I too get this in the winter months here in the arizona desert. I don't know about the roses you have that have lost there leaves they might be to far gone. The way I keep DM under control is to be strict about my spray program. It is the only way to keep mildew problems under control before it is to late. A strict spray program is important.
What works for me is Mancozeb, in your case I would spray every 7 to 10 days until gone and then keep up with a spray program. For me I spray mine about every 3 weeks or so in the winter months (I don't have to spray in the summer since it is so hot, mildew is not a problem). Do not use Mancozeb if temps are over 90F, spray in the morning so leaves are dry by nightfall. Some garden centers carry it, I order mine on line, just type in Mancozeb and retailers will come up.
Good Luck,
Carrie

it is my understanding that fungicides are non-specific. If you want to spray, perhaps copper on the ones that already lost their leaves. As long as the dm is not in the canes you are probably ok. It could be after they lose the dm leaves, the temp will warm up and the new leaves will be fine. Maybe you could heat them up a little with a hair dryer or something. I know when the temp gets 85 degrees or warmer bs is no longer a problem.

Ordinary mildew is hard to get rid of but downy mildew is extremely difficult once it has taken a hold on the plant. It is in the air in your area, not on the plant when you bought it. There is no need to get rid of your roses as there is a solution. Using any type of spray once a week is really too much and will effect the growth of the roses as you live in an area that roses do grow well in. I have answered quite a few questions regarding Bayer All In One sprays concerning the damage it does to roses so perhaps it would be a wisdom to hold off for now until the problem is cleared up.
If possible try and space your pots so the rose leaves are not touching each other. Downy mildew is spread by white strands that attach to the rose foliage and can infect another plant close by. The best thing to use on this mildew is dormant oil and suphur spray. Use only the summer strength and you'll find the directions on the label. Roses are able to push out new leaves three times before it effects their vigor so don't worry about the loss of the leaves. When the dormant spray has cleaned up your roses then you can use 1 tablespoon baking soda to 1 quart of water if you see any signs of it mildew again. Just spray it daily until the leaves are clean.
In regards to fertilizing, using a slow release such as Osmocote 14-14-14 will give the rose all that it needs for 6 months and it saves you work. Also roses love cool, damp roots and any type of mulch you have in your area will give them that. It also cuts down on the mildew problem. Fall is still the best time to plant roses in the PNW because the roots are still growing even when the soil is 40' Then you get a good set of roots to maintain the tall, new growth in the spring. Don't forget the PNW ( as well as other areas) has had a LONG dull wet spring. Everyone I know is complaining about their roses, included me. I planted over 100 roses in the garden and most have poor, stunted discolored leaves because of the cold weather. It is only now they are putting out healthy leaves and growth. This year the odds were against gardeners.

Thanks you to everyone who has posted advice.

However... each post told me something totally different.

How am I to know who is right and who is wrong?

I have read that Sulfur does not kill downy mildew.
The most consitent information I have found online mentions copper based sprays... is this correct?

I just checked on all 16 plants and they all look worse this morning than they did yesterday. The two that looked uninfected yesterday now have the downy mildew angular spots on their leaves :(

I am thinking that I need to defoliate every single bush and spray... I just need to know exactly what I have to spray with and how often...

I have seen a person on here called Buford>>> you seem to be very knowledgable... can you help me please???

I have been told by someone whom I respect as having a great deal of knowledge about roses that one needs to use a metal product which is used broadly used for raspberry wilt. "Metalaxil" is a drench, and "Alliette" is sprayed. I think "Alliette" has zinc. (spelling of products may not be exact).

Anyway, not being an expert, I have used "Alliette" several times when we have had a bad outbreak of downey mildew and it seems to work. It won't clear up the damage already done, but the new growth will be ok. We have also found that it may be necessary to prune out infected canes. Years ago, when we had a particulary bad case of downey mildew, which had gone into the rose roots, we used "Metalaxil" and it did save the plants. However, these products are impossible to get ( at least for the home gardener) in Canada, but they are ( as far as I know ) available in the U.S. My best suggestion to you is that you get in touch with your local Rose Society and they will help you with good advice.

I know that in these days of environmental concern, nobody wants to hear about chemicals. Unfortunately, often there is no other recourse when dealing with some plant disease. We would all like to be able to use some earth friendly product, but nobody can tell us for certain which earth friendly product really does the job. None, I suspect.

Now here is what is happening in my neck of the woods. I have only seen DM on a couple of plants - Jeri Jennings last winter when it was new. By summer it was green and growing again. Same thing is happening this year with my new Pope John Paul - it's been languishing with the cool weather. Leaves were a lime green shade and some purple blotches. But now that the temps have been in the 90s all week, it is turning a darker green and growing again (nice red leaves on new growth. No spray on either plant.
The PJP is planted right next to another rose purchased from same nursery and planted at the same time. This other rose (Scentimental) has not had any sign of DM at all. I don't know the answer but that's my take - wait for summer temps.

peachiekeen, you're quite right. I should also have mentioned that once the tempertures hit 80 degrees or so the downey seems to clear up. I'm told that it is not killed, but is at least inactive. The problem is in the rainforest parts of the country, the temperatures take a little too long to warm up suffiently, in some years.

