Roses forum→Having trouble with black spot disease on my roses.

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Name: "Birdman"
Queens, New York
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Theogaultier
May 19, 2020 1:05 AM CST
Hello, I joined recently. I have a question, my roses got infected with black spot, I've been dealing with this problem for almost a month, I first applied Infuse systemic disease control to see if that would help with the problem, waited for a week but didn't see any results, then I applied Rose RX 3 in 1 concentrate then waited another week and the roses are still in the same condition. Is there a fungicide anyone can recommend to deal with this problem? Thanks in advance.

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Name: Lynda Horn
Arkansas (Zone 7b)
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gardenfish
May 19, 2020 1:17 AM CST
Welcome! where do you live? I'll bet it's a humid climate, right? Here in Arkansas, blackspot is a way of life for rose growers; it is endemic. All my roses have it. You've gotten off to a good start controlling this. That's all you can do is to control it. It's a chronic condition. Remove the worst looking leaves but don't strip the whole bush. Pick up any infected leaves that have fallen to the ground beneath the bush. Be sure to spray the ground underneath for a radius of about three feet . Destroy all the infected leaves, don't put them in the compost. It's recommended to switch fungicides yearly, I've been doing this, and recently someone posted a tip that suggested switching in between spraying; one one week, another the next. I've also found it helpful to remove all the mulch underneath each year in the late winter when I cut them back And replace it with fresh mulch. I've also heard it's helpful to spray the bushes with dormant oil in the winter. I've not been doing that, but I will start this winter. If you do choose to alternate fungicides on a weekly basis, systemic fungicides last longer, so there will be more time between spraying. I'm currently using liquid copper. It works about as well as anything else I've tried. Good luck, and keep us posted!
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Mother Teresa
Name: "Birdman"
Queens, New York
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Theogaultier
May 19, 2020 2:46 AM CST
I live in Queens, New York. Last year I didn't have that problem so I was surprised this year when the black spot appeared on the roses, so I thank you for the recommendation, I'll try the methods you described and see how it goes! 😀😀
Name: Lynda Horn
Arkansas (Zone 7b)
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gardenfish
May 19, 2020 3:28 AM CST
You're welcome! I moved 5 years ago and thought I left the blackspot behind. ( I didn't move any of my roses).these are all new roses I have. They all have it now. That danged fungus ( the fruiting part of it ) is actually blown in on the wind from other infected areas. I know of at least one person that posts on this website that lives on Long Island, and I'm thinking she has it, too.
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Mother Teresa
Coastal Southern California (Zone 13a)
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jerijen
May 19, 2020 2:18 PM CST
It's a disease that flourishes in warm/wet weather. But you probably realized that.

Once leaves have spotted up, no amount of fungicide will turn them back to a normal, healthy, condition.

Here in normally dry Southern California, we had a good month or more of rain out of our normal "schedule" and we saw our share of blackspot here, too.
Name: Dennis Brown
The Big Island, Hawaii
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kohala
May 19, 2020 5:05 PM CST
You might check my post entitled "Another Discussion (Sorry) About Eradicating Black Spot." One of the posters suggested a method for controlling black spot that I used successfully. Most of the products on the market are designed to prevent black spot not eliminate it once you have it. I started by using Mancozeb every 5 days for three weeks. It appears to be a very harsh chemical but it did a number on black spot. Thereafter, I used a variety of preventatives, such as Serenade, potassium bicarbonate and sodium bicarbonate. Potassium bicarbonate is less harsh than the sodium version and doesn't burn my rose leaves. I live on Hawaii Island at 2300 feet above sea level. Usually, it is temperate with low humidity. However, we occasionally get downpours. I use one of the preventatives once a week or so and always after it rains.
Many of the members on this forum just live with black spot and enjoy the rose flowers, which do not seem to be negatively impacted. I respect this "method" and it is undoubtedly safer for the environment. I just got tired of looking at mostly leafless rose bushes.
Name: Suzanne/Sue
Sebastopol, CA (Zone 9a)
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Calif_Sue
May 19, 2020 5:28 PM CST

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Here's a link to the referenced thread above by Dennis.
The thread "Another discussion (sorry) about eradicating black spot" in Roses forum
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Name: seil
St Clair Shores, MI (Zone 6a)
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seilMI
May 19, 2020 7:54 PM CST
You need to repeat spraying according to the instructions on what ever fungicide you're using. Fungicides will not "cure" already infected leaves. It will only prevent uninfected or new leaves from getting it. Once a leaf is spotted it's done for. AND it will not cure any leaves that are already infected but not showing spots yet. So even after spraying more leaves will get spots until all the infected leaves are dead. It's like COVID, you may have it but not be showing symptoms...yet.

Black spot is a term given to a group of fungal diseases that consists of over a hundred different strains. Just like the flu! They all need particular weather conditions to show up. You may not have had a problem last year because you didn't have the particular conditions that your local strains like best but this year you do, so it has manifested itself. Black spot is everywhere. The spores are in the soil, mulch, air and all the other plants in your garden and neighborhood. It's a tiny spore that floats around on the air and can travel great distances.
It's EVERYWHERE! It is also the most common, universal bane of all rose lovers!
Name: Lynda Horn
Arkansas (Zone 7b)
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gardenfish
May 20, 2020 12:57 AM CST
Seil, couldn't have said it better! I can personally attest it travels in the air. Planted my present roses 5 years ago, no blackspot the first year. Forward to year 5, all of them have it.
Yesterday is gone. Tomorrow has not yet come. We have only today. Let us begin.
Mother Teresa
Name: David Tillyer
New York City (Zone 7b)
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BigAppleRoseGuy
May 20, 2020 9:44 AM CST
Birdman.
I just had to spray for a very bad case of blackspot. Leaves are yellow and dropping off. It's a mess. I'm in Manhattan and blackspot has started
early and is more severe this year. I hate it too! David
Name: "Birdman"
Queens, New York
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Theogaultier
May 20, 2020 10:47 AM CST
Ty for the advice guys.
Long Island, New York, USA (Zone 7a)
Region: New York Roses
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Ray_Gun
May 21, 2020 8:40 AM CST
It's very frustrating and seems like a never ending battle. You really have to start spraying in early spring and maintain it until it gets too hot for those spores. They prefer cool, wet spring weather. I just all but defoliated 2 of my 3 Peace roses because I was lazy in my winter clean up and it hung around and enjoyed a strong foot hold. It looks like it's on the canes now so I think I will need to chop those way down next year. I don't want to sacrifice blooms though so I'll continue spraying every few days.

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