I'm a little skeptical about you diagnosis, because downy mildew hardly occurs in the Carolinas and cannot survive our summer temperatures. The only time I've seen it was on potted plants offered for sale in spring. I actually bought one of these to back up my DM skepticism and cleaned it up with no further problem.

It is not a problem of the lower leaves, but rather starts on the new growth.

There was a big national panic about DM around 1993-95 that was caused by misinformation published in the ARS magazine at that time. Be careful as you read, because there are some completely false statements in print.

DM can be chronic in cool greenhouses or outdoors in places where temperatures rarely rise above the low 80s (coastal California). Occasionally there are outbreaks in the trade where "canners" are starting potted roses in winter or early spring under crowded conditions in cool damp weather.

There are many different downy mildew organisms with different hosts. Rose downy mildew attacks only roses or maybe closely related plants. It wouldn't be in the grass or soil.

You could have some other spot disease such as cercospoora, anthracnose, or alternaria. These are not grave problems. Ag extension will give you a diagnosis.

What Michael said. Downy will strip a plant of foliage within two or three days once it starts, and it starts with new foliage first. Most supposed cases of Downy are in fact Cercospora or Anthracnose misdiagnosed.

Go to your Ag agent to get a positive ID on pathogens you suspect may be out of the ordinary.

>I'm a little skeptical about you diagnosis, because downy mildew hardly occurs in the Carolinas and cannot survive our summer temperatures.

>Most supposed cases of Downy are in fact Cercospora or Anthracnose misdiagnosed.

Thanks so much for your replies!

I didn't make the diagnosis - The Old Rosarian mentioned that at the Peter Beales' forum. Once she diagnosed it, I did look up pictures of the disease and I could tell where she was getting the idea, though.

A month ago, I could have pointed you to my post and her reply, except that I haven't been able to get Peter Beales' public forums on my machine for weeks now. But if you can go there, just search for posts by MaryG, and look back in the summer of 2010 for posts of mine around late June/early July. My post will have a picture that she was responding to. I've forgotten the post a bit now, but I think the main question didn't concern those those two tiny bits of yellow on the leaves near the ground.

It seems fairly long ago now, but last summer was much cooler than normal around here (and for large areas of the country, as I recall). It would be nice to think that the disease would automatically have been killed at some point last summer, but I remember thinking last fall that the entire summer had gone by without any overwelmingly hot days that our old air conditioning couldn't handle.

Too bad I lost all my pictures in some recent computer problems, so I can't post it again, at least not anytime soon. I do know what Cercospora looks like and we do have that problem around here, but that diagnosis didn't immediately come to mind at the time, perhaps because I wasn't even thinking about those two yellow splotches at the time. Perhaps if the bright yellow splotches had gotten larger, I'd have paid better attention? But I have to say that from the pictures I've seen, it appeared that The Old Rosarian knew what she was talking about.

We also do have a ton of Anthracnose also, at least the kind that affect rhododendrons, but I don't think the slight yellow splotches looked like Anthracnose. I don't think it would have been Alternaria either.

If you're certain that she must have been wrong in her diagnosis, then the barest beginnings of RMV would be my own best guess. In both cases, it occurred on some ownroots of Iceberg, with one being the climbing form.

For sure the roses had no grave problems until they came down with the earliest symptoms of Rose Rosette Disease, so if it was a touch of Downy Mildew as she said, the roses managed to get by on their own, with the addition of some Wilt-Pruf. Wilt-Pruf was my attempt at protecting against the spread of RRD, but it didn't work to prevent RRD... Anyway, I know now that Downy Mildew sounds extremely unlikely.

Thanks for thinking of my suation, Michael and Paul. I think I'll quit worrying about this one now, as even if Downy Mildew is there, from the growing conditions you describe, the cure is coming in just a few months; the chances that we'll have another unusually cool summer are slim, so very slim. And Downy Mildew is probably not there, because if it is, it hasn't yet spread to three nearby roses in pots.

