What chemical affects the normal molting and development of insects?

The chemical that affects the normal molting and development of insects is correctly identified as insect growth regulators (IGRs). These compounds are specifically designed to disrupt the hormonal processes that insects rely on to undergo molting and transition through their life stages. By interfering with these natural processes, IGRs prevent insects from growing or maturing properly, ultimately leading to a decrease in their population.

Insect growth regulators do not kill insects immediately, as some traditional insecticides might; instead, they alter the development and reproduction of the target insects. This slow-acting nature can be beneficial in integrated pest management programs, allowing for sustainable pest control that minimizes resistance development in pest populations.

In contrast, other options like insecticides provide more immediate lethal effects on insects but do not specifically target developmental processes. Insecticidal soaps aim to suffocate and disrupt the cell membranes of soft-bodied insects, while horticultural oils function similarly by smothering pests or disrupting their feeding. However, none of these alternatives significantly alter the molting and developmental stages as IGRs do.