Combined efficacy of plant-based bioinsecticides and <i>Anystis baccarum</i> (Acari: Anystidae) on green peach aphid

Myzus persicae (Sulzer), a globally significant agricultural pest, poses considerable challenges to conventional chemical control methods due to widespread resistance development. This situation underscores the critical need for integrated pest management (IPM) strategies that combine biological and chemical control measures to achieve sustainable pest suppression. This study investigated the effects of three biopesticides on M. persicae and evaluated their safety for the predatory mite Anystis baccarum (Linnaeus) under laboratory conditions. Additionally, the potential enhanced effects of the combined application of combining these biopesticides with A. baccarum were examined in greenhouse trials. Results showed that all tested biopesticides exhibited concentration-dependent toxicity against M. persicae, with 1-d-old nymphs being the most susceptible life stage, while adults displayed the highest tolerance. Among the tested compounds, cineole and matrine showed higher toxicity than d-limonene. Formulations containing d-limonene (800-fold dilution) and matrine (1200-fold dilution) were considered safe for A. baccarum causing less than 15% mortality. Greenhouse experiments revealed that the combined application of biopesticides and A. baccarum enhanced aphid control efficacy compared to biopesticides alone. Specifically, the integrated treatments increased pest mortality by 4.7% to 14.1% within 72 h, achieved peak control efficacy ∼3 d earlier (reaching 80% control efficiency), and maintained high efficacy levels (63.4% to 76.9%) for up to 27 d post-application. Notably, the combination of matrine and A. baccarum produced the highest corrected efficacy, achieving 76.9% control efficiency at 27 d. These findings demonstrate that integrating matrine with A. baccarum simply enhances pest management efficacy while preserving natural enemy populations, thereby providing a promising strategy for IPM programs targeting M. persicae.