It is toxic to cockroaches both by topical application and by ingestion.[10] Hydramethylnon residues are much less active against cockroaches by contact than by ingestion.[11] A slow-acting poison is desirable, so they live long enough to return to the colony to share it with other cockroaches. In this way cockroaches that have eaten Hydramethylnon infect other cockroaches that have not had direct exposure to the baits.