Laboratory study on larvicidal activity of indigenous plant extracts against Anopheles subpictus and Culex tritaeniorhynchus

Abstract

Anopheles subpictus and Culex tritaeniorhynchus have developed resistance to various synthetic insecticides, making its control increasingly difficult. Insecticides of botanical origin may serve as suitable alternative biocontrol techniques in the future. The leaf acetone, chloroform, ethyl acetate, hexane, and methanol extracts of Aegle marmelos (Linn.) Correa ex Roxb, Andrographis lineata Wallich ex Nees., Andrographis paniculata (Burm.f.) Wall. ex Nees., Cocculus hirsutus (L.) Diels, Eclipta prostrata L., and Tagetes erecta L. were tested against fourth-instar larvae of malaria vector, A. subpictus Grassi and Japanese encephalitis vector, C. tritaeniorhynchus Giles (Diptera: Culicidae). All plant extracts showed moderate larvicidal effects after 24 h of exposure at 1,000 ppm; however, the highest larval mortality was found in leaf ethyl acetate of A. marmelos, E. prostrata, hexane, methanol of A. paniculata and C. hirsutus against the larvae of A. subpictus (LC(50) = 167.00, 78.28, 67.24, 142.83 ppm; LC(90) = 588.31, 360.75, 371.91, and 830.01 ppm) and against the larvae of C. tritaeniorhynchus (LC(50) = 99.03, 119.89, 88.50, 105.19 ppm; LC(90) = 479.23, 564.85, 416.39, and 507.86 ppm), respectively. These results suggest that the leaf hexane extract of A. paniculata and ethyl acetate extract of E. prostrata have the potential to be used as an ideal eco-friendly approach for the control of the A. subpictus and C. tritaeniorhynchus. Therefore, this study provides first report on the mosquito larvicidal activity of plant extracts against vectors from Southern India.

Larvicidal, ovicidal, and oviposition-deterrent activities of four plant extracts against three mosquito species

“…This result also agrees with that of Govindarajan et al (2011) who has shown that the larvicidal and ovicidal activities of crude leaf extracts of Ervatamia coronaria and Caesalpinia pulcherrima against A. stephensi, A. aegypti, and C. quinquefasciatus. Our result also agrees with that of Elango et al (2009) who showed that indigenous plant extracts such as Aegle marmelos, Andrographis lineate, Andrographis paniculata, Cocculus hirsutus, Eclipta prostrata, and Tagetes erecta have oviposition-deterrent, ovicidal, and repellent activity against Anopheles subpictus in Vellore District, Tamil Nadu, India. Similarly, Tawatsin et al (2006) too have reported that the relatively high oviposition-deterrent activity was obtained by essential oils of Curcuma longa, Zingiber officinale, V. trifolia, Melaleuca cajuputi, Manglietia garrettii, and Houttuynia cordata.…”

“…After the treatment, the counted eggs from each concentration were individually transferred to stored water cups for the assessment of hatchability. The percent egg mortality was calculated on the basis of unhatched eggs after 98-h posttreatment by employing the following calculation (Elango et al 2009). …”

Tagetes erecta Linn. and its mosquitocidal potency against Culex quinquefasciatus

“…quinquefasciatus larvae [19][20][21][22] . The extracts from T. erecta had larvicidal activity against Aedes aegypti and against the larvae of Meloidogyne incognita, respectively [23][24][25] but till now there is no report on the toxicity of T. erecta against Cx. quinquefasciatus Say.…”

Insecticidal Activities of the Essential Oil of Aegle marmelos (Linnaeus, 1800) against Aedes aegypti (Linnaeus, 1762) and Culex quinquefasciatus (Say, 1823)

“…Aegle marmelos (L), a tree under the Rutaceae family commonly known as "Bael", is a native plant of India with religious and medicinal importance [7]. The tree has a trunk with spiny branches and green leaves with three leaflets which release a fragrance when bruised [8].…”