Biology Reference
In-Depth Information
chains; found on living leaves causing leaf spots
or white mold.
Cercosporella pastinaceae (formerly
Ramularia pastinaceae
).
Leaf Spot
of parsnip.
Lesions are circular, very small, at first brown,
then with a white center and brown border.
Long, slender, septate, hyaline conidia are pro-
duced on exposed conidiophores. No control is
necessary.
Entylomella armoraciae (formerly
Ramularia
armoraciae
).
Pale Leaf Spot
of horseradish. Few
to numerous light green to yellowish spots appear
on leaves in early summer, the invaded areas
quickly turning thin and papery with dead por-
tions dropping out, leaving ragged holes late in
the season. Innumerable small sclerotium-like
bodies in the dead tissue carry the fungus over
winter, producing short knobby conidiophores in
spring, which either push out through stomata or
break through either epidermis. There is no spe-
cial control.
Ramularia
Pleospora
Ascomycetes, Dothideales
Perithecia membranous, paraphyses present;
spores muriform, dark; some species have
Alternaria
,some
Stemphylium
as anamorph state;
wide saprophytic and pathogenic relationships.
Pleosporaher barum (
Stemphylium botryosum;
S. sarcinaeforme
).
Leaf Spot
of clovers, Leaf
Blight of lilac,
Seed Mold
of China aster and
other plants. Spots on legumes are small, irregu-
lar, dark brown, sunken, changing to concentric
zonated light and dark brown areas. In final stages
leaves are wrinkled, dark brown, and sooty.
Conidia, like ascospores, are muriform, oliva-
ceous. Annual phlox has tan lesions. Asparagus
has purple spots.
Pleosphaerulina (Pringsheimia)
Entylomella
armoraciae
).
Pale Leaf Spot
of horseradish.
Ramularia pastinacae
armoraciae (see
▶
Ascomycetes, Sphaeriales,
Dothioraceae
Cercosporella
pastinaceae
).
Leaf Spot
of parsnip.
Ramularia primulae
Primrose
(see
▶
Perithecia innate, not beaked, paraphyses and
paraphysoids lacking; spores muriform, hyaline.
Pleosphaerulina sojicola (formerly
Pringsheimia sojicola
).
Leaf Spot
of soybean.
Leaf
Spot
.
Yellow blotches have ash-colored centers.
Ramularia vallisumbrosae
Narcissus White
Mold
, sometimes destructive on Pacific Coast.
Small, sunken, grayish or yellow spots appear
on leaves, especially near tips, increasing to
dark green to yellow-brown patches, on which,
in moist weather, spores are formed in white
powdery masses. The disease may become epi-
demic with the foliage killed several weeks
before normal ripening. Flower stalks of late
varieties may be attacked. Black “sclerotia” win-
ter in leaf fragments on ground, producing spores
in spring to infect young shoots.
Control
Spray with bordeaux mixture, starting
when leaves are 4 to 6 inches high. Clean bulbs
thoroughly after digging and replant in a new
location.
Ramularia variabilis
Foxglove Leaf Spot
.
Irregular spots, up to 1/4 inch in diameter,
brown with a reddish border, are formed most
often on lower leaves. Spores in tufts give
a white, moldy appearance.
Pseudocercosporella
Pseudocercosporella
capsellae
White
Leaf
Spot
on mustard greens.
Pyricularia
▶
Blights
.
Pyricularia grisea
Leaf Spot
on grass.
Ramularia
Deuteromycetes, Hyphomycetes
Conidiophores growing out from host through
stoma, clustered, short, dark to hyaline; conidia
hyaline, cylindrical, mostly two-celled, often in
