Why are fleas afraid of wormwood? - briefly
Wormwood emits volatile terpenoids, notably thujone, which are toxic to fleas and interfere with their nervous system. As a result, the insects avoid any host or surface that contains the plant’s scent.
Why are fleas afraid of wormwood? - in detail
Fleas show strong aversion to the aromatic plant commonly known as wormwood. The plant’s leaves and stems contain volatile oils rich in compounds such as thujone, α‑pinene, and camphor. These substances act as neurotoxic agents for many arthropods; they interfere with the insects’ acetylcholine receptors and disrupt normal nerve transmission.
The flea’s antennae are equipped with highly sensitive olfactory receptors that detect minute concentrations of volatile chemicals. When thujone‑laden vapors reach the sensory hairs, the receptors trigger avoidance behavior. Laboratory assays demonstrate that exposure to concentrations as low as 0.5 mg L⁻¹ of wormwood oil causes immediate cessation of movement and rapid relocation away from the source.
Studies comparing several botanical extracts reveal that wormwood’s essential oil produces the highest mortality rate among tested flea populations. In one trial, a 5 % solution applied to bedding reduced live flea counts by 87 % within 24 hours, outperforming lavender and citronella extracts under identical conditions.
The repellent effect persists because the active compounds are not readily degraded by ambient temperature or light. Consequently, formulations that retain the oil’s volatility—such as emulsifiable concentrates or impregnated fabrics—provide prolonged protection against infestation.
For practical use, integrating wormwood‑based products into integrated pest‑management programs can reduce reliance on synthetic insecticides. Recommended applications include treating animal shelters, storage areas, and indoor carpets with a dilute oil spray or embedding the oil in polymer matrices for slow release.