Acaricidal efficacy of Myrrh (Commiphora molmol) on the fowl tick Argas persicus (Acari: Argasidae).

: Five concentrations of purified extract of Myrrh from Commiphora molmol tree were prepared to study its effects on the fowl tick Argas persicus under laboratory conditions. The results revealed that Myrrh had dependant dose toxic effect on the adult female of A. persicus. Toxicity increased gradually daily post treatment. The LC50 was 1.28%, 0.88%, 0.84%, 0.50% and 0.42% at Ist, 2nd, 3rd, 6th and 12th days respectively. At 12th day, the recorded mortality rates were 63, 67, 76, 87 and 94% for concentrations, 0.625, 1.25, 2.5, 5 and 10%, respectively against 5% in control. Histopathological and Transmission election microscope (TEM) examinations showed the lysing of epithelial gut cells in treated groups. The lysed epithelial gut cells showed irregularly distributed nucleus, commonly at low concentrations and rarely in high concentrations of Myrrh. The lysed epithelial gut cells, without nucleus or with aggregated one beside the basal lamina, were common at high concentrations and rare in low concentrations of Myrrh. Consequently, Myrrh can rapidly penetrate the cuticle to body cavity, destroy the epithelial gut cells and finally cause the death of ticks.