Biology Reference
In-Depth Information
of pale, dead areas with definite, reddish brown
borders. Spores are five-celled, with two or three
setae, usually knobbed. The fungus is a wound
parasite.
Pestalotiopsis quepini var. macrotricha (for-
merly
Pestalotia macrotricha
).
Rhododendron
Leaf Spot
, gray blight, twig blight, widespread
on azalea and rhododendron after winter injury.
Dark or pale spots with black raised pustules are
scattered over stems and leaves. Spots are often
silvery gray on upper surface and dark brown
underneath, with densely gregarious acervuli
sooty from dark spores.
Pestalotiopsis sydowiana (formerly
Pestalotia
rhododendri
).
Rhododendron Leaf Spot
. Black
pustules are scattered without order over dried
brown areas of living leaves. Spores are broader
than those of
P. macrotricha
and have shorter
setae.
Pezizella
(Discohainesia)
oenotherae (see
Discohainesia oenotherae
).
Leaf Spot
,
Fruit
Rot
of blackberry, raspberry, and strawberry;
leaf spot of evening primrose, eugenia, galax,
loosestrife, ludwigia, mock-strawberry, May-
apple, peony, and sumac.
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Phacidium
Phacidium curtisii
Tar Spot
,
Leaf Spot
of
American holly, more serious in southern com-
mercial plantings. Small yellow spots appearing
in early summer age to reddish brown with nar-
row yellow borders. At end of season flat, black,
cushion-shaped stromata develop beneath the
epidermis. Leaves seldom drop prematurely, but
infected areas may fall out leaving holes. In years
of heavy rainfall berries as well as leaves are
spotted. Remove lower branches; clean up and
burn or turn under fallen leaves. Spray with bor-
deaux mixture.
Pestalozziella
Deuteromycetes, Coelomycetes
Phaeosphaeria
Conidia hyaline, one-celled, with a branched
appendage at apex; acervuli subcutaneous;
conidophores slender, simple or branched.
Pestalozziella
Ascomycetes; Dothideales
subsessilis
Leaf
Spot
on
geranium.
Phaeosphaeria maydis
Leaf Spot
on sweet
corn.
Pezizella (Allophylaria)
Phaeotrichoconis
Ascomycetes, Helotiales
Deuteromycetes, Hyphomycetes
Apothecia sessile, bright-colored, smooth;
paraphyses filiform, blunt; spores elliptical to
fusoid, hyaline, one-celled.
Discohainesia oenotherae (formerly
Pezizella
(
Discohainesia
)
oenotherae
).
Leaf Spot
,
Fruit
Rot
of blackberry, raspberry, and strawberry;
leaf spot of evening primrose, eugenia, galax,
loosestrife, ludwigia, mock-strawberry, May-
apple, peony, and sumac. Spots are irregular,
gray in center with a dark brown border. Fruiting
bodies are light amber discs; spores are amber in
masse.
Phaeotrichoconis crotalariae
Leaf Spot
on
areca palm; leaf spots on palms which are similar
in appearance are caused more often by
Bipolaris, Helminthosporium setariae
and
Helminthosporium (Exserohilum) rostratum
.
Phloeospora
Blights
.
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