Which of the following is a common effect of pesticide application on non-target organisms?

The correct answer highlights a significant concern in pest management practices—the impact of pesticides on beneficial insects. When pesticides are applied, they often do not distinguish between target pests and beneficial non-target organisms. As a result, the populations of beneficial insects, such as pollinators, natural pest predators, and other valuable species, can decrease significantly due to pesticide exposure. This decline can disrupt ecological balance and lead to long-term consequences for both agricultural productivity and environmental health.

In contrast, the other options suggest outcomes that are generally positive or neutral for ecosystems. Improved biodiversity, increased soil fertility, and enhanced water quality are not typical direct results of pesticide application, particularly when those applications are indiscriminate and adversely affect non-target organisms. Rather, these outcomes are associated with sustainable practices that protect various species, promote ecosystem health, and foster a resilient environment. Therefore, recognizing the detrimental effect of pesticide application on beneficial insects is crucial for Integrated Pest Management (IPM) strategies aimed at minimizing harm to non-target organisms while managing pest populations effectively.