Biological activities of chamomile （Matricaria chamomile） flowers＇ extract against the survival and egg laying of the cattle fever tick （Acari Ixodidae）

In the present work, the potential of acaricidal activity of chamomile flowers＇ extract was studied against engorged Rhipicephalus annulatus tick under laboratory condition. For this purpose, the engorged females ofRhipicephalus annulatus were exposed to two-fold serial dilutions of chamomile flowers＇ extract （0.5%, 1.0%, 2.0%, 4.0% and 8.0%） using ＂dipping method＂ in vitro. The engorged ticks were immersed in different plant dilutions （five ticks for each dilution） for l rain and they were immediately incubated in separate Petri dishes for each replicate at 26℃ and 80% relative humidity. Mortality rate for each treatment was recorded 5 d after incubation. The mortality rate caused by different dilutions of chamomile flowers＇ extract ranged from 6.67% to 26.7%, whereas no mortality was recorded for non-treated control group. The mass of produced eggs varied from 0.23 g （in 8.0% solution） to 0.58 g （in control）, with no statistical differences between the treatments and control （/＇〉0.05）. Also the chamomile flowers＇ extract in highest concentration used （8.0%） caused 46.67% failure in egg laying in engorged females while no failure was observed for non-treated control group. Macroscopic observations indicated that in effective concentrations of plant （4.0% and 8.0%）, patchy hemorrhagic swelling appeared on the skin of treated ticks. The results presented for the first time in this study imply that chamomile may be considered as a promising plant for biocontrol of cattle fever tick disease in the field condition.