What do you all think?
Whoops...forgot the image.
Looks like it to me. What's the story on this plant?
yes it is
Sorry but yes.
Definitely. Yes, do tell us the story about it. I'm quite interested since I'm in northern Ohio as well.
This picture is from a clump of Hosta 'Cynthia' taken in my front yard yesterday. Cynthia in general, and this clump specifically have been tested many times for HVX, and have always come back negative. Here are the lab results I received last week from a new round of virus indexing on this plant:
Host: Hosta 'Cynthia'
Diagnosis/ID: Not Detected for Lily Symptomless Virus (LSV)
Diagnosis/ID: Not Detected for Tobacco Mosaic Virus (TMV)
Diagnosis/ID: Not Detected for Tobacco Ringspot Virus (TRSV)
Diagnosis/ID: Not Detected for Tobacco Streak Virus (TSV)
Diagnosis/ID: Not Detected for Tomato Mosaic Tobamovirus (ToMV)
Diagnosis/ID: Not Detected for Tomato Ringspot Virus (ToRSV)
Diagnosis/ID: Not Detected for Tomato Spotted Wilt Virus (TSWV)
Diagnosis/ID: Not Detected for Potyvirus Group
Diagnosis/ID: Not Detected for Alfalfa Mosaic Virus (AMV)
Diagnosis/ID: Not Detected for Arabis Mosaic Virus (ARMV)
Diagnosis/ID: Positive for Cucumber Mosaic Virus (CMV)
Diagnosis/ID: Not Detected for Impatiens Necrotic Spot Virus (INSV)
Diagnosis/ID: Not Detected for Hosta Virus X (HVX)
Diagnosis/ID: Not Detected for Tobacco Rattle Virus (TRV)
This clearly shows that this Cynthia doe NOT have HVX, but it also shows that it does have Cucumber Mosaic Virus. I am not stating for a fact that CMV is what causes the wild patterns that Cynthia is known for, only that it is in the plant. For all we know, the CMV could be causing no symptoms at all, and there could be some other unknown Virus causing the strange variegation, or it could just be genetic, and not caused by a virus at all.
I found these results very interesting though.
Very interesting. I'm not familiar with CMV, it's not on the list of pathogens affecting Hosta published by Iowa State. Although the ink bleed in your picture is not classic, it is accompanied by collapsed tissue in one of the veins toward the upper right of your photo. But I would tend to believe the lab results.
I saw the pics of Cynthia on the Library. I'm shocked that people didn't send this out for testing earlier. It was introduced in 1984 and the Library writeup doesn't say anything about virus. I wouldn't touch a plant that looks like that.
So much confusion! what Is a novice to do?
H. Cynthia, H. Xanadu Paisley, and H. 'Filigree' have been oft accused of being HVX infected. H. Embroidery could be included in this list.
From what I've read and seen, these are all 'false positives'.
Just my 2c worth, and we keep all of them here and have used test strips on them all several times, and have yet to have a break-out.
I'd worry more about SnS (a notorious carrier) or H.
Stiletto' that we've seen ALL over the place infected!
What is a novice to do? Stay away from any plant showing strange mottling like this.
Thanks for the info Buckeye. When I saw the picture I was thinking it had to be some kind of virus, but Cynthia has been listed as one of those "mottled but HVX free" plants. It would be interesting to have more Cynthia tested to see if the CMV results come back positive on others too.
Buckeye, you are giving us quite an education on viruses that affect hostas. Thank you.
According to the University of Illinois-
"Some viruses that infect hosta include cucumber mosaic virus (CMV), hosta virus X (HVX), tomato ringspot virus (ToRSV), tomato spotted wilt virus (TSWV), impatiens necrotic spot virus (INSV), tobacco rattle virus (TRV), and arabis mosaic virus (ArMV)."
I don't know which is more prevalent but the fact that the Cucumber Virus can be spread by aphids makes it a greater risk to a collection than Virus X, in my opinion.
The "cure" for this is to yank up the infected plant and get rid of it as soon as possible. The problem is how to distinguish between the viruses and make a determination of what action to take. If the hosta is isolated and the plant, roots and all, can be removed and thrown away; or the spot will not be used for hostas again than that would seem to be the best bet if testing is not done.
