The characteristic smell emitted from two scale insects, Ceroplastes japonicus and Ceroplastes rubens .

The volatile components emitted from two scale insects, Ceroplastes japonicus and Ceroplastes rubens , were identified using GC-MS analysis. The major volatile components of the solvent extract from C. japonicus were α-humulene (35.8%) and δ-cadinene (17.0%), while those of C. rubens were β-selinene (10.3%) and β-elemene (5.1%). In GC/olfactometry, linalool, butyric acid, 3-methylbutyric acid, 2-methylbutyric acid, and vanillin were identified as the odor-active components of the extract from C. japonicus , in addition to trace amounts of trans -4,5-epoxy-(2 E )-decenal, 4-methyl-(3 E )-hexenoic acid, and phenylacetic acid. With regard to C. rubens, trans -4,5-epoxy-(2 E )-decenal, 3-methylbutyric acid, and phenylacetic acid were identified as the odor-active components. Besides, decan-1,4-olide (γ-decalactone) with milky cherry-like note and 3-hydroxy-4,5-dimethylfuran-2(5 H )-one (sotolone) with brown sugar-like note were also detected as the characteristic cherry-like sweet-and-sour note of these two scale insects.
Abbreviations: GC: Gas chromatography; GC/O: gas chromatography/olfactometry.