Comprehension : Comprehension

Q 405 / 466

UPSC CSE Prelims 2012

Chemical pesticides lose their role in sustainable agriculture if the pests evolve resistance. The evolution of pesticide resistance is simply natural selection in action. It is almost certain to occur when vast numbers of a genetically variable population are killed. One or a few individuals may be unusually resistant (perhaps because they possess an enzyme that can detoxify the pesticide). If the pesticide is applied repeatedly, each successive generation of the pest will contain a larger proportion of resistant individuals Pests typically have a high intrinsic rate of reproduction, and so few individuals in one generation may give rise to hundreds or thousands in the next, and resistance spreads very rapidly in a population.
This problem was often ignored in the past, even though the first case of DDT (dichloro diphenyltrichloroethane) resistance was reported early as 1946. There is exponential increase in the numbers of m vertebrates that have evolved resistance and in the number of pesticides against which resistance has evolved. Resistance has been recorded in every family of arthropod pests (including dipterans such as mosquitoes and house flies, as well as beetles, moths, wasps, fleas, Lice and mites) as well as well as in weeds and plant pathogens, Take the Alabama leaf-worm, a moth pest of cotton, as an example. It has developed resistance in one or more regions of the world to Aldrin, DDT, dieldrin, endrin, lindane and toxaphene.
If chemical pesticides brought nothing but, problem-if their use was intrinsically and acutely unsustainable — then they would already have fallen out of widespread use. This has not happened. Instead, their rate of production has increased rapidly. The ratio of cost of benefit for the individual agricultural producer has remained in favour of pesticide use. In the USA insecticides have been estimated to benefit the agricultural products to the tune of around $5 for every $1 spent.
Moreover, in many poorer countries, the prospect of imminent mass starvation, or of an epidemic disease, are so frightening that the social and health cost of using pesticides have to be ignored. In general, the use of pesticides is justified by objective measures such as lives saved, ‘economic efficiency of food production’’ and total food produced. In these very fundamental senses, their use may be described as sustainable. In practice, sustainability depends on continually developing new pesticides that keep at least one step ahead of the pests pesticides that are less persistent, biodegradable and more accurately targeted all the pests.
What does the passage imply?

EXPLANATION

Correct Option

The passage concludes by emphasizing that the practical sustainability of pesticide use depends on "continually developing new pesticides that keep at least one step ahead of the pests - pesticides that are less persistent, biodegradable and more accurately targeted." This statement directly implies the necessity of exploring and promoting alternative or improved approaches to pest management, which could encompass both novel chemical formulations and non-chemical methods, to counter the evolution of resistance and ensure long-term effectiveness.

Incorrect Options

  • Option (b): Too much use of chemicals is not good for the ecosystem. While the passage highlights the problem of pesticide resistance, which is an ecological concern, its primary implication is not a broad warning against chemical overuse for general ecological harm. Instead, it focuses on the specific challenge of resistance evolution and the strategies required for the sustainable application of pesticides. The passage also discusses the economic and social justifications for continued pesticide use.
  • Option (c): There is no scope for the improvement of pesticides and making their use sustainable. This statement directly contradicts the passage. The text explicitly states that "sustainability depends on continually developing new pesticides that are less persistent, biodegradable and more accurately targeted." This clearly indicates that there is significant scope for improving pesticides and making their use more sustainable.
  • Option (d): Both the statements (a) and (b) above are correct. This option is incorrect because statement (b) is not the most accurate or central implication of the passage.