Repellent and Attractant Effects of Chinese Medicinal Product Extracts on Plutella xylostella (Lepidoptera: Plutellidae)

ABSTRACT

Plutella xylostella (Linnaeus) (Lepidoptera: Plutellidae) is a major pest for cruciferous crops, reducing production and quality worldwide. The continuous use of synthetic pesticides has resulted in environmental pollution and insecticide resistance. Plant‐based extracts offer an eco‐friendly alternative. In this study, the oviposition effects of Chinese medicinal product (CMP) extracts on P. xylostella adults were evaluated using non‐choice oviposition bioassays under laboratory conditions and dual‐choice oviposition bioassays under net room conditions. The olfactory behavioral responses of adult P. xylostella to the screened extracts were assessed through electroatennogram (EAG) and Y‐tube olfactometer assays. The oviposition tests demonstrated that extracts of Illicium verum , Syzygium aromaticum , Astragalus membranaceus , and Rheum officinale at 6.25 mg/mL significantly affected female P. xylostella oviposition, with oviposition indexes of 40.07%, 77.53%, 49.60%, and −8.88%, respectively. EAG results showed that adult P. xylostella could perceive all CMP extracts at the five tested concentrations. In Y‐tube olfactometer trials, I. verum and S. aromaticum extracts showed strong repellent effects, while R. officinale attracted female P. xylostella . Astragalus membranaceus extract had attractant effects at 25 mg/mL but repellent effects at 12.5 and 6.25 mg/mL. In a netted room experiment, S. aromaticum extract demonstrated significant repellent effects against P. xylostella adults, while R. officinale extract showed attractant effects on P. xylostella adults, protecting the middle plant row for up to 6 days. These findings suggest potential applications of both extracts in push‐pull strategies for controlling P. xylostella by affecting oviposition and behavior.