Larvicidal effects of leaf, bark and nutshell of Anacardium occidentale on the larvae of Anopheles gambiae in Ebonyi State, Nigeria

Abstract

Comparative analysis of the larvicidal properties of aqueous extracts of leaves, bark and nutshell of Anacardium occidentale L. (Cashew) were evaluated on the larvae of Anopheles gambiae. Three concentrations of 10/100ml, 20/100ml and 30/100ml each of leaf, bark and nutshell were prepared in three replicates. The treatments were exposed to two durations of thirty minutes and one hour. After thirty minutes of treatment, the mean mortalities were 53%, 68% and 56% for leaf, 64%, 71% and 57% for bark and 53%, 68% and 58% for nutshell, while the mean mortalities after one hour of exposure were 68%, 70% and 93% for leaf, 84%, 93% and 97% for bark and 61%, 68% and 73% for nutshell. Analysis of variance (ANOVA) showed that at thirty minutes of exposure, there were no significant difference (P<0.05) between concentrations and the percentage mortality, but it was highly significant (P<0.01) after 1 hour of exposure. Quantities phytochemical analysis revealed the presence of tannin, oxalate, stearic acid, glucoronic acid and glutamic acid in the leaf, bark and nutshell extracts.