Abstract:
Sooty molds (Capnodiaceae) are saprotrophs
on the surfaces of leaves, and they take their
nutrients from honeydew exuded by sap-sucking
insects. We describe and illustrate the sooty mold
Fumiglobus pieridicola sp. nov., which, to the dismay of
gardeners, forms a thick black mycelial coating on the
leaves and twigs of ornamental Japanese andromeda
(Pieris japonica) in western North America. As a
mitosporic species with a pycnidium that lacks an
elongated neck and has at most a rudimentary stalk,
the species belongs in the genus Fumiglobus. Although
locally common, we found no specimens
identified under Fumiglobus or its synonyms in
regional herbaria and no record of any similar fungus
in host indices. Our species differs from others in
Fumiglobus in having smaller pycnidia and conidia
and in having intercalary as well as apical pycnidia.
We determined partial 18S and 28S ribosomal gene
sequences for F. pieridicola, the first for any Fumiglobus
species. Sequence analysis provides strong bootstrap
support for including Fumiglobus within Capnodiaceae.
We also determined 18S and 28S sequences
for the type species of the mitosporic genus Conidiocarpus, also in Capnodiaceae. We confirm
that Conidiocarpus is the anamorph of Phragmocapnias.
Following the rules of nomenclatural priority, we
propose the new combinations Conidiocarpus asiaticus,
Conidiocarpus betle, Conidiocarpus callitris, Conidiocarpus
fuliginodes, Conidiocarpus heliconiae, Conidiocarpus
imperspicuus and Conidiocarpus siamensis. We hope that describing the mystery fungus from our
region and providing sequences for its molecular
identification will lead to new studies on its biology
and distribution.