Best wishes,
Mary

I just dug up a rose with a fatal infection of DM. black/purple lesions covering the canes. :( Cool damp weather. One they get it they can't seem to shake it, though I have a 'Belinda's Dream' that seems to have completely recovered. Usually it is fatal. Also an apparently clean cutting taken from an infected plant and rooted seems to develop the disease as well, or are particular cultivars more vulnerable?

Downy doesn't make yellow lesions, they are purplish-black, at least until very late in their development, at which point yellow areas can develop surrounding the purple lesions, indicating widespread tissue death of the leaf. Rapid and devastating leaf drop occurs at that stage, and soft cane tips wither and show conspicuous lesion presence as well. I do hope that is not something you ever have to contend with. Severe infections are believed to become systemic in the plant, making recurrence in following years very likely, assuming the plant survives the first round of infection. See:

Here is a link that might be useful: Diagnosing Downy

Notice in the picture in trospero's link, how the purple spots stop when they hit a vein, producing a straight edge. Not all DM spots behave like this, but if you see a number of such spots, it is diagnostic for DM. Lesions from other spot diseases don't commonly have that angular shape. Other diagnostic points are spots starting on the newer foliage first and causing rapid leaf drop.

I know three different gardens in Tennessee that have been hit with serious DM. All three went through diagoses at UT by the plant pathologists there.

The one unifying theme was fall leaf drop. Massive early fall problem. None of the three were the same year. Those years Other gardens within a mile or two of the problem gardens didn't have a problem.

I think the timing might also be applicable on your side of the mountains. And I think that we should be thankful that summer heat comes on the way it does most years.

Too bad we can't look at my picture of the "Downy Mildew" Climbing Iceberg rose now while we're talking about this. I don't know whether the purple ended with the veins or not, but the third picture that Paul posted rings a kind of vague bell here. I do clearly remember reading The Old Rosarian's diagnosis and then comparing my picture with some other pictures of the disease online, and seeing some correspondence at the time. As best I can recall, only two leaflets showed yellow, but additional leaflets showed the dark purplish areas.

But for sure the plant didn't succumb shortly - nothing of the sort. Perhaps Wilt-Pruf slowed things down? Anyway, it succumbed when I threw it out due to RRD about a month or so later. The plant as a whole wasn't doing well, though I think the Downy area, if that's what it was, covered just a few leaves near the bottom of the plant. Areas above that were the real reason I posted, as I couldn't be sure what the problem was there. She may have said anything about that - I just can't recall, but I think she said something that I should have been able to identify myself, like blackspot or powdery mildew. I suppose the extra areas that came at the lower level were probably what confused me. I was probably looking for just one disease when it was more like two.

I do recall that I wasn't sure what it was, and I vaguely recall asking whether anyone was familiar with Sudden Oak Death (which, by chance, I had just read about on a camellia or rhododendron forum), since, also by chance, I had recently gotten some camellias from California that were by chance coming from an affected area that had only recently had its sale ban lifted. Camellias and rhododendrons are some of the host plants for that disease that otherwise I don't think had been seen around here.

And alternatively I was also wondering whether the sickly rose might have been suffering from something like Chilli Thrips, since I had some roses from SC - from a place where I had seen a map showing the Chilli Thrips getting close to.

Sometimes it doesn't pay to read up too much!

I'll just note that I have one other memory. I assume that it's unconnected, but I just made a theoretical connection in tossing around the idea of a sudden demise of any plant contacting Downy Mildew...

Right around the very same time, I was worried about RRD spreading through the bunch of newly arrived potted roses sitting close together with the rose that The Old Rosarian said looked as if it had a touch of Downy Mildew. I thought it would be worth a try to spray all those roses with Wilt Pruf in attempting to ward off RRD. I'd done that with the roses at the end of May, but ran out of product and didn't do a really thorough job of it then. So about a month later, I did a thorough job of spraying Wilt Pruf again. The two roses most directly downwind of the Climbing Iceberg happened to be the two General Gallienis that had arrived looking beautiful from Vintage and had done well after repotting. Anyway, the day after the spraying, one of the Gen. Gallienis was suddenly dying and the other came very close to dying but eventually recovered.

