I don't grow the rose, but Immunox WILL NOT handle your problem. First off, let's get rid of the BS and then start spraying with the right stuff to keep it under control. Both Manzate and Mancozeb contain the ONLY chemical that will actually kill the BS spore. If you already have BS, none of the other products on the market will touch it. So, mix Manzate or Mancozeb at the rate of 1 Tbsp per gallon of spray material, and spray every three days for three or four spray intervals and your BS should be under control. At that time you can go back to the following combo to keep it off. Use 1/3 tsp Banner Maxx + 1 Tbs of either Manzate 200DF or Mancozeb per gallon of water and spray every 10 to 14 days. Once you have the BS under control, this spray combination should kee you virtually BS free. The chemicals mentioned can be had from Rosemania...see link below.

Here is a link that might be useful: Rosemania

What about this product called Honor Guard? I heard something about it but I can't remember what.

Heirloom is a good rose (as mauve roses go), but it is susceptible.

The Bayer fungicide with tebuconazole is the best available (or Banner and other propiconazole products are comparable). However, the soil drench is probably not as efficient as the spray concentrate. Immunox is moderately effective but not as good.

Be aware that new spots you are seeing today result from infection one or two weeks ago.

A while back I posted a scientific dissertation with photos showing how the Bayer fungicide (tebuconazole) kills established black spot even when applied 19 days after infection. I will post it again if roseman doesn't believe that. Immunox also showed some curative effect, but only if applied earlier. Mancozeb is a surface-protectant, preventative fungicide.

Roseman please cut it out.We have mentioned how The Bayer fungcide Kills and controls blackspot many,many times.I don't know why you would keep saying it doesn't.

MichaelG, can you post the pics again please?

Honor Guard has the same active ingredient, propiconazole, as Banner Maxx (which is what I use) and Bonide Infuse.
Propiconazole has been very effective for me. Immunox only works on powdery mildew in my garden, it does not work on blackspot.

Fungicide-lol
The drench will not be enough in high blackspot country.The spray is.
Roseman had me foaming at the mouth.

This is a PDF. The "pages" tab on the left should be open, or you open it. Scroll down to p. 85 and click that page.

The right column shows leaves treated with tebuconazole (Bayer) 3 days (a), 7 days (b), and 10 days (c) after inoculation with blackspot. The pictures were taken 20 days after inoculation. The lower right has a small spot which probably had already appeared at the time of treatment with Bayer. It has not developed and the leaf will live. The finding is that Bayer cures blackspot already established in the leaf.

The fungicide myclobutanil is Immunox. Its column of leaves show that it can be curative if applies within a week of infection, but not later. The -strobin fungicides are similar to Compass. They were shown to be effective at preventing, but not curing, blackspot. Applied before inoculation but not after, they prevented disease slightly better than Bayer.

So many people have it exactly backwards in saying that systemic fungicides prevent but do not cure, while mancozeb cures. I wonder if this misinformation is in the CR manual or if everybody is taking it off the Rosemania page..

Here is a link that might be useful: blackspot study

I think the "Mancozeb is the only curative fungicide" theory has been true for so long that it considered gospel. Science has progressed and Bayer seems to have taken advantage.

Redsox - I love Heirloom, but it is BS prone. When my spraying schedule gets out of whack it always gives me a full color illustration of that fact.

If you are near a Southern States, they carry Eagle which works well. They also carry Mancozeb. The two of them will do a good job of cleaning up the BS mess. You will have to wait for the spotted leaves to all fall off and new ones grow before you have a good looking plant again. I use the old tried and true, Mancozeb three times three or four days apart and biweekly spraying with Eagle or Banner Max or something similar.

I can't vouch for the Bayer product, but I have no reason to doubt it's effectiveness. I haven't used it because it is not cost effective with the number of roses in my garden.

Eagle is the same as Immunox.

Harry, "the only curative fungicide"? Is there evidence that mancozeb is curative of blackspot at all? I think it stems from a very natural misunderstanding of the unfortunate term "contact fungicide" as a synonym for "surface protectant". Here is an explanation from Kansas State U:

"Contact fungicides are also known as protectants and pre-infection chemicals. They remain on the plant surface, and they need to be present before the infection occurs. . . . Some examples of contact chemicals are mancozeb, maneb, chlorothalonil, captan, and copper formulations. . . .
Systemic fungicides are also known as curative and post-infection chemicals. . . .Some examples of systemic fungicides available in formulations for homeowners are myclobutanil, propiconazole, triforine, and thiophanate-methyl."
--Megan Kennelly

Mike,
I don't know about evidence. When I first began reading this Forum, it seemed that everyone believed only Mancozeb could kill the spores. Times have changed.

I bought the Bayer today and also a 1 gallon sprayer, which is all I really need for my little collection so far. Should I just spray the Heirloom or all my roses? I have 5 HTs and 5 minis so far. And if I don't use all of the contents of the sprayer, should I dispose of it and how?

