Downy mildew has attacked my 'OP Baby Love seedling… these black ‘scorch marks’ have suddenly appeared in the recent cold wet spell we’ve had. It spread to some, but not all the leaves. I’ve removed the affected leaves that I could find and all the dead/fallen leaves and I’ve soaked the pot and the foliage in Fongarid (see here for details on use with Downy Mildew: http://www.publish.csiro.au/?act=view_file&file_id=APP978-1.pdf pages 9-10) to treat it. I REALLY don’t want to lose this seedling. It’s pretty big now (fills a 30cm pot) and it was about 30% defoliated… do you think I should try and propagate it NOW in case I lose it… I’ve been back through the archives and lots of people have said once they get it you can often kiss it good night 
What do you think its chances of a recovery would be??? It’s attacked my remontant 0-47-19 seedling too… couldn’t attack the crap ones I was going to cull anyway… just the real good ones cries
Chances are the Downy came in with some plant material brought in.
Heat will kill it. Getting your seedlings into a greenhouse if you can.
Kim tells a story about a friend of his that used a hot water drench successfully.
It’s nasty nasty stuff. I’ve only seen it here once, received one Winter with some plant material from Northern CA.
It can be devastating. Of course the heat here finally resolved the problem for me.
If you can keep your stuff alive till the weather changes most time they outgrow it. Some say once it’s in the plant it never really goes away.
It prospers in humidity over 85% especially in low air circulation. It is highly fungicide resistant. Copper and the group of chemicals that works on it is mostly a preventative and not a curative. The former is usually dormant only, anyhow.
I lost my first Royal Amethyst to it, as well as Natasha Monet, both the exact year they were planted. They came from … Arena? I think… I didnt put the pattern together until #2. I was more worried about finding a mauve that wasnt awful here. NM not only develpoed PM about 2 weeks after planting it but the graft began to sperate from the union!
If all else fails, you can turn this into a learning experient and try some safe stuff on it. I got rid of Crown Gall on my 15 year old copy of American Honor by spraying them open wounds with Chlorox, lol. it burned where ever the crown gall was removed but it also killed it. The stems, however, came out fine – just a little funky looking. Downy mildew is rather systemic, unfortunately, and not just tumorous like crown gall is. You could always play with peroxide, I guess =/ Or see if the roots will soak up neem oil water? I dont know…
Sorry it happened to your long distance baby =/
Spraying Neem does work if sprayed on early enough. I found that a combo of Neem and Agriphos (phosphite not phosphate) both mixed in the same spray, full dose as per label, worked well to stop the outbreak. I did have some leaf die back and droppage, so obviously it was a bit strong for the plant—but I did have many young plants die before I found that combo. Copper seems to have a protective role, but that is before the outbreak. I also tried the hot water, and the Chlorox but almost all of those so treated did die. I did end up with about 10 DM resistant/tolerant seedlings (untreated), of which I kept 4–and they are still exceptionally disease resistant plants. The heated, long sun exposure route in the greenhouse would be least toxic and still successful. With enough humidity and overcast conditions, DM hangs in there at much higher temps than most of the literature says. Even with the damaged leaves most of the Neem/Agriphos treated young plants did survive, Good luck!
I’ve treated it with Fongarid, which I had handy for immediate application, and it is in the greenhouse. We’ve had a nice warm day here, about 22
With Neem Oil, I was thinking of some article Henry posted a while back about root treatments/systemics of neem, as opposed to foliar. I dont know… just a thought.
I certainly don’t have a specific # of days to recommend keeping in a dry, warm greenhouse, but it certainly would be more than the 3 days that is commonly hyped. It varies with the rose, as some are much more susceptible to DM than others. My large bushes of Gemini (under their thick layer of leaves) were producing spores into July in '09. Last year Gemini was the only bush to produce spores that I found. This winter I have found one sprig with leaves producing spores on an offspring of Gemini, but we got up to 107F in November (4-5 day heat spell) and just two days ago got up to 96F for about another 3-4 day heat spell. This has seemingly stopped the DM, but it had only started. Catching it early does seem key.
Hi Simon,
Sorry to hear about your DM. Robert is right, HEAT is your best friend for getting rid of it. Keeping night time temps above 60 degrees seems to be best. I would keep it in the greenhouse for at least 2 weeks or until outside temps/conditions are unfavorable to DM. We get DM here bad about every 3 years or so in the Spring. I don’t think that I will ever be rid of it completely now.
One important concern, ‘Baby Love’ and derivatives seem a bit more susceptible to DM than others. I have found however, that ‘First Impression’ seems to pass along reasonable DM resistance. It is a hard trait to select for unless you have DM every year. Younger seedlings and recently pruned roses appear to be more susceptible in my experience.
Best wishes,
Jim Sproul
This year has been the worst for every fungus imaginable. The weather just isn’t warming up like it usually does and it has rained almost every day for weeks. It’s summer and I’m actually sitting here in a polar fleece jumper because it is still that cold. I’m usually stripped down to almost nothing by this time of the year. A quick walk around the garden this afternoon revealed there is now hardly a rose in the whole place that isn’t badly affected by DM with great big black scorch marks across their leaves. Air circulation isn’t an issue. The Roaring 40s winds see to that (keeping them in the ground is more of an issue). If things keep going the way they are 95% of my roses will be leafless before I go on Christmas holidays in 2 days time. I think I’m going to have to cut everything back hard and spray the Fongarid, or some other systemic fungus for DM, across the whole property to try and kill off the DM. I am not looking forward to this as it means I’ll be flowerless over the Christmas break, the rose garden is more than an acre in size, and pollinating is just getting into full swing. Powdery Mildew has been the worst this year that I have ever seen and black spot is starting to make an appearance… great seedling testing conditions that’s for sure
Hi Simon,
You wrote “great seedling testing conditions that’s for sure”. And with the little frowny face, I just want to make sure you don’t miss this excellent opportunity. ;0)
In all seriousness, don’t underestimate the value here. Here’s a great chance to see who the really tough guys are.
