A drawback of using common names instead of scientific names for identifying pests is that:

Using scientific names for identifying pests offers a level of specificity that common names often do not. For instance, a common name like "butterfly" could refer to many different species across various families, while a scientific name indicates the exact species being referenced, providing clarity on its characteristics and behaviors.

When using common names, there's a significant limitation in understanding the relationships between different organisms. For example, two insects that appear similar and are called by the same common name may actually belong to entirely different families and have very different ecological roles or responses to control measures. This lack of precise relationships conveyed by common names can lead to misunderstandings in pest management and affect how a particular pest is treated.

In contrast, common names are not universally understood and can differ from one region to another, which can further complicate communication among professionals in the field. While common names may be easier to remember, they do not offer the same level of scientific information that is crucial for effective pest identification and management.