RMV in some roses from this year

Just a small warning to watch out for RMV in new roses bought this year. I had to throw out all my Lilac Rose (DA) and Mabella at work today because they had very obvious classic symptoms. I didnt want to risk passing it on. Thanks goodness the boss agreed with me when I explained (he's pretty good).

Thanks to Simon for the post about RMV not long ago. I hadnt known much about it before then and most probably had it in our roses for sale in past years.

Oh that's rotten luck Ripley. I've got a Lilac Rose too, she's in a pot so if rust appears I can move her far away.

Well the blackspot Capital of the World is living up to its name here, even though I sprayed early
The aphids are blossoming too.

Rip. I hope you contacted the suppliers and told them and received credit for these roses. It will keep on happening if people don't say anything about it. It will only stop if the propagators know it will ultimately hit their hip pocket. Then maybe they will be more careful about the source of their propagating material and in turn we will benefit from uniformly higher quality plants. There is no excuse for it these days. You can use seedlings as virus free understocks and you can subject infected plants to thermal therapy to kill the virus of in chronically infected varieties (like 'Peace' is a classic example). I still have infected plants here but only because I am setting up a thermal therapy chamber to kill it off.

The boss said he would tell the suppliers but wouldnt worry about getting a credit/refund as it was only a couple (7) of roses. Cant really argue with him, hes the boss. I still dont really understand how a large well known rose company can have this in their stock and not know/do anything about it. Are all Peace infected Simon?

Well... some would say it is... it can take a while to show up too... so far my three year old plant has shown no signs of it so personally I would say no, not all plants are infected but it would be getting pretty close unfortunately.

As far as knowing about it and not doing anything about it... there can be lots of reasons. It shows up differently on different varieties... some can show very little in the way of symptoms whilst others can almost look variegated. Some varieties are chronically infected. Contrary to what some might say it is not epidemic in old roses because RMV was virtually unknown prior to the 1920s (until some bright spark tried grafting a prunus species onto a rose - RMV's real name is Prunus Nectrotic Ringspot Virus) ... about the time people started using 'Dr Huey' as an understock. It is wide spread, however, in roses grafted after this time. Own root old (pre 1920s) roses are unlikely to have it (another good reason to try and produce own root roses... RMV would NEVER have been a problem if we didn't have such a reliance on grafting roses to develop so may weak garden plants for the sake of a few nice blooms.. this is my inspiration to hybridise... to make weak garden roses a thing of the past). There is also a wide spread accepatnce of the disease in roses because it doesn't kill the rose. It weakens it and reduces flowering capacity but generally doesn't kill it. So people live with it. My way of thinking is that there is so many awful roses out there that consistently under-perform... what if the reason they under-performed was because they were chronically infected with RMV and imagine how well they might do if cleansed of the virus... at least we might be able to evaluate them more fairly!

The other reason it is generally accepted is that it can't (easily) be passed on from plant to plant by any other means except grafting. There is no documented case of it being passed on via pruning tools or insects such as aphids and there is no documented case of it being passed on via pollen (nor has it been shown to be present in ovules (aka unfertilised eggs) that develop into seeds - this is why one can assume seedlings are free of THIS virus.. of course there are other viruses that roses might have that ARE transmitted via pollen and seed.

There has been only one documented case of RMV being transmitted from one rose to another. These roses were planted close together and their roots grew into each other and where they came into contact they root-grafted allowing the virus to infect the neighbouring plant. This was proven to be the the route of transmission by putting glyphosphate onto one plant resulting in the death of both.

At other times people are ignorant of the disease. In Australia the disease can often be difficult to see. The virus is temperature sensistive and is killed off, or its population severely depleted, in hot weather. This reduces the symptoms in parts above the ground but the virus continues to live in the roots where it is cooler. That's why roses shipped to Tas so often show the symptoms up straight away... because we have milder weather. In some cases one might think.. well this is a rare rose, or a heritage rose, so virus or not we will offer it because we don't want it to disappear.

So there are many reasons. Personally, I believe every grower should send samples of their stock (understock and budwood) to be tested and if positive they should undertake remediation in the form of thermal therapy. It has been shown that prolonged and sustained exposure to an ambient termperature of 38 degrees Celicus for a period of 28 days will kill the virus in the above ground portions of the plant. I have had a discussion with Dr Malcolm M. Manners, of Florida Southern College, who routinely cleanses roses of RMV and it is quite ingenious the technique that he has developed. First they will allow an infected plant to dry out and show visible signs of stress. When plants are stressed all their metabolic processes slow down in an attempt to preserve what resources they have left. This helps them survive the high temperatures (though there is still a lot of die-back). The plant is placed in a thermostatically controlled chamber that is kept at 38 degrees Celcius for 28 days. The chamber has lights in it and a water dripper is fed into each pot. After 38 days the dead-portions are removed and the most terminal buds are removed and grafted onto virus free seedlings or previously cleaned rootstocks. When (if) they take, leaves are sent away for testing and if virus is found the process is repeated and if it isn't it is considered clean. The original plant is discarded as the virus will still be present in the root system. At Florida Southern Collgege, Dr. Malcolm M. Manners cleanses many varieties that are then released back into the nursey trade. Getting them tested is cheap. Here in Tassie there is a lab I've contacted to do this and they charge about $80 per test. So... given that a thermal chamber is easy to build and further testing is cheap... I don't understand why more people aren't getting onto it to get rid of it... I think it really comes down to apathy or in some cases ignorance... ok... that's my soap box time over... I'll be quiet now

haha dont be silly Simon, its a real problem like you say. If enough people know more about the problem and start complaining then maybe the propagators to be willing to try a bit harder to get rid of it, seeing as tho its so easy to do.

