Insecticidal potential of extracts, fractions, and molecules of Aconitum heterophyllum Wall ex. Royle against aphid Aphis craccivora Koch (Hemiptera: Aphididae)

BACKGROUNDAphis craccivora is the major sap-sucking pest of leguminous crops and vector of plant viruses that cause damage to plants and reduce yield. Indiscriminate and nonjudicious use of synthetic insecticides led to resistance development and harmful to environment. Therefore, it is important to discover plant-based lead(s) which can replace synthetic insecticides. In the current study the residual toxicity of extracts, fractions, and isolated compounds of Aconitum heterophyllum were evaluated against A. craccivora to identify lead(s) for further development of botanical formulation. RESULTSIn residual contact assay, ethanolic (LC50 = 2837.17 mg L-1) and aqueous methanolic extracts (LC50 = 2971.59 mg L-1) were effective against A. craccivora. Among fractions, the n-butanol fraction of the aqueous methanolic extract (LC50 = 986.96 mg L-1) was found to be most effective, followed by the ethyl acetate fraction of the ethanolic extract (LC50 = 1037.52 mg L-1) and the n-hexane fraction of both extracts (LC50 = 1113.85 to 1233.11 mg L-1). Among pure molecules, aconitic acid was found to be the most effective (68% mortality; LC50 = 1313.19 mg L-1) and was on a par with azadirachtin 0.15% EC (66% mortality; LC50 = 1921.10 mg L-1). Furthermore, from the effect of ethanoic extract on detoxification enzyme inhibition in A. craccivora we concluded that the target site of action of this extract in A. craccivora might be glutathione S-transferase. CONCLUSIONSThe parent extract/fractions of A. heterophylum showed promising activity against A. craccivora. Among phytoconstituents of the active extract and fractions, aconitic acid was found to be on a par with azadirachtin 0.15% EC. (c) 2022 Society of Chemical Industry.

Automated summary

In the current study, the residual toxicity of extracts, fractions, and isolated compounds of Aconitum heterophyllum were evaluated against Aphis craccivora. The ethanolic and aqueous methanolic extracts showed effective control against A. craccivora. Among the fractions, the n-butanol fraction of the aqueous methanolic extract was the most effective, followed by the ethyl acetate fraction of the ethanolic extract and the n-hexane fraction of both extracts. Aconitic acid was identified as the most effective pure molecule. The study also suggested that the action of the ethanoic extract might involve the inhibition of glutathione S-transferase in A. craccivora.