The Feeding Effect of Polyphenolic Compounds on the Colorado Potato Beetle [Leptinotarsa decemlineata (Say)]

Colorado Potato Beetle, Leptinotarsa decemlineata (Say) is a serious pest of potato plants and devastates additional crops such as eggplant, tomato, pepper, and tobacco by its voracious feeding. Plants of the Lamiaceae family produce a large number of polyphenols with insecticidal activity. In this study we tried to identify if some of these compounds could be used as antifeedants and if there is any influence of these compound on food conversion by the Colorado Potato Beetle whose 3 instar larvae were fed food contaminated with quercetin, naringenin, vanillin, p-coumaric acid, catechin, caffeic acid, vanillin acid, rutin and phloroglucinol in 1.33, 0.66 and 0.11 mg/cm doses. Several compounds remarkably decreased larval growth and inhibited their feeding. The flavonoids were almost ineffective, having little or no effect on growth and/or food deterrence of the larvae, whereas phenols and phenolic acid demonstrated a very high efficiency. _____________________________________________________________________________________________________________