Powdery Mildew Help

10 years ago

I've been dealing for over a year with powdery mildew that came home on a violet from a local greenhouse. This greenhouse is notorious for keeping unhealthy, diseased violets, but I guess I couldn't help myself. I have read quite a bit online already about powdery mildew treatment. I bought some Physan 20 which controls, but does not kill, the powdery mildew. I understand that preventive measures are best when it comes to powdery mildew (in other words, don't bring it home), but is there anything that can help more than the Physan 20? Is there anything that can stop it dead in its tracks?

I have already gone through my collection and cleared out some of the ones that seemed to be most affected. I also keep a fan on at night to circulate some air. Since many of my violets have had it, it doesn't seem reasonable to try to separate the affected plants. I believe they all need treatment. I just read on this forum about a product called Green Light Fung-Away, but Amazon doesn't carry it and I doubt my local stores do either.

So what works for some of you?

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Comments (3)

irina_co
10 years ago
I heard good things about Spectracide Immunox. You can get a concentrate on Amazon.

http://www.amazon.com/Spectracide-51000-Multi-Purpose-Fungicide-Concentrate/dp/B0035H0RA8

They have 3 in one Spectracide in Lowe's - but I do not know about other 2 components. You need only myclobutanil - the active ingredient for PM.

The label on the concentrate from Amazon says - 1 oz per gallon - for outside plants. I would use half of this amount and try on 1 plant first. If it doesn't show bad effects in a week - I will spray the whole collection 3 times - 10 days apart. Use a drop of dishwasher soap in a spray bottle - Dawn or Ivory - warm water - and if possible - distilled water - not to stain the plants - if your tap water is on a hard side.

Fung-Away is also a preventative - it is potassium bicarbonate, it is similar to baking soda - but with potassium instead of sodium. So if you have a bad case - preventatives do not work.

Next time you see a poor sick critter - do not bring it home.
Harawlins
Original Author
10 years ago
I'll definitely look into the Spectracide on Amazon. When should I use the dish soap? Would that be instead of the Spectracide or along with? I thought I almost had it under control using the Physan 20 judiciously. I guess not.

And that does happen to be one of my weaknesses! :(

Thanks for the advice!
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irina_co
10 years ago
Dish soap helps to wet the surface of the leaves - so you will have the fungicide attached to the leaf. Otherwise the solution can just run off.

Powdery Mildew is a fungus that is not just sitting on the surface of the leaves. It grows into the plant tissue. Preventatives - they help to prevent an infestation when it is still on a surface, you need systemic fungicide to kill the infection from inside. That's why Physan was not working that well. The fungus was always coming back from inside the leaves.

Some varieties are PM magnets. Get rid of them - they can be a latent source of infection - every time the season comes - they will be covered wioth it - and share with the neighbors. There are plenty of resistant varieties.

So if you see something in a store covered with PM - it is one of PM magnets. It is a good sign that it will be like this all the time.

I.

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