Tannins as Insect, Mollusc, Bacterial, and Fungal Control Factors

4 Tannins as Insect, Mollusc, Bacterial, and Fungal Control Factors 

This section overlaps with Sects. 7.7.4.1 and 7.7.4.2, as much of the work relating to insect and fungal control is common with the work reported there. 

A recent study by Pospisil (197) showed that tannin may be used as an exogenous antifeedant factor. In this study, Colorado potato beetle larvae refused to eat potato Solarium tuberosum) leaves treated topically with tannic acid solution. In contrast, the larvae of Heliothis spp. exhibited attenuated growth on, but not antifeedant behavior toward a diet containing condensed tannin from Gossypium 

In contrast. Mole and Waterman (147), using in vitro model studies, have demonstrated that both hydrolyzable and condensed tannins may stimulate tryptic hydrolysis due to tannin-induced structural changes in the substrate protein. Condensed tannins have also been shown to possess algicidal activity (18). Much work remains to be done on the ecological role of tannins, which should be a fruitful field of research now that tannins of defined structure are readily available. 

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