Biology Reference
In-Depth Information
one-celled, allantoid or fusoid; parasitic on
leaves; anamorph states of
Rhytisma
.
Melasmia falcata
Tar Spot
of persimmon.
Melasmia menziesiae
Leaf Spot
tar spot of
azalea.
Monochaetia monochaeta
Leaf Spot
on chest-
nut, white, red, and coast live oaks, winged elm,
hickories, especially destructive in the Southeast.
Spots are large, 1 to 2 inches in diameter, with
pale green or yellow centers with a red and brown
border or concentric zones of gray, yellow, and
brown.
Symptoms appear most often in late summer
when loss of green tissue is not so important.
Micropeltis
▶
Blights
.
Micropeltis alabamensis
Black Leaf Spot
on
magnolia.
Lembosina (Morenoella)
Microstroma
See
Lembosia
under Black Mildew.
Lembosina quercina (formerly
Morenoella
quercina
).
Leaf Spot
,
Black Mildew
of red and
black oaks; twig blight of white oak, common in
Southeast. Spots are purplish black, roughly cir-
cular, up to 1/3 inch across, on upper surface and
irregular brown areas on underside. Mycelium is
superficial in early summer, but by late summer
there are subcuticular hyphae and a black shield
formed over a flat cushion of fertile cells. Asci are
mature and shield is fissured by spring.
Morenoella
▶
Basidiomycetes, Exobasidiales
Sporodochia small, white, breaking through epi-
dermis; conidiophores hyaline, one-celled, some-
what clavate, bearing conidia on short sterigmata;
spores hyaline, one-celled, small, oblong;
parasitic. “Conidia” are now known to be
basidiospores.
Microstroma juglandis
Leaf Spot
,
White
Mold
,
Downy Spot
,
Witches' Broom
of pecan,
walnut, and hickory. Yellow blotching of upper
side of leaves and a glistening white coating on
underside, due to pustules with enormous num-
bers of spores, may be accompanied by prema-
ture defoliation. On shagbark hickory the fungus
also invades the stems, causing witches' broom
up to 3 feet across. Leaves formed on them in
spring are yellow-green, with white powder on
underside. Leaflets are small, curled, and soon
drop. Prune out witches' broom; spray with bor-
deaux mixture.
Lembosina
quercina
).
Leaf Spot
,
Black Mildew
of red and
black oaks; twig blight of white oak, common in
Southeast.
quercina (see
▶
Mycosphaerella
Mycosphaerella angulata
Angular Leaf Spot
of muscadine grapes. Many small, angular black
spots, more conspicuous on lower surface of
leaves, which may turn yellow and die.
Mycosphaerella arachidis
Peanut Leaf Spot
.
▶
Microthyriella
Cercospora arachidicola
.
Mycosphaerella berkeleyi
Peanut Leaf Spot
.
▶
Fruit Spots
.
Microthyriella cuticulosa
Black Spot
of holly.
Dark spots on leaves of American holly, Georgia.
Cercospora personata
.
Mycosphaerella (Anamorph, Pseudcercospora)
bolleana
Leaf Spot
of fig, and rubber-tree.
Mycosphaerella (Anamorph, Asteromella
brassicae) brassicicola
Ring Spot
of crucifers,
chiefly cabbage and cauliflower, sometimes brus-
sels sprouts, broccoli, and turnip. Dead spots in
leaves, small
▶
Monochaetia
Cankers and Diebacks
.
to 1/2 inch, are surrounded by
▶
