Volatiles mediated an eco‑friendly aphid control strategy of Chrysanthemum genus

Abstract

The chrysanthemum aphid Macrosiphoniella sanborni is one of the most severe crop pests for the cultivated chrysanthemum. It is urgent to find efficient and eco‑friendly control strategies to promote the chrysanthemum industry's sustainable development. In this study, an aromatic wild species Chrysanthemum aromaticum were introduced to hybrid with Chrysanthemum nankingense to breed aphid-resistant offspring, and the role of the constitutive volatiles was revealed. Fifty interspecific hybrids were obtained and identified by morphology and SSR test. The aphid resistance of 28 robust hybrids was evaluated by combining the greenhouse test with the field test. Then, chrysanthemum aphids were exposed to the volatiles of two parents and ten hybrids to ensure volatiles influenced their choice. Sixty-five major compounds were detected in the parent and hybrid leaves using solid phase micro extraction-gas chromatography-mass spectrometry (SPME-GC–MS). Nineteen featured compounds of aphid resistant lines were selected by PCA analysis. Cis-4-thujanol was confirmed to be an effective repellent by the Y tube choice experiment and direct exposure tests. These findings have important implications for more eco-friendly control options of chrysanthemum aphids. C. aromaticum and these aphid-resistant hybrids can be used as breeding materials directly. Cis-4-thujanol has excellent potential to formulate natural insecticides.