Question

What are biopesticides? Why are they preferred over chemical pesticides? Describe the mechanism of biopesticides for controlling pests.

Answer 1

Hint: Biopesticides is made up of two words, Bio which means biological or organic, and pesticides which means agents to kill pests. Thus, biopesticides are the biological agents that can be used as pesticides. Also, biopesticides are safe for the environment.

Complete answer: -Biopesticides are the organisms that are applied over the crop plants to destroy the pests. They are used to destroy weeds and small pests. Biopesticide is a biological method of controlling pests.
-Biopesticides are preferred over chemical pesticides because they do not contaminate the environment. The chemicals in chemical pesticides are extremely toxic and harmful to the environment. Not only this but they are also harmful to animals and humans if they ingest such crops. Also, chemicals deteriorate the natural quality of the soil in the long run. When the run-off with the surface water they cause water pollution and eutrophication of water bodies. Also, if the chemicals percolate in the soil, they contaminate the underground water table.
-Thus, biopesticides are a safer option to save the environment. In biopesticides, such organisms are introduced in the crop fields which are the natural predator of the pests, but they do not affect the crops. These predators keep a check on the pests. In this way, the pest is not eliminated entirely and the biodiversity of the crop field is not changed. Because the more the variety of a place, the more sustainable it is. And the pest is also under control and managed. Complete eradication of the pests would lead to the disruption of the food chain. And if one community is eliminated, so the community underneath it, which it controls, springs. This leads to a disturbed balance of the ecosystem. Thus, biopesticides do not alter the natural food chains. This kind of farming is usually called organic farming, and this system is known as a system of checks and balances.

Note: Biopesticides are usually of two kinds, Bioherbicides and Bioinsecticides. Bioherbicides are used to control weeds biologically. For example – The Opuntia weed can be controlled by using the insect Cactoblastis cactorum. Bioinsecticides are the living organisms that are used to repel or kill insects. For example – Pheromone is sprayed to attract males. These males then become unavailable for reproduction.