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Powdery mildew and black spot

I am experiencing both these issues on a few plants and would like to know how you deal with them. I am open to both organic and chemical treatments. The nursery I frequent, a lot, gave me some 'Serenade' to try. With what is available in canada how do you deal with these fungus issues?

SCG

Comments (7)

  • wayne
    9 years ago

    One of the roses that I have gets blackspot every year, this spring I sprayed it and a hawthorn and mountain ash with dormant oil each for a different problem. The blackspot has returned, it never causes a problem to this rose but looks crappy. I have 2 different pavement roses right close to it, time will tell if they are going to get it as well. Not sure about the Powdery mildew except planting resistant varieties.

  • don555
    9 years ago

    I use something called "Funginex" which you mix at I think 3 mL per litre, then spray the infected plants. I've had it around awhile, not sure if it is still sold, but it did seem to do the trick for me.

  • SouthCountryGuy Zone 4b-5 SE BC
    Original Author
    9 years ago

    Wayne I am considering removing the plants. I just like these polemoniums.

    Don I am curious if you still have the original packaging if you could tell me what the main active ingredient was. Wondering if it is copper or sulphur.

    SCG

  • don555
    9 years ago

    Neither. Active ingredient is Triforene, 6.5% in the concentrate, before diluting to spray on plants. Says it is a "systemic fungicide which controls and prevents black spot and powdery mildew, the two most common diseases of roses and ornamentals." Made by Green Cross. I've also used it to treat damping off in seedlings.

  • SouthCountryGuy Zone 4b-5 SE BC
    Original Author
    9 years ago

    Thanks don, can't get it in canada anymore.

    SCG

  • prairie_northrose (3b north of Calgary AB, Canada)
    9 years ago

    Digging up this post as BS is slowly taking over my new rose garden. First it was on one Emily Carr, now another Emily Carr, and now a miniature.

    No BS so far are Winnipeg Parks, Quadra, Rugela and Prairie Princess. But I have seen Winnipeg Parks infested at other garden centers....

    I checked around today to see what was available, and this is what I came across:

    - the garden center I frequent said they dust "the Rose Doctor" on their roses to prevent blackspot. Contains Folpet - 5%, Malathion - 4%, Carbaryl - 5%.

    - other fungicide dusts I came across contained Captan

    Other fungicides also noted:
    - sulphur, liquid spray form - greenworks
    - powdered sulphur ("wettable?") - greenworks
    - lime sulphur - greenworks?
    - QST 713 strain of dried Bacillus substiis - Natria (by Bayer?)
    - copper sulphate in various sprays/dusts

    I also learned that anything systemic is not available in canada.

    I am currently testing powdered sulphur mixed with water, and also being vigilant in cutting off any leaves with blackspot and putting them in the garbage. I read bark mulch can be an issue. I have also read that cow or horse manure used instead of bark mulch can help as it acidifies.

    For powdery mildew, diluted milk, with frequent applications, has worked for me in the past on rosemary plants.

  • SouthCountryGuy Zone 4b-5 SE BC
    Original Author
    9 years ago

    Thanks for revisiting this.

    I used Serenade and Powdered garden sulphur to spray on my roses for black spot. I was not diligent in removing all leaves but the erratic spraying program I had seemed to stop it from spreading. The only thing I didn't like about the sulphur was the light white stain it left on some leaves. I also have bark mulch and will replace it under the infected plants after they drop all their leaves.

    I, too, stayed away from anything with an insecticide. Speaking of insects I never had one aphid this year....weird.

    I got tired of the polemonium that was trying to take over the world and its powdery mildew and shovel pruned them (I can see Ostrich smiling).

    Next year I think if I get on the blackspot faster it won't be a problem. I would hate to have to remove the worst one as it is one of my favourite roses.

    SCG