Vermont phÅ“nix. [volume] (Brattleboro, Vt.) 1834-1955, 1912-11-08
CHESTNUT BARK DISEASE.

The chestnut bark disease stands as
the most destructive plant disease that
has ever swept through this country
1t was first recognized in the vicinity of
New York city in 1904 (although prob
ably present some years earlier), and
has spread rapidly into at least ten
states and caused financial losses which
will no doubt exceed s25, 900, 900. So Sc
we're are it's ravages that thousands of
dollars are now being expended in efforts
to check it's spread into uninfected ter
ritory. 1t has demonstrated the neces-
sity for the study of the diseases of
plants and the Importance of precau-
tionary measures for the prevention and
spread of such pests.
The disease is caused by a fungus
(Diaporthe parasitica) which lives para
sitically in the bark sending it's minute
thread like processes in all directions
from the point of attack until the trunk
or branch is completely girdled, after
which all beyond this point dies On
the younger parts on which the bark is
smooth the disease appears as slightly
discolored sunken areas which gradu-
ally enlarge and finally become covered
with yellow. orange or reddish brown
spots about the size of a pin head.
These spots are the fruiting bodies which
in damp weather produce great masses
of spores for the distribution of the
fungus. On the older branches and trunk
where the bark has become thick and
rough, there Is no marked change in ap-
pearance. but the fruiting bodies may be
seen in the cracks. after the death of
the tree the fruit fungus continues to
live and spread into the dead bark and
may produce fruitng bodies for a num-
Der of years and must always be looked
upon as source for the spread OF the
disease. The leaves and burs on branch
es which have been killed by the disease
become discolored and do not fall as
readily as those killed by frost. Dis
ca sed trees which are not killed quickly
produce great numbers of sprouts at the
base and just below the points of in
lection. These young sprouts are very
susceptible to the disease and usually die
either the second or third year.
1t is very doubtful If the fungus can
gain entrance to a tree except through
wounds. 1t is probably carried from
place to place by boring insects, and by
birds Especially woodpeckers). 1t is
also carried on infected timber shipped
into uninfected territory. Many new
points of infection have been traced to
diseased nursery stock. Nurserymen
should use every caution to prevent the
spread OF the disease by keeping a care
full oversight OF their stock Unfortu-
nately, the disease cannot always be de-
tected at the time of shipment and must
be kept under careful supervision by the
grower.
The spread Of the disease has been so
rapid, the destruction OF our chestnut
growth 80 great. and the financial losses
so heavy that It has attracted the at
tention OF the scientists OF the United
States department of agriculture and OF
the section OF country over which 1t Is
spread. Large sums Of money are being
expended in fighting It, but up to the
present time no satisfactory or econom-
ical method has been devised. The
planting OF chestnuts In the infected dis
tricts Is a waste Of both time and mon
ey and cannot be recommended. Indi-
viduai trees and small paintings may be
protected to some extent by frequent
cutting out Of the diseased parts and
painting the wounds with coal tar. In
doing this all the prunings must be
burned.
When forest areas become affected,
their final destruction IL practically GER
tain, and the owners are advised to con-
vert the entire chestnut growth into
salable material as rapidly as possible
Otherwise, IT will prove complete loss
Material too small for lumber should