Resistance is population-specific
Research documents resistance mechanisms and reduced susceptibility in bed bugs, including to pyrethroid insecticides. A product can perform differently across populations and conditions.
A household sighting cannot identify the resistance profile by appearance.
More is not the answer
Increasing concentration, repeating too frequently or mixing products can breach the label and increase exposure without improving harbourage coverage.
Professional selection considers formulation, placement, previous treatments and non-chemical actions.
Integrated management reduces dependence
Combine identification, inspection, physical removal, heat or steam where suitable, authorised residuals where selected, encasement or isolation, and monitoring.
The exact mix should follow evidence and be reviewed when activity persists.
Sources and further checks
Open the source before acting on information that may change, including council services, prices, tenancy rules and product labels.