4-Methylnonan-5-ol is a pheromone component isolated from certain Lepidopteran pests (such as specific noctuid moths). It is often used as a specific attractant for monitoring field pest populations. When mixed with a small amount of pheromone synergists, it can significantly improve trapping activity. In crop pest control, it can accurately reflect the occurrence dynamics of pests, reduce the capture of non-target organisms compared with traditional light trapping, and enhance monitoring specificity.