Biology Reference
In-Depth Information
with raised, orange-cinnamon margin; stem
cankers circular to elliptical, wrinkled or fissured,
grayish white with raised orange margins.
Elsino¨ fawcettii
Sour Orange Scab
,
Citrus
Scab
,
Verrucosis
on citrus fruits, except rare on
sweet orange. Lemons, sour orange, King orange,
bitter orange, and calamondin are very suscepti-
ble; Mandarin and Satsuma oranges, tangerines,
and all grapefruit except Royal and Triumph are
moderately susceptible. Climatic conditions
play a part. Grapefruit and lemons in the
Rio Grande Valley are less susceptible than
in Florida, but Satsumas in Alabama are
more susceptible than those in Florida.
Known in the Orient since ancient times, scab is
believed to have come to Florida on Satsumas
from Japan. It was first recorded there in 1885;
the fungus was identified as a
Sphaceloma
in 1925.
Tender growth is most readily infected, and
the disease is most important on young trees. On
leaves, minute, semitranslucent spots change to
raised excrescences with corky crests, pale yel-
low to pinkish, then dull olive drab with a conical
depression opposite the crust. Foliage may be
wrinkled or stunted. Fruits have slightly raised
scabs or are warty with corky crests, which may
grow together into large irregular patches. Scabs
on grapefruit may flake off as the fruit matures,
with the area remaining green. Spores are spread
by wind, rain, dew-drip, possibly by insects. The
young fruit of grapefruit is very susceptible right
after petal fall, but becomes progressively resis-
tant and is practically immune when it reaches
3/4 inch in diameter. Temperature range for
severe infection is from 59
to 73
F. Excessive
nitrogen increases scab. The pathogen winters on
infected leaves, sometimes fruits.
Control
Apply a neutral copper spray or
bordeaux mixture just before growth starts in
spring. A second copper spray, just after flowers
shed, controls melanose as well as scab.
Elsino¨ ilicis
Chinese Holly Spot Anthracnose
.
Numerous black spots, 1 to 2 mm, coalesce to
large black patches on upperside of leaf mostly
the apical half, with distortion. Shoots and berries
have brown to gray lesions with slightly raised
margins.
Elsino¨ jasminae
Jasmine Scab
. Reported from
Florida. Spots numerous, round or irregular, up to
2 mm.
Elsino¨ ledi
Ledum Spot Anthracnose
, wide-
spread on ledum, Labrador tea, and salal in
Northwest, leucotho¨ in Florida. Leaf spots are
grayish white with red-brown borders and purple
margins. The disease is not serious.
Elsino¨ lepagei
Scab
on sapodilla and canistel
in Florida (found on young nursery stock in cans).
Small, raised spots, gray at center.
Elsino¨ leucospila
Camellia Scab
, also recorded
on ternstroemia in Florida. Some corky excres-
cences on camellia foliage are due to this patho-
gen, others to moisture relations.
Elsino¨ magnoliae
Magnolia Scab
on
Magno-
lia grandiflora
from Georgia to Louisiana. Spots
are circular to angular, with black papillae in
centers, on upper leaf surface along midrib, mar-
gin, or tip. Infected leaves may drop.
Elsino¨ mangiferae
Mango Scab
. Spots usually
originate on underside of young mango leaves but
become visible above. They are circular to angu-
lar, dark brown to black with olive buff centers.
Spots on mature leaves are larger, slightly raised
with narrow brown margins and dirty white cen-
ters. Stems have irregular grayish blotches; fruit,
gray to brown spots with dark margins.
Elsino¨ mattirolianum
Spot Anthracnose
on
madrona and strawberry tree (
Arbutus
spp.) in
California.
Elsino¨ parthenocissi
Virginia Creeper Soft
Anthracnose
. Leaf spots are few to numerous,
circular, scattered or along midribs and veins;
they have buff centers with narrow brown mar-
gins; fruit spots are grayish white; lesions on
petioles are somewhat
raised. Also reported
from pepper-vine.
Elsino¨ phaseoli
Lima Bean Scab
. First United
States report from North Carolina probably from
imported seed. Lesions on pods, stems, and
leaves.
Elsino¨ piri
Pome Fruit Spot Anthracnose
on
pear, apple, and quince in moist sections of west-
ern Washington and Oregon, more prevalent in
home gardens than commercial orchards. Fruit
spots are small, up to 2 mm, red or reddish purple
with pale centers, upwards of 100 on an apple.
