For black spot disease I’ve successfully been using a combination of Liquid Systemic Fungacide II and Mancozeb. Recently I’ve not been able to locate Mancozeb so hoping someone has an additional “formula” that works. Thank you for your thoughts……
Where do you live? Go to Amazon and get some Manzate Pro-Stick it is on sale, 6 pounds, powder. 1 Tablespoon per gallon dissolve in a different container before mixing in your spray tank. I use it every time I spray.
Perfect……thank you very much
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You might look into rotating with chlorothalonil or a copper-based fungicide if Mancozeb is unavailable in your area. A lot of rose growers have had decent results alternating a systemic product with a contact fungicide to help prevent resistance buildup.
Good sanitation also makes a huge difference with black spot removing infected leaves, improving airflow, and avoiding overhead watering can reduce pressure quite a bit.
I’ve also heard some people are having success with biofungicides like Serenade, though results seem more variable depending on climate and severity.
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