Biology Reference
In-Depth Information
Alternaria tenuissima (formerly
Alternaria
tomato
).
Nailhead Spot
of tomato, a leaf, stem,
and fruit spot. On leaves and stems the disease is
much like early blight (see
Aristastoma
Deuteromycetes, Coelomycetes
A. solani
under
Blights) with small dark brown spots with
yellow margins. But on fruit the disease is quite
different. Very small tan spots, 1/16 to 1/8 inch in
diameter, become slightly sunken, with grayish
brown centers and darker margins. Spores pro-
duced abundantly on fruit and foliage are spread
by winds and splashing rain. Treat seed and spray
as for early blight. Varieties Marglobe, Pritchard,
Glovel, and Break O'Day are quite resistant to
nailhead spot. The same fungus causes ghost spot
of apple.
Alternaria
▶
Pycnidia brown, globose, erumpent, separate,
with dark brown setae near ostiole;
conodiophores short, simple; conida hyaline,
several-celled.
Aristastoma oeconomicum
Zonate Leaf Spot
of cowpea, kidney bean.
Aristastoma sp.
Leaf Spot
on desert-rose.
Ascochyta
Alternaria
tenuissima
).
Nailhead Spot
of tomato, a leaf,
stem, and fruit spot.
Alternaria sp.
Leaf Spot
of schefflera, and
umbrella tree.
tomato (see
▶
Blights
.
Ascochyta abelmoschi (possibly identical with
A. phaseolorum
).
Leaf Spot
,
Pod Spot
,
Stem
Spot
of okra. Dark, small, water-soaked spots
slowly enlarge, turn brown, with many large
black pycnidia in concentric rings in dead tissue.
Young okra pods are severely infected, and the
mycelium grows into the seed.
Ascochyta althaeina (see
▶
Amerosporium
Deuteromycetes, Coelomycetes
Phoma exigna
).
Leaf Spot
of hollyhock, rose-mallow.
Ascochyta armoraciae
Leaf Spot
of horse-
radish.
Ascochyta aspidistrae
Aspidistra Leaf Spot
.
Large, irregular pale spots on leaves.
Ascochyta asteris (see
▶
Pycnidia superficial, discoid to cupulate, hairy;
spores one-celled, hyaline.
Amerosporium
trichellum (see
Colletotrichum trichellum
).
Leaf Spot
and
Stem Spot
on English ivy.
Colletotrichum trichellum (formerly
Amerosporium trichellum
).
Leaf Spot
and
Stem
Spot
on English ivy. In some cases stems are
girdled, causing collapse and death.
▶
Phoma exigna
).
Leaf
▶
Spot
of China aster.
Ascochyta
Stagonos-
poropsis hortensis
).
Leaf Spot
,
Pod Spot
of
beans, on snap, kidney, lima, and scarlet runner
beans, reported in Oregon.
Aschochyta
Leaf Spot
on big bluestem, little
bluestem (both species of
And ropogon
and on
indiangrass.
Ascochyta cheiranthi
Leaf and Stem Spot
of
wallflower. Grayish spots up to 1/2 inch
long, may girdle stems. Leaf spots are circular
to elongate, brown with darker brown
margins. Dark pycnidia contain hyaline, two-
celled spores. Leaves wilt and fall; potted plants
may be infected. Keep greenhouse on the
dry side.
boltshauseri
(see
▶
Annellophora
Deuteromycetes, Hyphomycetes
Conidiophores brown, simple, slender, elongat-
ing by successive proliferations through conidial
scars; conidia brown, multiseptate, obclavate to
fusoid.
Annellophora phoenicis
Leaf Spot
of date
palm.
