What is the primary effect of a mild dish soap and water spray?

It lowers surface tension, leading to dehydration or suffocation on contact

A topical treatment often recommended for existing populations, especially in hard-to-dry areas like sheds, involves mixing mild dish soap with water. This solution is categorized as a contact killer, not a smell-based deterrent. The soap works because it dramatically reduces the surface tension of the water component. This reduction allows the solution to spread easily and penetrate the woodlouse more effectively than pure water would. Upon penetration, the woodlouse suffers dehydration or suffocation due to the disruption of its respiratory or protective functions. This method aims to kill the pest directly where it is found by attacking its physical structure or immediate need for moisture balance.