Shenandoah herald. [volume] (Woodstock, Va.) 1865-1974, 1911-07-28

BLlGnTS DISCUSSED.
[From winchester Star
During the past few weeks the
Agricultural Experiment Station
has been almost daily in receipt
of inquiries concerning the po-
tato blight and the bean blight.
and in travelling last week from
Blacksburg to Frederick county
/ had a chance to see the ext
teusive losses they have caused.
The loss from these blights will
rua up to thousands of dollars in
the Valley.
The potato crop is sueffring
from an epidemic of early blight,
SO called because it makes its
first appearance about the time
the potatoes are in blossom. 1t
is caused by fungus which at
tacks the potato leaves and
causes circular or eliptical brown
spots. The dead leaves are curl
ed, and eventually the fungus
kills the stock also. The ap-|
pearance of the disease at this
time of the development of the
potato plant stops the growth OF
the tubers, and the result is best
expressed by the well-worn
phrase, small potatoes and fewl
in the hill"
The early blight develops rap
idly in hot weather. and is favor
ed by the presence of insects,
tip-burn or any other unfavor-
able agent. Insects especially |
spread the disease by carrying
the germs on their mouth paris
and introducing these germs into
leaves which they bite or pune
ture. Therefore, the fewer iu-|
sects on the vines the less likely
they are to blight. The blight
itself can be prevented. however,
by spraying the vines with
Bordeaux mixture and doing it
early. OF course, it is too late
to spray now, after the vines are
half dead. The only thing to
do now is to dig the potatoes and
resolve to spray next year.
The bean blight, which is also
destructive this year, attacks
principally the bean leaves.
Irregular, water soaked patches
appear, especially at the mar
gins, and spread into the leaf.
Later, in dry weather, these
patches become brown and
papery. The death of so much
of the leaf tissue stops the form
alton of beans even if the diseas e |
does not always spread to the
pods.
= It is of very little use to spray
the vines With Bordeaux mixture,
the disease is caused by a germ
inside of ike plant. This germ
may live over on infected
seed; hence seed from a diseased
fiald, should not be used. Some
growers recommend the disinfec-
ton of the seed in hot water
before planting. They dip the
seed for ten minutes in water
having temperature of 122 de-
grees Fahrenheit; then keep the
treated seed out of any vessel
which have contained diseased
seed, or. better still, plant at
once.
Tis bean blight is also largely
spread by insects and may be
prevented by keeping the plants
free of leaf hoppers, lice, etc.
The point was brought to my
notice very recently by the ex-
perienco of a market gardener in
Roanoke county. He had sprav-
ed his bean field with kerosene
soap emulsion to kill leaf hop
pers. In this he was successful,
and by destroying the leaf hop
pers he kept his field entirely
free from blight, while all around
him other gardeners lost heavily
with blight.
Furthermore. it is advisable to
pull up and burn all blighted
plants which are done bearing.
By such preventive measures one
may more readily procure healthy
crops.
Howard S. REED,
Middletown Laboratory for Or
chard Diseases.