Biology Reference
In-Depth Information
Bordeaux mixture and other copper sprays
have been recommended. Spray applications
should start soon after plants are set and be
repeated weekly, or more often. Emerson Pascal
is blight-resistant.
Cercospora carotae
Early Blight
of
carrot. Lesions on leaves and stems are
subcircular to elliptic, pale tan to gray or
brown or almost black; lobes or entire leaflets
are killed. The disease is more severe on young
leaves and builds up as the plant grows. Spores,
produced on both leaf surfaces, are spread by
wind.
Control
Rotate crops and clean up refuse.
Cercospora microsora
Linden Leaf Blight
,
general on American and European linden.
Small circular brown spots with darker borders
coalesce to form large, blighted areas, often
followed by defoliation; most serious on young
trees.
Cercospora sequoiae
Arborvitae Blight
,
Fire
Blight
, on oriental arborvitae and Italian cypress
in the South; destructive in ornamental plants.
First reported from Louisiana in 1943, the fungus
was named as a new species of
Cercospora
in
1945, but it is nearer
Heterosporium
in spore
character. Affected leaves and branchlets are
killed, turn brown, and gradually fall off, leaving
shrubs thin and ragged. The lower two-thirds of
the bush is affected most severely, with a tuft of
healthy growth at the top. When close to a house,
the side away from the wall shows most symp-
toms. Plants crowded in nurseries are killed in
1 to 3 years, but in home gardens they may persist
for years in an unsightly condition. Conidio-
phores in fascicles produce conidia after girdling
cankers have killed the twigs. There is often
a swelling above the girdle that resembles an
insect gall.
Cercospora sordida (
Mycosphaerella tecomae
)
(see
be purplish; the fungus fruits on underside of
leaves. The blight is seldom important enough
to warrant control measures.
Cercosporidium
Cercosporidium punctum
Stem and Foliage
Blight
of fennel.
Choanephora
Zygomycetes, Mucorales
Mycelium profuse; sporangia and conidia pre-
sent; sporangiola lacking. Sporangium pendent
on recurved end of an erect, unbranched sporan-
giophore with a columella, containing spores
provided at both ends and sometimes at the side
with a cluster of fine, radiating appendages.
Conidia formed in heads on a few short branches
or
an erect
conidiophore
enlarged at
the
tip;
conidia
longitudinally
striate, without
appendanges.
Choanephora cucurbitarum
Blossom Blight
,
Fruit Rot
, common on summer squash and pump-
kin, occasional on amaranth, cowpea, cucumber,
okra, and pepper; on sweet potato foliage, on
fading hibiscus, on vinca, and other flowers.
This blight is often found in home gardens in
seasons of high humidity and rainfall. Flowers
and young fruits are covered with a luxuriant
fungus growth, first white, then brown to purple
with a definite metallic luster. The fruiting bodies
look like little pins stuck through this growth.
Both staminate and pistillate flowers are infected,
and from the latter the fungus advances into
young fruits, producing a soft wet rot at the blos-
som end. In severe cases all flowers are blighted
or fruits rotted.
Control
Grow plants on well-drained land;
rotate crops. Remove infected flowers and fruits
as noticed.
Choanephora infundibulifera
Blossom
Blight
on hibiscus and jasmine.
Leaf Blight
on
soybean.
Pseudocercospora sordida
)
Trumpetvine
Leaf Blight
▶
from New Jersey to Iowa and
southward.
Pseudocercospora sordida (formerly
Cercospora sordida
)(
Mycosphaerella tecomae
).
Trumpetvine Leaf Blight
from New Jersey to
Iowa and southward. Small, angular, sordid
brown patches run together; edge of leaflets may
