Insecticidal and Enzyme Inhibition Activities of Leaf/bark Extracts, Fractions, Seed Oil and Isolated Compounds From Triadica Sebifera (L.) Small Against Aphis Craccivora Koch

Abstract

Aphid, Aphis craccivora Koch (Hemiptera: Aphididae) is a major sap-sucking insect pest of leguminous crops and also transmit plant viruses leading to economic yield loss. Insecticidal activities of T. sebifera have not been reported against A. craccivora and other insect pests till date. In this study, residual toxicity of leaf/bark extracts, seed oil, fractions, isolated compounds and its combinations; synergistic activity of leaf/ bark extract with seed oil and its enzyme inhibition activities against A. craccivora was studied. Among extracts, ethanolic bark extract 80% (LC50=5115.98 mg L-1) was more effective against A. craccivora than other extracts. Among fractions, n-hexane fraction of leaf (LC50=425.73 mg L-1) and ethyl acetate fraction of bark (LC50=813.45mg L-1) was more effective. Among compounds, gallic acid was most effective (LC50=1303.68 mg L-1) than shikimic acid and quercetin (LC50=1725.09 and 1855.93 mg L-1, respectively). Seed oil (LC50=850.94 mg L-1) is more superior than extracts/fractions/compounds. All the combinations showed toxicity and synergistic activity. Leaf/bark extracts and seed oil (0.25-2 mg L-1) significantly inhibits the AChE and GST activity in A. craccivora. Based on field bio-efficacy studies, the leaf extract/seed oil or their combinations can be recommended for development of botanical formulation for the control of aphid.