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Author Topic: thalictrum downy mildew  (Read 574 times)


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  • Country: scotland
thalictrum downy mildew
« on: September 12, 2023, 09:52:01 AM »
Do thalictrum get aquilegia downy mildew?  My thalictrum delavayi didn't flower very well this year.  I've just noticed there are brown blotches on the stems.


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  • Country: us
Re: thalictrum downy mildew
« Reply #1 on: September 12, 2023, 05:02:24 PM »

If it is fungal, a full strength vinegar wash might clear it up. If not try Captan or other commercial fungicide.
Marc Rosenblum

Falls City, OR USA

I am in USDA zone 8b where temperatures almost never fall below 15F -9.4C.  Rainfall 50" 110 cm + but none  June-September.  We seldom get snow; but when it comes we get 30" overnight. Soil is sandy loam with a lot of humus. 
Oregon- where Dallas is NNW of Phoenix


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Re: thalictrum downy mildew
« Reply #2 on: September 12, 2023, 09:33:27 PM »
I agree with Marc that a fungal spray is needed but your description does not fit with it being powdery mildew.


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