Figure 1.

Emission of volatile compounds from herbivore-damaged and adjacent undamaged leaves of Populus nigra (black poplar) trees infested with blue willow beetles (Phratora vulgatissima). (A) The foliage of young trees of 20 different P. nigra genotypes was divided into basal and apical sections with PET film and 20 adult beetles were released on the basal foliage. A second set of PET film-divided trees was left as controls without beetles. After 41 h, volatiles were collected using a dynamic headspace collection system and analyzed by GC-MS/FID. (B), (C) Emission of major groups of volatiles was recorded from beetle-damaged and adjacent undamaged foliage in relation to controls- emission from corresponding regions of trees not subject to P. vulgatissima herbivory. Data are presented as mean ± SE, n = 20 (one representative of each of 20 genotypes). Asterisks indicate significant differences between beetle-infested tress and the controls: *, p< 0.05; ***, P < 0.001; Mann Whitney U-tests. (D), (E) Relative proportion of the major groups of volatiles presented with respect to the full P. nigra odor blend. A full list of all P. nigra volatiles detected is given in ref. 10.