Biology Reference
In-Depth Information
(see
Fig. 5
). Ascospores are developed in spring
in tar spots on fallen overwintered leaves and are
forcibly ejected, to be carried by air currents to
young leaves overhead.
Control
Collect and burn fallen leaves. Spray in
early May with copper, repeating in 3 weeks in an
unusually wet season.
Rhytisma andromedae
Tar Spot
on bog rose-
mary and lyonia.
Rhytisma
Ramulispora
Deuteromycetes, Hyphomycetes
Conidia on sporodochia, two-to many-septate,
hyaline to subhyaline, oblong to fusoid, irregu-
larly united or branched at base; produced in
gelatinous masses.
Ramulispora sorghi
Copper Spot
of turf
grasses, sooty stripe of sorghum, Sudan grass,
and Johnson grass. Black superficial sclerotia
are formed on both leaf surfaces, with conidia in
pinkish gelatinous masses. Spots on leaves are
straw-colored with purple borders. Dead areas
in turf are small, 1 to 3 inches, copper-red to
orange. Velvet bent grass in acid soil is very
susceptible. Liming the soil may help.
Pseudorhytisma
bistortae
).
Tar Spot
on polygonum.
Rhytisma liriodendri
Leaf Spot
on tulip-tree.
Rhytisma punctatum
Speckeled Tar Spot
of
maple, a black speckled leaf spot on all species
but especially on silver, striped, and bigleaf
maple in Pacific Coast states, rare in the East.
Black, raised specks, pinhead size, are formed
in groups on upper leaf surface, in yellow-green
areas about 1/2 inch in diameter. Such areas
retain their color even after leaves have faded in
the fall.
Rhytisma salicinum
Tar Spot
of willow, on
pussy willow and other varieties. Spots are very
thick, jet black, definitely bounded, 1/4 inch in
diameter. The fungus winters in old leaves which
should be raked and burned.
bistorti (see
▶
Rhizoctonia
Rots
.
Rhizoctonia solani
Leaf Spot
of
▶
tobacco,
California pepper-tree (Schinus).
Rhytisma
Schizothyrium
Ascomycetes, Rhytismatales
Ascomycetes, Dothideales
Apothecia concrete with epidermis and in black,
stroma-like spots, tar spots, on leaves; spores
filiform, typically hyaline.
Pseudorhytisma bistortae (formerly
Rhytisma
bistorti
).
Tar Spot
on polygonum. Black tarry
spots similar to those on maple.
Rhytisma acerinum
Tar Spot
of maple, espe-
cially on cut-leaf varieties. Black, thickened,
raised, tarlike spots, up to 1/2 inch in diameter,
are formed on upper leaf surface. They may be
numerous enough to cause some defoliation but
ordinarily are more disfiguring than destructive.
Red and silver maples are commonly affected in
the East. The lesions are light yellow-green
at first, forming black stomata in summer
along with the conidial stage (
Melasmia acerina
)
Brown scutellum or shield, radiate at margin,
with a single hymenium underneath; apothecia
round to linear, opening with a cleft or lobes;
spores hyaline, two-celled.
Schizothyrium
gaultheriae
(see
Schizothyrium
pomi
).
Leaf
Spot
on
▶
wintergreen.
Schizothyrium pomi (formerly
Schizothyrium
gaultheriae
).
Leaf Spot
on wintergreen.
Sclerotinia
Blights
.
Sclerotinia homoeocarpa
Leaf Spot
on peanut.
▶
