Figure 1. Proportions of A. alliariae plants attacked by Oreina leaf beetles and by the rust U. cacaliae.

Graphs show data from two sites: Emosson (A and C) and La Fouly (B and D). Three groups were treated with single or combined chemical inducers of plant defences (n = 20 in each case), three others were used as their respective controls (the treatments and corresponding controls are shown in the same colour, n = 5), and finally one group was left with no manipulation (free control in white, n = 5).