Powdery mildew?

[escape]

The white patches on leaves - is this powdery mildew?

If so, do I cut off the leaves? I've sprayed the plant with baking soda a few times in the past several weeks, but it doesn't seem to be working. Should I try neem oil?

 

[Logan]

It looks like powdery mildew, I've had it on marrow plant leaves and I just left it, it didn't hurt the plant or the production of the marrows.