Biology Reference
In-Depth Information
Control
Prune and burn dead twigs and heavily
infected branches; paint wounds with
a disinfectant followed by tree paint; avoid inju-
ries. Copper sprays may help.
Botryosphaeria stevensii Canker, on juniper.
Ceratocystis (Ceratostomella)
Ascomycetes, Micrascales
Perithecia with very long beaks, carbonaceous or
leathery; ascospores hyaline, one-celled; brown,
ovoid conidia and one-celled rodlike endospores
formed inside tubelike conidiophores and
extruded endwise. Some species are important
tree pathogens; see
▶
Oak Wilt and
▶
Dutch Elm
Disease under Wilts.
Ceratocystis fimbriata f. sp. platani (
Endo-
conidiophora fimbriata
f. sp.
platani
).
Canker
Stain of London Plane
,
Plane Blight
,onLondon
plane and also on American plane or sycamore.
This serious disease started as a killing
epidemic in the Philadelphia area about 1935,
destroying city shade trees by the thousands
there and in Baltimore during the next few
years. The disease now extends from New
Jersey to North Carolina and Mississippi.
Trees show sparse foliage, smaller leaves, and
elongated sunken cankers on trunks and larger
branches. Cross sections through cankers reveal
blue black or reddish brown discoloration of
wood, usually in wedge-shaped sectors. First
year cankers may not be more than 2 inches
wide and a yard or so long, but they widen
annually, girdling and killing trees in 3 to
5 years. Several cankers coalescing around the
trunk kill more quickly. Once infection starts,
thetreeisdoomed.
Ascospores and the two types of conidia are
produced in moist spring weather (see
Fig. 1
).
They may be spread by rain a short distance, but
most dissemination is by man in pruning opera-
tions, and ordinary tree paint carry viable spores.
Some beetles may be vectors. Infection is solely
through wounds.
Control
Do not try to save trees where trunk has
been invaded; diseased branches may sometimes
be removed, cutting at least 3 feet from infected
area. Do not prune unless absolutely necessary
and then only in winter when trees are less sus-
ceptible. Use tree wound dressing fortified with
a disinfectant.
Ceratocystis sp.
Canker
and
Dieback
on poplar.
Botrytis
Blights
.
Botrytis cinerea
Canker
of rose.
▶
Caliciopsis
Ascomycetes, Coryneliales
Stroma lobed, each lobe containing a single loc-
ule, which is finally wide open; perithecia
stalked; asci on long slender stalks; spores dark,
one-celled.
Caliciopsis pinea
Pine Canker
on eastern white
pine and other species, also on Douglas fir. Can-
kers are sharply depressed areas in bark, reddish
brown and smoother than rest of bark, up to
several inches in diameter. Small, globose, clus-
tered black pycnidia, and stalked perithecia
looking like slender black bristles, arise from
stroma in cankered bark. The disease is most
serious on suppressed saplings.
Encoelia (Cenangium)
Blights
.
Cenangium
▶
Encoelia
pruinosa
).
Sooty-Bark Canker
of aspen, on
Populus tremuloides
in Rocky Mountain area.
Encoelia pruinosa (formerly
Cenangium
singulare
).
Sooty-Bark Canker
of aspen, on
Populus tremuloides
in Rocky Mountain area.
Cankers on older trees, at any point on trunk up
to 60 to 70 feet may extend 10 to 15 feet before
they girdle the tree. The bark is sooty black with
a thin white outer layer.
singulare (see
▶