I find it difficult to water and spray before the sun is on the roses in the morning. Then I fear leaf burn. I have 2 little kids and by the time I can get out there to water and spray the sun is coming. If I spray at 5:00 or 6:00 PM that is fine but I can't water right before because I don't like to water late in the day. What do I do?

Mix just a half-gallon of spray.

You don't need to fear leaf burn with Bayer under moderate conditions. You don't necessarily have to water immediately before spraying, as long as there is plenty of moisture in the soil and the plants are not stressed, as they might be in mid- or late-afternoon sun. You don't need to worry about watering late in the day if you are going to apply fungicide, which of course contains plenty of water.

Put water in the sprayer before the spray material. Afterwards, rinse the sprayer thoroughly including pumping water through the hose.

Water the day before if that is easier.

Yes, spray all of your roses. Just because they don't show any active blackspot, blackspot is there none the less.

jody, I think you are confusing the Bayer all in one (fertilizer, insecticide and disease control) that is used as a drench and the Bayer Disease Control, which is used as a spray. A 32 oz concentrate costs about $14. I use 1.5 ozs to two gallons of water to spray about 60 roses. A bottle will last me the whole season. It's very cost effective. And it works great. It will stop blackspot if you have it and prevent it if you don't.

Modern mauve roses are generally susceptible to black spot. Yes, all-of-them. The only one I found resistant is Reine des Violettes and even she will eventually get it if not sprayed.

I don't believe in drenching the soil with pesticides. Yes I uphold your right to use Bayer Drench (are you listening Pete?) but I'M not going to do it. My common sense dictates that dumping toxic chemicals into the water table isn't a good idea. And I do not need a thick scientific report to justify my decision.

Remove the dropped leaves from the ground. Remove the yellow spotted leaves from the plant. Water your rose well then spray as directed on the box with Mancozeb in the early morning on Monday, Wednesday and Friday. That will take care of your problem.

I only use it once in the Spring-lol
spray is MUCH more effective.

I have not used artifical chemicals and I have NO BS

Michaelg,

I did not see anything in the article on Trioforine, though that is also a systemic fungicide. the reason I ask is because I am using that to get rid of a little BS I have on a few plants. I am using Ortho Rose Pride, which Contains 6.5% systemic fungicide: Triforine. By reading that article, I should be switching to Bayer and throwing out the Ortho, but Ortho has a 6.5% active ingredient, whereas Bayer has a 2.9%. I know they are different systemics, so is tebuconazole over twice as effective as Triforine?

Please define artificial chemical so we can have a good laugh-mean chemical compound by any chance? Are you referring to one not occurring naturally? If so why would it be artificial-? If it exists its real.

Redsox,
My husband does spray with the Compass/BannerMax/Mancozeb mentioned, and has also had success with the Bayer spray that kills blackspot.
The main thing I wanted to say is that HEIRLOOM is the 1ST ROSE of our 72 to get MAJOR BS if he is late or forgets to spray them!
:0) Phyl

The CR (Consulting Rosarian) manual does not say that mancozeb kills the spores. It lists mancozeb under "Surface Protectant" and says that the action is to create a barrier on the leaf that limits the penetration of the germ tube that is created when a blackspot spore germinates. The more completely the barrier covers the leaves, the less able the spores are to be able to "take hold" via the germ tube and cause further infection. The manual notes that this type of fungicide has to be on the leaf before the spore lands in order to be effective.

So, to be correct, the three-day mancozeb spray helps prevent the spread of blackspot infection by blocking the germ tubes created during the germination process on the existing leaves. Then starting a regular spray with a systemic will help with the other modes of action. The articles and feedback from forum menbers say that tebuconazole acts as both a surface and a systemic fungicide.

Is there a comparable spray interval to the "three-day mancozeb" treatment using tebuconazole? I think MichaelG mentioned once a week. Has anyone tried something similar? What was the result?

mgleason--
I haven't seen any blackspot trial results for triforine vs. propiconazole or tebuconazole, but my impression is that it is not as effective. In my garden, triforine certainly did not give 100% control with careful weekly application, even with discarding the really terrible BS magnets. But it was the standard control for about 20 years, and I'm sure it would be fine for the Midwest, adequate anywhere. The best reason for switching to propiconazole or tebuconazole would be that you can do longer spray intervals with equal or better control.

Diane--
Thanks for answering my question about the CR manual, and I'm glad to hear it has the same information about mancozeb as scientific sources (surface protectant, not eradicant). I've no doubt that heavy application of mancozeb would prevent any further infection. But if I were anxious to stop a BS outbreak, the first thing I would do is apply Bayer, since it will kill infections already well established. People who use Bayer weekly (I don't) say they have zero blackspot. I don't think having zero blackspot needs to be a priority in the garden, but it does suggest that Bayer is a superior product. Banner might be as good, but it should not be applied weekly.