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.