If you're not opposed to chemicals, IMO Green Light Fungaway is the best. If you'd prefer a more natural approach, flowers of sulfur in a saltshaker (I use a cheese shaker like used at a pizza place) sprinkled on the affected areas helps.

HTH,

Celene

Thank you so much, Celene. I remember some kind of solution that used baking soda... I have sulfur somewhere though. Good Idea!

I think DH threw my sulfer out when we moved. It's tough to find in this town, so I ended up with Safers Fungicide, ready to use in a hand spray bottle. I will let you know how things go. When I was at the nursery purchasing this, the head gardener told me that everyone was having problems with PM, since we haven't had the heat in the month of October we usually have.

My big tuberous has it too. Does anyone know whether the colonies of the mildew are isolated, or are they just the visible bits? I bought some sulphur-based fungicide and burned holes in the leaves the first time through using too much. Now I spray on a dilute solution, as per the directions, but it doesn't seem to be helping. I'm wondering whether dabbing solution right onto the colonies with a q-tip would work better.

I had terrible powdery mildew on a tuberous begonia, sprayed it with sulfur fungicide and burned it, then left it to get worse with the powdery mildew.

Then I googled organic solutions to the problem and found a website that told about zucchini growers in Brazil who switched to a dilute solution of milk that worked so well that they stopped using expensive and toxic chemicals.

The dilution is 1 part milk to 9 parts water. Skim is better, less likely to go rancid on the plant, said the site. I made up half a cup of milk from powdered milk, diluted it and sprayed the top and bottom of the begonia's leaves and its stem. The mildew disappeared almost entirely.

We'll see how it goes. Even if the respite is temporary, it's fantastic to have a solution that works. !! Yay.

Try it. So cheap.

This is Kamala again. The website is Garden Guides and here is the link to the article, which says that the dilute milk solution also acts as a foliar feeder, and that New Zealand melon growers and possibly wine grape growers are trying the milk solution.

Here is a link that might be useful: Garden Guides