what's this on my kale?
I've been growing kale in my winter greenhouse for years; this is the first time I've had this grayish-white hairy or moldy-looking stuff growing on it. This stuff washes off, with real scrubbing, and the leaves still taste all right. I've sprayed pyrethrum (in case it was insect-related) and Actinovate (in case it was fungal) and the stuff doesn't go away. Now some is appearing on my tatsoi. The chard and lettuce aren't affected.
Any idea what this is or how I can get rid of it?