Hello all,

I'm having trouble with my 5 year old Chinese Elm. The leaves are turning
yellow and brownish-black spots are apparent on most of these yellowing
leaves, leaves then drop off. I assume it's BLACK LEAFSPOT, caused by
Stegophora ulmea. I've tried some fungicidal Rose Spray but it doesnt seem
to be helping, have also tried a Baking Soda/oil/pure soap based homemade
spray with no apparent success. Any suggestions?

Thanks in advance,

Mark

On 31 Jan 2005 at 0:06, Mark Mantolfo wrote:

Hello all,

I'm having trouble with my 5 year old Chinese Elm. The leaves are turning
yellow and brownish-black spots are apparent on most of these yellowing
leaves, leaves then drop off. I assume it's BLACK LEAFSPOT, caused by
Stegophora ulmea. I've tried some fungicidal Rose Spray but it doesnt seem
to be helping, have also tried a Baking Soda/oil/pure soap based homemade
spray with no apparent success. Any suggestions?


There's a more benign possibility: old age.

Elms aren't evergreen. Sometimes it seems that they are, but
they're not. But even if they were, leaves get old, blotchy,
yellow (or brown or red or whatever) and fall off.

And this is the time of year these kinds of things show up.

In any event, if you HAVE a fungus, It's unlikely that you can
cure it. Consumer fungicides are better at prevention than at
cure and (IMHO) they're not terribly good at prevention. Remove
all dead and spotty leaves (including those that have already
fallen) and throw them away where they will not be able to
contaminate this tree or annoy other trees (garbage is fine).

Then, don't over water. Wait 'till the soil is dry. DON'T
spray leaves. Give the tree sunlight and a lot of good
ventilation. And wait for spring to see what happens.

Assumption: You have the tree inside. If so, bad idea. But if
you live in freezing weather (as so many do this time of year)
you are stuck with it inside for the remainder of the cold
season. But as soon as daytime temperatures are reliably in the
50s (F) or so get it outside and keep it there. Bugs and
ailments are twice as common indoors than out.

Why is it a bad idea to have a tree inside? Well, despite the
claims made by ignorant (or unscrupulous) dealers, ELMS ARE NOT
INDOOR TREES. And if you think about it, Ma Nature hasn't made
ANY trees whose natural habitat is indoors, though some tropical
and semi-tropical species can live there if they must. In the
long run, though, elms aren't one of them.

Anyway, it could well be old age (even if it IS a fungus;
sickness tends to go after us elderly folks). Get rid of the
leaves and wait for spring.

Jim Lewis - - Tallahassee, FL - "IF YOU'VE
SEEN ONE REDWOOD TREE, YOU'VE SEEN THEM ALL."
- Forestry expert, Ronald Reagan

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I congratulate you for trying to find out what your pathogen is!
However, I then have to nag you that black spot of rose is a completely
different pathogen, and unless the pesticide label specified efficacy
against black spot of elm, you have no reason to think a rose spray is
legal or is going to work. I don't have access to my reference books
right now, but if you go to your state's extension webpage and look up
elm diseases (NOT rose diseases) it should have what's legal for you.
I'm guessing chlorothalonil, maneb or mancozeb. However....

If the elm has been indoors for a while, it's doubtful it has black
spot, which can't spread in indoor conditions. Black spot needs rain
to splash inoculum and dew to cause infection, and whatever pitiful
misting you do isn't going to allow infection. Most fungi need 4-6
hours of free water in order to infect leaf tissue. I'd tend to agree
with Jim that an indoor elm is going to be unhappy and stressed and I
wouldn't be surprised to see it drop leaves.


Mark Mantolfo wrote:
Hello all,

I'm having trouble with my 5 year old Chinese Elm. The leaves are
turning
yellow and brownish-black spots are apparent on most of these
yellowing
leaves, leaves then drop off. I assume it's BLACK LEAFSPOT, caused by
Stegophora ulmea. I've tried some fungicidal Rose Spray

Thanks for your replies,

I should have pointed out that I am in Melbourne, Australia (South Eastern
Australia) and we are in mid summer here. We had some hot and humid weather
2 weeks ago for several days (28-35C, 82-95F) which I'm sure caused this
infection. I had my bonsai on a porch during this time that gets direct sun
until about 1pm and is shaded the rest of the day.

