How do bedbugs die after treatment with a cold fog? - briefly
The cold fog delivers a desiccating insecticide that penetrates the cuticle, causing rapid dehydration and cellular disruption, which kills the insects within minutes to a few hours. Residual particles stay active on surfaces, eliminating any remaining bugs that were not immediately affected.
How do bedbugs die after treatment with a cold fog? - in detail
Cold‑temperature aerosol treatments eliminate bedbugs through a combination of physical disruption and biochemical stress. The fog consists of micron‑sized droplets containing a desiccant (often silica‑based) and a cryogenic carrier gas such as liquid nitrogen or refrigerated compressed air. When the mist penetrates cracks, seams, and fabric folds, each particle contacts the insect’s cuticle.
-
Cuticular desiccation – The droplets rapidly absorb moisture from the exoskeleton. Bedbugs lose up to 30 % of body water within minutes, leading to loss of turgor pressure and failure of the tracheal system. Dehydration stops respiration and disrupts hemolymph circulation.
-
Temperature shock – The cryogenic component drops the local temperature to –20 °C to –30 °C for a brief period. Rapid cooling depresses neuronal activity, causing loss of motor control and paralysis. Cellular membranes become rigid, impairing ion exchange and leading to irreversible metabolic failure.
-
Chemical toxicity – Some formulations include low‑concentration insecticidal agents (e.g., pyrethroids or pyrroles) that remain active at low temperatures. These chemicals interfere with sodium‑channel function, compounding the neurotoxic effect of the cold shock.
The lethal process follows a predictable timeline:
- Immediate immobilization – Within seconds of exposure, bedbugs exhibit uncoordinated movements and cease feeding.
- Onset of dehydration – Between 5 and 15 minutes, cuticular water loss exceeds the species’ tolerance threshold.
- Cellular collapse – Between 15 and 30 minutes, membrane rigidity prevents ATP synthesis, resulting in irreversible organ failure.
- Mortality confirmation – After 30‑45 minutes, the majority of exposed individuals are dead; a small fraction may survive if sheltered from direct fog contact.
Efficacy depends on several variables:
- Fog penetration depth – Successful treatment requires the aerosol to reach hidden harborage sites; otherwise, survivors can repopulate.
- Droplet size distribution – Particles between 5–15 µm ensure adherence to the insect cuticle without excessive runoff.
- Ambient humidity – Low ambient humidity accelerates desiccation, while high humidity can delay mortality.
- Population density – Overcrowded infestations may require multiple passes to achieve complete coverage.
Residual effects are limited; once the fog dissipates, the temperature returns to ambient levels, and the desiccant particles lose activity. Therefore, follow‑up inspections and possible additional applications are recommended to confirm eradication.