How do chalks act against bedbugs? - briefly
Chalk, primarily calcium carbonate, desiccates bedbugs by absorbing moisture from their cuticle and disrupting their respiratory spiracles, leading to rapid dehydration. Its fine powder also coats surfaces, creating a barrier that hinders the insects' movement and ability to lay eggs.
How do chalks act against bedbugs? - in detail
Chalk, primarily composed of calcium carbonate, exerts several adverse effects on Cimex lectularius when applied as a dry powder. The mineral’s abrasive particles cling to the insect’s exoskeleton, disrupting the waxy cuticle that prevents water loss. This disruption accelerates desiccation, leading to rapid mortality in exposed individuals.
The alkaline nature of calcium carbonate raises the pH on the insect’s surface. Elevated pH interferes with the integrity of the chitin-protein matrix, weakening structural bonds and impairing the molting process. Bedbugs attempting to shed their old exoskeleton encounter incomplete ecdysis, resulting in lethal deformities.
Physical contact also impedes locomotion. Fine chalk particles fill the tarsal pads and joint articulations, reducing grip and limiting movement. Immobilized insects are more susceptible to predation, environmental stresses, and subsequent chemical treatments.
Practical deployment follows a straightforward protocol:
- Apply a thin, even layer of chalk to seams, mattress folds, and cracks where bedbugs hide.
- Reapply after cleaning or laundering to maintain coverage.
- Combine with heat treatment or insecticide dusts for synergistic effect.
Effectiveness varies with environmental conditions. Laboratory assays report mortality rates of 70‑85 % after 48 hours of continuous exposure, while field trials show reduced infestation levels when chalk is used as part of an integrated pest‑management program. Limitations include reduced efficacy on heavily insulated surfaces and the need for regular reapplication to compensate for particle displacement.