What is the role of insecticides in pest management?

Insecticides play a critical role in pest management primarily by targeting and controlling insects and related arthropods. These organisms can be significant pests that cause damage to crops, transmit diseases, and disrupt the ecosystem balance. By utilizing insecticides, pest managers can effectively reduce insect populations, minimizing the adverse effects these pests have on agricultural output and plant health.

While the other options mention control over weeds, alteration of plant growth, and control of nematodes, these functions are outside the specific purpose of insecticides. Weeds are typically managed using herbicides, which are designed to specifically target unwanted plant species. Altering plant growth is generally associated with the use of growth regulators or fertilizers, not insecticides. Nematodes, which are microscopic roundworms that can harm plants, are commonly managed through nematicides, not insecticides. Therefore, option B accurately reflects the specific and intended use of insecticides in pest management practices.