The Daily Sentinel

Reports have already begun
to come in of seed potatoes rotting
in the ground. The trouble
is caused by a fungus, or mould
that attacks the piece of the tuber
in the ground on the cut surface.
The disease was so bad
last year in some fields that
ninety per cent of the seed rotted
in the ground. In some cases
this rot started so soon as to
prevent the pieces of tubers
from sprouting at all.

In other cases it started later, rotted
the seed, then the fungus attacked
the stem. Plants may be found
in any field during the season more
or less affected with this disease.
The plants lose their green color and
the edges of the leaves turn yellow
or die. If the stem be pulled up, the
bark will be found all right, but the
splitting of the stem longitudinally
will show the sap wood of the stem
colored brown or yellow or in the
last stages black. Microscopical examinations
of a cross-section of the stem will show the fungus
growing in the cells and across the sap tubes
of the stem. The injury, to a large
extent, at least, comes from the clogging
of the sap circulation by the hyphia of this fungus.

This plant, or fungus, that causes
the disease, is one of the species of
Fusarium, the same or similar to the
one that causes the blight or so-called
"sleeping-disease" of the tomato. No
direct remedy is known for it. One
fact that is of some assistance in combating
it is that the disease is much
more prevalent on land previously
planted to potatoes than on alfalfa
or clover land. Another thing that is
quite noticeable in studying the nature
of the disease, is that potatoes
planted whole are not attacked to
such an extent as the cut ones because
of the inability of the fungus
to get into the stem.

Treatment of seed with formalin,
corrosive sublimate, sulphur, lime,
etc., have not given any perceptible
relief from it.

It is probable that in many cases
at least much of the disease is carried
to the field in the seed potatoes. The
same fungus causes the "dry rot" of
potatoes in the storage cellars. It
has been very noticeable during the
past winter that cellars with poor
ventilation, no matter how cool and
dry they were, had a high per cent
of potatoes affected with this dry rot.
Good ventilation and as low a temperature
without danger of frost in
the cellar is probably the best safeguard
against loss from this cause.

E. R. BENNETT.
Potato Specialist, Colorado Experiment
Station Fort Collins.