Thanks for telling us about this Simon, as I have been reading some about it lately.

I have a Peace that is not infected.

Me too... and it's still a dud

Mine is not all that bad, blooms slightly more than Papa Meilland.
Perhaps a cross with Elina as it's still being used as a breeder.
That may be where those bad unhealthy HT's are coming from.

To all those that have been alerted to RMV.

Make sure you fertilise, check PH and manure your rose before giving it the chop for it may be suffering from a nutrition problem and not RMV.

That's the problem with this virus as it comes in two forms and is sometimes difficult to diagnose 100% in some cases.

I have a New Dawn that has never had it in the past 20 years, An own root
taken from it 4 years ago showed signs of it this month but I would bet it's not RMV

I'd agree with this Bruce... and would add that there appears to be more than two different viruses that cause RMV symptoms and that the symptoms yous see can be different depending on what virus is present or what combination of viruses are present. I have a Cherokee Rose at the moment that is showing symptoms different to that I've ever seen before. It looks like little round targets of yellow that vary in size from 1-2mm up to 6-7mm in diametre. It gives a most unusual marbling effect. This is why I started the RMV image folder in the gallery because so that people can see that there are many different expressions of the disease... I'll have to photograph this laevigata form and add it to the collection

Are we over reacting, as Bruce has said, "could' it be a deficiency. I am skeptical to a point, who found it and where is it written in plain English, not paper from a funded grant to keep a Dr or PHd student on payments, this is only my thought. I only seem to see things out of the USA, no other sitings, why not Germany or Great Britain

What are you skeptical about David? How wide spread it is? Come for a walk around my roses and I'll show you just how prevalent it is. There are deficiency symptoms that make things difficult however there are also fairly recogniseable symtoms of classical RMV too... it's up to us to become familiar with them and then make a fuss about it.

Deficiency versus RMV, as I said to Wedge on a different matter, pictures that have been recorded of both could be misconstrued as either one, Yes I am sceptical, but open minded to. Simon who is the leader in the field on RMV and how do I find papers written by him, I am not saying it does not occur.

Back shortly, have to feed Benny the goat.

I tried ringing Mistydowns once before Christmas but they weren't there. But I will ring in the new year.
As the roses I want this year comming are probably not available at any other mail order rose nursery, I have to hope these roses are clean of virus or that most of them are. I would rather have the virused rose here than not have the rose at all. Hopefully the virus doesn't have much effect here over the years seeing we are a warmer climate. Can a rose fight this virus and eventually have a immunity to it ? Or the roses that survive it are the naturally selected ones to go on with.
I would pay more for a rose that had been cleared of Mosiac Virus. It must be hard for the growers as they must test all their rose varieties to be sure, heat treat the ones that have it and then re test, plus keep their rootstocks clean. As well as all the rest that goes along with propagating and selling roses.

Nope - once it has it... it has it for good. There are resistant varieties... but none that are immune. I would also argue that we shouldn't be trying to breed resistant ones. We should be trying to erradicate it instead.

I do not know how to to take part of what someone has written so this is from Karen's post at 10.30 today.

Can a rose fight this virus and eventually have a immunity to it ? Or the roses that survive it are the naturally selected ones to go on with.

After reading a link that Simon, posted on "Inheritance" do not quote, cause I again do not know how to find it at present. The paper or talk was by a fellow named Vanderplank, I think he has gone further than "Mendel" has, although he uses words that are not in common use to the general public (my words), makes good scientific papers, Mendel used new words for the first time and people did not understand and I think Mr Vanderplank has to, I assume we will get used to them as we do over time.

The short of this is, if I have not read his article wrong, he is thinking along what Karen has said, as I read it, breed with it to, at the end breed it out, again only my thinking on this.

Update on Bruce's Peace. I checked a 4 year old budded 'Peace ' plant taken from the original plant and it is showing some sign on the old leaves where RMV usually appears first. The rootstock has never had RMV or been budded before, I am sure it's in the Sion ( Peace Plant)

So the search goes on to find one not infected, possibly the one at Gulgong or Woodstock. A very knowledgable rose grower once told me that they were all infected and I am inclined to agree.
Simon may be the first if he gets the thermal cabinet up and running. His plant is supposed to be a dud so I suspect RMV because there are two we know of that are very worthwhile.

RMV is just so hard to diagnose for some plants don't show it until stressed. I can understand plants being sold thinking they are healthy so don't be too hard on the nursery. I only budd 200 a year so can keep an eye out for the problem but wonder how these large nurseries check for this problem. I think the only way to judge is if they sound concerned when it's reported then I consider them a tryer to sell quality plants. However if they give an indifferent reply and do nothing then I wouldn't buy plants from them again.

Hi Bruce, I will look at the Peace bush tomorrow, have a close look at the leaves.

I'd love to help.. but my 'Peace' doesn't have any leaves to check

When looking at "Peace" do not forget it is born with "BLACK SPOT", IMO

Late this afternoon I was dead heading my Summer Fairytale Weeper ( aroud 5 years old and I found Mosiac Virus on its leaves. Its pretty sad to have this on your weeper when you have paid $65 or $75 for one. My weepers were from T***** . I have seen the virus on my Fairy weeper in the past too. I will take some photos of it tomorrow.
Bruce, this might have been one of the ones you were talking about in the budwood I brought or sent you.
Simon, where are the Mosiac photos you have here ? I can't find them.

I was thinking, there is no excuse for any new release rose from any rose supplier to have Mosiac virus. The parent rose is born without the virus, all that has to be done is to bud onto clean rootstock. Simon, have you had any new release rose with Mosiac virus yet ?

I am going to email T***** about my weepers having Mosiac Virus and ask what they are doing about it these days. I will check the other weepers tomorrow before I do.

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