The efficacy of Syzygium aromaticum and Rosmarinus officinalis oils in the emulsion and nano-emulsion forms, Pyrimethanil, and Serenade ASO in controlling Botrytis cinerea was investigated. Data showed that S. aromaticum nano-emulsion had the greatest inhibitory effect on B. cinerea growth, followed by Pyrimethanil, S. aromaticum emulsion, and Serenade ASO. The highest concentration of 3% S. aromaticum nano-emulsion completely inhibited B. cinerea growth as a Pyrimethanil treatment. Postharvest application on strawberries with artificial inoculation and stored at 5 and 20 °C had a variable effect on fruit grey mould reduction. In the first season, when stored at 5 and 20 °C, S. aromaticum nano-emulsion caused the least fruit grey rot, followed by Pyrimethanil, S. aromaticum emulsion, and Serenade ASO, in that order. However, after a second season of storage at 5 and 20 °C, S. aromaticum nano-emulsion had the greatest inhibitory effect, followed by Pyrimethanil, Serenade ASO, and S. aromaticum emulsion, in that order. In all treatments, storage at 5 °C increased total soluble solids (TSS%) compared to storage at 20 °C. SEM images of B. cineara hyphae treated with S. aromaticum nano-emulsion, Rosmarinus officinalis nano-emulsion, and Serenade ASO revealed degenerative and lysis changes in hyphal morphology. In comparison to thick, elongated, smooth-surfaced control hyphae, shrunken hyphal cells had either no cytoplasm or cytoplasm depleted of organelles.