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 transmits plant viruses, leading to economic yield loss. Indiscriminate and repeated use of insecticides for control of aphid leads to the development of resistance, and is harmful to the environment, non-target organisms, etc. Plant-based extracts/seed oils (SO) are the best alternatives to insecticides. Insecticidal activities of Triadica sebifera have not been reported against A. craccivora and other insect pests to date. In the current study, the main objective was to study the insecticidal activities of leaf/bark extracts/fractions, seed oil, isolated compounds, and their combinations against A. craccivora. Results showed that, among the extracts, ethanolic bark extract 80% (LC50 = 5115.98 mg/L) was more effective against A. craccivora. Among fractions, the n-hexane fraction of leaves (LC50 = 425.73 mg/L) and the ethyl acetate fraction of bark (LC50 = 813.45 mg/L) were promising. Among compounds, gallic acid was the most effective (LC50 = 1303.68 mg/L) compared to shikimic acid and quercetin. SO (LC50 = 850.94 mg/L) was superior compared to extracts/fractions/compounds. All the combinations showed toxicity and synergistic activity. Leaf/bark extracts and SO significantly inhibited the AChE and GST activity in A. craccivora. Based on field bio-efficacy, the leaf extract/SO or their combinations can be recommended for the control of aphids.

Characterization of Triadica sebifera (L.) Small Extracts, Antifeedant Activities of Extracts, Fractions, Seed Oil and Isolated Compounds against Plutella xylostella (L.) and Their Effect on Detoxification Enzymes

“…All the concentrations of leaf and bark extract against larvae of P. xylostella in the current study showed an inhibitory effect on GST and AChE except leaf/bark extract 0.5% and seed oil 0.25%. The present results confirmed our previous studies, where the leaf, bark extract, and seed oil of T. sebifera showed significant inhibition of GST and AChE in A. craccivora [ 19 ]. The leaf extracts, seed oil, and their binary mixtures of T. sebifera showed excellent and promising antifeedant and synergistic activity against larvae of P. xylostella.…”

“…The other metabolites present in the bark ethanol aqueous extract are scopoletin, β-sitosterol, stigmasterol glycoside, kaempferitrin, and coumarin/glycosidic derivative compounds. Similarly, the deterrent activity of seed oil may be due to the presence of saturated (6.73%) and unsaturated fatty acids (26.33%) as per earlier reports [ 19 ].…”

“…In the current study, the leaf, bark extract and its binary mixtures, fractions, and seed oil of T. sebifera act as antifeedants against the larvae of P. xylostella and reduced the consumption of leaf. In the field conditions, the application of leaf/bark extract, its fractions, and seed oil on the plants/crops significantly reduce the damage by target pests and also showed promising efficacy against aphids [ 19 ]. In addition to the reduction in intake of food through their effects on chemoreceptors and taste receptors in the gustatory sensilla.…”

“…The present study confirms the feeding deterrence of the ethyl acetate fraction of Pergularia daemia against Helicoverpa armigera and S. litura [ 37 ] and the butanol fraction of Catunaregam spinosa against Pieris rapae and P. xylostella [ 38 ]. The deterrence of the fractions against P. xylostella in the current study might be due to the presence of metabolites of hexadecanoic acid, galaxolide, ethyl phthalate, octadecanoic acid, ethyl ester, and 1-octadecene in the n -hexane fraction of leaf and bark [ 19 ]. The ethanol leaf extract (RC 50 = 575.74 mg/L) showed more repellence against P. xylostella as compared to bark and seed oil.…”

“…T. sebifera was selected in the present study due to the availability of plant material and seeds in different parts of India (Himachal Pradesh, Uttarakhand, Jammu and Kashmir, Uttar Pradesh, and Tamil Nadu) to study the insecticidal activities against P. xylostella . No report on insecticidal activities of T. sebifera against P. xylostella has been reported to date except for Aphis craccivora [ 19 ]. Therefore, in the present study, we explored the characterization, antifeedant/feeding deterrence, repellent, synergistic, and detoxifying enzyme inhibition activities of seed oil, leaf, bark ethanol aqueous extract, and its fractions against larvae of P. xylostella .…”