Abstract
The objective of this study was to evaluate the acaricidal activity of a paste made from freeze-dried methanolic extracts of air-dried leaf powders of Azadirachta indica, Eucalyptus hybrid, Saraca asoca, and Murraya koenigii against Rhipicephalus (Boophilus) microplus on cellulose paper. The extracts were tested in both single form (100% and 50% concentration) and dual combination (prepared by mixing equal proportions of the extracts in 100% concentration). The results showed a direct proportional relationship (p < 0.05) between the concentration of the extracts and the mortality percentage at 72 h post-treatment, as well as the inhibition of oviposition (I.O.) percentage. The highest mortality rate of 98.75 ± 1.25% and I.O. of 44.47 ± 0.87% was observed with the A. indica extract at 100% concentration, followed by E. hybrid, S. asoca, and M. koenigii. The combination of A. indica and E. hybrid extracts had a mortality rate of 87.5 ± 5.59% and I.O. of 42.91 ± 0.44%, followed by the combinations of S. asoca: E. hybrid, A. indica: S. asoca, E. hybrid: M. koenigii, and A. indica: M. koenigii. The extracts of A. indica and E. hybrid demonstrated the highest mortality and inhibition of oviposition percentages compared to the other extracts in both single and dual combinations. These extracts required 72 h to reach their maximum mortality.