Journal of Environmental Biology

Laboratory evaluation for comparative insecticidal activity of some synthetic pyrethroids against vector mosquitoes in arid  region

 

S. K. Bansal and  Karam V. Singh

Desert Medicine Research Centre (ICMR), New Pali Road, Jodhpur - 342 005, India

 

(Received: 1 March, 2005 ; Accepted: 29 October, 2005)

 

 

Abstract: Comparative efficacy of three synthetic pyrethroids viz., cypermethrin, lambdacyhalothrin and cyfluthrin was evaluated against Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus, the three important mosquito vectors prevalent in arid region.  Studies were carried out on late 3^rd or early 4^th instar larvae of these species using standard WHO technique. Based on concentration mortality data LC₅₀   and LC₉₀  values along with their fiducial limits, regression equation, chi-square (χ²)/ heterogeneity of the response have been determined by log probit analysis. LC₅₀  values as observed were 0.0064, 0.00060 and 0.00012 mg /l  for cypermethrin, 0.0090, 0.0019 and 0.0010 mg /l for lambdacyhalothrin and 0.0087, 0.0005 and 0.0004 mg /l  for cyfluthrin for the above three vectors respectively.  The results showed that larvae of Cx. quinquefasciatus were most susceptible followed by Ae. aegypti and An. stephensi to all the pyrethroids tested. The chi-square values calculated during the analysis did not show any heterogeneity of the response. Experiments conducted with adults of An. stephensi, Ae. aegypti and Cx. quinquefasciatus with three synthetic pyrethroids viz. lambdacyhalothrin (0.05%), cyfluthrin (0.15%) and deltamethrin (0.05%) showed that all the three compounds are very effective and a 98- 100% kill was observed when subjected from 15-60 min. time exposure. This study would be useful while planning use of these insecticides for the control of adult mosquito vectors in this area.

 

Key words: Synthetic pyrethroids, Vector mosquitoes, Arid region.

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