Question

A farmer had been using a particular insecticide for a long time. What consequences will it have on -
(a) insect population
(b) soil ecosystem

Answer 1

Consequences of prolonged utilization of insecticide on

a) insect population: Initially the insect population will decrease but as the same insecticide is used over and over again gradually the insects will develop resistance to the insecticide and will be unaffected, with the resistant gene being transferred to the progenies the insect population will increase over time.

b) Soil ecosystem: Insecticides have detrimental effects on insects similarly they can also infect the soil micro flora and fauna, those that are responsible decomposition of organic matter, fixing Nitrogen etc which enriches the soil in organic content or humus and Nitrogen respectively. The killing of these micro-organisms by the insecticides will result in loss of soil fertility and desertification.