Chestnut tannin induces gut degeneration in Aedes albopictus mosquito larvae.

). Gut ultrastructural characterization observed through TEM indicated that, after treatment, the midgut epithelium degenerates, with evident modifications of microvilli and the peritrophic membrane. To unveil the reasons behind the higher bioactivity of CT2, the tannins were examined and compared through elemental analysis and spectroscopic, chromatographic, and mass spectrometric techniques. By these means, differences in the content of minor components between CT1 and CT2 were evidenced, even though their identity could not be ascertained. Lastly, we assessed the oviposition deterrence exerted by CT2 on Ae. albopictus females in the field as a complementary activity. In conclusion, CT2 appears to be a promising tool for the control of Ae. albopictus larvae and gravid females, even if its full chemical characterization still needs to be elucidated.