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verticillium wilt in sugar maple

Posted by arbordave S-E MI (My Page) on
Wed, Aug 13, 14 at 20:45

I've tried posting to the original thread (Aug 11) on this subject, but my post keeps getting rejected ("Message Rejected, We apologize for any inconvenience, but this thread no longer exists on this forum.")

Regarding verticillium wilt in maple cultivars - different cultivars probably do vary in their susceptibility to verticillium. I've seen a couple references indicating that 'Jade Glen' and 'Parkway' Norway maples have better resistance compared to other Norway cultivars.

I haven't been able to find any info regarding the degree of susceptibility of the sugar maple cultivar 'Commemoration', but more than once I've observed what I assumed was verticillium on Commemoration maples in my area.


Follow-Up Postings:

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RE: verticillium wilt in sugar maple

check out this web site

Here is a link that might be useful: verticillium wilt


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RE: verticillium wilt in sugar maple

I agree, Arbordave. It's not all about the rootstock. I have no opinion, one way or other, about the susceptibility of 'Commemoration' to vw. But, I would be surprised for there not to be some variation in response from different cultivars.

BTW, here's a link to the original thread, for those interested....

Here is a link that might be useful: Original Thread


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RE: verticillium wilt in sugar maple

The same nursery FWIW said they prefer "Flax Mill Majesty" (also sometimes just called 'Majesty') for better resistance.

I'm not as familiar with that cultivar.


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RE: verticillium wilt in sugar maple

VW is a strange disease anyway. It's present in many areas, yet a large percentage of susceptible plants, at least woody plants, don't succumb to it. It seems to strike rather randomly and of course weak/stressed plants most likely to get it.

For herbaceous plants it seems to produce more widespread damage, at least in my experience.


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RE: verticillium wilt in sugar maple

  • Posted by whaas 5a SE WI (My Page) on
    Thu, Aug 14, 14 at 9:55

Based on a conversation with JF Schmit they said it would have to be a cutting not a graft.

Are these cuttings or grafts?

Can anyone confirm if it would still have resistance if it was grafted? Logically it doesn't seem like it would.

HM,
I'd be curoius what they say about Flax Mill Majesty drought tolerance and fall color. I was considering had this one due to its frost crack tolerance.


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RE: verticillium wilt in sugar maple

Good question, whaas.

Did Schmidt speak as to whether any one cultivar had more or less susceptibility to VW in their experience?


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RE: verticillium wilt in sugar maple

  • Posted by whaas 5a SE WI (My Page) on
    Thu, Aug 14, 14 at 11:34

No it was a general conversation about maples. There was a potato field next to my lot years and years ago so I was curious about VW.

I talked to a young lady there and can't recall her name. THis is two years ago already.

The link provided by tmore list cutlviars that apparently have VW resistance but again I bet its by cuttings.

I have no scientific evidence at this point, its just logical here say.


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RE: verticillium wilt in sugar maple

tmore's link only mentiones A. rubrum cultivars that are resistant, not A. saccharum. IIRC rubrum as a species is a bit less susceptible than saccharum, which itself is less susceptible than A. platanoides.


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RE: verticillium wilt in sugar maple

I will stay with the position that it is about the root stock until someone can produce strong evidence to the contrary. Verticillium enters through the roots, and the roots are a different genetic makeup than the grafted top. Unless something can be show to be transported to the roots that are essential for resistance, or a common genetic type is susceptible and grafts to Commemoration primarily, or a large randomized blind study, then conformation bias is the most likely explanation.

Arktrees


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RE: verticillium wilt in sugar maple

One more thing to add to the above. The above all assumes grafting is done with clean materials, clean scions, clean hands, and clean tools and good grafting practices. As many of us realize, control practices in the industry seems to be worse and worse. So a contaminated knife in grafting could easily spread this disease, and it could be that the genetics of the graft would play a role then, or even be the source of the disease.

Arktrees


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RE: verticillium wilt in sugar maple

The link below says (in reference to olive cultivars):
"Cultivar resistance or the use of resistant rootstocks has been extensively studied as a way to potentially prevent losses from Verticillium wilt (See Table 1). There is no known rootstock that has been successfully used to protect trees. It appears that the fungus can move through the resistant rootstock into the susceptible cultivar, killing the top."

