine. These are often used as substitutes for organophosphates and carbamates. These are clothianidin, nitenpyram, thiamethoxam, acetamiprid, clothianidin, nithiazine and thiacloprid.

The other plant products include caffeine, nicotine, and neem products. Insecticides are poisons and we must be very careful.