White Powder near the end of flowering

Has anyone ever seen this before ? What is it, advise ?
Thanks

that looks like chlorine have you used any tap water to spray on your plants? could be that.... otherwise i dont have a clue id love to find out tho .....

Worst case of mildew ive seen(looks like its snowing inside). Not much you can do now the buds will be moldy. Dehumidifiers fans and more fans next grow.

well done buds thats one thing i did not think of

Definitely some bad pm (powdery mildew). I have some popping up too. I'm using Neem and high temps now but on the recommendation of others, I am going to try some serenade later today.

good luck - it sucks. you will have to scrap your current grow and start a new one.

No question it is a very very bad case of Powdery Mildew, but you ca save the harvest, is this gonna suck? yes! Can you recover the buds? yes! Should you smoke them without doing this? NO!!!
http://www.youtube.com/watch?v=S7jE7qzfgQs