Viruses in plants, not people!
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Humans are not the only ones who are at risk from a virus. Plants can also be under attack from virus species that are plant pathogens.
Of course you can't photograph the virus itself, but when a plant is infected, you can see the ways in which the virus changes the appearance of the leaves, or sometimes all parts of the plant. The symptoms can be quite striking, and can make interesting photographs. Mosaic viruses cause mosaic-like patterns on leaves. And sometimes a virus can affect a plant in other ways: for example, Cucumber Mosaic Virus, when it is on Nandina domestica, can cause extreme stunting, and make the leaves come out really weirdly: dark red, narrow, and curving downwards.
Some viruses only attack one genus of plants, but some others, including the Cucumber Mosaic Virus, attack a very wide range of plants in different families.
Because many of the viruses have long names, they are usually referred to by their acronyms, so Pagoda Yellow Mosaic Associated Virus is known as PYMAV, and Cucumber Mosaic Virus is CMV.
Here are some plant viruses that I have observed. Please note that @jameskdouch, a virologist in Melbourne, Australia, has given me much assistance by commenting on and correcting my putative virus identifications. And @juhatuomola, a plant pathologist in Helsinki, Finland, has been very helpful too.
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Hackberry Mosaic Virus -- on Common Hackberry, Celtis occidentalis
https://www.inaturalist.org/observations/31357525
Pokeweed Mosaic Virus -- on American Pokeweed, Phytolacca americana
https://www.inaturalist.org/observations/46662447
Cucumber Mosaic Virus -- on Heavenly Bamboo, Nandina domestica
https://www.inaturalist.org/observations/46777373
Ribgrass Mosaic Virus -- on Carolina Bluebells, Mertensia virginica
https://www.inaturalist.org/observations/46777665
Rose Rosette Emaravirus -- on Multiflora rose, Rosa multiflora
https://www.inaturalist.org/observations/46447203
Pagoda Yellow Mosaic Associated Virus -- on Japanese Pagoda Tree, Styphnolobium japonicum
https://www.inaturalist.org/observations/46880397
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NOT IDENTIFIED MORE PRECISELY
Rose mosaic virus -- one or more of a group of four unrelated viruses which attack Rosa chinensis
https://www.inaturalist.org/observations/46141366
Virus on Erigeron:
https://www.inaturalist.org/observations/41071740
Virus on Common Blue Violet, Viola sororia:
https://www.inaturalist.org/observations/46778090
Mosaic virus on Kirengeshoma (a garden plant):
https://www.inaturalist.org/observations/27344440
On June 4th I found symptoms of an interesting, new-to-me plant virus or viroid quite near where I live, on a seedling on White Mulberry. It might perhaps be hop stunt virus, HSVd:
https://www.inaturalist.org/observations/48527613
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A "GOOD VIRUS"
Badnavirus on Japanese Aucuba, Aucuba japonica -- the effects of this virus are highly prized by horticulturists. The virus is transmitted in the seeds from one generation to the next. I guess we have to consider it to be a cultivated virus.
https://www.inaturalist.org/observations/38013503
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TWO VIRUSES I PHOTOGRAPHED ELSEWHERE IN NORTH AMERICA
Cucumber Mosaic Virus on Beach Naupaka, Scaevola taccada, in Sanibel, Florida
https://www.inaturalist.org/observations/36415969
Begmovirus on Merremia in Nevis West Indies
https://www.inaturalist.org/observations/11184816
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תצפיות
תמונות/קולות
מה
נגיפים (ממלכה Viruses)מתצפת.ת
susanhewittתיאור
On Common Jewelweed, Impatiens capensis.
Is this Tobacco Mild Green Mosaic Virus? Or is it Impatiens Necrotic Spot Virus?
תמונות/קולות
מתצפת.ת
susanhewittתיאור
This multiflora rose has a bad case of the RRD virus. As well as the usual symptoms, it also has this remarkable occurrence of "cresting", known more scientifically as "fasciation", where a mutation in cells of the growing tip of the twig has cause the twig to grow into this bizarre large flattened disc shape!
Please also see:
תמונות/קולות
מתצפת.ת
susanhewittתיאור
This tiny plant is a Heavenly Bamboo that was put in about three years ago. It has not really grown at all since then.
The plant is very stunted, the new foliage is very dark red, and the leaves are extremely narrow and somewhat downward pointing.
The plant has never flowered or fruited.
תמונות/קולות
מתצפת.ת
susanhewittתיאור
This appears to be a mosaic virus on Mertensia virginica, Virginia Bluebells.
תמונות/קולות
מה
נגיפים (ממלכה Viruses)מתצפת.ת
susanhewittתיאור
On White Snakeroot, Ageratina altissima.
