I am wondering if this could be Downy Mildew. Hopefully some can chime in.

Have downy on most of my roses and the ones thatre really bad the canes look the same accept the black spot on the cane does look like canker but most bushes infected with downy will also get dieback n canker along with reddening of the canes. please I advice u to burn it n rid of it ASAP!!! I'm mourning over what I have to do with all 200 of my rose bushes bc of the downy outbreak !! It started with one bush and now all are infected! ! It's extremely contagious so my advice, burn the bush as far away from other roses as possible! Please do not trash it bc it will infect other roses within a great distance. just by wind the spores can infect other bushes it does not have to have water to transfer!!! And check your other bushes!! For purple, brown or black spots along the veins of the leaves !! black spot will cross the leaf veins and have a feathery appearance around the outer edges. Downy spots will be more solid in color and when it hits a leaf vein it follows it instead of crossing it. It can start out with spots or splotches then the spots will grow rapidly and if u look under the top leaf growth u might find a spot or two ( very small) that looks powdery-ish. It could be a reddish color or white. Downy is very devastating so the loss of one bush to protect others isn't much of a loss. I hope all goes well with your roses!!

I apologize downy does need water it's powdery mildew that doesn't!!! But downy is still the worst disease to have and extremely hard to rid of!!!!!

I wish I could have seen the leaves you removed as it is easier too tell if it's downy mildew. The canes looked cankered to me. Either way yes they need pruned too below the darkened parts. Sterilize pruners between cuts as this is easy to spread. Would you remember if any leaves resembled these photos.

Blackspot or Downy Mildew? | rosemaniablog

Rachel, what makes you think you need to burn a rose bush just for downey mildew. You should just remove all infected leaves and spray with Aliette (fosetyl aluminun), Subdue 2E or Subdue Maxx (copper metalaxyl), or Stature DM (dimethomorph). For heavens sake dont burn the rose. This is a temporary disease that the rose can recover from

Thanks everyone!

Rachel that's terrifying just hearing how contagious it is, and 200 roses lost that's just plain scary. It does indeed look like a mix of downy and canker as you suggest The dark splotches are more red to my eye than it shows in the photo. It looks like it's also on the crown of the rose :( I I guess tomorrow when its bright out I will destroy it and inspect all my other roses for similar symptoms as you described.. The conditions for downy which appear to be prolonged humid wet weather at 65-75 degrees is exactly what we've been having lately.

Patty, I do not recall exactly seeing those patterns but I can't be sure they weren't there..I do remember it being rather green though for this late into winter.

SoFL, even if the infection is at the crown spraying it will help? The way downy looks reminds me of FireBlight on my small Asian Pear trees that started on one and spread to all of them where they eventually all got infected and died by the end of summer.

Yikes!! I had that on my Perfume Delight not last summer, but the one before. I can't remember iif it got better. I will have to make sure it's healthy or else burn it.

Carol

I think its worth trying to save it by spraying if anything. Maybe keep it away from the other roses while its sich as i see its in a pot. I just cant imagin poor rachel having to destroy an entire rose garden due to downy mildew. But honestly ive never battled it in my garden and it seems dreadful. Good luck everyone.

I would suggest isolating the rose then cutting all the bad parts bag and dispose of them. One rose is never worth losing the whole bunch in my opinion anyway. After cutting post a photo of whats left. It some what appears as thou the crown might not be salvageable.

So it looks like all of the other roses have no sign of downy mildew with the exception of Sonia, which is actually in my bed of roses... It's not too bad though on Sonia, just on the top so I cut a few stems off and sprayed.

With Perfume Delight I decided to discard it since it's so bad I didn't want to bother and risk further infection. It's bare root season now so I'll just pick a fresh one up.

Thanks everyone. I'm just looking forward to the change of season now so downy won't have a chance!

Perfume Delight must be suceptible to DM because it's the only one out of my 50 roses that got it. And yours has it too.

