Yes, if you are referring to Rose Mosaic Virus. Certainly in the United Kingdom and Northern Europe (Europe is becoming a very big place!) all commercially grown roses are grafted onto fresh seed-produced understock - predominantly R.coriifolia froebelii 'Laxa' - and the virus is not spread by seed propagation. I understand that because a variety of understocks are used in different climate zones of the US, none of which come readily from seed, understocks are propagated from cuttings which will be infected with the virus if the stock plants are infected.

Regards,
Jon

Henry,
Jon is correct for the cooler parts of Europe. Towards the South, they run into more virus, in that cuttings are used more ( esp. Spain, Italy, and areas close to Mediterranean) R. Indica. Also, R. indica can have crown gall problems.
In the north, seedling understocks have virtually eliminated virus from the industry. R. multiflora and R. laxa (and selections of both) are common in Holland, Germany, UK, Denmark, Polland, etc.

Hello Henry

I agree with Jon and will add to Gary writings that very few smaller nurseries are using indica understocks.

When you get severe virus symptoms more than one virus is found from analysis.
Most virus strains are not obvious and little debilitating if alone. Combined they are very much deletorious.

When grafting with cutting raised undrestock viruses from the root are added to those of the scion. That is the problem. And that is why own root roses are so popular in the US when allmost unknown in Europe.

Friendly Yours
Pierre Rutten
St Raphael
French Riviera

Thank you, Jon, Gary, and Pierre. Pierre, thank you especially for the "When you get severe virus symptoms more than one virus is found from analysis.
Most virus strains are not obvious and little debilitating if alone. Combined they are very much deletorious."

This may help explain why in the U.S. some say that in their garden a virus has had no effect on health while others say just the opposite.

Benoit Moury, Loic Cardin, Jean-Paul Onesto, Thierry Candresse, and Alain Poupet have published in Phytopathology, Volumn 91, pages 84-91,(2001) that 4 percent of cut-flower roses from different Europen sources were infected with Prunus necrotic ringspot virus (PNRSV).
I found the article itself hard to follow as, in addition to 1200 plants (100 origins, each origin represented by 12 plants, the mix consisted of 70 different rose cultivars and four different rootstock species); they also examined 500 additional plants from one collection - Sophia-Antipolis, France, and 100 plants in another collection - southeastern France and Italy. They report that they found 80 plants that were suspected to be virus infected, but I did not find a clear statement of what the ELISA tests of the 80 found. They did say approximately 1 % of the total of the plants in the trial were infected with PNRSV (was that 1 % of 1200, if so that would indicate only 12 plants; or was it 1 % of 1700, in which case it would result in 17 infected plants; or was it 1 % of 1800, in which case one would of found 18 virused plants). It would appear that the first interpretation is the correct one since they then state: "Twenty-three additional isolates were identified in the other collections looked at". Assuming this to be the case, one comes up with 35 total virused plants. 35 virsued out of 1800 does not equal 4 % so you can see where my confusion comes from.

The abstract reads: "Progression of the disease under greenhouse conditions was very slow". Now, the abstract is all that most scientists will read so most authors proof-read it very carefully - in other words I would not expect an error in a abstract. However, in the article the following appears: "Our observations show that the progress of PNRSV infections in roses grown in greenhouses is very slow (or nonexistent), because in our trial only 1 % of the plants were PNRSV infected 2 years after planting (without taking particular cautions for isolation of the plants or disinfection of the tools used for pruning)." Does this mean 1 % of the plants that were not infected at the beginning of the trial; or does this mean that they started with 1 % and ended up with 1 %; or does this mean that they did not know what they started with but ended up with 1 %?
Can anyone clarify this paper?

The authors of the paper would be the best people to provide that information.

Hi, Mr. Field, you got my hopes up to see a reply so quickly.
Although I did pass French for one of my Ph.D. requirements, that was many-many-many years ago. My questions in French may possibly only add to the confusion as could my interpreting any replies made in French. Often, before papers are published, they are presented to local audiences and/or regional groups. I was hoping that someone on the net was familar with the paper. If not, I was planning on writing the authors as you suggest.

