Insecticidal and larvicidal activities of medicinal plant extracts against mosquitoes

Abstract

In recent years, use of environment friendly and biodegradable natural insecticides of plant origin have received renewed attention as agents for vector control because they are rich in bioactive chemicals, active against a limited number of species including specific target insects, and biodegradable. The present study was carried out to evaluate the adulticidal, repellent, and larvicidal activity of crude hexane, ethyl acetate, and methanol extracts of eight plants, viz. Aristolochia indica L., Cassia angustifolia Vahl, Diospyros melanoxylon Roxb., Dolichos biflorus L., Gymnema sylvestre (Retz) Schult, Justicia procumbens L., Mimosa pudica L., and Zingiber zerumbet L., were tested against adult and early fourth instar larvae of Culex gelidus Theobald and Culex quinquefasciatus Say (Diptera: Culicidae). The effective adult mortality was observed in methanol extract of A. indica, ethyl acetate extract of D. biflorus, and ethyl acetate and hexane extract of Z. zerumbet against C. gelidus and C. quinquefasciatus (LD(50) =37.75, 78.56, 129.44, 86.13, 80.06, 112.42, 53.83, and 46.61; LD(90) =166.83, 379.14, 521.50, 289.83, 328.18, 455.72, 181.15, and 354.50 ppm, respectively). Complete protections for 150 min were found in hexane and methanol extract of A. indica and Z. zerumbet at 1,000 ppm against mosquito bites. The highest larval mortality was found in the hexane extract of Z. zerumbet, ethyl acetate extract of D. biflorus, and methanol extracts of A. indica against C. gelidus (LC(50) =26.48, 33.02, and 12.47 ppm; LC(90) =127.73, 128.79, and 62.33 ppm) and against C. quinquefasciatus (LC(50) =69.18, 34.76, and 25.60 ppm; LC(90) =324.40, 172.78, and 105.52 ppm), respectively, after 24 h. The plant extracts are potential to be used as an ideal eco-friendly approach for the control of the Japanese encephalitis vector, C. gelidus, and lymphatic filariasis vector, C. quinquefasciatus.

Repellent effect of Salvia dorisiana, S. longifolia, and S. sclarea (Lamiaceae) essential oils against the mosquito Aedes albopictus Skuse (Diptera: Culicidae)

“…Even if the number of aromatic plants used in different countries for their mosquito-repellent properties continues to grow (Karunamoorthi et al 2009;Michaelakis et al 2009;Kamaraj et al 2010;Conti et al 2011;Elango et al 2011;Pitarokili et al 2011), to our knowledge, there are no studies on the repellent activity of S. dorisiana, S. longifolia, and S. sclarea EOs against A. albopictus. Among different sage species, only S. sclarea and S. officinalis L. EOs were tested for their repellence against mosquitoes.…”

Larvicidal activity of medicinal plant extracts and lignan identified in Phryma leptostachya var. asiatica roots against housefly (Musca domestica L.)

“…Many medicinal plant extracts have been reported to show insecticidal activities against several insect pests (Alexenizer and Dorn 2007;Elango and Rahuman 2011;Senthikumar et al 2009;Kamaraj et al 2010). In this study, good larvicidal activity against larvae of M. domestica was achieved with the extracts of P. leptostachya var.…”

Antiplasmodial potential of medicinal plant extracts from Malaiyur and Javadhu hills of South India

“…The acetone, chloroform, ethyl acetate, hexane, methanol and petroleum ether extracts of the leaf and seed of S. torvum were active against the fourth-instar larvae of the malaria vector, A. subpictus, and the Japanese encephalitis vector, C. tritaeniorhynchus ). The complete egg hatching inhibition and larval development inhibition for leaf and seed ethyl acetate, acetone and methanol extracts of S. torvum indicated in vitro anthelmintic activity against the parasitic nematode of small ruminants Haemonchus contortus (Kamaraj et al 2010d). …”