Mark Windham is a friend; unfortunately the group studying RRD through the USDA didn't get their funding last year so research ground to a halt. If there's no money, nothing much gets done. The info that the disease is a virus came from that group as did PCR tests and mostly info about new cultivars and how commercial mass plantings can be handled.
Nebraska was the first state were RRD was described. Glenn Viehmeyer had several acres of rose bushes over in North Platte UP on the planes in the High Plains research area. He thought the disease in his beds came down from Canada from Morden . (I have his letters about this.)
Then Viehmeyer found thousands of RRD infected plants of R. multiflora that had been planted for erosion control to the south of the Platte River. He also found it on wild roses up on the Dismal river north of North Platte. It's no longer on the dismal; I looked and found only healthy wild roses there.
1. How soon do roses show signs of RRD in new spring growth from the ground?Pretty much instantaneously. We've seen it on climbers, minis, HTs, gallicas, and some FLs where canes were cut back the previous year.
2. Should I start a miticide program now - if so what product do you recommend? How soon and how often should I spray as new foliage emerges all over the place? (I never spray but I'm willing in this extreme case)
In your part of the world A recent PhD paper showed that the vector mites aren't that common in spring and seem to have a major population surge in early fall. (Do your maple trees or poison ivy have the blister mites show up in fall? the blister mites are also acarid mites and they seem to like new growth as the days get a little bit cooler.) Hort oil soaking the plants may help: the mites don't have the kind of respiratory system we think of as breathing; they respire through their 'skin'.
3. How long should I maintain the red alert watch for RRD?
We don't get to relax.
I'm presuming at least all this season, but what about next spring? What is the outer limit of the incubation period? Something to watch for that isn't in the literature is winter. This is wierd, but for some reason, some plants with RRD will send up normal canes, but with very small tender leaves in the middle of winter, not a whole bush just a cane or two, and then cold will kill it-leaving a solid black cane.
There's incubation from mites, but I think there's also a root to root transmission we need to watch for. And that's not tied to seasonal growth although a Nebraska winter may slow it down.
4. If I identify roses that I'm sure are affected, are there measures i should take beyond digging them out and moving to miticide in the rest of the roses? Watch their neighbors for odd symptoms, including a place where there might have been cane to cane abrasion and spread that way. The paid scientists have not seen this; I lost a great David Austin Climber when I thought I'd caught RRD in time way out on a huge cane of James Galway only to see more a month later on a cane that had been rubbed by the sick part of the sick cane.
Watch for Powdery Mildew out of season.
5. I couldn't resist ordering from Palatine even if I end up losing them, so what should I do to keep them safe as possible? Potting roses doesn't seem to be a solution if there's the risk of RRD everywhere. Should I spray them with something now to avoid them getting infected? Preventative miticide doesn't seem like it would be appropriate.
Work on air flow in you garden. The mites are microscopic and drop out of air flow where the wind drops....when it comes over a fence, comes over trees, hits the side of a building.
I learned the hard way that conditions in a garden change and as trees mature, if they get too densely leafed out, the mites that used to the transported past a garden, their descendents (from up wind) will be dropped where their ancestors weren't.
6. What's the link to your written information on RRD so that I can read up on this condition more thoroughly? I don't want you to have to explain things you've already written up elsewhere.
http://www.rosegeeks.com
7. Are you open to helping me check pictures of growth this spring if I'm not sure? If so, what's the least invasive way to ask you for input.
Send me pictures, I finally have decent internet (ahem, no more limited Hughes net). If I don't know the rose, maybe someone else here grows it and will know its quirks.
8. Anything else I should be doing that isn't covered above? It's going to be a brutal spring and summer, but I'm willing to do what it takes.
This is important : you can save some roses with a shovel. A friend to a chain saw to the foot of one of her climbers because one side of the roots were coming up sick and the other side wasn't. Eight years later, the healthy side remains healthy and has filled in what ws missing.
If you see RRD out on a cane, it moves by phloem transport downwards. You CAN take cuttings out from that spot and have a good chance of them producing a healthy rose. I did bring back a huge cane of multiflora from Virgina, it had RRD at one leaf axil, Seven days later, RRD emerged at the next leaf axil down, on the same side of the cane. Tendays later, another RRD eruption, same side . I then decided I was getting depressed watching it die in my kitchen, so I burned it.
I have trouble with Hybrid Teas and seeing their symptoms earliest. I think it's because they are bred to grow up more than out.
Three adjectives: aberrant, excessive and unexpected. And more than two symptoms.
Now for more questions.
Ann abpeck @att.net
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rose fertilizing
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