Evaluation of larvicidal efficacy of indigenous plant extracts against Culex quinquefasciatus (Say) under laboratory conditions

Authors: JAVAID IQBAL, FAISAL ISHTIAQ, ABDULAZIZ S. ALQARNI, AYMAN A. OWAYSS

Abstract: The present study focused on the insecticidal potential of easily available local botanicals using a simple but effective method. Seven indigenous plants (Cinnamomum tamala (taiz pat), Aloe vera (aloe vera), Datura alba (datura), Allium sativum (garlic), Allium cepa (onion), Zingiber officinale (ginger), and Ocimum basilicum (niazbo/basil) were tested for their larvicidal efficacy against Culex quinquefasciatus (Say) under laboratory conditions. The evaluation of a series of five concentrations (1%, 2%, 3%, 4%, and 5%) of aqueous plant extracts against the 4th instar larvae revealed convincing larval mortality effects at 24 and 48 h after exposure. Larval mortality showed a significant concentration-dependent correlation. No mortality was observed in the control. The LC₅₀ values demonstrated garlic as the most effective (1.37%), followed by taiz pat (1.48%) and aloe vera (1.96%), at 24 h. Moreover, the LC₅₀ at 48 h showed high efficiency by aloe vera (0.37%), followed by garlic (0.55%) and taiz pat (0.98%). The sequence of LC50 values for the other plants were onion (2.20%) < datura (2.49%) < niazbo (5.32%) < ginger (7.48%) after 24 h and datura (1.13%) < niazbo (1.17%) < onion (1.24%) < ginger (2.43%) after 48 h. Taken together, the aqueous extracts of all plants exhibited potential efficacy against C. quinquefasciatus larvae and could be considered as potent natural larvicidal agents. These plants may be recommended for use in mosquito management programs as potential alternatives to synthetic insecticides. The simple aqueous extraction method is easy and inexpensive and can be used at the home level for mosquito management.

Keywords: Aqueous extracts, botanicals, larvicidal activity, mosquito

Full Text: PDF