Sarah Raven's Kitchen and Garden

Hi, It seems its a bumper year for pests and diseases in my (very small) patio garden. Everything I have is in pots and I have just noticed yet another annoying something that is on the rampage. Plants affected are apple mint (virtually decimated), lemon balm, greek oregano and golden oregano all are showing signs of revival. All the leaves are destroyed and any left are dry, tattered and holed. There are strange whisps of cobwebby stuff clinging to bits of leaf - any ideas what is doing this and how I can kill/prevent it continuing?