The Bridgeport evening farmer. [volume] (Bridgeport, Conn.) 1866-1917, 1917-01-31
NEW POTATO DISEASE.

A potato disease appearing on GER
tain soils and apparently associated
with the lack of potash in the COM
mercial fertilizers used was prevalent
last summer in various sections OF the
East. According to specialists of the
Bureau of Plant Industry, United
States Department of Agriculture. the
trouble was largely controlled by the
use Of stable manure. The disease
may be expected to appear again with
increased severity during the coming
season in many potato-growing sec
tons, from Maine to Virginia, and
probably also farther south. 1t was
first noted in scattered fields in 1915.
In 1916 it became serious and gen.
eral over considerable areas Last
year the disease was first observed
late in June in Maryland and Virginia
and during the latter part Of July IN
Maine. The affected plants first de-
velop a downward rolling of the leaf
margins, accompanied by a peculiar
bronzing of the surface, sometimes
mistaken for spray injury. Since 1t
occurs on unsprayed as well as on
sprayed plants, it can not be due TO
the corrosive action of sprays. me
foliage gradually turns brown-not
yellow-and the plants ripen prema-
turely. Death of the leaves and
sudden collapse of the stems at the
ground level 'follow.\ The yield, OF
course, is much reduced.
The disease is found more COM
monty on fields Of early-maturlng va
rieties, but is not restricted to them.
It also appears first on early planted
fields.
What is more striking is the very
apparent association of the trouble
with certain soil types, at least, IN
Maine, where this relation, as well
as other features of the trouble, are
being Investigated by the department
experts in cooperation with the
Maine Agricultural Experiment. Sta
ton.
Soils which originally supported
the growth of soft woods, or mixed
growth lands developed the diseas-
/, ed condition in it's most severe type,
while the hardwood ridges showed it
least or not at all. The trouble APP
peared first in the swales or lowlands,
where the natural drainage was not
so good as on the higher ridge land.
When the disease appeared at all on
the higher ground, it was of a less
severe type. u
Specific fungi are frequently found
on the stems Of the collapsing plants,
and some Of these most constantly
seen belong to disease-producing
groups. Their relation to the trou-
BILE is being investigated, but the
present indications suggest that they
are not the primary cause but have
attacked the plants already seriously
weakened by other agencies.
Fertilizer experiments in progress
on affected fields demonstrated that
the plots receiving potash showed lit
tie or no signs of the trouble, even
where the other plots were entirely
dead. Stable manure also held the
disease in almost complete control.
Investigations of the trouble by the
department are incomplete, but the
present indications are that it is due
to insufficient potash, or, perhaps, In
some soils at least, to an excess Of
nitrates in the presence Of a minimum
potash supply. Farmers who are
unable to secure potash fertilizer for
their potato fields but who have sta
BILE manure may insure their crops
against attack by it's use. In sec
tions where certain types of soil have
been observed to suffer from the dis
able to plant potatoes on these types
next year, it is strongly recommend
ed that potash fertilizer or stable
manure be applied if either are OBJ
tainable.