Effects of solvents and surfactants against Haemaphysalis bispinosa

As per the report published by FAO (2004), the tick population in India has developed resistance against all the available acaricides. Hence, newer methods of control including potential herbal agents are required to reduce the problems caused by the ticks. Most of the herbal extracts or their fractions are dissolved in polar or non-polar solvents or detergents before tested for acaricidal activity and these diluents should be of little acaricidal activity. In the present study, adult immersion test (AIT) was carried out on adult engorged female Haemaphysalis bispinosa ticks to detect the acaricidal activity of different solvents viz., nbutanol, glycerol, acetone, ethanol, methanol and surfactants (at 1 per cent dilution) like dimethyl sulphoxide (DMSO), tween 20 and triton X- 100. The study revealed that methanol was the least toxic solvent while tween 20 (1 per cent) was the least toxic detergent against H. bispinosa.