I _think_ (theory #1) that they both became ill and one died because of that individual variety's response to the Wilt Pruf spray, but forty some nearby roses didn't show such strong effects. But both of those of that particular variety had leaves that turned purplish black and dried up totally. The one that died lost all its leaves and the other one lost most of them, but recovered. I do recall that entire canes turned purple-black and that it started at the tips. The one that recovered looks fairly good now, though I had to end up cutting out an entire cane - at least half of the small rose - to get rid of an RRD-affected cane. I was going to plant it with some totally isolated plants in a different, sunny section of the yard... but if it might have actually had a bout with Downy Mildew (alt theory #2), then I don't suppose that's a good idea.

On the other hand, I don't know where else I might put the General Gallieni, since it's not that shade tolerant, as roses go. Where it's sitting in a pot right now is approximately where it has been sitting all this time - in the sunniest area we have that's not the precious almost full-sun spot near the street.

I am planning on a bunch of roses now for the general area where the Downy Mildew occurred, if it occurred, and wondering what to do with a rose that might/might not still be harboring the residuals of a Downy Mildew problem.

[i]Question:[/i] If General Gallieni stays in its pot sitting out in the heat of July, will that automatically take care of killing whatever pathogens might still be hanging around the plant, or are they so internalized within the plant systems by now that outdoor temperature makes no difference at that point? That, of course, assumes that theory #2 about the sudden death/illness of the General Gallienis applies - that the problem was Downy Mildew, not the Wilt Pruf spray (theory #1). Theory #2 implies that the spray job just happened to coincide with the sudden death/illness due to other reasons (Downy Mildew). I guess I haven't quite figured out how to get a Downy Mildew Experienced rose safely past spring and into the safe heat times of July, if and assuming the July heat will take care of the disease residuals within the plant.

Please feel free to shoot down either or both theories and offer your alternative ideas! Gosh, I wish I had that picture now. If Peter Beales' makes the posts available again here, I'll direct you to the post & picture.

Thanks again for all your comments!

Best wishes,
Mary, totally uncertain but theorizing anyway...

Please help!
I just finished digging up absolutely all of my beautiful rose bushes-all 34 of them because they were infected with Rosette disease. Unfortunately, I had never heard of this disease until I started seeing strange new growth on many of my roses. I took in a sample to a nursery and they confirmed it was rosette disease and told me there is no remedy other than to get rid of them. I feel so devastated and sad. My question is: What else do I have to do to be able to grow any roses in the future? I believe my bushes had this virus for over a year and so it spread throughout my property. I plan to get rid of all the mulch and the soil they were planted in. Do I need to do anything else? Is there a treatment for the soil to keep this terrible disease from infecting any future roses that I plant? Any help would be appreciated. Thanks!

Hi David,

You should start a new thread with RRD or Rose Rosette Disease in the title. Also, where exactly do you live?--the disease is normally spread via nearby wild multiflora that was intentionally infected for weed control. Unfortunately, RRD is often confused with Roundup or herbicide damage.

There is a great e-book on this subject by Ann Peck.

Here is a link that might be useful: Ann Peck's RRD e-book

On the supposed Rose Rosette Disease, I strongly recommend that you contact Baldo Villegas through his Bugs & Roses home page.
I'm a little doubtful of RRD in your area. It has been found in CA, but .... This would be a disturbing and odd place to find it.
See if maybe Baldo can look at some foliage samples for you.
As noted above, Roundup damage can look very much like RRD symptoms, and in your area, I'd consider that more likely.

Jeri

Here is a link that might be useful: Baldo's Bugs & Roses Page