Larvicidal potential and retention efficacy period of citronella leaf oil against Aedes aegypti L.

The mosquito vector Aedes aegypti L., plays an important role in transmission of diseases including dengue, chikungunya and zika fever. In this study, citronella leaf oil extracted by hydro-distillation technique has been evaluated for its efficacy against this vector. Citronella leaf oil (100, 125, 150, 175 and 200 ppm) when tested, 150 ppm was found to be the effective larvicidal concentration against 4^th instar larvae. LC₅₀ and LC₉₀ toxicity values were observed to be 107.10 and 141.59 ppm, respectively. GC-MS analysis indicated the presence of β-citronellal, geraniol, elemol and β-citronellol as the major components, which might be causing the larval mortality. Retention efficacy of the oil was found to be up to 84 hr in terms of larval killing and during this retention period, a significant delay in development (L4 to adult) was also observed. No effect of storage was observed on its larvicidal efficacy even after six months.