I received another article: "Incidence of Rose Viruses in Spain", M. Cambra, J.L. Martinez-Torres, M.J. Benaches, E. Camarasa, and M.T. Gorris, Acta Horticulturae, vol 246,pages 309-312, (1989).
They studied 4,730 rose samples. They found 4.2% of the roses had Prunus necrotic ring spot virus. The breakdown was: 44.0 % of the minatures, 1.1 % of the hybrid teas, and 1.5 % of those budded on Manetti rootstocks. They state: "The high rate of PNRSV contamination in minature varieties seems to be associated to their long existence."
Later in another paragraph they say:"....since this virus is pollen transmitted (in addition to grafting)."

Correction: the statement - "1.5 % of those budded on Manetti rootstocks" is incorrect; it is stated in the table as: "Manetti Rootstocks .......1.5 % ".
They later state: "The rate of contamination in Manetti rootstock is quite low; this is probably due to the usual nursery practice of preventing mother plants from flowering."
Their next statement is: "Manetti plants giving PNRSV positive, might have been graft-contaminated in the most part."
This last part is confusing to me as why would plants grown for understock use have a graft? What is the practice in Spain, are Manetti rootstocks grown from seeds or cuttings?

I am interested in what is the natural spread of rose viruses. In designing any experiment one normally calculates the number of samples required to obtain a result that has a 95% confidence level. I think the results of this type of calculation for rose virus spread are interesting.
If the natural spread in a field is 1% a year and one checked the field at the end of one year, one would have to examine 2377 plants to be able to report the results as having a 95% confidence level (1.0 +/- 0.4)%.
If the natural spread in a field is 4% a year, and one checked the field at the end of one year; one would have to examine 9220 plants to be able to report the results as having a 95% confidence level (4.0 +/- 0.4)%. To be able to report a (4 +/- 1)% spread, the number of plants should be 1475. To be able to report a (4 +/- 2)% spread number, one would need to examine 369 plants. To be able to report a (4 +/- 3)% spread number, one would need to examine 164 plants.
The number of plants required for a quantitative study are probably larger than what most researchers would want to undertake. Another approach is a qualitative study to see if the spread is non zero. If designed correctly, positive results of such a study would have a definite meaning but negative results would not. An example of such a study appears to be the published paper by R. H. Converse and A. B. Bartlett, Plant Disease Reporter, volumn 63, pages 441-444, (1979). They studied 21 wild rose plants from 17 Oregon, U.S.A. locations. 5 plants out of the 20 that were tested by agar-gel diffusion (1 plant was not tested) were found to have tobacco streak virus. The positive testing plants came from 4 of the 17 sites (2 positive out of 2 tested from one site; 1 out of 1 tested from another site; 1 out of 3 from another; and 1 out of 1 from another).
(The wild rose was not identified in the paper, I suspect that it was R. Setigera.)

Here is a link that might be useful: Link to do your own calculations

This is what appears to be (from my literature search) the latest British contribution on virus spread:
Title: Epidemiology of 3 viruses infecting the rose rosa-spp in the UK.
Author: THOMAS B J
Published in: Annals of Applied Biology. volumn 105, pages 213-222 (1985).
Abstract: "Epidemiology of 3 viruses infecting the rose [Rosa spp.] in the UK.Studies on the epidemiology of arabis mosaic (AMV), prunus necrotic ringspot (PNRSV) and strawberry latent ringspot (SLRV) viruses were made in relation to commercial production of standard and bush roses. AMV or SLRV apparently induced either symptomless infection in rose cultivars and Rosa spp., or leaf symptoms ranging from small chlorotic flecks to severe chlorotic mosaic and, occasionally, plant death. Infection of R. canina 'inermis' or R. corymbifera by an isolate of SLRV from R. corymbifera also severely depressed flowering and hip formation. Whereas this isolate could be graft-transmitted to all Rosa spp. tested, isolates from R. rugosa and R. multilfora failed to be graft-transmitted to R. canina 'inermis' or R. corymbifera. No difference was detected in graft-transmission tests of Rosa spp., with several isolates of AMV or PNRSV. In plantings of up to 7 yr none of the viruses was transmitted through pollen to healthy roses grown in nematode-free soil, and only SLRV was readily seed-transmitted, particularly in R. rugosa. In soil containing viruliferous nematodes, AMV and/or SLRV were transmitted to .apprx. 80% of healthy plants. AMV and particularly SLRV were each damaging to field-grown maiden rose bushes cv. Fragrant Cloud. SLRV delayed the onset of flowering, and reduced the number and size of blooms. Diseased bushes were less vigorous, and half or none of the AMV- or SLRV-infected bushes, respectively, conformed to the British Standards Institution specifications for maiden bush roses. These results are discussed in relation to the commercial production of field-grown roses in the UK."

