MOULD!? Please help me my plant may have mould? ** Pics**

Okay so i just realized two or 3 days ago that my largest plant had some kind of white stuff on the leaves. I was concerned and came back today and took pics. when i first discovered the "mould" i was going to fertilize them and i the one with the "mould" on it anyways. There was not so much dead and yellow when i went to check on it a couple days ago.. could this have been caused be the mould or maby i over fertilized it? Please help me someone. how go i fix this so i can harvest my largest plant

hey man ya have powdery mildew.........and its a pain but can be treated with a ..organocide
if your humidity is to high it will cause powdery mildew at night when light are off and room cools below 67 degrees it will grow on leaves

im growing outside anyone know any good home remadies?

Neem oil spray