Effect of various solvents on mortality, oviposition, fecundity inhibition, and hatching rates of Argas persicus.

Herbal acaricides present promising alternatives to chemical acaricides due to the widespread issue of acaricidal resistance. Most herbal acaricides have to be extracted in solvents. It is important that the solvents used for extracting these herbal extracts show the least activity. In the present study, Argas persicus engorged females were evaluated for the toxicity to various solvents, including hexane, ether, chloroform, glycerol, acetone, ethanol, methanol, Tween 20, Triton X-100, and DMSO. Additionally, correlations among various underlying parameters were assessed. A negative correlation was observed between adult tick mortality and both the mean egg mass and the fecundity index. Similarly, the mean egg mass also exhibited a negative correlation with the percentage inhibition of fecundity. The results indicated that methanol was the least toxic solvent for hydroalcoholic extraction, whereas Triton X-100 was found to be the most suitable solvent among those tested. These results help identify solvents with minimal intrinsic acaricidal activity for use in herbal acaricide formulation studies.