Toxicity effects of Etlingera elatior (Zingiberaceae) against Epilachna indica (Coleoptera: Coccinellidae: Epilachninae)

This study  investigated the effect of Etlingera elatior flowers towards the ladybird beetle, Epilachna indica pest of Solanaceae plant. Five kg of wet weight of E. elatior  was extracted using 99.9% n-hexane for three days, and concentrated by rotary evaporator at 79ºC. The beetles were subjected to experiment using the plant hexane  extract, with 10 replicates of petri dish, each with 10 adult beetle individuals. It causes mortality towards the beetles within the first 24 hours. Bioassay using treatment of 2000ppm, 5000ppm, 10000ppm, 20000ppm, 50000ppm, and control showed  that by using 5000 ppm, mortality of E. indica was  the most  within the first 24 hours. Flash column chromatography and thin layer chromatography (TLC) were used to separate the components. The fractions obtained from flash column chromatography were used for bioassay.Then, another bioassay was run using the spots that were obtained on the fractions of TLC plates, and the highest mortality within the first 24 hours was recorded in fraction of 90:10 (hexane:diethy ether). The compounds found in the crude extract of E. elatior include 2-tridecanone, undecanone and dodecanol.Probit analysis and ANOVA were used to analyze the data obtained.