I am so sorry for your massive loss already this year.
You are seeing and confirming a lot of the things we've seen here.
Where wind hits a wall, and the mites drop out, it's a rough place to be trying to grow roses.
"Since the mite most likely moves and infects during hot dry months like July and August, wouldn't any of the RRD I saw this year in May and early June be a result of infection from last year?"
The scientific papers that reported on mite populations reported massive populations in Iowa in September. And that is probably still true there. But I think that our spring heat wave which you often share gives an earlier season spike in the mite populations. I think that when the reservoir plants (R. multiflora with RRD and mites) start to feel a pinch in terms of how much water they have, then their mite population disperses. My 2% of my rose garden loss occurred after a ground baking heat wave.

I think if your roses had gotten sick last fall, you would have seen the symptoms on growth much earlier this spring, as in March and April. (That's what happened to local gardens here.) I really don't think you missed symptoms; you're already to the place where you are looking past the blooms to what the plant is supposed to be.

One friend has saved a climber that had RRD go into the roots, but only to one side of the roots; her husband took a chainsaw to the roots and isolated one side from the other, and dug out the bad side.
We've got a sort of save going on right now. Seven Sisters had its second strike (and we only allow one strike now) and DH dug it out last year. Some wide ranging roots were left behind. The first come-back root came back with RRD. So we dug it out. Then six weeks later, some more growth came up and (knock on rose-wood) it's healthy. Then about two feet away , more healthy stems came out of the ground. I know these aren't seedlings. Seven Sisters has a really distinctive leaf when compared to the ten or so other roses on its fenceline. It going to take a while for the new stems to replace the old, but so far, they look good.

When you prune, prune to encourage airflow.
Are you spraying miticides for spider mites?
Can you interplant with some low growing mints?

*** We don't have RRD in this area. Yet.
But I'd like to learn more, anyhow.

Ann Said:
Are you spraying miticides for spider mites?

*** Do miticides help to control RRD?

Can you interplant with some low growing mints?

*** What does Mint do?
And, Ann -- Can RRD be spread by insect vectors or hummingbirds, as happens with the fuchsia gall mite?

Jeri

Cygon 2E is the only miticide I know that kills the particular kind of mite that spreads Rose Rosette Disease (RRD). It is very helpful at keeping the mite population down. I hate spraying such a toxic substance but what else can I do? Once RRD shows you've got to act quickly.

Of course, I haven't followed my own advice. Right now I'm closely watching a VINEYARD SONG for RRD. It sent up five witches brooms earlier this year. The leaves at the bottom looked normal so I let them develop and all but one have matured into normal looking canes. I've seen this happen before. It can be really easy to mistake new growth for the disease. However, one cane didn't "straighten out". Instead it suddenly started growing down and then turned black and died. Otherwise the plant itself looks healthy. In fact it is one of my more lush looking low growers. I'm worried but still hopeful.

About miticides: Cygon 2E is no longer available and it was field proven to kill the mites that spread RRD. Cygon was systemic. Avid is the only miticide approved for use on Eriophyid mites which include the mite that's proven to spread RRD. But we don't know if avid will kill that species/specific mite. The Allington, Staples and Viehmeyer paper and corespondence the gentlemen left behind reported that spider mites destroyed their test populations of P. fructiphylus, and the only way they could study fructiphylus was to maintain spider mite free growing areas.
Samsthumb has just taken a real hit, and it came as a surprise. That's a lot of roses and it makes me wonder why. Now on a tangent, I have some spider mites in my roses and with time, the predaceous mites and predaceous thrip populations in my roses build up and the spider mite population declines. BUT if I were to spray to control the spider mites directly, I'd be taking away the slow but steady buildup of predators (That Jim Amrine has seen attacking Phyllocoptes fructiphilus, the RRD vector mite). So, I'm wondering if Samsthumb can do more to put predators in her garden. And the mint question is related as there are articles about the predators of pests in the size range of interest being very happy in established mint patches.

Can birds spread the mites? It's unproven. But an OGR garden near Fort Worth was destroyed by RRD, and the owner told me he really suspected the birds helped the mites along as the big roses that were excellent bird habitat were the sickest in his garden. Other insect vectors? Again possible because the mites can land almost anywhere and may hitch rides. Hummingbirds don't land where the mites are (leaf axils, the protected spots) and I wonder if hummingbird wings would blow a mite away?

A recent PhD at Iowa State also documented other insects and mites that are resident on multiflora with RRD. But they haven't looked at the other 'bugs' as vectors. The first scientific paper (Allington, Staples and Viehmeyer) looked at spider mites as vectors and reported that they didnot vector RRD.

And no hope of any development of a biological control that feeds on the mites, I suppose.

That's why we don't panic over spider mites. Between water and beneficials, they only show up as spot infestations.
I asked about the hummers because as you know, we grow a few fuchsias, and hummers DO vector fuchsia gall mites. (Of course, so would my hands, if I am not careful.)
But as long as I grow resistant varieties, and keep an eye out for outbreaks, we manage with those OK.

Jeri

Ann, I don't spray any insecticide unless it's Cygon on RRD roses. I have found if I spray much I end up with aphids galore and thrips. I have lots of praying mantis, but what would the predator of these microscopic mites be? I don't really have a problem with spider mites again because I don't upset the balance in my garden by blanket spraying insecticide. I don't have a personal problem with sprays but again I have screwed up my garden balance a couple of years and learned my lesson. I will try to plant some mints around my roses and see if that helps. Have you seen that ownroot have more of a problem that grafted, that is when you cut back the witches' brooms do you find a difference in recovery? All of mine that have recovered from RRD were grafted. It is sad to note that Cygon is no longer available, that's another strike against roses in my area.

"Have you seen that ownroot have more of a problem that grafted, that is when you cut back the witches' brooms do you find a difference in recovery?"

My successes in cutting off single sick canes happened in fall. One was an own root Rouletti, another was Charles Austin on multiflora rootstock (it's pix is in the book).
I think the fall heat that had high evapotranspiration rates (more moisture going out from the roots than returning each evening) may have been the saving grace.
Dang, I guess I could count Seven Sister coming back from errant roots, but that is NOT many roses to have saved in seven years. Dang. Dang. And I really think I see the problem early.
One more: American Pillar late last spring, RRD way out on one big massive cane. So that's a spring save.

When I've seen the disease in early spring, as the roses are leafing out for the first time, it was coming out from established canes fairly close to the roots in patterns that said the roses got sick in fall, and it got into the canes and roots. Those are often HTs and some of my big Teas and Noisettes.

Whenever I see witches brooms or other symptoms, I immediately cut the cane back as low as I possibly can.

I have had two isolated canes develop this year with the narrow leaves -- resembles a marijuana leaf. I cut both off, and so far the rose bushes look fine.

I waited too long to react last year, and dug up around 16 - 18 rose bushes.

I replanted in the effected area, and rabbits decimated many of the new plants, and many of those I lost.

I have some very nice looking rose bushes that are established without problems and which were not infected, next to a bed of lame looking rose bushes that were planted this year and were eaten by rodents.

This RRD is a very serious potential problem if it is not recognized early. I should have responded earlier, but didn't know what it was.

I feel your pain. I lost quite a few a 2-3 years ago with RRD. I really feel that dry weather has a lot to do with RRD or at least its fast spread in my garden. It was during a dry fall when we had a lot of wind and no rain. I think the wind spread it but had there been water with it, to deter them or wash them away once they arrived. It was the last year one could buy Cygon that I had that large outbreak. Maybe I just bought up all the Cygon. :)