Catoctin clarion., 1915-06-03
Blight Of Apple And Pair.

Blight is now prevalent on apple and
pear trees in nearly all parts of Mary
land. On some apple trees practically
all the fruit has been destroyed. The
loss in many orchards in the State is
very serious.
This disease has been present to some
extent ever since fruit was first grown
in this country, but some years becomes
worse than usual. It is also found on
wild hawthorn, crab-apple, service berry,
and on many similar cultivated shrubs.
1t is very injurious to ounces.
The blight first appears in the blossoms,
where the bacteria which cause it are
carried by bees, or sometimes other IN
sects. The germs multiply in the nec-
tar of the flowers, and from single
such flower, bees may infect the whole
orchard.
The disease spreads downward from
the flowers between the wood and bark,
killing two to ten inches of the twig a
day, but later it progresses more slowly,
and in apples usually dies out on the
young twigs; but sometimes, and usually
in pear, 1t keeps extending, killing large
branches, or the whole tree, or forming
cankers in the bark in which the bacteria
begin to multiply in the exuding sap
around the cankers, or sometimes in
late infected twigs. This is the source
of infection in the spring
The blight often goes through short
spurs, or sprouts, or wounds Of any kind,
into the body Of the tree. even near or
below the ground. Many trees or large
branches are girdled and die In this way
every year.
CONTROL.
The most effective treatment consists
in cutting out the diseased parts. In
young orchards and in nurseries where
there Is naturally but little blight, and
in old orchards In seasons when blight is
not serious, by cutting out every blight
ed twig and canker as soon as possible,
giving special attention to the body and
base of the tree, bad outbreak may be
prevented in following years. 1t is also
necessary to destroy all blight in the
neighborhopd on wild or cultivated trees
as the bees may carry it long distances.
Bees are, however, necessary to pollen
ate the flowers.
When old bearing trees are badly in
fected, winter Is the best time to cut o ut
the blight. The cuts on large branches
or in the trunk should be brushed with a
disinfectant and when dry protected by
painting with white lead in linseed oil.
In cutting blight in the growing season,
it is important to wipe the pruning in
strument after each cut on a cloth or
sponge wet with either carbolic acid,
concentrated lime-sulphur, Ave per cent
formalin, or other disinfectant to pre-
vent reinfection Of the next cut. Cut
twigs several inches below where the
blight shows, as in spring the germs ex-
tend much farther in than they show on
the outside.
Keep water sprouts and all spurs off
the trunk and main limbs of pear and
susceptible apple varieties so that one
useless blighted spur or sprout may not
girdle and destroy a whole branch of
tree.
Some varieties such as Yellow Trans
parent. Wealthy, York Imperial and Fall
Pippin apple and Bartlett pear are very
susceptible, others like Keffer and Wine
sap are less injured.
1t will be seen from the above that
little can be done now in badly affected
orchards to prevent further injury this
season, but the community should organ
ize to prevent the spread of this serious
disease another year.
j. q. S. NORTON,
State Pathologist.