How does tar soap work on bedbugs? - briefly
Tar soap coats bedbugs with a sticky, oily layer that blocks their spiracles and penetrates the cuticle, leading to suffocation and dehydration. The soap component reduces surface tension, allowing the tar to spread uniformly and immobilize the insects quickly.
How does tar soap work on bedbugs? - in detail
Tar‑infused soap combines petroleum‑derived tar with conventional surfactants. The tar component is rich in polycyclic aromatic hydrocarbons and phenolic substances that are toxic to arthropods. When the mixture contacts a bedbug, the surfactant lowers surface tension, allowing the tar to spread across the insect’s exoskeleton.
- The surfactant breaches the waxy cuticle, exposing underlying lipids.
- Tar’s lipophilic molecules infiltrate the cuticular membrane, dissolving structural lipids.
- Lipid loss accelerates water loss, causing rapid desiccation.
- Phenolic compounds penetrate the nervous system, disrupting synaptic transmission and leading to paralysis.
- The combined action results in mortality within minutes to a few hours, depending on exposure concentration.
Application typically involves spraying a uniform coating on infested surfaces, bedding, or directly onto insects. The residual film remains effective for several days, as tar adheres to fabrics and cracks, maintaining contact with hidden bugs. Re‑application may be required after thorough cleaning or when the film becomes visibly degraded.
Efficacy declines if insects develop behavioral avoidance or if the formulation is diluted below lethal concentrations. Tar‑based products can irritate human skin and respiratory passages; protective gloves and ventilation are recommended during use.