Raising two ot three generations during the summer, they can defoliate the entire plant, leaving only the leaf veins and stalks. Although they look like small caterpillars, they develop into a non-stinging wasp-like fly.
So I have started checking daily and picking the green larvae off by hand.
Luckily our resident blue tits are now raising their chicks, and they have discovered this perfect food source so close to their home. So I have a couple of eager helpers!
Here are some pictures of the blue tit parents flying in and out of the nest box. They are taken from my son's bedroom widow. Not the best quality, but you get the idea ...
(I especially like the blurry shape of the bird flying off!)
