The Bridgeport evening farmer., 1916-12-15

IS THREATENING
AMERICAN TREE

Washington, ID. C., Dec. IA. - The
| poplars of this country are now
threatened by a dangerous fungus dis
ease which has evidently been I'M
ported in recent years from Europe.
! This disease attacks the twigs, limbs,
and trunks Of the black and Lombar-
dy poplars (Populus nigra) and of the
Carolina poplars or cottonwoods (Pop-
| illus deltoides), and may be expected
to attack other species Of poplars and
cottonwoods, in regions not yet in
vestigated according to the plant pa
biologists of the U. S. Department Of
Agriculture.
This disease is caused by the fungus
Dothichiza populea. It occurs first
in the form Of cankers or depressed
dead areas in the bark much in the
same manner as in case Of the blight
Of chestnut trees, which is caused by
q distinctly different fungus. The
effect of the fungus on poplar and
cottonwood trees is as follows: Can
kers are formed at the point Of at
tack, spread rapidly and often gMdle
the twig, limb, or trunk at the point
Of attack, killing the part above the
canker. Trees attacked on the trunk
become spike topped" The death
Of limbs and twigs gives the trees a
ragged appearance, which spoils their
beauty, and later kills them. This
is especially the case with black pop
lars which are frequently planted in
rows along boulevards and avenues.
The European poplar-canker is most
severe in its effect on stored and trans
planted nursery stock. Trees when in
transit, and when heeled in the ground,
or freshly transplanted in the spring,
are readily attacked by the fungus and
ruined within a very short period of
time. This disease is spread by
means Of spores produced in fruiting
bodies in the form Of small pimples
or pustu1es in the bark of the cankers.
From these pustules in springtime
there are exuded small, sticky, cream
colored tendrils which soon change to
a tawny-olive or even a walnut-brown.
These tendrils contain millions Of
spores which spread the disease in va
rious ways
The fungus causing European pop
lar-canker was first found in Troyes,
| France, and described in 1884. In
1908 the first serious outbreak to be
noted was reported and the disease
described by the. French pathologist
u0iaCrOlX. sss An outbreak Oh the OlS-
ease in Italy was reported in 1907
| This disease was first reported in
America by a correspondent of the
Plant Disease Survey in 1915, from
| Massachusetts, and New Hamphire, but
| the causa1 fungus was not correctly
| identified During the present year
/ the pathologist Of the Department
found the disease prevalent in small
ar cas- in certain districts in the fol-
lowing states: New Hampshire, Mas
sachusetts, Rhode Island. Connecti-
| cut, New Jersey, Pennsylvania, Della
ware, Maryland, Ohio, Nebraska and
| New Mexico. The 1centers Of infec-
lttions appear to- be in every case either
certain nurseries now known to con-
tain diseased trees, or points where
poplars received from such nurser-
les have been planted. AS this dis
ease was not known In the United
States till recently, it is evidently an
| important one, and must be dealt with
as such. ~
| Additional information as to the ex-
tent Of the spread Of this new canker
disease in the country is desired. Own
ers Of diseased poplar or cottonwood
| trees may greatly assist If they will
notify the Bureau of Plant Industry,
u. 8. Department of Agriculture. =