plant damage

My broccoli plants seem particularly hard-hit this year- with more leaf damage than others in the garden. Probably because I have not figured out and thwarted the pest, yet. Still picking occasional caterpillars from white cabbage butterflies, but this is something else.

There are pale squiggly lines and on the underside it's a raised edge, like a swollen vein. I think it is leaf-miner bugs...