Classification of Herbicide Based on Chemical Nature or Composition
Compounds having chemical affinities are grouped together. This is useful in liting and characterising herbicides.
i) Inorganic Herbicides:
Contain no carbon actions in their molecules. These were the first chemicals used for weed control before the introduction of the organic compounds, example are:
a) Acids:
Arsenic acid, arsenious acid, arsenic trioxide sulphuric acid.
b) Salts:
Borax, copper sulphate, ammonium sulphate, Na chlorate , Na arsenite , copper nitrate.
ii) Organic Herbicides:
Oils and non oils contain carbon and hydrogen in their molecules.
a) Oils: Diesel oil, standard solvent, xylene-type, aromatic oils, polycyclic , aromatic oils etc.
b) Aliphatics:
Dalapon, TCA, Acrolein, Glyphosphate methyl bromide.
c) Amides:
Propanil, butachlor, alachlor, CDAA, Diphenamide, Naptalam, Propachlor.
d) Benzoics:
2,3,6 TBA, Diacamba, tricamba, chloramben, Fenac.
e) Bipyridyliums:
Paraquat , diquat.
f) Carbamates:
Propham, chloropham, barban.
g) Thocarbamates:
Butylate, dilate, triallate, EPTC, molinate, pebulate, vernolate, benthlocarb, aslum, cycolate.
h) Dithiocarbamates:
CDEC , Metham.
i) Nitralin ( Benzonitrates) :
Dichlobenil , bromoxynil, ioxynil.
j) Ditroanilines ( Toluidines) :
Benefin, nitralin, trifluralin, butralin, dinitramine, fluchlorine, oxyzalin, penoxalin.
k) Phenoxy:
2,4-D, 2,4 , 5-T, MCPB, 2,4-DB, 2,4- DP, 2,4 , 5-TP (silvex)
l) Triazines:
Atrazine, simazine, ametryne , terbuteryne, cyprazinc, Metribuzin, prometryn, propazine.
m) Ureas:
Monuron, diuron, fenuron, neburon, flumeturon, mothabenzathiazuron- buturon, chlorbromuron, chloroxuron, norea siduson, metoxuron.
n) Uracils:
Bromacil, terbacil, lenacil.
o) Diphenyl Ethers:
Nitrogen, flurodifen.
p) Organic Arsenicals:
Cacodlic acid, MSMA, DSMA.
q) Others:
Bentazon, Piclaram, Pyrazon, Pyrichlor, endothall, bensulphioe, MH, DCPA.