fungicide for powdery mildew

Discussion in 'Garden Pest Management and Identification' started by janetdoyle, Jul 12, 2007.

  1. janetdoyle

    janetdoyle Active Member 10 Years

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    I am fighting powdery mildew on a New Dawn rose on a small fenced patio, planted in-ground, but unfortunately I guess against a trellis on a brick chimney wall -- no air circulation? I have never seen powdery mildew on New Dawns in Nova Scotia summers, but here in Saanich, Vancouver Island, I was also surprised to see it on this particular rose. I am using copper sulfate mixed in water, but hate the residue which remains on the leaves -- the white spots are as unsightly as the mildew, and I feel it is damaging the leaves a bit also. Now I have powdery mildew on a potted ornamental vine, a type of evergreen clematis with strong thick leaves.

    Rather than use copper sulfate, is there a permitted fungicide that is clear liquid? Would rubbing alcohol (diluted) kill the plants? I used in Nova Scotia a clear liquid fungicide which smelled like alcohol, something like No-Damp [and would No-Damp work as a foliar fungicide?] a fresh clean sort of smell, and it worked very well and left no residue. Is this available here? [can't remember the name of it]...
     
  2. Ron B

    Ron B Paragon of Plants 10 Years

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    The foundation is sucking all the water out of the soil and making the rose mildew. Soak the roots.
     
  3. janetdoyle

    janetdoyle Active Member 10 Years

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    Thank you, Ron B, those roots are soaking; I purchased some ready-to-spray Safer's fungicide which is much nicer to use that the copper sulfate powder in water, and doesn't seem, so far, to leave a residue the way the copper sulfate solution does.
     
  4. Ron B

    Ron B Paragon of Plants 10 Years

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    I would also hose it down repeatedly, in the morning. I wouldn't spray fungicide.
     
  5. janetdoyle

    janetdoyle Active Member 10 Years

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    Reply to Ron B. re hosing down New Dawn in mornings: can you explain the reasons for this, does it remove mildew spores? Or just hydrate the leaves so that the plant doesn't lose so much moisture? Hosing it will knock off a lot of the bloom, depending on the strength of spray. I presume you don't mean "mist", or is that that case? Does mildew, then, attack very dry plants and is it not really related to moisture, but only heat? I certainly have seen it on neglected plants in dry locations... I am always interested in the "why's"...
     
  6. mort

    mort Active Member

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    Hi,
    I had a vibernum in a very hot location that repeatedly suffered from powdery mildew. It has responded well to more frequent watering at the root level and is now looking great this year without any sprays or other attention. Is the clematis suffering from wilt or powdery mildew?
     
  7. janetdoyle

    janetdoyle Active Member 10 Years

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    Reply to mort: yes, the evergreen clematis has some trace of powdery mildew, but it is receiving the extra water treatment as well, so I think it will be better off.
     
  8. Ron B

    Ron B Paragon of Plants 10 Years

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    Avoid the flowers when hosing. Yes, not talking about roses specifically from this point many mildews are associated with dry conditions. Spores blow around in summer and land on leaves. Some germinate if leaves are dampened by fog or dew, others take their own moisture droplet with them. After they have germinated and covered the leaf it does seem hosing has an interfering effect. Do it when the plant will not be left sitting damp for a long time, such as early in a hot day that will dry it quickly.
     

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