Rusts - Westcott's Plant Disease - page 324

invariably a Cronartium , although this stage has
often gone under the name of Peridermium .
Cronartium appalachianum ( Peridermium
appalachianum ). I on Virginia pine, North Caro-
lina, Tennessee, Virginia, West Virginia.
Girdling bark lesions with columnar aecia.
Cronartium coleosporioides Ponderosa Pine
Rust , widespread in Rocky Mountains; II, III on
Indian paintbrush.
Cronartium coleosporioides ( C.
filamentosum ). Western Gall Rust , Paintbrush
Blister Rust . 0, I on lodgepole, ponderosa and
Jeffrey pines, in West; II, III on Indian paint-
brush, birds-beak, owls-clover and wood-betony.
Slight swellings are formed on twigs, trunks, and
branches; many lodgepole pine seedlings are
killed.
Cronartium comandrae Comandra Blister
Rust . 0, I on ponderosa, Arizona, and lodgepole
pines in West and pitch, mountain, jack, loblolly,
Austrian, Scotch, and maritime pines in the East;
II, III on bastard toadflax ( Comandra spp.).
Destructive effect is limited to distribution of
toadflax, which is widespread but locally
restricted to small areas. Ponderosa pine
suffers most severely, with many seedlings and
saplings destroyed; occasionally a large tree is
attacked.
Cronartium comptoniae Sweet-Fern Blister
Rust .0, I on two-and three-needle pines; II, III
on sweet-fern and sweet gale in northern pine
regions and south to North Carolina, and on
Pacific wax-myrtle on Pacific Coast. Young
pines may be girdled and killed, but are fairly
safe after attaining a trunk diameter of 3 inches.
Losses in nurseries and plantations are high,
especially among lodgepole and ponderosa
pines. Affected stems swell slightly near the
base with long fusiform swellings or depressed
streaks on eastern hard pine; pitch oozes out from
insect wounds in these areas. Killing of main
stem often results in multiple-stemmed shrublike
trees. Orange aecia appear on 3-year seedlings,
preceded by pycnia the year before; spores are
wind-borne many miles to herbaceous hosts.
Control Remove Myrica species for several hun-
dred yards around nurseries or pine plantations,
and allow no large groups within a mile.

Cronartium conigenum Pine Cone Rust .0,I
on cones of Chihuahua pine; II, III on oaks in
Southwest. Cones develop in large galls produc-
ing aecia with distinct, erumpent peridium 2 or
3 years after infection.
Cronartium harknessii Endocronartium

harknessii ). Western Gall Rust . 0, I on Jeffrey,
ponderosa, lodgepole, and digger pines; II, III on
Indian paintbrush, lousewort, owls-clover, or
omitted, with direct infection from pine to pine.
Cronartium occidentale Pinon Blister Rust .0,I
in pinon and Mexican pinon; II, III on currant,
gooseberry and flowering currant. This rust can-
not be told from whitepine blister rust on Ribes
hosts, but is differentiated by the type of pine
attacked. Aecia on Mexican or single leaf pinon
are distinct sori; on pinon they form broad layers
under bark.
Cronartium quercuum f. sp. fusiforme Rust
on pine.
Cronartium quercuum f. sp. fusiforme -
Southern Fusiform Rust , 0, I on hard pines in
southern states, especially loblolly, slash, and
pitch pine; II, III on evergreen oaks on underside
of leaves. Pine stems have pronounced spindle-
shaped swellings, sometimes with witches'
broom. Branch infections that do not reach the
main trunk are not serious, but those that go on to
the trunk may kill the tree. Longleaf pines are
rather resistant, and shortleaf P. echinata almost
immune. Pines well spaced in good locations
grow more rapidly and may have more rust than
those in poor sites. It has also been reported on
oaks.
Control Prune branches yearly before swellings
reach main stem.
Cronartium quercuum ( C. cerebrum ) Eastern
Gall Rust . 0, I on pines, especially scrub and
shortleaf in the South; II, III on chestnut, tanbark
and oak. Globose to subglobose galls are formed
on pine stems; in spring aecia break through the
bark in more or

(see

▶

less cerebroid (brainlike)

arrangement.
Cronartium ribicola White Pine Blister Rust .
0, I on eastern white pine from Maine to Virginia
and Minnesota, on western white pine in the
Pacific Northwest, on sugar pine in California;
II, III on currant, flowering currant and