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microfungus
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 |