Hi - I'm so sorry to hear that you are dealing with this awful disease! My Climbing Pinkie had a "suspect"cane last year. It was totally separate from the main plant, so I cut it out and am keeping my fingers crossed, so far so good. I HAVE seen infected multiflora in my area, though, so although I am certainly no expert, I can offer the comment that at least to me your KOs look ok. I have KO, and its new growth does tend to be reddish. Hopefully some much more knowledgeable people will weigh in on this, but in the meantime, please accept my condolences and my (unfortunately relatively uneducated) guess that your KOs are ok.

As for the meidilands, I don't know these roses at all, so I don't really want to comment one way or another. Hopefully somebody else will be able to help you out on this!

Best,

Frances

Nice house.

Hate to say it but you have a lot of RRD. I used to have tons of infected RRD in the woods behind my house and I would lose around 5% of my roses every year. Sometimes it would effect one branch, I would cut it down as far as I could and hope it wouldn't return. Sometimes it worked.

I doubt you'll be able top get rid of it completely but some things you can do to help control it are....

Get something like roundup and spray all the mutiflora you can spray practically. I've found you need to make it stronger than usual. Maybe use 1.5x what the label states. You probably need to spray every month or so until you get rid of it all.

Don't worry about doing things like buring the infected canes or treating them like they're toxic waste. Just throw the infected canes in with the infected multiflora. It won't matter one way or the other when surrounded with a RRD infestation.

If a bush has more than one infected cane, dig it up and throw it in with the infected multiflora and get a new rose or a new something else. There's no point in getting upset over it. Plants die. It's part of gardening.

I used to use something called liquid sulphur to combat black spot. It made my roses smell like sulphur. I don't know if it was a coincidence or not, but when I used this, my RRD infection rate went down. Maybe the little mites don't like sulphur.

Don't spray insecticides to prevent it. The vector is a tiny air borne mite. You must get rid of all that infected Multiflora that's the source of your infection.
To find out more about RRD and possible prevention, read Ann Peck's web book.
She's probably the best expert on it.

Here is a link that might be useful: RRD web book

Kidhorn,
Thanks for the report on the liquid Sulphur. Dr. Jim Amrine told me he wondered if sulphur would kill the mites. Reason: the mites don't breath as most creatures, but respirate through their 'skin'. And he thought that if they took in S2O instead of CO2 (being similarly sized molecules) it might kill them.
When I looked into it, all I could find was micronized sulphur, which particles were larger than the mites. So their breathing them in became unlikely.
Do you have or could you send me some info on the sulphur you used?
Ann

It's bonide liquid sulfur. It's sold at a lot of places. It works well to control blackspot and it's supposedly organic. I think the sulfur is organic, not sure about the brown goo the sulfur is suspended in.

If you get some, make sure you mix it up in its bottle every now and again. Every bottle I've had I didn't mix it up over the winter and it formed a hard brick in the bottom of the bottle. Made it useless. I don't know how to unbrick it.

No guarantees, but I found that the yellow brick that happens in bottles of Lime Sulphur when it sits, is easily soluble in HOT water. The hotter, the faster it dissolves. After I commented on that, Mike wrote about the solubility of some polysulphides.
Maybe it's worth a try even if it's diluted a bit?

I'll give the hot water a shot. I have a 1 gallon jug that I only used half of. What do I have to lose?

Thanks for the info.

OK, so it's Memorial Day and I'm really hoping someone is around to help, since I need an answer by tomorrow morning. (Yes, I'm a terrible procrastinator, LOL!)

First off, RRD was definitively diagnosed by the state university plant pathology lab in both my climbing pinkie and in a sample I took from a multiflora rose on my property. We are having the fields around our house that are full of infected multiflora bushhogged tomorrow evening. Based on information I have gleaned from this forum about alternative ways of combating RRD, I have purchased sulfur and wilt pruf. I was planning to mix it all up and hit the roses with it first thing tomorrow, then cover them in plastic (clear plastic painter's dropcloths) and hope for the best while the fields get mowed and for a few days afterwards, in the hopes of keeping any mites that are disturbed during the bushhogging off of my garden roses. But I have some questions:

1) It is supposed to be 80 degrees tomorrow - too warm to spray sulfur? I have a powdered sulfur from Bonide that I was planning to mix with water. It's been an abnormally cold spring here and today was the first day it hit 80 degrees. I had planned to spray on Saturday, but the weekend got away from me. I have read that you aren't supposed to spray it when it's warm, but it doesn't say exactly what happens or exactly how warm is too warm. Also, considering I am planning to cover the roses with painter's plastic dropcloths, you can probably figure on a greenhouse effect that will make the temperature at the roses much warmer than 80 degrees.

