Effectiveness of Kratom (Mitragyna speciosa Korth) leaf extracts against adult of sweet potato weevil (Cylas formicarius Fabricius) in laboratory conditions

Abstract

The result showed that the hexanolic leaf extract of Kratom presented rather high effect to this weevil with >70% mortality at 24 h after treatment. Besides, Kratom leaf extracted by using ethanol and acetone showed lower effect against this weevil. The hexanolic extract presented extreme toxicity to weevil with LC50 values of 3.50, 2.88 and 2.27% at 24, 48 and 72 h after treatment, respectively. This extract at 4% concentration exhibited repellency effect with > 77% significant difference compared with the control group. In addition, this extract showed high efficiency on oviposition inhibition for weevil (>89%) at 5% concentration, significantly different as compared with the control group.