Biology Reference
In-Depth Information
Fig. 1
Peach Leaf Curl;
deformed leaf; palisade
layer of asci formed on
curled portion; germinating
spore
and one or all leaves from a bud. The leaves often
look as if a gathering string had been run along
the midvein and pulled tight. Leaves may drop,
lowering vitality of tree, with partial or total
failure to set fruit, and increasing chances of
winter injury. Young fruits may be distorted or
cracked. Defoliation for several seasons kills tree
outright.
The fungus has no summer stage, and the asci
are formed not in a fruiting body but in a layer
over infected surfaces, giving them a silvery
sheen. Before leaves fall, ascospores are
discharged from this layer, and land on bark or
twigs and bud scales, there to germinate by bud-
ding into yeastlike spores, which remain viable
over winter, sometimes for 2 years. In spring they
are washed by rain to opening leaf buds.
Control
One spray during the dormant season
gives effective control. This is best applied just
before the buds swell, but can be done any time
after leaf fall in autumn when the temperature is
above freezing. Applications after the buds swell
have little effect.
Taphrina faulliana
Leaf Blister
of Christmas
fern; T. filicina,
Taphrina japonica (
T. macrophylla
).
Leaf Curl
on red alder. Young leaves are enlarged to several
times normal size and curled. They dry up after
ascospore discharge, and a new crop of healthy
leaves is formed.
Taphrina populina
Leaf Blister
,
Yellow
on
poplar.
Taphrina populina
Poplar Yellow Leaf Blister
.
Conspicuous blisters, small to large, an inch or
more in diameter, are brilliant yellow on the
concave side when the asci are fully developed;
later the color changes to brown.
Taphrina robinsoniana, T. occidentalis,
T. alni
Catkin Hypertrophy
of alder. Scales of
catkins enlarge and project as reddish curled
tongues covered with a white glistening layer.
Infection can be reduced with a lime sulfur spray.
Taphrina sacchari
Maple Brown Leaf Blister
.
Taphrina ulmi
Elm Leaf Blister
. Very small
blisters on elm leaves. Dusting nursery trees
with sulfur has helped.
Taphrina weisneri
Cherry Witches' Broom
,
Leaf Curl
on wild and cultivated cherries, T.
flavorubra, on sand cherry; T. flectans, on west-
ern wild cherry; T. farlowii, leaf curl and fruit
pockets on eastern wild cherry; T. confusa,on
chokecherry; T. thomasii, witches' broom of
cherry-laurel in California.
on
sensitive
fern; T.
struthiopteridis, on ostrich fern.
Taphrina flava
Yellow Leaf Blister
of gray and
paper birches in northeastern states.
