Question

[3]
(a) Organic farmers perfer biological control of diseases and pests to the use of chemicals for the same purpose. Justify.

(b) Give an example of a bacterium, a fungus and an insect that are used as biocontrol agents.

Answer 1

(a) Organic farmers prefer biological control of diseases and pests to the use of chemicals for the same purpose. Due to the following reasons:
(i) Biological control of diseases and pests reduces dependence on toxic chemicals. [0.5]
(ii) These chemicals being biodegradable does not accumulate or pollute the environment. [0.5]
(iii) They protect or conserve non-target organisms since they are species - specific. [0.5]

(b) Bacterium - Bacillus thuringiensis [0.5]
Fungus - Trichoderma [0.5]
Insect - Ladybird. [0.5]