But, again you're right - if you want to wait for hot temperatures your roses will perk up.

Try Mancozeb from Rosemania, this fungicide is great for treating Black Spot too.
http://www.rosemania.com/shopsite_sc/store/html/page5.html

jay- i could have sworn i wrote this article! i was struggling here in vancouver with the exact same situation a few weeks ago. some of my roses that were supposedly resistant to disease succumbed to DM. on the flip side though, some have rebounded that i thought were surely going to meet my shovel. i have been spraying every 7-10 days with Bordo copper spray and it seems to work. you need copper for DM- sulphur will no do it.i am now struggling with a new problem- my leaves are all yellowing and falling off right before my eyes; i am convinced it is due to the rotten spring here in the PNW. stay in touch with me- as we have identical issues.

Powdery Mildew and Downy Mildew are two entirely different things. Go to Rosemania.com and see what they recommend. A very wise rosegrower, CR, and professor of horticulture told me to shovel-prune anything that had a bad case of Downy Mildew and to treat the entire bed of roses in that area. Powdery Mildew goes away with sunlight and warmer nights and Mancozeb or other similar agents.

Part of the confusion is, I think, due to the fact that several posters seemed to mix up powdery mildew and downy mildew. I doubt that oil products would help to get rid of downy mildew. The usual recommendation is Aliette and Stature.
Both are very pricey.

Aliette, by bad luck, I paid much for and I have a lot of in my chemical fridge. Too bad that there are not many rose growers close by so I could share some.

Statute was better priced at Atech (?) in Hendersonville than at Rosemania, so if someone lives close by and really needs this stuff it may need a price check.

Jay, you live in a region that is very friendly to roses (I live is the same region (Oregon)). I have over 70 roses and seldom having any problems with Powdery Mildew, Downy Mildew or Rust. Depending on the weather, black spots are coming sometimes. However, I see those problems only on roses that are neglected in some way, especially the roses in containers are sensitive to being neglected.

You wrote that you are doing well regarding fertilizing and proper soil/container sizes..., but I think the cause of the problems is in the soil, watering or fertilizing. Container 20-30 gallon are sufficient (my are smaller than that). Do you over-ferilize? I use very little fertilizer (once or twice a year, and only 1/3 suggested dose of Bayer), however, I use a good mulch and natural soil augmentations. I think that your roses are weakened (on the root level) and they are an easy target any kind of problems.

Hi Jay,
Good news is once the temps get over 80 the downy will subside. Bad news is you need to treat now with Alliete or Stature.
Here's a good website with both at decent prices.
http://btgrowersupply.stores.yahoo.net/fungicides.html
Just copy and paste.
Michael

Yes, Aliette is what I used. Thanks, Ceterum, for reminding me the name. I ended up giving mine to a person with a greenhouse who had a couple hundred roses in the greenhouse and had bought one that infected all his. Unfortunately, he lost them all anyway. I think they were too far gone by the time he realized it was downy mildew and not just a brownish/purplish discoloration from cooler weather.

I just wanted to take the time to thank everyone who took the time to offer there advice. It's kinda hard to go back with all of these posts and name everyone specifically so thank you again everyone. :o)

Aliette and Stature are my answer. Thank you kayli-gardener,Ceterum and Michael(newjerseyrose)-for the link. I also 100% agree with you rose_marek since these are all new pottings as of Mid Winter.

This would have never gotten so out of control if I only knew 2 months ago I was dealing with Downy Mildew and not blackspot.

One more question though... the Mancozeb is way more economical for me... will that control a current case of downy mildew or is it just a preventive. I am aware it does kill blackspot spores but what about downy mildew?

Since it is so early in the season here in the PNW I defoliated all 16 bushes yesterday. It just seemed like it would be better for the plant to use it's energy on new growth that is protected rather than the stress to the plant having to deal with diseased leaves. I swear that each time I checked them today even though they all are defoliated now... that they just looked and felt healthier to me. Crazy eh?... but I really feel it. :o) No different than when I felt they were coming down with something days before the symptoms were actually visable. Actully it seemed like it was hours... Is this actually true with what I am learning about rose gardening? Something just doesn't look/feel right on one of those numerous daily visits into the garden and hours later they have a fungus or pest problem that wasn't as clearly visable earlier.

I also pruned back a few canes that seemed to have damage when I defoliated on Monday. I was only able to find a product at Lowes called Garden Dust by a company called BONIDE. The directions said that it could be mixed with water and made into a spray so I did that. The active chemical is 7% Copper Sulphate. It was the only product they had that contained copper and also the only product that actually said on the label that it could be used for downy mildew. However the label is not that clear and does not state whether it is a preventative aid or curative... or both. Any thoughts on this from anyone? Until I find out if Mancozeb will work(since it's more economical) or get a hold of Aliette or Stature this weekend I am hoping the spray I did this morning with the product by BONIDE will help. Joebar you are in my area also and said that a copper spray worked for you so I am keeping my fingers crossed this one I have is good enough until the weekend. It only cost $6.97 at Lowes which has me question it's effectiveness... who knows... maybe I just got a good deal and it's all that I will need. Any thoughts anyone?

Thanks again to everyone who took the time out of their day to help me with this... it's sincerely appreciated.
Jay