Before you do anything drastic, make sure to study the various reactions of your roses to this extreme disease challenge. You might find some are shrugging it off fairly well. That kind of information could be incredibly useful.
Best wishes, Tom
Taking note already… I can put together a very small list so far inlcuding:
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All the rugosa roses (Alba, Pink Grootendorst, Scabrosa, Ann Endt) seem clean. All my rugosa seedlings from Frau Dagmar are doing well. My rugosa x moderns are doing ok but are copping it from powdery mildew.
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Some of the wichurana roses… esp. ‘Temple Bells’ are clean. Nothing seems to phase this rose. Its progeny seem to be doing well too. Flower Carpets Scarlet, Pink, Yellow, and Apple Blossom are largely unaffected and my single pink seedling is clean. Flower carpets white, amber, and red are badly affected. Snow Carpet is only partly affected. Dorothy Perkins is a mess. Summer Evenings is better than average at about 80% free so far. Immensee is clean. Albertine is a mess as is Heidesommer… the wichurana hybrids are pretty hit-and-miss.
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The Multiflora roses are affected but not very badly. The closer to multiflora they are the better they are. My little Baby Faraux/Sweet Chariot x multflora seedling is largely unaffected. Trier is unaffected.
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Two Tea out of all the Tea I have are unaffected. They are Lorraine Lee and Nancy Hayward (a hybrid gigantea).
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Lamarque is only partly affected.
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The only HT unaffected is an Alister Clark rose called ‘Lady Huntingfield’.
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The only China/polyantha unaffected is the bush form of Cecile Brunner. The climber is a mess. The fairy isn’t too bad but nothing to get excited about.
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None of the gallica are affected.
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None of the moss roses are affected including my moss seedlings.
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The damasks are affected badly.
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All the modern minis are badly affected… even Popcorn and Little Wonder. Two that aren’t, however, are Laura Ashley and Nozomi.
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Knockout is unaffected by anything.
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Carefree Wonder seems pretty good so far.
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Species unaffected: wichurana, bracteata (clinophylla seems affected as a seedling… not sure I like much about clinophylla yet… it’s not done much to impress me here so far), gigantea, multiflora, setigera, longicuspis sinowilsonii, laevigata, rugosa(as mentioned), banksiae (all of them). My spin. seedlings are ok but not 100% free.
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Paul’s Carlet Climber seems ok.
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Euphrates is free of DM, has a little PM, no BS (or any other acronym), but has serious dieback.
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Golden Chersonese is partly affected.
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Everything else pretty much is badly affected. The worst, so far, are the Delbards…
This is only scratching the surface really… but these were the ones that stood out this afternoon.
IME Teas suffer terribly from DM.
Your weather pattern sounds exactly like Bonitas’ three yrs. ago, when we experienced fog and mist daily often 'til 2-3PM. well into July-August. I live at the end of a canyon and more time than not we are fighting high winds. I can water when it is dry but it is more than just difficult to fight that constant moisture when temps hover in the 50’s to 60’s. I have often wondered why the extreme coastal roses don’t all succumb to DM.
The educational/experiential part of this is probably the only upside. I also found climbling Cecile Brunner extremely susceptible as was dbl Pink Knockout whereas Red knockout was quite resistant. Something in the disease resistance did not sport. I lost 2-Jeanne LaJoies,(but one suvived), Black Pearl, Deep Secret, Pink Iceberg, Mr. Lincoln,Hot Cocoa and several David Austins. Anything that was compromised (they were recovering from gophers having eaten their roots) also totally melted. Black Magic and Charles Aznavour were planted in less than favourable spots and when moved after the outbreak was halted, did recover, but 2 yrs later are still not totally back; great recovery was seen in Gemini, Lynn Anderson, Pinata and Summer Wine. Some of the roses that have remained the healthiest are probably not coincidentally also passing along that factor to the greatest number of offspring, which is something I have started to take notice of. It was very upsetting at the time to not be able to get a handle on the outbreak, which led me to spray more often and at dbl doses. Now I look at it as a very enlightening experience, and have worked at making the soil much healthier (microrhizae, humic/fulvic acids, etc) and feel that the roses need little to almost no protective sprays. But I have kept one rose that seems to be the canary in the gold mine-Daydream seems to be especially susceptible to DM, and the minute it suddenly wilts/or turns purple, out comes the spray. DM is in the neighborhood so I’m of the thought that getting rid of the easiest early alarm (it recovers-and I trim out all the damaged material) is like getting rid of my junk yd dog while living in the ghetto.
lol, Daydream was a very odd rose. Its like Ballerina, but stiffer and slightly smaller, but instead of mildew, it sneezes and loses all of its leaves to blackspot, lol. I recall it having a sort of wine-pinkish red bark that was pretty cool though.
It appears that roses with thin tissues seem to be more highly prone, but maybe that is a superficial pattern. Who knows.