Here is a link that might be useful: verticillium wilt of olive


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RE: verticillium wilt in sugar maple

Then the "resistant" Olives weren't resistant, but tolerant. Big difference. Besides this can't be generalized to very different family of plants, with radically different native habitats. Olives are adapted in a very different MUCH DRIER climate that Sugar Maple would very rapidly succumb in.

Arktrees


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RE: verticillium wilt in sugar maple

Arktrees, I think you have the idea correct, although not everyone would use the terms the same way you do and arrive at the same conclusion (or, state the conclusion the way you did). Basically, it's not about whether the roots (rootstock) lets the disease in, but about how the tree (both the rootstock and the scion) deals with the disease.


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RE: verticillium wilt in sugar maple

My apology if my posts were taken in a negative way, it was not my intent. I was trying to be precise in language, description, and reasoning since it seemed to be more of discussion of merit of the original postulate of suceptibiliy of the original thread. Nothing was directed at any poster in any way.

Arktrees


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RE: verticillium wilt in sugar maple

I thought the olive link was pertinent because it discussed how certain cultivars are consistently susceptible regardless of the rootstock they're being grown on. Seems reasonable to conclude that specific maple cultivars may be consistently susceptible (or resistant) regardless of their rootstock.


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RE: verticillium wilt in sugar maple

  • Posted by whaas 5a SE WI (My Page) on
    Fri, Aug 15, 14 at 10:06

I don't see any data on long term observations (at least I didn't see the dates posted in the study) in which the apparent resistant culitvars did indeed recover.

It states several recovered later from initial signs of a specific strain. What does several mean? What does initial mean? Could the resistant cultivars contract/show the disease at a later date?

If a plant still gets the disease just as easily as a non-resistant cultivar, whether or not its severe from the onset, and doesn't successfully recover then its not resistant...you just buy time. No?

"None over what time period? of the resistant and very resistant cultivars were killed and most (most? so some where worse?) showed disease
levels of 7 to 13%. It should also be noted that in several cases trees that showed initial
Verticillium wilt symptoms (non-defoliating strain) later recovered from the disease."

My take away is that there aren't any VW resistant sugar maples. Perhaps tolerant but where are the trials to back it up?


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RE: verticillium wilt in sugar maple

Arktrees, I don't see ANYTHING wrong with your post or the words you used. It's just that not everyone separates out the words resistant and tolerant as you do (although there is plenty of reason to do so). I guess some of what I am saying is that tolerance can be viewed as resistance to a disease. In addition to that, the line between the two words is not always as clear-cut as one might initially imagine.

Whaas, I don't believe that the disease, once established in a plant, ever necessarily goes away. What can occur, with vigorous growth, is a walling-off so that the disease is contained and overcome at least until the compartmentalization fails. Compartmentalization always fails, but sometimes that time period may exceed the life of the tree. So, with a vigorous tree, it very possible for the tree with vw to eventually die of something else besides vw, or for vw to only be one factor that contributes to the eventual failure.


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RE: verticillium wilt in sugar maple

  • Posted by whaas 5a SE WI (My Page) on
    Fri, Aug 15, 14 at 22:46

Brandon, for me resistant and tolerant are two distinct ideas.

Resistant is to not allow/be immune and tolerant is to allow/live with.

I see the point though.


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RE: verticillium wilt in sugar maple

Whaas, thanks for pointing out that distinction. I found a reference (see link) that discusses Norway maple cultivars that makes a similar comment to yours. It states: "We use tolerance rather than "resistance" because resistance is so often used to mean fungal exclusion or lack of colonization, an extreme that we did not observe."

But other references seem to use the terms interchangeably - see these:
http://www.uky.edu/Ag/Horticulture/Geneve/teaching/PLS320/Verticillium wilt factsheet.pdf
https://www.clemson.edu/extension/horticulture/nursery/ipm/book_files/chapter_10

"Resistant" is also used in reference to trees that tolerate insect attack, such as ash trees that are able to survive attack from EAB. Here it doesn't mean complete immunity, but rather limited extent of damage.

Here is a link that might be useful: verticillium & norway maple cultivars


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