Pesticides are one of the notorious organic pollutants in our environment. They are classified according to the pests as insecticides, fungicides, herbicides, algaecides, avicides, bactericides, miticides, molluscicides, nematicides, piscicides, and rodenticides. But major classes of pesticides are insecticides, herbicides, fungicides, and others that are grouped as miscellaneous pesticides. About 1693 pesticides are available in the world; most of the pesticides are organic chemicals, and some are inorganic and biological species . These pesticides control insects by killing them or by changing the behavior of pests through a delivery system such as spraying, baits, slow-release diffusion, etc. The insecticides are classified as organochlorine compounds (biphenyl aliphatic, hexachlorocyclohexane, cyclodienes, and polychloro terpenes); organophosphate compounds–esters of phosphorus (phosphates, phosphonates, phosphorothioates, phosphorodithioates, phosphorothiolates, and phosphoramidates); organosulfur compounds, which contain two phenyl rings with a sulfur atom; carbamates; formamidines; dinitrophenols; organotins; pyrethroids (first-, second-, third-, and fourth-generation pyrethroids); nicotinoids; spinosyns; fiproles or phenylpyrazoles; pyrroles; pyrazoles; pyridazinones; quinazolines; benzoyl urea, botanicals (pyrethrum, nicotine, rotenone, limonene, or d-limonene and neem); synergists or activators; antibiotics; fumigants; insect repellents; inorganics; miscellaneous classes of insecticides (methoxyacrylates, naphthoquinones, nere-istoxin analogues, pyridine azomethine, pyrimidinamines, tetronic acids); and some miscellaneous compounds of insecticides, which include etoxazole, pyridalyl, amidoflumet, pyriproxyfen, buprofezin, and tebufenozide .