Harnessing Koelreuteria paniculata Seed Extracts and Oil for Sustainable Woolly Apple Aphid Control

Abstract

The woolly apple aphid—WAA (Eriosoma lanigerum Hausmann, 1802) poses a significant threat to intensive apple production. Given the limitations of conventional synthetic pesticides, there is an urgent need for effective and sustainable pest management strategies. Botanical extracts derived from plants with insecticidal properties mitigating aphid populations without adverse environmental impacts are scarce where WAA is concerned. Thus, the pertinent study aimed to investigate the aphicidal potential of Koelreuteria paniculata seed ethanolic extract (derived from the seed coat) and mechanically extracted oil (derived from the seed itself). At concentrations of 2.5% and 5%, both solutions expressed undeniable insecticidal potential, providing absolute (100%; oil) or significant (86–100%; ethanolic extract) mortality rates both in vivo and in vitro. Predominant phenolic compounds determined in the ethanolic extract were gallic and protocatechuic acids and three derivates—p-coumaric, quercetin, and luteolin acid derivates—contributing to more than 90% of the total phenolic content, while phenolic compounds were not detected in the oil, indicating activity of different active compounds. Although deriving from different seed parts and distinct extraction methods, both ethanolic extract and oil exhibited significant aphicidal effects against WAA. The integration of botanical extracts from invasive species into pest management practices supports ecological balance and sustainable agricultural productivity, fostering a healthier environment and more resilient agricultural systems.