תמונות/קולות
מה
נגיפים (ממלכה Viruses)מתצפת.ת
susanhewittתיאור
On Viola sororia.
The leaves that are at the top and side of this plant show unusual color patterns that suggest a virus.
תמונות/קולות
מתצפת.ת
susanhewittתיאור
On Japanese Pagoda Tree, Styphnolobium japonicum.
A couple of years ago this tree was cut down all the way, flush with the ground, but it sprouted back up quite vigorously.
תגובות
Susan,
Very informative! I makes me wonder about some of my Autumn Olive shots. For some reason I have to shoot all the weird ones. Here they are:
https://www.inaturalist.org/observations/7791507
https://www.inaturalist.org/observations/15904529
https://www.inaturalist.org/observations/16976177
https://www.inaturalist.org/observations/17611011
https://www.inaturalist.org/observations/26471654
https://www.inaturalist.org/observations/28391232
The entire plant is never affected like this.
Do you think these are the result of a virus?
Super interesting stuff, Susan! Really enjoyed this journal entry. :)
Thanks Sam for your kind comment, glad you liked it. :)
@ken-potter -- I will attempt to ask
plant pathologistvirologist @jameskdouch what he thinks of your variegated twigs on Autumn Olive, Elaeagnus umbellata.I have had almost no botany training at all, but to me, those variegated parts look like bud sport mutations, which I think happen by chance rather than being cause by a virus.
And something that often happens with plants is that horticulturalists select the variegated ones to become "cultivars" because they are more decorative, but then, some time after the pretty variegated bush is planted, it will often start sending out plain green shoots.
The all-green parts, being more vigorous, grow much faster, and if not carefully pruned away, they will take over, leading eventually to a big green bush with a few variegated twigs at the base of the plant. I see that quite often with variegated euonymus in my neighborhood here in NYC.
@susanhewitt I’m not a professional plant pathologist, but I am a virologist, and plant viruses happen to be easier to observe than animal viruses. Note that you tagged the wrong Ken Potter.
@ken-potter I am confident your images show genetic variegation, caused by a mutation, that may have been cultivated by horticulturalists or may have occurred in situ. Genetic variegation is commonly associated with pale leaf margins and green centres, whereas viruses tend to cause randomly distributed spots or trace the veins.
Thanks so much @jameskdouch -- sorry that I D'ed you as the wrong kind of professional, and thanks so much for giving me so much help with various plant virus IDs. Also thanks for letting me know about my typos on Ken's screen name.
That’s ok. I’m happy to help.
@jameskdouch @susanhewitt Thank you for all the help! I'll continue to document variegated specimens I encounter. Maybe someday we'll learn something more conclusive on the subject :)
@ken-potter,
It's already pretty conclusive:
If any of your observations were way out in the wild, where no-one could have planted a bush, then you can say the variegated part of the plant was caused by a mutation (a so-called "bud sport") which occurred naturally without any intervention.
If, however, any of your observations were in places where someone might have planted a decorative bush a while ago, then it is possible that bush was originally all variegated, and then it grew more and more into the wild green kind until all that was left were a few twigs at the bottom and sides.
@susanhewitt
I'd like to turn "pretty conclusive" into "conclusive" even if only in my own mind even though I think that might be impossible 😊 The ones documented by me so far are "way out in the wild" (as you define that) with untold numbers of other specimens everywhere throughout the tri-county area that I pretty much stay within 95% of the time. It's a real nuisance around here where you just can't escape it. All you can do is learn how to navigate through these bushes without getting cut up and deal with it, though I do love the berries. It's all over my property in front of the woods, aside my house, behind my house and along the buffer zone out back. My sub was built in a cleared woods with the planners leaving as many of the trees and other flora as they found it. Locals who's families go back to the 1800s tell me it was introduced to feed the deer herd but it, honeysuckle and multiflora rose have really taken over many areas. Thanks for all the info you've sent me on this! Take care!
So then I would say, congratulations, you can be certain that:
The variegated part of the plant was caused by a mutation (a so-called "bud sport") which occurred naturally without any intervention by humans or by a virus.
Thanks Susan! I'll go with that! I've always had a curiosity about things that are odd. And now you have me looking for viruses! 😂
@ken-potter -- I would expect that you have Hackberry MosaicVirus where you are, assuming that you have Common Hackberry trees?
The effects of that virus should start showing up soon, during the month of June.
UPDATE: Two days ago I found symptoms of an interesting new-to-me plant virus or viroid quite near where I live, on a seedling on White Mulberry. It might perhaps be hop stunt virus, HSVd:
https://www.inaturalist.org/observations/48527613
@susanhewitt
Unfortunately I have never seen a Hackberry tree (that I know of) but a I'll keep my eyes open.
Thanks!
Ken
This is encouraging!
Yes, once you really start looking, you will find quite a few I think.
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