Integrated evaluation of Chrysanthemum × morifolium (Ramat.) Hemsl. essential oil, compared with α-terpineol, β-pinene, borneol, and camphor: In vitro and in situ antibacterial activity against selected microorganisms and insecticidal effects on bruc

The present study evaluated the antimicrobial, antibiofilm, in situ food model, and insecticidal activities of Chrysanthemum × morifolium (Ramat.) Hemsl. white essential oil (CMEO) in comparison with its major constituents α-terpineol, β-pinene, endo-borneol, and camphor. CMEO was chemically characterized by GC–MS and contained mainly α-terpineol, capric acid, β-pinene, α-pinene, and camphene, together accounting for almost the entire identified fraction. In vitro , CMEO showed broader and stronger antimicrobial effects than all the tested constituents against a panel of Gram-negative and Gram-positive bacteria and Candida spp., as reflected by markedly lower MIC 50 /MIC 90 values, particularly for Yersinia enterocolitica and Candida albicans . In vapor phase tests on apple, pear, parsley, and Hokkaido pumpkin slices, CMEO produced high and concentration-dependent growth inhibition in all microorganisms, including a biofilm-forming Salmonella enterica strain, whereas the individual constituents showed only limited or inconsistent activity, particularly at lower concentrations. Crystal violet assays showed that CMEO inhibited established Salmonella enterica biofilms with MIC 50 = 2.46 mg/mL and MIC 90 = 2.64 mg/mL, while the individual constituents required markedly higher concentrations, with α-terpineol showing the strongest activity among them (MIC 50 = 1.38–3.60 mg/mL). MALDI-TOF MS profiles and MSP dendrograms confirmed clear and time-dependent differences between planktonic and surface-attached cells on wood and stainless steel, with more pronounced shifts in the presence of CMEO. In insecticidal assays, CMEO caused high mortality of Callosobruchus maculatus and Megabruchidius dorsalis down to 25–12.5%, whereas the individual constituents showed only moderate effects, with α-terpineol being the most active (LC 50 = 24.74% for C. maculatus ; LC 90 = 32.62% for M. dorsalis ). Overall, the data demonstrate that CMEO consistently outperforms tested individual constituents across all models, confirming that no single constituent alone accounts for the observed biological activity of the oil. • Chrysanthemum × morifolium essential oil (CMEO) shows strong antimicrobial activity. • CMEO outperforms β-pinene in antimicrobial and antibiofilm assays. • Strong in situ antimicrobial activity in fruit and vegetable models. • CMEO inhibits Salmonella enterica biofilm formation. • CMEO shows insecticidal activity against bruchine beetles.