The University of Illinois says that the professional treatment for CMV is a spray with mineral oil to kill the aphids which transmit the virus. Of course the infected plant would have to go as well.
In trying to educate myself the non-HVX viruses are transmitted by aphids, nematodes (the real bad actor) and thrips. I think this suggests that having these viruses would be a far greater danger to a mass of hostas than HVX would be; especially if basic sterilization techniques were used.
My takeaway is to have a test kit and not jump to conclusions as, what I would do for HVX would be entirely inappropriate for other more dangerous viruses.
HVX seems relatively easy to contain with good sanitation. I know this will cause many a great deal of anxiety, but nematodes seem to be a far greater danger to one's collection than HVX. I can't read minds, but I think Buyckeye is gently leading us to this fact.
Good information about CMV, Jon. But I haven't noticed aphids on my Hosta. Have you? Can CMV also be spread by mechanical means (i.e. plant sap)?
I've never seen ANTS around my hostas,and where there are aphids there should be ants, shouldn't there? I have columbine in one of my hosta beds and columbine have thrips, usually. But no thrip looking "trails" on nearby hostas. It doesn't mean a thrip might not try a nip.
Fine Gardening showed pictures of a CMV infested virus several years back and reported it as a "rare" occurance, but rare is a not very precision term.
I have not seen aphids on my hostas, Steve. Maybe they are busy munching under the leaves or they are too busy munching on easier (and maybe more delicious) other plants. Many sources relate it does happen though and it is listed by many as one of the primary means of transmission of CMV to hosta; Tobacco Rattle Virus as well and probably other viruses. It can be transmitted by sap as well....and by touch.
It is far more contangious than HVX which requires sap transmission and cannot exist outside of live tissue.
Looking quickly I notice that HostasDirect, Walter's Garden and Shady Oaks include regular testing for CMV in their testing regimens. I'm sure most other good suppliers do as well, these are just the 3 that popped up.
The fact that these viruses are not not hosta specific also complicates the issue as it allows different paths for introduction to hostas.
With all the things to worry about in hosta growing, I am begining to think HVX is far down the list of problems to worry about. To me nematodes are public enemy number one both by themselves and because of their ability to transmit disease.
Buckeye15, Have you tested any of the other plants that fall into that mottled category or have you ever heard of any cases of it being spread to neighboring plants. Cynthia has been around for a long time and I know many people that grow it but have never heard about it infecting another plant.Rob
To address a few of the points and questions, I don't have a lot of answers, but will try. I have owned this clump for almost 15 years, long before I had ever heard of HVX. Then I got a copy of the Hosta Handbook, and Zilis made it clear that it was a genetic anomaly, and not a virus, so of course I felt relieved. He again mentions the same thing in the Hostapedia. If this hosta has been run through extensive virus indexing other than HVX then I am not aware of it. I just had an opportunity to get it tested, and I jumped at the chance.
I agree with Chris that it would be very interesting to test other clumps of Cynthia to see if the results could be duplicated. Frankly I am skeptical as to whether the CMV is causing the variegation pattern in this plant. By the 4th of July this plant will be all green and not show the color again till next spring. I have never seen nor heard of this look spreading to surrounding plants, and this is the first mottled plant I have submitted for extensive testing.
I have seen thrips in hostas before, and they can be a vector for some viruses. I have never personally observed aphids on hosta, but I wouldn't entirely rule it out. Heck, I have seen bagworms attached to hosta, so who knows. By the way, not all aphids can be vectors of viruses. There are many different species of aphids, and only some act as vectors. I have seen wooly leafhoppers on hosta flower scapes before, but I have no idea whether they can vector any diseases.
While there are a number of other viruses that can infect hostas, I would never minimize the dangers of HVX. It is still a serious problem and is not going away. In fact, if not for the efforts of Chis at Hallson Gardens, it would be much, much worse. Chris has done a great service for the hosta world by spreading the word, and encouraging people to fight back against the the suppliers of diseased plants. For that I applaud him.