Which method falls under the category of source reduction in mosquito control?

The correct choice, which is eliminating standing water, is defined as a source reduction method in mosquito control because it directly targets the breeding habitats of mosquitoes. Mosquitoes lay their eggs in or near standing water, and by removing these water sources, you effectively eliminate a key component of their life cycle. This proactive measure reduces the mosquito population by depriving them of the environment necessary for reproduction.

In contrast, the other options involve reactive strategies rather than preventive action. Applying pesticides and using larvicides are methods that intervene after mosquitoes have developed in an area. They manage existing mosquito populations but do not prevent new mosquitoes from being born if breeding sites still exist. Setting traps, while effective in capturing adult mosquitoes, does not address the root of the problem, which is the presence of standing water where mosquitoes breed. Overall, eliminating standing water is the most effective way to prevent mosquito populations from establishing in the first place, aligning perfectly with the principle of source reduction.