What diseases are passed on

Do we know for sure what diseases are and are not passed on thru pollen and seed? Gall? Rose Mosaic Virus? Stem rot? Etc?

I know Rose Mosaic Virus can be transmitted by seed. Not sure on pollen. But there is a scientific paper some where that shows a small percentage of transmitance.

Rose Gall is actually caused by an insect. So the answer on that one is no.

About a yr ago +, I purchased ‘Walking in Sunshine’ and after it leafed out noticed it had mosaic. It was otherwise healthy, with bright yellow blooms, and I used it for both seed and pollen. I will have to check, but I believe I have at least 3-4 seedling offspring that have mosaic, from those crosses. The seedlings have been incredibly vigorous, spotless, and even in almost full shade are mildew free.

[attachment 461 2012newseedlings171.jpg] This shot that I embedded in another thread has a Walk in Sunshine seedling in the center-showing how healthy (typical of these seedlings) they are. I have noticed that the ones showing mosaic are not as vigorous, but they are otherwise disease free. I will get a photo to post of the several seedlings showing the mosaic, but there isn’t much doubt that this was passed on by the parent, which I did not realize happened. I am almost positive that downey mildew can also be passed on, but since those seedlings die pretty fast, it is hard to present hard evidence.

This year I have a few seedlings with an apparently virused Prairie Sunshine as the seed parent. I noticed that many of the cotyledons were a little wrinkled, which looked like a virus symptom. The first emerging leaves have not yet shown any symptoms. I’m going to keep them…who knows, if there is something really nice perhaps it could be sent to UC Davis to get cleaned up.

I have just noticed that my Carefree Beauty has PM, interesting?

I don’t believe that there is a significant risk of PNRSV (or other) virus being transmitted through seeds. I believe the risk of spread via pollen is even smaller; near zero. I highly doubt fungal or bacterial diseases are transmitted through either pollen or seed, but I suppose its possible. I would have to be shown proof before I took it seriously as a threat, honestly.

It seems far more logical to me that any bacterial or fungal “transmission” would come from seed coat contamination, your hands or other implements or the soil/climate. The “seed” are sealed. Unless there is a breech of seed coat integrity, no bacteria or fungi should be able to get inside until germination.

My Carefree Beauty has always been susceptible to PM, and generously passes along that trait. For these reasons I use it very sparingly for hybridizing. But it gets nothing else, and is a blooming machine, so what is a little mildew that is sure to pass without any major complication?

Hopefully, the mildew season is as fleeting as it can be here. If once they develop into a decent plant, they continue mildewing, I get rid of them.

Howdy Kim;

What you have to imagine , that a plants sap flow is similar to our own circulatory system, its brings all types of goodies to nourish and stimulate growth within our bodies. Pollen , undeveloped embryo’s and fertilized embryos would need this nutrient to develop and anything in the sap flow would probably be also introduced. Not sue about fungus, rust or bacteria, but virus’s I would not exclude, I never use a virus infected plant as a seed parent or pollinator.

My seedlings if touched slightly by PM , I normally see if they grow out of it, if not they go. Those seedlings where leaves and stems are coated white , do not last very long.

I understand what you’re saying Warren.

I’m curious about gall transmission. I was not aware it was caused by an insect - I thought it was bacterial and transmitted thru contaminated soil. But since the bacterium actually changes the DNA of the host plant, is it not possible that it could be transmitted thru seed or pollen?

@Warren: “I never use a virus infected plant as a seed parent or pollinator.”

Can we conclude, therefore, that you have verified the infection status of every plant you use in breeding? I mean, you don’t simply rely on visual evidence of infection to confirm or deny the presence of virus, do you?

I have had many plants in my 20+ year old collection, particularly roses that have been around for 80 years or more, that have grown symptom free for the first ten years or more, only to produce one or two leaves that clearly display classic “zigzag” pigment break markings. I also have a number of roses that I know for a fact are infected with RMV (Moore’s 0-47-19 and ‘Little Darling’ to name but two) and yet neither displays visual symptoms. (Well, 0-47-19 did produce a few marked leaves one year, only on a handful of leaves: it was indisputably virus markings.) ‘Queen Elizabeth’ is another example; I have never seen the pigment break markings, and yet it is well-known that every plant of it has RMV, at least the original plants released in commerce. (I’m not sure, but hasn’t Davis produced a cleaned version of it?)

