Read the following statements regarding biological weed control.
A. It is ecofriendly because of no pollution.
B. It is long lasting because of its slow action.
C. A particular weed can be controlled in inaccessible areas.
D. It can lead to 100% control of a particular weed.
E. It is economical in the long-run.
Choose the correct answer from the options given below:
Show Hint
Biological control targets suppression, not eradication.
Since complete (100 %) eradication is ecologically impossible, any option containing statement "D" is incorrect.
Step 1: Understanding the Concept:
Biological weed control utilizes natural enemies (insects, pathogens, or herbivores) to suppress weed populations below economic damage thresholds. Step 3: Detailed Explanation:
Let us analyze the statements:
- Statement A: It is environmentally safe, non-polluting, and chemical-free. Thus, A is correct.
- Statement B: It is long-lasting because the bioagents are self-perpetuating, not because of their "slow action". Thus, B is conceptually weak.
- Statement C: Bioagents can fly or crawl to inaccessible areas (hilly terrains, water reservoirs) to control target weeds where manual spraying is impossible. Thus, C is correct.
- Statement D: Biological control never leads to 100 % eradication.
If the host weed is completely eliminated, the obligate bioagent population will starve and die. A natural predator-prey equilibrium is maintained where both co-exist at low levels. Thus, D is incorrect.
- Statement E: Because it is self-sustaining, it requires no repeated material or application costs, making it highly economical in the long run. Thus, E is correct.
Therefore, statements A, C, and E are correct. Step 4: Final Answer:
The correct option is 3, which corresponds to A, C and E only.
