INFLUENCE OF FEEDING OF FRANKLINIELLA OCCIDENTALIS PERGANDE (THYSANOPTERA:THRIPIDAE) ON THE POLYPHENOLIC COMPLEX IN THE LEAVES

PAPADAKI, M., V. HARIZANOVA and S. DAGNON, 2008. Influence of feeding of Frankliniella Occidentalis Pergande (Thysanoptera: Thripidae) on the polyphenolic complex in the leaves. Bulg. J. Agric. Sci., 14: 405-409 Production of polyphenolic complex compounds in plants contributes to protecting them against herbivores and often determines their forage nutritional value and the insect preference for them. The thrips Frankliniella occidentalis is one of the most important insect pests on vegetable crops in greenhouses on the island of Crete (Greece). We recently showed that its preference for several vegetable cultures is variable, ranging from highest levels for eggplant to lowest ones for tomato plants. To test whether this differential preference was associated with the production of polyphenolic compounds in the leaves, we compared the profile of polyphenols in control (undamaged) and damaged leaves (evoked by F. occidentalis attack) of eggplant and tomato, by using reverse phase HPLC. We showed that feeding of F. occidentalis causes alterations in the quantity of several phenolic acids (chlorogenic acids) and flavonic glucosides (rutins), which are believed to play an important role in plant defence against insect pests. These alterations are different in tomato leaves compared to those of eggplant, indicating that changes in the quantities of compounds from the polyphenolic complex might be associated with the different preference of F. occidentalis for feeding on these vegetable hosts.