I like double ground hardwood mulch or pine bark mulch. Sometimes I will use pine needles depending on the application. However, over time hardwood mulch breaks down and enriches the soil. You should be able to buy some of chemicals from Southern Agriculture in Hendersonville, NC. Did you know there is an Asheville Blue Ridge Rose Society? They are a great group of rose lovers and have a website.
I’m new to this forum but not to black spot. I’m in Tampa, so at this time of year still wet and hot—that is, humid. I have been consistently spraying with topical fungicide throughout the summer—alternating mancozeb with occasional copper fungicide. But it has suddenly gotten much worse. I plan to add a systemic fungicide (if the rain stops long enough to use it). I already own Thiomyl so thought I would use that. It was suggested that I use it as a drench. I would rather not do that as there are other plants in the same bed with my roses. But I’m willing to because my rose tree just looks so sad. But if I could spray rather than drench I would prefer that.
I am the process of ordering some other systemic fungicides, but I think I should spray sooner rather than later. Any thoughts on this? Florida can be very frustrating throughout summer (which goes until roughly mid-November. …)
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Thiophanate only lasts for no more than 10 days. Combine a systemic like propiconazole or myclobutanil with Mancozeb, every 10 to 15 days for best control of black spot. Add a seaweed product like Maxicrop which will promote rose leaf health.
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Which maxicrop product to you recommend? There seem to be a number of variations. I use Alaskan Fish fertilizer periodically, but this looks different…I was interested that they say you can soak seeds in the liquid version to aid in germination.
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I use the powdered one, but they have it in the liquid. It is great to uses it as a spray or drench.
Azoxystrobin just arrived…still waiting on others. Should I use it or wait for Eagle or Manzate (which won’t arrive for another week)…
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I would use it with the thiophanate methyl. You only need 1/3 to 1/2 tsp per gallon of Azoxystrobin. It is upwardly systemic so when you spray the bottom half of canes and leaves it can move up through the rose. I have found this chemical so helpful in preventing black spot.
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I’m a bit confused…You use the thiophanate methyl along with Azoxystrobin? Or do you alternate them? They’re both systemic so I would have thought that using them together was overkill…. So now very curious!
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There is a synergy between the DMI fungicides and the strobilurins (e.g, Heritage (aka Azoxystrobin), Pageant). When used together they provide more efficacious control of black spot. You do not want to spray fungicides with the same mode of action alone or you will build up resistance to the races of black spot in your garden ( there are approximately 12 races in the US). When you combine a systemic fungicide with a contact fungicide (e.g, Mancozeb, Chlorothalonil aka Daconil) there is little risk of causing resistance. I don’t only use Azoxystrobin, I usually it use it when black spot disease pressure is high, like when there is rainy weather. Typically I combine Mancozeb with either propiconzole or myclobutanil. Keep in mind that Daconil can cause damage to rose leaves when the temperatures are above 80 degrees Fahrenheit. Therefore, I only use it in the spring and fall.
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The temperatures go over 80 most of the year here… I spray very early in the morning --well before dawn. But 8 hours later it can be 95 degrees.
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Then use Mancozeb and not Daconil.