What bothered me was nobody wanted to look for a pathogen. Fears that the
Ag Dept would poo-poo the condition, the tests would be too costly or no one
would really take the time to elucidate a 'true' pathogen (like 'You got a
virus. Take 2 aspirin and call me in the AM").
K Barrett

"al" wrote in message news:2tWNg.1992$FS.1358@trnddc04...
What bothered me about what Bob Gordon wrote was that they still had not
identified the pathogen and suspected it might be a viral/fungus
combination. Without the pathogen, how can it be identified as belong to
a specific phylum?

I found two terms in the library that lead to much more information about
microscopic organisms that live inside plant cells and tissue and which
may cause vascular plant diseases.

Anyway, I heard about MLOs in botany 101 and since I went no furthur I
know nothing more than that, as the instructor mentioned one day during
this whorl wind introduction to botany, is that they are "ill defined
organisms" that seem to be behind many plant diseases. For instance, the
pathogen that causes Dutch Elm Disease is among the pathogens called MLOs.
They are not all fungi.

MLO (microplasma-like organism) seem to be heavily studied and there is
lots of specific plants with named disease syndromes where MLOs have been
isolated and determined to be the pathogen causing the symptoms. If you
add the word orchid to a search of microplasma-like organism it turns up
nothing.

The terms mycoplasma-like organism and mycoplasmic organism were very
helpful. Myco NOT Micro. Myco refers to fungi. (So "mycofungus" would be
wrong and annoying in a manner similar to using the terms fungi and fungus
interchangeably: you'd have to have a clue in order to even notice.)

Mycoplasma has it own wikopedia-like entry.
http://microbewiki.kenyon.edu/index.php/Mycoplasma
with general information that people worried about "microfungus" might
want to read.

When you connect this one of the '"myco" terms with "orchid" in a search
you DO get a number of interesting hits. The term still refers to a group
of parasitic fungi or fungi-like organisms living in the cells and that
vascular tissue of plants AND animals, and does not refer to a specific
pathogen, so this may be why symptoms vary so wildly. Mycoplasma-"like"
also makes me think that whatever they are talking about are not true
fungi and why fungicides, even strong systemic ones, sometimes fail to
help.

I think if the pathogen of this mysterious disease "microfungus" is ever
isolated it my be more properly named/grouped with microplasma, mycoplasma
or mycoplasma-like organisms

"Pat Brennan" wrote in message
...
BobGordon "Culture of the Phalaenopsis Orchid"

. . ."sometimes a condition prevails that is caused by a systemic
infection of microfungi. As there are literally hundreds of these, the
symptoms vary from plant to plant.

Some of the more common are a spotty, ill-defined chlorosis; a streaky
chlorosis beginning at the edge of the leaf where it looks as if the leaf
edge had been burned with a match or candle; a red-brown coloration
appearing at the apical third or half of the lower leaves followed by a
dehydrated and senescent (old) appearance and also mesophyll tissue
collapse where deep pitting becomes apparent on the surface of the
leaves. This latter condition can also be caused by cold water and by
virus infections. However, in the latter instance, the pitting is usually
dark-brown to black in appearance rather than the white to light fawn
caused by fungi.
.
.
.
We still don't have a handle on what is causing the disease yet or even
what it is, but efforts are underway at two state universities. It may
be a fungal disease and virus in combination, confusing the diagnosis,
but there is little question that the disease weakens the plant and
leaves it susceptible to more common ailments such as Pseudomonas
cattleyae.

Bayleton may be the agent that is correcting the problem, however, There
have been reports that the Bayleton alone will correct the problem.
There is one report that Subdue alone corrected the problem.

Symptons of the problem are similar to those of a photo of a specimen of
fungal leafspot caused by Guignardia sp. shown on page 84 of the 1986
edition of the AOS's Handbook on Orchid Pests and Diseases. However, to
date, that disease only has been reported in vandas and ascocendas. If
the disease is fungal in nature, it does not respond to the standard
culture tests. At least three efforts have resulted in no germination."


BobGordon '"Phal Cultu A Worldwide Survey."

"Microfungus Phal growers may be facing a major newly-discovered
(observed?) problem. This is the yellow pitting, necrotic spotting of
the leaves, preliminarily diagnosed by John Miller and Rob Griesbach as a
micro-fungus.
. . . Growers who have followed various recommendations on ridding their
collection of this problem have largely been unsuccessful. Nothing
sprayed, drenched or applied in any manner seems to make any inroads on
the disease. . . .--T. Happer"

"Systemic Microfungus To my knowledge, Ernie Campuzano of Butterfly
Orchids in Newburry Park Ca, was the first grower to experience the
microfungus problem on a large scale. . . . Ernie had all the symptoms
Tom Harper talks about above and related the problem to John Miller, who
in turn related it to Don Baker of Stoufer Labs. Don identified the
problem as a systemic microfungus and developed the following therapy. .
. .-editor"

I would say symptom are, in the order of appearance, yellow chlorosis,
more defined yellow spotting, pitting, large areas of grayish brown
tissue collapse.

Pat