Evaluation of toxicity assay of the methanolic extract of oleander leaves against fall armyworm

Abstract

Oleander (Nerium oleander L.) is a shrubbery plant with various functions as an ornamental, medicinal, bio-fungicide, and bio-insecticide. The study aimed to investigate the acute toxicity assay of methanolic extract of oleander leaves on fall armyworm (Spodoptera frugiperda J.E. Smith). The study was conducted in a Complete Randomized Design (CRD) for upper and lower concentrations. The upper and lower concentrations' results were calculated to find the intervals and then used to determine the Lethal Concentration (LC) with four repetitions using probit analysis. In addition, the mortality, food, and weight were calculated using Analysis of Variance (ANOVA). The results showed that concentration interval values from the lower limit to the high of the extract of methanol oleander leaves were: 0.23%; 0.32%; 0.45%; 0.63%; and 0.88%. The probit analysis showed that the toxicity of oleander extract concentrations at 48 Hours after Treatment (HAT) was LC50 by 0.86% and LC95 by 2.42%. The lethal concentration on the last day (D-20) of LC50 and LC95 was 0.54% and 1.76%, respectively. During the 20 days of the observation period, fall armyworm larvae only consumed 162.36±13.48 mg of baby corn at the highest concentration (0.88%), compared to 665.47±22.60 mg at the control. The oleander extract also affected the larvae's weight and time consumption. The resulting concentration of extracts of oleander methanol can be used to control fall armyworm larvae.