Down here nr Toulouse we have the “Gendarmes” too, but I have never seen them being a pest by way of eating any of my crops! A few years ago I did have the Colorado Potato Beetle. At first I did not know what they were, they are so attractive! But it did not take long to see what damage they did! Now I look underneath the leaves of the potato plant to look for their eggs, I do the same for Cabbage White. If I find any eggs I just wipe them of, crushing them. Did not have a problem with the Colorado last year, they tend to over winter in the ground so watch out if you had them last year!!