Identification of a nasty fungus

David Pinero ZUBP40A at
Wed Jan 24 19:37:24 EST 1996

   I am currently involved in viable air sampling as part of a Grant 
project. I have screened around 300 Andersen air-impactor samples 
containing each an average of about a hundred colonies. In the past, 
overgrowth problems caused by fungi like Rhizopus, Mucor and Trichoderma 
species have occurred in malt agar samples. However, recently I came 
across what was the messiest, nastiest overgrowing fungus that beats the 
fastest growing Rhizopus isolate by a landslide. After only four days, it 
not only covered the standard sized petri dish, but also grew out of it, 
about an inch high, forcing the lid open and crawling out down to the 
base of the plate. Thick fluffs spread in all directions. This really 
took me by surprise. After cleaning and disinfecting, I searched the 
literature that I have available, but I couldn't identify for sure this 
fungus. Here is a description if anybody wants to help me:

   Isolated from air at New Orleans, Louisiana
   Very broad hyphae (7-10 um) resembling a zygomycete, but septate 
throughout. Sterile along most of the colony, except along the edges, 
where large amounts of  arthroconidia (the only reproductive structure 
found so far) break off. Arthroconidia large, 7-20 um long, variable in 
shape but starting off rectangular; some have branching points. 
   Colony is orange in color. Has a sweet but unpleasant smell. Texture 
is very fluffy, dense (sort of like furry, not thin hairy).
   My best guess is monilia sp., but I had some experience with isolates 
of Monilia Sitophila that are quite different (thinner texture, fast but 
not so fast growth, more branching, and more widespread conidiation); I 
don't have any information on other Monilia species.

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