Biology Reference
In-Depth Information
Leaf Blister and Leaf Curl Diseases
A single genus,
Taphrina
, is responsible for most
of the hyperplastic (overgrowth) deformities
known as leaf blister, leaf curl, or, occasionally,
as pockets.
undersurface, convex and yellow on the upper
surface. Individual blisters are 1/4 to 1/2 inch
across but often become confluent, causing the
leaf to curl. Ascospores are borne on the surface
of the blistered area. The disease is most serious
in a cool wet spring.
Control
A single dormant eradicant spray,
before the buds swell, controls the disease; later
sprays are ineffective.
Taphrina carnea
Birch Red Leaf Blister
.
Taphrina castanopsidis
California Chinquapin
Leaf Blister
.
Taphrina communis
Plum Pockets
, common
on American plums; T. pruni, on European spe-
cies, not in United States; T. prunisubcordata,
in western United States. Leaves, shoots and
fruits become puffy and enlarged into reddish or
white swollen bladders. Fruits are sometimes ten
times the size of normal plums. Most garden
plums are of foreign origin and not susceptible
to the American species of
Taphrina
. Bordeaux
mixture applied in spring before flower buds open
gives satisfactory control.
Taphrina coryli
Hazelnut Leaf Blister
.
Taphrina deformans
Peach Leaf Curl
, general
on peach, also on nectarine and almond but not on
apricot. This is an old disease, known in the
United States for well over a century but not
quite so important since 1900, when a control
was worked out. Young leaves are arched and
reddened, or paler than normal as they emerge
from the bud, then much curled, puckered, and
distorted, greatly increased in thickness (
Fig. 1
).
Any portion or the entire leaf may be curled,
Taphrina
Archiascomycetes, Taphrinales
Parasitic on vascular plants, causing hypertrophy.
Asci in a single palisade layer, not formed in
a fruiting body; hyphal cells become thin-walled
chlamydospores; on germination the inner spore
protrudes from the host and is cut off by a septum
to form an eight-spored ascus, which may
become many-spored
by
budding
or
the
ascospores.
Taphrina spp
Maple Leaf Blister
. Leaves after
expanding in spring show dark spots, shrivel, and
fall. The disease may be locally epidemic; it is
more common in shaded locations.
Taphrina aceris
Western Maple Leaf Blister
.
Taphrina aesculi
Leaf Blister
of California
buckeye; yellow turning to dull red; witches'
broom formed.
Taphrina australis
American Hornbean Leaf
Curl
.
Taphrina caerulescens
Oak Leaf Blister
on var-
ious oak species, with red oak particularly sus-
ceptible but often defoliating and sometimes
killing water, willow, laurel, and live oaks in the
South. Blisters start on young partially grown
leaves
as
gray
depressed
areas
on
the
