In 1994 we reported the first results of an experiment aimed to study the pattern and structure of induced phenolic compounds in pear trees infested by Psylla pyricola, a pear leaf sucker or mechanically damaged. Here, we present the results of further chromatographic and mass spectral analysis performed on extracts of leaf samples collected at various-time intervals (before infestation and damage, first nymphs on leaves and after 12 hours, 24 hours, 2 days, 5 days, 14 days and 30 days, respectively) from pear trees which were either Psylla-infested, or mechanically damaged, or both. The results are compared to samples from an uninfested control tree of the same age and size.

Groupe Polyph
J. Vercauteren , C. Choze , M.C. Dumon , J.F. Weber

Scutareanu, P., Boon, J. J., Claeys, M., van der Doelen, G. A., Ma, Y. L., & Sabelis, M. W. (1996). HPLC pattern and composition of leaf polyphenols in pear trees infested by Psylla Pyricola and mechanically damaged. In J. Vercauteren, C. Choze, M. C. Dumon, & J. F. Weber (Eds.), Polyphenols Communications 96 : 18th International Conference on Polyphenols, Bordeaux (France), July 15-18, 1996 ; vol. 2 (pp. 393–394).