ABSTRACT
The study is aimed to investigate the acaricidal effect of Allium sativum (garlic) and Allium cepa (onion) oils on different stages of Boophilus annulatus hard tick. Engorged B. annulatus females were collected from naturally infected cattle. A number of engorged ticks were incubated at 28 °C and 85 % relative humidity to lay eggs, which were incubated to obtain larvae that were used in the study. The used garlic and onion oils were prepared by steam distillation and were analyzed by gas chromatography. These oils were dissolved in ethanol, methanol alcohols, and, partially, in water. The oils were tested in different concentrations; 1, 2, 5, 10, and 20 %. These concentrations were applied on adult ticks by adult immersion test; on larvae by larval immersion technique and on eggs. The 20, 10, and 5 % of garlic oil dilutions in ethanol and methanol killed all adult ticks and larvae within 24 h. Similar results were obtained for 10 and 20 % garlic oil dissolved in water. The effect of 10 % aqueous solution of garlic oil on embryonated eggs was clear as its addition to these eggs led to their in ability to hatch, deformity in shape, and change in color. The 10 and 20 % onion oil in ethanol and methanol alcohols killed 76-86 % of the adult ticks within 72 h post-application. While, all larvae died within 24 h postsubjected to these two concentrations. These concentrations (10 and 20 %) of onion oil in water killed 56-80 % of the treated ticks. Moreover, 10 % aqueous solution of onion oil prevented hatching of embyonated eggs. We concluded that garlic and onion oils have acaricidal effect on all stages of B. annulatus at concentrations higher than 5 %. Only garlic oil could kill 100 % of adult ticks at concentrations from 5 % in alcohols.
