Use of Crude Extract of Chromolaena odorata (L) R.M. King & H. Rob Leaf in Controlling Rice Brown Planthopper (Nilaparvata lugens Stål)

Abstract

Nowadays, the invasive Siam weed, Chromolaena odorata, a nuisance weed in agricultural farms, can be exploited as an alternative choice to replace the synthetic pesticides. This present endeavor, therefore, aimed to explore the potential adulticidal ability of ethanolic leaf extract of C. odoratafor control Nilaparvata lugens. Dry plant material was soaked in 95% ethanol for seven days with a ratio of 1:10 (w/v). Afterwards, the efficacy of plant extract against N. lugens was estimated using spraying method in different concentrations (0 (control), 25, 50 and 100% (w/v)).Twenty five samples were transferred to each pot cultured with three rice seedlings and covered with the paper box. In each trail, four replications were designed. Mortality counts of insect were monitored at regular intervals i.e. 24 and 48 hours after treatment. It was revealed that N. lugens held median lethal concentrations to eradicate 50% Lethal Concentration (LC₅₀), (% (w/v)) of the treated them in 24 and 48 hours of 93.573 and 37.751. Additionally, the concentration at 100% (w/v) of C. odorata leaf extract showed the highest effectiveness in controlling the larvae with 74% (w/v) cumulative mortality after exposure for 48 hours. Moreover, the mortality rate increased when exposed to a higher concentration in all trials. It was possible that this plant extract trended to be further applied in controlling N. lugens. Before using this plant extract in the area, chemical profile, extraction technique, optimal formulation and feasibility of extraction form should be initially determined.