Evidence for Prunus necrotic ringspot virus in rose pollen (Sour Cherry Necrotic Ringspot virus is a synonym).

Title: ROSA SP. - RESERVOIR OF THE SOUR CHERRY NECROTIC RINGSPOT VIRUS

Author: Helena Baumgartnerovd
Author's affiliation: Institute of Experimental Phytopathology and Entomology Slovak Academy of Sciences
900 28 Ivanka pri Dunaji, Czechoslovakia
Abstract: "Within the survey of the health conditions of park and habitation greenery a virus disease of two cultivars Rumba and Cardinal was revealed. Biological and serological tests confirmed the sour cherry necrotic ringspot virus. The virus from diseased leaves and pollen of roses was positively mechanically transmitted on the tested plants: Cucumissativus L., Cucurbita maxima cv. Reisen Melonen Gelber, Chenopodium quinoa Willd., Momordica balsamina L. From serological tests we have obtained a positive reaction using the dropping precipitation reaction and the difuse agar-gel test, as well as the antiserum against the sour cherry necrotic ringspot virus prepared from our own virus isolate and the antiserum obtained from Dr. Fulton."

Here is a link that might be useful: Link for above

Hello Mister Kuska,

According to the fact viruses arises from two factors:
1)-Grafting onto hybrid stocks (thus multiplied by cuttings)
2)-The time one variety is grown in one defined place (i.e. a rare variety wich exist only in one public collection)I think the only thing to do is as follows:
-Have virus-free clones for each variety, by finding them or treating virused one like Dr Manner's method;
-Multiply them own-root or grafted on stocks produced by seeds only;
-Have them grown in at least three different places, if possible on three differents continents (e.g. America, Europe and New-Zealand/Australia/South Africa).
Maybe it would be better to drop hybrids stocks completely and search for native alternative wildroses (This would of course be somewhat difficult in the southern hemisphere, but it seems R.Multiflora does well in Australia)and promote own-root multiplication wherever possible.
See you,
Pete.

ISHS Acta Horticulturae 94: XI International Symposium on Fruit Tree Virus Diseases
FRUIT TREE VIRUS INFECTIONS OF WOODY EXOTIC AND INDIGENOUS PLANTS IN BRITAIN
Author: J.B. SWEET
Abstract: "In a study of woody ornamental and indigenous plants in Britain apple chlorotic leafspot virus (CLSV) was detected in 9 genera of Rosaceae, spy epinasty and decline and stem pitting viruses in 3 genera, prunus necrotic ringspot (PNRSV) and sooty ringspot viruses in 2 genera and prune dwarf (PDV) and pear vein yellows viruses in single genera. Apple mosaic virus (ApMV) was detected in four plant genera including the Hippocastanaceae and Corylaceae.
In a nationwide survey CLSV was detected in 25% of hedgerow hawthorns (Crataequs spp.) and in 5% of hedgerow blackthorn (Prunus spinosa L.). PNRSV and PDV were also detected in 4Â5% of hedgerow blackthorn. No aphid or seed transmission of CLSV was detected in hawthorn.

PDV was detected in 25% of P. avium seedlings and PNRSV, but not ApMV, was detected in roses, their pollen and in 1% of rose seedlings. No seed or pollen transmission of ApMV was detected in Aesculus species.

Pome fruit viruses significantly reduced the vigour of some Sorbus species and PNRSV and PDV reduced the bud takes of respectively Rosa and P. serrulata cultivars."

Here is a link that might be useful: link for above

I read in old Czech rose book from experienced Czech nurseryman only a short information that America's roses are prone to viruses. The different conditions play surely the main role as time-proven European rootstocks don't fit to America's conditions very well, according to some reports at least. Jana