Carol

SoFlo rose I'm the last person on this earth to destroy a rose bush!!even one!! That's why I still have ALL my roses and bc so, my new roses are getting downy ( even with spray!!) I've been battling downy for over 9 months now. Months ago when I found out for sure its downy, I went through all 200 bushes. I cut back the diseased canes, stripped off every leaf, then sprayed with alliette! At first, they looked nice with clean growth but within a couple weeks the downy returned. I have to say the signs of the disease varies greatly between cultivars. On some bushes it's so so similar to black spot. On others, it looks like I splashed purple/black ink on my roses. I understand the grief of a lost rose bush! Im telling you from my own personal experience, Downy is devastating & weakens the entire bush rather quickly!! Spray helps but doesn't rid of it and EVERYTIME the weather favors it, the downy will show again and your roses will decline rapidly and spread to the rest even faster!!!! I ENCOURAGE ANYONE TO RID OF A BUSH IF THEY SUSPECT DOWNY!! I'm in the process of fighting it and I'm not winning !! my bushes started with leaves being infected then to the flowers and now the canes!! On a majority of my bushes the canes are getting bad and these bushes most likely have to go Downy isn't curable, just bc it appears when the humidity n temp. favor the disease doesn't mean it's easy to wait it out. It stays dormant in the bush. When the environment no longer favors the disease, my bushes are so weak n scraggly, I can't tell it's stopped spreading. I have some friends from Tampa rose society that say if there's one or a couple infected bushes for the sake of others who grow roses nearby and for my other bushes, it's best to burn the bush so it doesn't spread. Even tho it requires standing water for four hours to germinate it's a quick, fast spreading disease trust me!! I pray none of you have to deal with it!! I wish when I thought I was seeing downy on a couple roses that I had someone to clarify that's what it was and a chance to rid of those bushes right then !! it would've saved me so many roses and so much heartache !! However! I was extremely hopeful and knew I could take this challenge head on, possibly beat this disease and save my bushes but that doesn't seem to be the case!! I told myself I wouldn't get rid of even one!! I could strip n spray and fix it until the weather passes but it's not that simple. It eventually became worse. You can only strip the leaves so many times and the bush weakens drastically. I'm looking for the brooksville rose society to join n hopefully find ANYONE who has had to battle downy so I can figure out how to rid of this evil!! If I have to throw out all bushes and rake the Entire 3acres 50 X's for infected leaves & wait a few months until it's clear to bring in new roses.. Then so be it!! I'm tired of the battle ! Dan 8gw if u have any questions about downy, feel free to email me anytime!! Rachelcross31@icloud.com I'm not an expert but I can share my experience. If I were u, I would check your roses on a daily basis now for a week or so to make sure there's been no further spread and since u sprayed, I would go as far as spraying again 5 days apart for a total of 4 applications to make sure the disease will not have a bit of chance spreading in your rose garden!! It seems like a bit much but if u end up with a downy outbreak, it's devastating and the work to keep it under wraps is even more demanding, that's the hardest part!! Downy is pretty common in Cali . Those are spray recommendations I got off of (ARS??) site. I believe it was American rose society but could've been a different rose society?? Anyways, Good Luck!!!

A 2015 thesis (in Spanish, except for the Conclusion Section) concludes the following:

"In accordance with the above, the following recommendations:

 Apply the potassium phosphite at the foliage at a dose of 8 g/liter during the cultivation cycle of rose (Rosa sp.) to reduce the incidence and severity of fungal diseases caused by "powdery mildew" (Sphaerotheca pannosa) and by "downy mildew" (Peronospora sparsa).

 Include the use of phosphites in the integrated management of the foliar diseases in the cultivation of roses."

See: http://www.dspace.uce.edu.ec/bitstream/25000/4548/1/T-UCE-0004-14.pdf

See also:

http://www.researchgate.net/profile/Hilda_Silva-Rojas/publication/236172158_Fungicide_spray_programs_to_manage_downy_mildew_(Dryberry)_of_blackberry_caused_by_Peronospora_sparsa_in_Michoacn_Mxico/links/00b7d51b0eadeb2dfd000000.pdf

Dan, your second photo is one for concern, Downy Mildew(DM) is started from humid weather events. Looking at the pot you have invited DM. the leaves are a source of DM. Remove the leaves and place the pot somewhere DRY. You have been given some good advice, the only thing I would say is when you cut the rose back, cut it further than you need to as the DM infestation is smaller than the eye can see so would be past the visual. The disease does over Winter so I would repot as soon as possible, washing the whole plant top to bottom in a fungicide which you can purchase where you live. I would even get a new pot.

Thanks for tips and articles everyone!

Rachel, I am definitely checking them as much as I could. Thankfully none of the others are showing any signs of infection, I'm glad I caught this before it escalated.

David, the leaves were from a plum tree it was placed under. I figured it would just decompose and turn to humus, but I'll be sure to remove it next time. I have disposed of the diseased plant because it just doesn't look worth saving at all.