Monday, March 26, 2012

IUCN's 100 Worst Invasive Species

I'm not sure why I didn't come across this sooner, but today is the day I learned about IUCN's list of the 100 Worst Invasive Species.  Not surprisingly, there are some fungi (and two fungus-like protistans) on there, though not as many as I might have thought.  They list five species, of which I would have guessed that four of them.  Reflecting their bias towards macroorganisms,  there are NO bacteria on the list, but two viruses (which are not even alive, in my well-supported opinion) and one non-funguslike protist (the avian malaria pathogen, Plasmodium relictum, an apicomplexan).  Also, the invasives are bad because they are disease agents of larger, more charismatic eukaryotes.  They do indicate that the criteria for selection includes "serious impact on biodiversity and/or human activities". 

Their five fungi and funguslike organisms?
Cryphonectria parasitica (Ascomycota), causal agent of chestnut blight
Ophiostoma ulmi (Ascomycota), causal agent of Dutch elm disease
Batrachochytrium dendrobatidis (Chytridiomycota), causal agent of frog
Phytophthora cinnamomi (Oomycota), causal agent of Jarrah dieback etc.
Aphanomyces astaci (Oomycota), causal agent of crayfish plague

The last of these, I had never heard of before.  I'd heard of the genus before, but I'd forgotten that it's an oomycete genus. The IUCN describes these as "macrofungi", though I would say none of them really are, except the pycnidia and perithecial stromata of C. parasitica are visible to the naked eye.  

Wednesday, March 7, 2012

Alaskan rust spores identified!

At long last, the news I've been waiting for!  The mysterious Alaskan orange goo, thought at first to have been eggs of something, or possibly the dinonflagellate Noctiluca, later discovered to be rust spores, has been positively identified. The mystery rust is Chrysomyxa ledicola, which causes spruce-labrador tea needle rust.  The spores identified were the urediniospores, which is known as the repeating stage of macrocyclic rusts.  It is common for rusts to produce ba-jillions of spores, especially urediniospores, to keep reinfecting their alternate hosts.  In this case, that alternate host is labrador tea Ledum spp., though the NCCOS webpage lists it as Rhododendron tomentosum.   That name isn't accepted by, which is my source for this kind of information.  That fact helps explain how the source of the orange goo was originally so mysterious.  While the primary host, spruces (Picea spp.), are a group that would be difficult to hide that many spores on without someone taking notice, labrador tea is a common understory plant that wouldn't raise as many alarm flags.