You have to remember that North American nurseries (and many European ones as well) produced their roses by immediately budding a seedling selection onto understock once it had been identified as worth evaluation, as part of the evaluation process. (The original “own root” seedling was then discarded as useless) And you can guess what understocks were used, and the infection status of most (or all) of this understock material can be assumed, given the time period. I think it is far more realistic to assume most roses bred and introduced in this country in the 20th century by the “big boys” hit the marketplace as infected plants. I’m not sure how much your country’s industry escaped this problem, but I think its fair to wonder.

I always wondered why it was said that some newly released roses were released with RMV- if they were immediately budded for further testing that would make sense. Shame the original seedlings weren’t then set aside as future mother plants.

My original Carefree Beauty which I have had for about 9 years only started showing RMV about 2 years ago and interestingly in late summer when the virus is supposed to be down in the roots due to the heat.

My next door neighbor has close to 100 Queen Elizabeths raised from cuttings and beautifully “variegated.” They thrive, they bloom constantly and are all at least 20 years old.

Jim P

That’s how they were built for testing, Jim. As soon as anything looks promising, they’re budded to quickly build stock for mass plantings for further testing. Once the decision is made to go with the variety, the stock has to be quickly built for release and to provide bud wood to others who buy it for production. Initially, little was known about infection and even less attention was paid to it. We had easily half a century of known infection before anything COULD be done about it and a little while more before any serious efforts were made in those directions.

It was EASY for every plant released to have been infected. All it required was the first budding to be on infected stock. Malcolm Manners stated on Garden Web that Dr. Basye insisted on propagating everything he created on his badly infected Fortuniana, even though Malcolm offered him his treated stock. Basye liked his particular Fortuniana and it didn’t seem to matter to him it was infected. He was a rose breeder. Imagine the concern a corporation run for profit had about infection.

Dr. Buck had several experimental stocks available to him, yet his seedlings were introduced infected. Most came to market through Roses of Yesterday and Today as he and they were friends. He named Amiga Mia (My Friend) for Dorothy Stemler. Their nursery was notorious for their infection rate. So much so, Dr. Manners states he has a test to identify if a rose carries the characteristic strain of RMV from ROYAT. I have access to an Earth Song, which is a direct plant from one Dr. Buck personally handed a gentleman who personally handed the cuttings from it to Bob Edberg (Limberlost Roses) who personally handed them to me, who personally handed them to Sequoia Nursery, who rooted it and gave plants back. This wasn’t something which came through commerce to today, but a plant Buck grew at Iowa State in the greenhouses which he shared with this man personally. It IS infected. If that plant, which hadn’t seen commercial propagation before being shared, is infected, what hope should there have been for anything being pushed through the commercial pipeline to emerge without infection?

Ralph Moore grew Queen Elizabeth and a radiation induced White Queen Elizabeth at Sequoia Nursery. Both plants were personal gifts to him from Dr. Lammerts and were shared before the rose hit the market. Both were infected, which is why he refused to propagate from them. They were very seldom pruned, never sprayed, probably never fertilized, and received only rain and ground water out in the back of the nursery. At the time of closing, they were still well over six feet tall and much greater in diameter than tall. Pre production plants which came from the R&D section of the business, not the commercially propagated stock, and they were infected before release. Should there have been any hope for uninfected commercial stock?

Judith you are right

I was not aware it was caused by an insect - I thought it was bacterial and transmitted thru contaminated soil.

I was assuming you were talking about Moss Gall which comes from an insect called Diplolepis rosae. But I guess you were talking about crown gall or stem gall which is caused by a bacteria Agrobacterium tumefaciens or A. rubi depending on which type you are talking about. Sorry for the confusion.

For more info on the insect type you can go to



This year I have a few seedlings with an apparently virused Prairie Sunshine as the seed parent. I noticed that many of the cotyledons were a little wrinkled, which looked like a virus symptom. The first emerging leaves have not yet shown any symptoms. I’m going to keep them…who knows, if there is something really nice perhaps it could be sent to UC Davis to get cleaned up.[/quote]

Prairie Sunshine = Prairie Sunrise or ???

In Oregon, root and crown gall usually appear if the rose is planted in a heavily water saturated area. Then, it is passed on mechanically on blades from pruning, where the disease is spread to the upper branches.

Mark - Yup, Prairie Sunrise. Sorry.

Hmmmmmm maybe I should have said I only breed from roses which visually show no virus over a long period of time or at the time of pollination and use of pollen. The rootstock mentioned, I have a good idea what it is, I have a preference for using Indica Major. It is a little thorny but growth comming off it is usually pretty good.