Last Sunday I was at the special event of the Potomac Rose Society and the U.S. National Arboretum, called: Rose Rosette Disease: an update. It was a discussion by Dr. Mark Windham of his ongoing research conducted on Rose Rosette Disease (RRD) that he started in 2012. He was selected by the American Rose Society to lead a three-year study of RRD and how to manage and prevent the spreading of the disease by commercial growers as well as by rose lovers.
I have been introduced to RRD, and shown a plant with the disease, but for some reason I did not take it too seriously; it was bad, but controllable I thought. Needles to say, I was shocked with the information from Dr. Windham. If I am not mistaken, someone has lost 4000 rose plants. Now that was a lot of plants----so, what can we do?
We need to know how to recognize the symptoms. Be familiar how the RRD looks like.
You can easily find lots of images if you search online under 'rose rosetta virus'. However, the symptoms do not appear early on. We need a very strong magnifying glass or a microscope to recognize the virus. They are invisible without them. They look like a tiny yellow or brown banana with whiskers on one end. The virus cannot fly, but they travel with the wind. There is no rose yet that is immune to RRD. Another problem is that the symptoms are not always the same, and the symptoms do not appear quickly. And it just needs one tiny virus to take a bite of our rose bush to inject the virus into it, So if we are vigilant, when we find a suspicious growth on one branch, we could cut out the branch, and hope for the best, but if the plant is close to other plants, there is a big chance the others are infected also, but still no visible symptoms.
Dr. Windham thinks it is best to get rid of the diseased plant ASAP, carefully dig the plant out completely, not leaving any roots--it may grow back, already infected-- and put the whole plant in a black plastic bag, tie the plastic closed and put the bag in the sun, so the virus will die and then dispose the bag with the dead rose plant.
RRD is not new, but it has spread quickly when mass planting of roses become popular, around the time when Knockout roses became available. The roses are planted close together and it makes the spread easier. The virus seems to like multiflora, and it kills them, So the roses grafted on R. multiflora are considered more susceptible to RRD but no rose is immune.
Best thing that we can do at this time is learning to recognize the symptoms and there are lots of excellent articles about them with images. I just read
http://www.clemson.edu/extensi...
and
http://pubs.ext.vt.edu/content...
and I have learned a lot from them. There are many more that I have not read yet. I do not have my own photographs of an RRD afflicted rose bush, and I do not want to 'borrow' and post something copyrighted. But please familiarized yourself with how RRD afflicted rose bushes look like and help control the spreading of RRD.
Dr. Windham told us what he does when he has acquire new rose plants.
He plants them in containers and place them in a separate area, far from his other roses. After a year or two, if the roses are still healthy and he likes them, then he gives them their permanent places with the other roses.
