Biology Reference
In-Depth Information
Control Knock off old shucks and leaf stems
before trees leaf out in spring. When they are
wet after a rain, a slight jarring of branches will
make such diseased material drop. Prune off low
limbs for better air circulation. Four protectant
sprays are required in Georgia, five in Florida.
Cladosporium cladosporioides f. sp. pisicola
(formerly Cladosporium pisicola ). Pea Scab ,
Black Spot of pea. Dark spots covered with
velvety mold are formed in moist weather on
leaves, stems, where black streaks may develop
into cankers and pods may be distorted. The
fungus is seed-borne, and lives in soil in plant
refuse.
Cladosporium coreopsidis Reported on core-
opsis in Wisconsin, causing stunting and suppres-
sion of flowering.
Cladosporium cucumerinum Cucumber
Scab , general on cucumber in greenhouses, an
important transit and storage decay of musk-
melon, sometimes serious on late-planted squash.
The disease was first noted in New York in 1887.
Leaves with water-soaked spots may wilt, stems
have slight cankers, but most injury is to the fruit.
First symptoms, while cucumbers are still small,
are gray, slightly sunken spots, sometimes exud-
ing a gummy substance. They darken with age,
and the collapsed tissue forms a pronounced cav-
ity, lined with a dark green velvety layer of
greenish mycelium, short conidophores, and
dark, one-to two-celled spores. On leaves, these
fruiting fascicles are extruded through stomata.
The disease becomes epidemic after mid-sum-
mer, when night temperatures are cold or with
heavy dews and fog.
Control Resistant cucumber varieties include
Maine No. 2, Wisconsin SR 10, SR 6, and
Highmoor. A long rotation is advised.
Cladosporium pisicola
Spilocaea (Fusicladium)
Leaf Spots .
Fusicladium dendriticum (see
Spilocaea
pomi ). Conidial stage of the apple-scab fungus.
Venturia inaequalis .
Fusicladium eriobotryae (see
Spilocaea
pyracanthae ). Loquat Scab , widespread on
leaves, stems, fruit of loquat.
Fusicladium photinicola (see
Spilocaea
photinicola ). Christmasberry Scab on Photinia
arbutifolia .
Fusicladium pyracanthae (see
Spilocaea
photinicola ). Pyracantha Scab , widespread on
leaves and fruit.
Fusicladium saliciperdum (Syn.
Venturia
Pollaccia saliciperda ).
Willow Scab , Blight , first noticed on willow in
Connecticut in 1927, apparently introduced from
Europe.
Pollaccia saliciperda (formerly Fusicladium
saliciperdum (Syn. Venturia chlorospora ). Wil-
low Scab , Blight , first noticed on willow in Con-
necticut in 1927, apparently introduced from
Europe. Repeated defoliation has killed thou-
sands of trees in the Northeast. Young leaves
are attacked and of ten killed in spring, almost
within a few hours, and from the leaf blades the
fungus enters twigs, kills back young shoots, and
causes cankers. Olive green felty spore masses are
formed on the long veins on underside of leaves.
Overwintering is as dormant mycelium in twigs
infected the previous spring. Another fungus,
Physalospora miyabeana , is found with the scab
fungus, and the two together form the disease
complex known as willow blight. Physalospora
usually attacks later in the season than
Fusicladium and causes cankers on larger stems.
Control Prune heavily to remove diseased parts.
Spray with bordeaux with excess lime.
Spilocaea photinicola (formerly Fusicladium
photinicola ). Christmasberry Scab on Photinia
arbutifolia . Brown velvety spots appear on
leaves, flower stalks, and green berries; the
berries being disfigured when mature. Prune in
winter to remove dead wood and foliage. Spray
before blossoming with bordeaux mixture.
chlorospora)
(see
Cladosporium
cladosporioides f. sp. pisicola ). Pea Scab , Black
Spot of pea.
(see
Fusarium
Rots .
Fusarium heterosporum Head Scab of tall
fescue.
 
 
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