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Abstract BACKGROUND Myzus persicae Sulzer and Brevicoryne brassicae L. are economically important aphid pests of oilseed rape (OSR) and the primary vectors of turnip yellows virus. Control options are constrained for many aphid pests due to pest resistance to synthetic chemical insecticide active ingredients or their withdrawal from market. Physically acting bioinsecticides may offer an alternative control option, yet their efficacy against aphids and compatibility with natural enemies outside of horticultural production systems is poorly understood. Three bioinsecticides based on fatty acids, silicone polymers or surfactants were tested against two economically important aphid species and non‐target effects on their natural enemies, Diaeretiella rapae M'Intosh adults and mummies as well as Chrysoperla carnea Stephens larvae, were also assessed. RESULTS Under direct exposure, fatty acids, silicone polymers and surfactants all caused aphid mortality ( B. brassicae 90–56%, M. persicae 63–20%) within 72 h. Diaeretiella rapae mortality was 100% 24 h after exposure to fatty acids and silicone polymers while Chyrsoperla carnea mortality was 66% and 100%, respectively. Residual exposure caused limited mortality in aphids ( M. persicae 0%, B. brassicae ≤10%) and natural enemies ( D. rapae ≤33%, C. carnea ≤13%) compared to the sulfoxaflor synthetic chemical insecticide control (66–100%). CONCLUSION Fatty acids and silicone polymers significantly reduced numbers of aphids but showed acute toxicity to parasitoids under direct exposure. Their lack of residual activity means that precise targeted application to pest populations is required but allows natural enemy populations to recolonise treated areas rapidly. These bioinsecticides may provide supplementary control within OSR integrated pest management programmes when applied strategically. © 2026 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
Tonks et al. (Tue,) studied this question.