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