Larvicidal potential of medicinal plant extracts against Anopheles subpictus Grassi and Culex tritaeniorhynchus Giles (Diptera: Culicidae)

Abstract

Mosquito control is facing a threat due to the emergence of resistance to synthetic insecticides. Insecticides of botanical origin may serve as suitable alternative biocontrol techniques in the future. The acetone, chloroform, ethyl acetate, hexane, methanol and petroleum ether extracts of leaf, flower and seed of Cassia auriculata L., Leucas aspera (Willd.), Rhinacanthus nasutus KURZ., Solanum torvum Swartz and Vitex negundo Linn. were tested against fourth instar larvae of malaria vector, Anopheles subpictus Grassi and Japanese encephalitis vector, Culex tritaeniorhynchus Giles (Diptera: Culicidae). The larval mortality was observed after 24 h of exposure. All extracts showed moderate larvicidal effects; however, the highest mortality was found in leaf petroleum ether, flower methanol extracts of C. auriculata, flower methanol extracts of L. aspera and R. nasutus, leaf and seed methanol extracts of S. torvum and leaf hexane extract of V. negundo against the larvae of A. subpictus (LC(50) = 44.21, 44.69, 53.16, 41.07, 35.32, 28.90 and 44.40 ppm; LC(90) = 187.31, 188.29, 233.18, 142.66, 151.60, 121.05 and 192.11 ppm, respectively) and against the larvae of C. tritaeniorhynchus (LC(50) = 69.83, 51.29, 81.24, 71.79, 44.42, 84.47 and 65.35 ppm; LC(90) = 335.26, 245.63, 300.45, 361.83, 185.09, 351.41 and 302.42 ppm, respectively). These results suggest that the leaf petroleum ether, flower methanol extracts of C. auriculata, leaf and seed methanol extracts of S. torvum and leaf hexane extract of V. negundo have the potential to be used as an ideal eco-friendly approach for the control of the A. subpictus and C. tritaeniorhynchus. This is the first report on the mosquito larvicidal activity of the medicinal plant extracts.

Tagetes erecta Linn. and its mosquitocidal potency against Culex quinquefasciatus

“…Phytochemicals are less environmentally harmful than synthetic agrochemicals. It has renewed the interest in the research on these compounds, considering them as an ecologically safe alternative [9,10] .…”

Phytochemical extractions from the leaves of <i>Ravenala madagascariensis</i> from Sundarban area and its effect on southern house mosquito (<i>Culex quienquefasciatus</i> Say 1823) larvae

“…To set up a larval colony larvae were kept in a plastic tray filled with dechlorinated tap water with proper hygiene. Larvae were fed with a mixture diet of Brewer yeast, dog biscuits and algae in a ratio of 3:1:1 respectively (Kamaraj et al, 2011). Within the tray, larvae became pupae, and then those were transferred to an insectary (45×45×40 cm) for adult immergence.…”

Mosquito larvicidal potentiality of wild turmeric, <i>Curcuma aromatica</i> rhizome, extracts against Japanese Encephalitis vector <i>Culex vishnui</i> group

“…They were kept in dirt-free plastic trays filled with tap water and were fed with a mixture of brewer yeast, dog biscuits and algae in 3:1:1 ratio (Kamaraj et al, 2011). Pupae were transferred from the trays to insectaries (45×45×40 cm).…”