Larvicidal potential of certain plant extracts of the family Lamiaceae against Anopheles subpictus (Diptera: Culicidae)

Abstract

The present study was undertaken to check and compare the virtue of plant extracts in relation to larvicidal activities against Anopheles subpictus. The lethality and toxicity of methanolic and aqueous extracts of Ocimum sanctum, Ocimum basilicum, Leucas aspera and Coleus amboinicus to early 4 th instar larvae of A. subpictus were determined in the laboratory. All plant extracts of Lamiaceae showed moderate effect against the larvae of A. subpictus after 24 hours exposure as evidenced by low lethal concentration and lethal time and the lethality varied in larvae and the crude plant extracts. The mortality rate was recorded after 24 hours of exposure and LC50 was determined. Larval mortality between 80% and 92% was observed in methanolic extract and 60-85% in aqueous extracts of selected plant species. The highest larvicidal activity against A. subpictus was obtained with methanol extract of O. sanctum. The present findings have paramount implications in the practical control of mosquito larvae and adults in the aquatic ecosystem as the medicinal plants studied are routinely accessible in enormous quantities. These plant extracts are easy to prepare, inexpensive, and safe for mosquito control which might be used directly as larvicidal agents in small dimension aquatic habitats or breeding sites around human dwellings.

Larvicidal, Ovicidal, and Repellent Activities of Leucas stachydiformis (Hochst. ex Benth.) Briq Essential Oil against Anopheles arabiensis

“…Identifcation of potential insecticides and repellents from natural product resources, such as plant extract and essential oils is one solution for the abovementioned problems. Previous studies have demonstrated that members of the genus Leucas possess larvicidal [9][10][11][12], ovicidal [13], and repellent [14] activities. Terefore, the present study was designed to investigate the larvicidal, ovicidal, and repellent activities of the essential oil of leaves of Leucas stachydiformis (Hochst.…”

Larvicidal, Ovicidal and Repellent Activities of Leucas stachydiformis (Hochst. ex Benth.) Briq Essential Oil against Anopheles arabiensis

“…Identi cation of potential insecticides and repellents from natural product resources, such as plant extract and essential oils is one solution for the above problems. Previous studies have demonstrated that members of the genus Leucas possess larvicidal [9][10][11][12], ovicidal [13] and repellent [14] properties against different stages in the life cycle of mosquito vectors. Therefore, the present study was designed to investigate the larvicidal, ovicidal, and repellent activities of the essential oil of leaves of Leucas stachydiforms (Hochst.…”