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H yalomma dromedarii (Acari: Ixodidae) is considered the most common tick species infesting camels in Africa, Asia, and the Middle East. The adverse economic impact of H. dromedarii ticks comes from irritation, annoyance, anemia, secondary skin infection, tick fever, and is considered as a vector for various devastating diseases (Abdel-Shafy et al., 2012; Abdullah et al., 2016; Yadav et al., 2017).Eco-friendly control of ticks is currently a crucial challenge (Benelli et al., 2016; Khater et al., 2016) where, the control of tick infestations is primarily based on the use of synthetic chemical acaricides. Due to widespread chemical applications, ticks have acquired resistance to the majority of acaricides; moreover, acaricides leave residues in foods and cause environmental pollution (Ghosh et al., 2013). Therefore, there is a need to discover eco-friendly alternatives for these chemicals. Use of herbal medications has research Article Abstract | The pesticidal effect of petroleum ether and ethyl alcohol extracts of Melia azedarach and Artemisia herba-alba against active stages (larvae, unfed adults and engorged females) of the camel tick Hyalomma dromedarii was evaluated by larval and adult immersion tests. Extracts were subjected to gas chromatography-mass spectrometry to identify the major active constituents. Histological sections of semifed females were evaluated to monitor the changes occurring in the cuticles and guts. The LC 50 values indicated that the petroleum ether extract of A. herba-alba was more toxic against larvae (1.83%), followed by unfed adults (2.37%) and then engorged females (3.1%). However, the petroleum ether extract of M. azedarach exhibited its activity in the reverse order, i.e., it was more toxic against engorged females (3.96%), followed by unfed adults (5.47%), and then larvae 10.99%. The LC 50 values of the ethyl alcohol extracts of A. herba-alba and M. azedarach on larvae, unfed adults, and engorged females were 19.60% and 22.75%, 79.81% and 19.44%, and 29.63% and 11.1%, respectively. The egg productive index (EPI), egg number, and hatchability percentage were low in the treated females. Abnormalities were observed in the cuticles and guts after treatment with plant extracts. In conclusion, the two plants M. azedarach and A. herba-alba exhibited good acaricidal activities against the active stages of H. dromedarii and might be used in the control of the camel ticks.

Purpose The current study aimed to investigate the efficacy of zinc oxide nanoparticles (ZnO NPs) synthesized by Melia azedarach aqueous extract to control Hyalomma dromedarii tick, and to evaluate their toxic effects on Swiss albino mice. Methods ZnO NPs were synthesized using M. azedarach aqueous extract. UV–visible spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive spectroscopy were used to characterize the synthesized NPs. Egg, nymph, larva, and adult immersion tests were used for bioassay of tick stages with the synthesized ZnO NP. A toxicity study was performed on Swiss albino mice after treatment with 1/10 of the oral LD50 of ZnO NPs (8437 mg/kg) for 5 successive days by oral gavage. Results The LC50 of ZnO NPs on the eggs, larvae, and nymphs was 11.6, 8.03, and 3.9 mg/ml, respectively. The reproductive performance of females treated with ZnO NPs was lower than that of untreated females. The hematological results showed an insignificant increase in the level of white blood cells with normal red blood cells, hemoglobin, in addition to normal platelet count. The biochemical analysis showed an insignificant increased level (P > 0.05) of alkaline phosphatase and alanine aminotransferase. The liver and kidney suffered few histopathological changes after oral administration of ZnO NPs. Conclusion These results suggest that ZnO NPs have good acaricidal activity against eggs, larvae, and engorged nymphs of H. dromedarii. ZnO NPs minimized the number of eggs laid by engorged females and the hatchability of their eggs. ZnO NPs did not affect unfed adults. The toxicity results of the mice revealed insignificant changes in the hemogram, biochemistry, with liver and kidney suffering few histopathological changes. Future studies are needed to assess application routes (topical vs oral). Based on these findings, ZnO NPs may be incorporated in the control of camel tick H. dromedarii.

The present study aimed to evaluate the in vitro efficacy of four medicinal plant extracts: petroleum ether and ethyl alcohol extracts of the ripen fruits of Melia azedarach and whole aerial parts of Artemisia herba-alba against the two inactive stages of the camel tick Hyalomma dromedarii, embryonated eggs and engorged nymphs in comparison to reference acaricide Butox Ò 5.0 (Deltamethrin). Egg and nymphal immersion tests at four concentrations with three replicates were used. The deformity in larvae hatched from treated eggs and adults moulted from treated nymphs were observed and photographed by light microscope (LM) and scanning electron microscope (SEM). The results showed that M. azedarach and A. herba-alba extracts revealed higher significant toxic effects on embryonated eggs and engorged nymphs comparing with the reference acaricide (Butox Ò 5.0) and control. In egg emmersion test, the LC 50 of petroleum ether extracts of M. azedarach and A. herba-alba was 3.14 and 3.91%, respectively and LC 50 of the respective ethyl alcohol extracts was 1.77 and 2.45%. In nymphal immersion test, LC 50 of petroleum ether extracts of M. azedarach and A. herba-alba was 0.26 and 1%, respectively, and LC 50 of the respective ethyl alcohol extracts was 4.17 and 8.7%.Abnormalities were observed by LM and SEM in the larvae hatched from the treated eggs as incomplete development of legs and mouth parts as well as shrinkage mainly in legs and mouthparts of adults emerged from treated nymphs. In conclusion, all extracts and petroleum ether extracts of the two plants have great potential to be developed as a novel acaricidal for controlling eggs and nymphs of H. dromedarii, respectively.