Biology Reference
In-Depth Information
Glomerella cingulata
Leaf Spot
, widespread on
queen palm, dracaena, and maranta. Sobralia
blight of orchids. Dark discoloration starts at tip
of leaves and advances toward base.
Glomerella cingulata
Leaf Spot
on apple,
aucuba, wampi,
common and less important toward fall. Asco-
spores are formed in spring in perithecia on fallen
dead leaves; conidia are produced as a creamy
exudate of spores in summer. The fungus also
winters as mycelium in dormant buds.
Control
Rake and burn fallen leaves. Chemical
control is required only in a wet spring, difficult
to determine in advance.
and
croton. See
under
▶
Gnomoniella
Gnomonia
Ascomycetes, Diaporthales
Anthracnose
.
Gnomonia comari
Leaf Spot/Blotch
and
Fruit
Rot
of strawberry.
Gnomonia fragariae
Leaf Spot
,
Leaf Blotch
of
strawberry. Often associated with
Dendrophoma
causing leaf blight, but not connected.
Gnomonia nerviseda (formerly
Gnomonia
caryae
var.
pecanae
).
Pecan Liver Spot
.Dark
brown circular spots, mostly along midribs on
underside of leaves, appear in May and June. In
autumn the color changes to cinnamon brown, and
dark fruiting bodies appear; there may be premature
defoliation. Spray in May with bordeaux mixture.
Pecan Vein Spot
. Lesions resemble pecan
scab on veins or leaf stems; sometimes a narrow
brown lesion extends nearly the length of
a midrib. Defoliation may be moderate or severe.
Stuart variety is especially susceptible. Spray
with bordeaux mixture just before and just after
pollination; repeat 3 to 4 weeks later.
Gnomonia ulmea, Anamorph,
Gloeosporium
ulmeum
(see
▶
Perithecia in substratum, beaked, membranous,
separate; spores hyaline, one-celled.
Gnomoniella
Mamianiella
coryli
).
Leaf Spot
on hazel, frequent in northern
states.
Gnomoniella fimbriata (see
coryli
(see
▶
Mamianiella
▶
fimbriata
).
Leaf Spot
of hornbeam.
Mamianiella coryli (formerly
Gnomoniella
coryli
).
Leaf Spot
on hazel, frequent in northern
states. Controlled with bordeaux mixture aided
by cleaning up fallen leaves.
Mamianiella fimbriata (formerly
Gnomoniella
fimbriata
).
Leaf Spot
of hornbeam.
Gonatobotryum
Deuteromycetes, Hyphomycetes
Conidiophores dark, with spiny inflations at inter-
vals, around which are borne ovoid, dark, one
celled conidia.
Gonatobotryum apiculatum
Leaf Spot
on
witchhazel.
Stegophora ulmea
).
Elm Black
Spot
,
Black Leaf Spot
of Elm, general on
American, English, and Chinese elms.
Gnomonia
▶
caryae
var.
pecanae (see
Gnomonia nerviseda
).
Pecan Liver Spot
.
Stegophora ulmea (formerly
Gnomonia ulmea
,
Anamorph,
Gloeosporium ulmeum
).
Elm Black
Spot
,
Black Leaf Spot
of Elm, general on
American, English, and Chinese elms. Spots on
leaves are small but conspicuous, shining coal
black, and slightly raised. Leaves may turn yellow
and drop, with severe defoliation in a wet season,
especially on Siberian elm. Defoliation in spring
means death of twigs, but the disease is more
▶
Graphium
Deuteromycetes, Hyphomycetes
Synnema or coremium tall, dark, with a rounded
terminal mass of conidia embedded in mucus;
simple, hyaline conidiophores; oblong conidia
reproducing by budding; parasitic.
Graphium sorbi
Leaf Spot
of mountain-ash.