Insecticidal Effects of the Flavonoid-rich Fraction of Leaves Extract of Gamal (Gliricidia sepium) on the Coffee Mealybugs (Planococcus citri Risso.)

Abstract

Aims: To find out whether flavonoid-rich fractions of aqueous and methanolic extracts of gamal plant leaves, Gliricidia sepium (Jacq.) Kunth ex Walp., can be used for eradicating coffee mealybugs, Planococcus citri Risso. Study Design: Completely randomized design using five concentration levels repeated three times. Place and Duration of Study: Department of Biology, Faculty of Mathematics and Sciences, University of Lampung, Bandar Lampung, Indonesia between December 2015 and May 2016. Methodology: Mealybugs that found to infest coffee berries (Coffea robusta L.) were reared and grouped into two. Both groups were fed consecutively with flavonoid fractions of aqueous and methanolic extracts of gamal plant leaves with the concentration of 0% (as control), 0.01%, 0.02%, 0.03%, and 0.04%. The percent mortality of insects was examined at the 12th, 24th, 48th and 72th hour. Results: Thin layer chromatography analysis of aqueous and methanolic extracts yielded consecutively one and seven fractions of flavonoid.  Both type of extract affected mortality rate of the insects in a concentration-related manner, however based on LC50 and LT50 values the water fractions showed a higher effectiveness than that of methanol. Conclusion: It is suggested that flavonoid-rich fraction of gamal leaf extracts is potent to be used as bioinsecticide for coffee mealybugs, Planococcus citri Risso.