Feeding Deterrent Concentrations of Jasmonates

Cis-jasmone and methyl jasmonate were purchased from Sigma-Aldrich. Pure compounds were diluted in pure ethanol (96%; Merck, Darmstadt, Germany) at a ratio of 1:10 (vol/vol). Subsequently, distilled water plus Triton X-100 (0.05% vol/vol; Sigma-Aldrich) as surfactant was added to obtain 15 and 50% feeding deterrent concentrations (FDC₁₅ and FDC₅₀), required to reduce feeding damage on the treated leaf disc by 15 or 50%, respectively, compared to control leaf disc in choice assays (Egger et al., 2014 (link)). For cis-jasmone, FDC₁₅ was about 0.29% (hereafter referred to as ‘low concentration’) and FDC₅₀ was about 0.66% (‘high concentration’); for methyl jasmonate, the low concentration was at about 0.08%, the high concentration at about 0.77%. The control solution consisted of ethanol and distilled water with the surfactant at a ratio of 1:10.