I use NEEM oil spray. Since it is organic, does not have side effects on the vines. So I spray as often as needed.
You cannot get rid of PM by just one or two spraying. Chances are you will miss some. Then go ahead and spray them next day or the day after. Best you can do is to keep then checked.

I use GreenCurecolor> which is organic potassium bicarbonate and spray as needed and especially after rain. Usually every week. I spray to prevent and treat as I have crepe myrtle trees. I have not sprayed my veggies yet. So far it has worked great on the crepe myrtle. If you decide to order and want free shipping try this link. http://www.muckbootsonline.com/GreenCure_Fungicide_p/gcfs.htm

DL

Disclaimer: I am in no way affiliated with GreenCure or Muck Boots Online. I only offer this information because I have used the merchant and the product with success.

Here is a link that might be useful: Green Cure