Powdery Mildew

[PaulB]

Where I am in So. California, there has been a tremendous influx of powdery mildew and black rot in the past year. I know the mildew is airborne (spores) and impossible to see until it's working on your plants, but my question is:

Does Powdery Mildew affect orchids?? Seems Black Rot and PM travel together. So far, I haven't seen it on my orchids, but wondering.
I lost a wonderful grape vine this year because of PM and Black rot. Last year, the entire grape output was ruined. A lot of people in the area have the same problem, according to my local nursery.

[orchids4me]

For powdery mildew example on roses I heard once on a gardening radio show I listen to every sunday morning in northern California, mix baking soda and water and spray them I don't know the percentage water to baking soda but I wonder if this would work on orchids as well?
Well hopefully one of the members with more experience will chime in on this topic.
Good luck!

[PaulB]

Yes, there are different ways to deal with it. I've even used diluted vinegar on the roses this year, which works almost instantly, but several applications might have to be done to get rid of it completely. On the grapes, the plant must be treated just a few days before the buds open and treatments every ten days or so. A lot of grape growers are using a ten to one milk/water mixture when it is sunny, not cloudy and it works well. Milk. Regular milk. I and a few others I know have used it and it works. I did lose a very healthy and abundant producer, however, because the damage had gone too far.

The mildew of course is spurred on by humidity, which is why I'm inquiring about orchids being affected. I've not seen it with any of mine, but wondering if it would be an issue. The spores are airborne and microspopic, so one doesn't know until it starts wreaking its havoc on plants.

[-k-]

PM can be a major pain... I manage to escape it this year for my outdoor crops..ie: pumpkins, squash...etc.. by spacing them just a little further apart than I have in prior years to promote better air circulation and it help a real lot. . .
Never had it on orchids so I can't really comment on that...