Two of my junipers and an ornamental plum tree of mine aquired powdery
mildew during this time also, which I have since pretty much got on top of.
It seems my error was in spraying the leaves of my bonsai in the evening
during hot and humid conditions. I understand some fungi actually thrive
under hot (even dry?) conditions. I've heard some type of sulphur based
fungicide might work but am reluctant to use until I get more information.

Thanks

Mark

"Jim Lewis" wrote in message
news:41FCAAFB.26189.33139F@localhost...
On 31 Jan 2005 at 0:06, Mark Mantolfo wrote:

Hello all,

I'm having trouble with my 5 year old Chinese Elm. The leaves are
turning
yellow and brownish-black spots are apparent on most of these yellowing
leaves, leaves then drop off. I assume it's BLACK LEAFSPOT, caused by
Stegophora ulmea. I've tried some fungicidal Rose Spray but it doesnt
seem
to be helping, have also tried a Baking Soda/oil/pure soap based
homemade
spray with no apparent success. Any suggestions?


There's a more benign possibility: old age.

Elms aren't evergreen. Sometimes it seems that they are, but
they're not. But even if they were, leaves get old, blotchy,
yellow (or brown or red or whatever) and fall off.

And this is the time of year these kinds of things show up.

In any event, if you HAVE a fungus, It's unlikely that you can
cure it. Consumer fungicides are better at prevention than at
cure and (IMHO) they're not terribly good at prevention. Remove
all dead and spotty leaves (including those that have already
fallen) and throw them away where they will not be able to
contaminate this tree or annoy other trees (garbage is fine).

Then, don't over water. Wait 'till the soil is dry. DON'T
spray leaves. Give the tree sunlight and a lot of good
ventilation. And wait for spring to see what happens.

Assumption: You have the tree inside. If so, bad idea. But if
you live in freezing weather (as so many do this time of year)
you are stuck with it inside for the remainder of the cold
season. But as soon as daytime temperatures are reliably in the
50s (F) or so get it outside and keep it there. Bugs and
ailments are twice as common indoors than out.

Why is it a bad idea to have a tree inside? Well, despite the
claims made by ignorant (or unscrupulous) dealers, ELMS ARE NOT
INDOOR TREES. And if you think about it, Ma Nature hasn't made
ANY trees whose natural habitat is indoors, though some tropical
and semi-tropical species can live there if they must. In the
long run, though, elms aren't one of them.

Anyway, it could well be old age (even if it IS a fungus;
sickness tends to go after us elderly folks). Get rid of the
leaves and wait for spring.

Jim Lewis - - Tallahassee, FL - "IF YOU'VE
SEEN ONE REDWOOD TREE, YOU'VE SEEN THEM ALL."
- Forestry expert, Ronald Reagan


************************************************** **************************
****
++++Sponsored, in part, by Mike Page++++

************************************************** **************************
****
-- The IBC HOME PAGE & FAQ: http://www.internetbonsaiclub.org/ --
+++++ Questions? Help? e-mail +++++

On 31 Jan 2005 at 13:59, Mark Mantolfo wrote:

Thanks for your replies,

I should have pointed out that I am in Melbourne, Australia (South Eastern
Australia) and we are in mid summer here. We had some hot and humid weather
2 weeks ago for several days (28-35C, 82-95F) which I'm sure caused this
infection. I had my bonsai on a porch during this time that gets direct sun
until about 1pm and is shaded the rest of the day.

Two of my junipers and an ornamental plum tree of mine aquired powdery
mildew during this time also, which I have since pretty much got on top of.
It seems my error was in spraying the leaves of my bonsai in the evening
during hot and humid conditions. I understand some fungi actually thrive
under hot (even dry?) conditions. I've heard some type of sulphur based
fungicide might work but am reluctant to use until I get more information.

Thanks

Mark

Yup. It always helps to know where people are from.

If you have a good plant nursery near you, someone there should
be able to recommend a suitable fungicide. I have no idea what's
available under Australian law.

Jim Lewis - - Tallahassee, FL - Nature
encourages no looseness, pardons no errors. Ralph Waldo Emerson

************************************************** ******************************
++++Sponsored, in part, by Mike Page++++
************************************************** ******************************
-- The IBC HOME PAGE & FAQ: http://www.internetbonsaiclub.org/ --
+++++ Questions? Help? e-mail +++++