2) The roses are just starting to bloom - it's the beginning of the spring flush. Will spraying with wilt pruf and/or covering the roses with clear painter's plastic dropclothes screw up the blooming or hurt the plant?

3) Do I need to do all these things (wilt pruf, sulfur, and plastic dropcloths) or can/should I leave something out? I don't want to make things worse by doing something I shouldn't....

Thanks very much!

I was thinking that the sulphur couldn't be done in hot weather. I hope Ann stops back to answer your questions. I had to get rid of my Mons. Tillier due to RRD. There is a lot of multiflora about 1/2 mile from my house. I will have to check it for RRD. I hope you are able to get it under control.
I have a couple bushes where I cut back to the ground and on one I cut the cane off. No sign yet but I sort of expect more.

Carla

Bushhogging alone will not kill off the MF roses. My suggestion is to whack them down low then spray each one of them with a woody brush killer. I am as against chemical killing as another, but sometimes it is the only viable choice, and it can be done responsibly.

I am sorry for your struggles with the RRD. I am brand-new to roses, so still have most issues ahead of me, yet.

Bushhogging does stir up a lot of dust, and will there be mites in that dust? Just wondering.

The reason for bushhogging now is to reduce the size of the mite habitat.
The mites make really large populations on R. multiflora, much larger than on other roses (people have counted and published on this).
By taking out the multiflora before the mite populations surge, and that time is reported to be August and September, the disease pressure on her garden should be greatly reduced...by orders of magnitude.

I've sprayed sulfur in hot weather and it didn't hurt the roses. I suppose if the roses were dehydrated and I sprayed in 100 degree weather, it would likely do damage, but I wouldn't worry about spraying in the next week or so.

I agree with greenhaven. MF roots are stubborn and if left intact, will quickly grow back. Ideally, you should spray the leaves with roundup a week before bushhogging, but the best thing to do after the bushhogging is painting the stumps with roundup concentrate. I suggest getting a drill and drill a small hole in the stump and let the concentrate sit in the hole.

I would forget about the plastic covering. 15 minutes of sunlight on the plastic will likely cook the roses.

Ann's explanation makes sense. Will the reduced MF habitat cause surging mite populations to seek feed elsewhere? As in the cultivated roses? Not trying to be difficult, just trying to understand the subject in depth.

If populations surge in August and Septmeber there is plenty of time to employ a two-pronged approach to mite comtrol among diseased MF. If they get treated right away with a woody-brush killer THEN bushhogged in a week or two, or cut short then treated with poisons, you are going to find your efforts exponentially rewarded...rather than having to do the same thing again next year.

The guy who's doing the bushhogging for me is experienced in pasture management and multiflora control. His suggestion was to mow everything down low, wait 2-3 weeks for things to green up, then hit the area with 2-4-D, which kills broadleafed plants but not grasses. He says doing that plus keeping the fields mowed low and not letting them out of control again should take care of the multiflora in the immediate vicinity.

Sadly, it's also going to take care of the wild blackberry bushes that are the reason I let the fields grow out of control in the first place. The blackberries are in full bloom already making me grieve for what looked like a potential bumper crop. Oh well - guess I'll have to plant my own berry patch.

What I do about the thousands of infected multiflora that aren't on my property is another problem entirely....sigh.

Just finished reading through lkplatow's thread in Antiques...looks like you have competent help in the MF arena and with Ann assisting you along.

Let us know how it goes, okay?

We don't have an in depth understanding of the mites, just a PhD on them and much of that was done on lab work.
They are so danged small that you can't just follow one around.

I think of their brains as a series of if/then statements.
If good food, reproduce.
If not rose/leave for rose substrate.
If predator/ leave.
If wind/float away.
If crowded/ leave.
If land on rose/stay.
If land on not rose/leave.

It's hard to outthink that level of decision making.
I can't give anyone (including myself) guarantees. But I'm limiting my losses, and that's what I set out to do and to share what I learned while trying to do it.