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Simon, is that the same mosiac virus that infects vegies ?? I have a very good friend who used to grow top quality Zucchinis up here and he used to occassionally get mosiac virus. It affected the fruit so he used to pull the plant out immediately he saw it so it wouldn't infect the others. When i used to help him pick his crop, he didn't even like anyone smoking as he explained that there's even viruses that you can get from the tobacco that can infect the zucchinis.

From memory, Dave, that's the Tobacco Mosaic Virus. The one that is infecting roses is actually a range of different viruses but the one that is most prevalent is called the Prunus Nectrotic Ringspot Virus (PNRSV)... we usually lump them all together just as RMV because the average Joe can't tell the difference without laboratory testing (which only costs about $80 per test so IMO is totally worth it for commercial growers). The only way to pass RMV onto a rose is by grafting an infected scion onto a clean rootstock or the other way around. There is a recorded case of transmission by root grafting caused by plants being planted too closely together so their roots could overlap and graft together. It cannot be passed on by cutting/pruning implements, dirty pots, pollen, seeds, aphids, or any other means... such are the myths surrounding RMV. It is thermally sensitive so in periods of very warm weather the virus is mostly killed off in the above ground portions and persists in the roots. Symptoms are usually hard ot find at this time. During periods of cool weather symptoms can reappear... stress doesn't really have anything to do with symptoms appearing though may affect how effectively a plant is able to resist the infection. I've been talking a fair bit with Prof. Malcolm Manners in Florida about this particular virus to understand it better... he's probably the foremost authority on RMV in the world and is curing roses infected with RMV using a technique called Thermal Therapy (which to cut a long story short is basically 38 degrees celcius for 28 days followed by budding onto clean rootstocks)... this is why I have been talking with him as I think something like this should be done here in Australia to try and erradicate the virus... The above transmission method only applies to PNRSV and unfortunately there are other viruses present in roses that cause RMV-like symptoms that CAN be passed on by pollen and seeds etc Dr David Zlesak in the U.S. is working with others at the moment to characterise these other viruses as well so they too can be better understood. It seems that the thermal therapy, however, is effective in treating a large range of them.

Re the posting of Roses,
My mother had a large Rose garden in the 60's and 70's and often ordered stock from Roy Rumsey in Dural. We lived in Maitland,Nsw, and she was often exasperated as the order sometimes went vis Maitland ,South aust,before arriving in a rather dead state at our place.An order once went via maitland,sa,then maitland WA.It was really deceased!
I suspect things have improved.

This is all very interesting reading.
I was thinking I might sell budwood latter on when my bushes are bigger
( if they survive this winter ) and I would sell small quantities. But then I would have to work out which ones of my bushes had mosiac virus. The other day I saw that watermark on one of my new Thomas roses, a older Hybred Tea I think it was. I will have to start listing them when I see the affected leaves on them.
I also have it on a weeper I got from Treloars about about four years or more ago.
Simon, do you know if it is possible to have roses tested ? And would it be too expensive for backyard growers ? Also is there a a big rose grower that has Mosiac free roses ?
I might ring Judy at Mistydowns and ask her what they are doing to avoid Mosiac Virus, as they have thje type of roses I want.
Breeding our our roses might be a way to adviod Mosiac virus.

Another question. How come the virus can spread so easily through plant tissue, and yet it doesn't get past on through rose seeds ?

Karen... I have ordered roses from lots of the bigger growers and received virus infected stock from all of them.. I would not say one was any better than the other. There are labs that can test for it at about $80 per test (when I enquired down here in 2008). You can test your own if you have 'Ophelia' or 'MME Butterfly' so I've recently found out. These varieties are used because they are particularly susceptible to RMV and show the symptoms very early and very clearly. You make cuttings of either of these two and bud onto them and wait and see. It's not conclusive evidence but it's pretty accurate (but time consuming). The only documented mode of transmission is by grafting (either onto infected stocks, using infected scions, or by root grafting caused by plants being too close together). The virus spreads through the tissue easy enough and it has been found in pollen (but not seeds as far as I know) but even when infected pollen is used there seems to be some kind of barrier preventing the transmission of the virus because no one has been able to infect an uninfected plant with RMV with infected pollen. This is all from reading the literature and from discussions I've had with Prof. Malcolm manner at Florida Southern College. There are a lot of myths floating around and a lot of bad science being spouted by some on the net but the facts are a little less fantastic. There also seems to be a barrier against the virus in the development of seeds. Malcolm told me just the other day actually, when I asked him whether pollen could be tested, that even if we did find virus in the pollen it did not prove that it was contagious via the pollen because no one has been able to infect an uninfected plant with infected pollen. What you need to understand is that RMV is a group of different viruses (that can sometimes work together even making things worse), and all of them come from other groups of plants. For instance, the most prevalent virus in Australian roses is thought to be Prunus Necrotic Ringspot Virus (PNRSV). This originated in prunus as the names suggests and it is tranmistted via pollen and seeds in prunus. In roses, however, it has not been successful in doing so. That's not to say it never will because viruses mutate and evolve too. There are also other viruses that CAN be passed on via the pollen and seeds... for example we cannot export roses into the U.S. becuase their Dept of Ag. have determined that a virus called rose wilt virus is here and that it is contagious via pollen and seeds etc. I only leant of this yesterday actually when Malcolm said so in his email. So.. the virus thing is much bigger than mpot people realise... I would love to set up a thermal therapy facility here to cure Australian roses too... but that would require big $$$.

Simon, can you please take some pictures of the steps involved, whlie you do the budding.

I'll do this for the T-budding I do... won't be doing any chip budding attempts until about March, according to Bruce, when my understocks will be ready...

The new Marechal Niel at Ruston's, in the Tea-Noisette-China Collection, (from Thomases' ) turned out to be Duchesse d'Auerstadt. There is one in the main garden but like many MN's, it's not strong. What we hope is a robust clone of Marechal Niel has been planted recently, but it won't be big enough for budwood for a couple of years.

Margaret

I thought my MN was growing to strong. I have had a couple that did nothing and passed away. The "one" I got from Thomas's last year is going great guns.

But is it no great loss as I like the Duchesse anyway and surprisingly the one that I had is very slow growing compared to the "one" we got from Thomas's. They are in different spots oin the garden though.

Gary

Re Noisettes,
Margaret i have just planted 2 duchesse d'auerstadt plants obtained from Ladybird roses as very young plants,they are taking off so will let you know what happens.I have some others which are all vigorous,the one that impresses me most so far is Reve d'or,it is already catching up to others planted 6 months earlier and is constantly producing large blooms.
regards,Stephen

stephen

If I rmeber correctly the duchesse and MN are bothe sports of Rev d'or.

Our Rev d'ors are also fast growing. Ours bloom in flushes (as do out teas so it probably something to do with the weather up here) and get covered in flowers.

I have struck a couple of Rev d'ors and they are growing faster than the original budded ones that we have had for many years..

Gary,
My readings suggest Reve D'or was quite a parent and is still being used by Mr
Viraraghavan from India who crosses it with R.Gigantea.
Reve d'or sported Duchesse,parented William Allen Richardson,Pauls Scarlet climber,and Aglaia,an important ancestor of the Hybrid Musk group.
It is one rose that when I have the expertise and time I would be interested to breed from.
Stephen

Yes it is a wonderful rose

Rev d'Or



Duchesse d Auerstadt



William Alan Richardson