Biology Reference
In-Depth Information
Black Mildew
Asterina
The terms black mildew, sooty mold, and black
spot have been used to some extent inter-
changeably. In this text the term sooty mold
is restricted to those fungi living on insect
exudate and hence not true parasites. Included
here under Black Mildew are parasitic fungi
that have a superficial dark mycelium. They
are members of the Erysiphales (Meliolales
according to some classifications) and hence
similar to powdery mildews except for the dark
color, or they belong to the Hemisphaeriales,
characterized by a dark stroma simulating the
upper portion of a perithecium. In a few cases
the diseases are called black spot rather than
mildew.
Ascomycetes, Asterinales
Asterina
species are parasites on the surface of
leaves and are usually found in warm climates. In
some cases the disease is called black mildew, in
others, black spot. The perithecia are dimidiate,
having the top half covered with a shield, a small,
round stroma composed of radially arranged dark
hyphae. Underneath this stromatic cover, called
scutellum, there is a single layer of fruiting cells;
paraphyses are lacking; spores are dark, two-
celled. The mycelium, which is free over the
surface, has lobed appendages, hyphopodia,
which act as haustoria in penetrating the cuticle
and obtaining nourishment from the host.
Asteridium lepidigenum (formerly
Asterina
lepidigena
).
Black Mildew
on lyonia, Florida.
Asterina anomala (see
Limacinula anomala
).
Black Mildew
on California-laurel, California.
Asterina delitescens
Black Spot
on redbay.
Asterina diplopoides
Black Spot
on leucotho¨.
Asterina gaultheriae (see
Schizothyrium
pomi
).
Black Mildew
on bearberry, Wisconsin.
Asterina lepidigena (see
Asteridium
lepidigenum
).
Black Mildew
on lyonia, Florida.
Asterina orbicularis
Black Spot
on American
holly and
Ilex
spp.
Limacinula anomala (formerly
Asterina
anomala
).
Black Mildew
on California-laurel,
California.
Apiosporina
Ascomycetes, Pleosporales
Perithecia and mycelium superficial; mycelium
with setae and perithecia usually hairy;
paraphysoids present; spores two-celled; dark.
Apiosporina collinsii
Witches' Broom
of ser-
viceberry (
Amelanchier
) widespread. Perennial
mycelium stimulates the development of numer-
ous stout branches into a broom. A sooty growth
on underside of leaves is first olive brown, then
black. Numerous globose, beadlike, black peri-
thecia appear in late summer. The damage to the
host is not serious.
