What are pesticides and herbicides? Explain giving examples.
Pesticides: The chemical substances which are used to kill or block the reproductive process in harmful organisms such as rodents, mites, bacteria, fungi etc. Synthetic (man-made) pesticides are broad-based in their action, that is they harm much more organisms than these intended. These substances are non-biodegradable. Pesticides can be divided into three types namely insecticides, herbicides and fungicides.
Herbicides: Herbicides or weedicides are used to kill weeds. Weeds are undesirable plants which grow along with the main crops. Common herbicides are:
(i) 2, 4-D (2, 4-dichloro phenoxy acetic acid)
(ii) MPCA(2- methyl-4-chloro-1-phenoxyacetic acid)
(iii) Butachlor.
The herbicides called triazines are widely used to kill weeds in corn fields.
