I was just reading this on MB3. In their article section they have pretty good info on growing hops. Here it is:http://morebeer.com/articles/growing_hops
almost looks like mildew. but it looks more like it could be a magnesium deficiecy.http://customers.hbci.com/~wenonah/min-def/hops.htm
Take a look at the underside of the leaves… Mine looked like that and it turned out to be spider mites and moth eggs. If you see any super tiny red dots on the underside of your leaves, it’s spider mites. If you see any isolated small gray patches of eggs covered in a webbing like material, it’s moths. The good news is you can get rid of them by spraying the underside of your leaves with a hose every couple of days until they’re gone if that’s what your problem is.
Then there was the beetle attack which I don’t care to get into right now… That one required a combat helmet and a lot of tenacity. I will defend my hops at all costs! :lol:
Did you happen to have a cold, clear night when those leaves were smaller, but not cold enough to kill the leaf outright? Could be frost damage.