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Powdery mildew cures??

Posted by woohooman San Diego z 10a (My Page) on
Thu, Oct 11, 12 at 22:38

Is there REALLY an effective organic fungicide to fight powdery mildew??

I've tried neem, sulfur dust/spray, and baking soda with absolutely no success.

Don't tell me -- Milk! Why would I think that milk would work?? The same places I've read the above remedies worked are the same places that mention milk!

Sorry for sounding pessimistic. I really do prefer to do things organically, but sometimes it just seems that there aren't any good organic remedies for certain diseases and pests.

I'm not going to pay hundreds of dollars for beneficial insects integrated into my backyard garden every year just to have them go next door.

Anyhow... anybody have any tricks for powdery mildew?

Anything that WORKS would be appreciated.



Follow-Up Postings:

RE: Powdery mildew cures??

  • Posted by feijoas Temperate New Zealan (My Page) on
    Fri, Oct 12, 12 at 6:03

Kevin, I'm afraid my experiences with powdery mildew don't offer much as far as getting rid of it.
I think a lot depends on having plenty of organic matter in the soil; for plant nutrition of course, but even more so to maintain moisture.
I find powdery mildew takes over when plants are water stressed. Like most people's summers, later it gets, the drier things are.
But by the end of the season at my place, when it really starts to slow down the zucchini, I'm rather relieved!

RE: Powdery mildew cures??

Understanding why Powdery Mildew appears often helps with control. Sulfur is effective if applied before signs of PM appear while other controls can be effective when properly applied.
Baking Soda (Sodium Bicarbonate) mized one teaspoon per quart of water, Fat Free Milk and water mixed 50/50, Potassium Bicarbonate, and Neem oil have all been effective at controlling PM, but not at curing the problem. Since the spores that cause PM are blown in on the wind there probably is nothing that will cure this problem.

Here is a link that might be useful: About Powdery Mildew

RE: Powdery mildew cures??

First, you need to understand that you can't cure powdery mildew - once it is present (and you see the symptoms), it's present and the best you can expect is to control the spread. Period.

Fungicides are prophylactic, not curative. They can sometimes prevent the disease, will often limit the spread or contain the disease but they will not eliminate or "fix" existing diseased tissue.

Powdery mildew is most often a cultural ailment. It arises typically in late season when temperatures are warm, soils are dry and humidity typically high. Lack of good air circulation can exacerbate the condition. Not a lot one can do about temps or humidity but making sure the soil is adequately moist and improving circulation can go a long way to slowing the disease. Knowing what plants are most susceptible and treating before you see any signs can help. FWIW, with most woody plants, PM is more of a cosmetic issue than a serious threat to plant health. Also, PM spores cannot live in water - hosing down the plants early in the day (so there is adequate time for the foliage to dry properly to deter other fungal issues) can help as well - you can actually wash the spores off the leaves.

The reason milk is often recommended - and with good reason - is that it is a natural anti-fungal/anti-bacterial agent. It also contains lactic acid, which alters the pH of the leaf surface and makes it inhospitable to the fungal pathogen. This is the same principle behind the use of baking soda as well. btw, it doesn't make any difference what formulation of milk you use - powdered, fat free, high octane - it all works the same.

RE: Powdery mildew cures??

So, What you all are saying is milk and other remedies CAN keep the population of spores down if I start treating the foliage with said remedy prior to actually SEEING any spores??


RE: Powdery mildew cures??

Yes, any fungicide regsistered for PM, including those home remedies like the milk, baking soda, etc., will help to prevent the spread of fungal spores to unaffected foliage and if applied prior to infection (usually before the symptoms are evident), should prevent the problem altogther.

But do follow good garden sanitation and proper cultural practices as well - all the spraying in the world won't help significantly if you are just welcoming the disease by offering poor growing conditions.

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