The Barre daily times. (Barre, Vt.) 1897-1959, 1917-01-29
NEW POTATO DISEASE.
Prevalent Last Season in Eastern Sec
tons.

A potato disease appearing on certain
soils and apparently associated with thu
lack OF potash in the commercial fertil
izers used was prevalent last summer il
various sections of the east. According
to specialists of the bureau of plant in,
ldustry, the trouble was largely con
trolled by the use of stable manure. The
disease may be expected to appear again
with increased severity during the com,
ing season. in many potato-growing sec
tons, from Maine to Virginia, and prob
ably also farther south 1t was first
noted in scattered fields in 1915. In 1916
it became serious and general over con-
siderable areas, Last year the disease
was first observed late in June in Mary.
land and Virginia, and during the latter
part of July in Maine. The affected
plants first develop downward rolling
of the leaf margins, accompanied by a
peculiar bronzing of the surface, some
times mistaken for spray injury. Since
Int occurs on unsprayed as well as on
sprayed plants, it can not be due to the
corrosive action of sprays. The foliage
gradually turns brown-not yellow-and
the plants ripen prematurely. 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 commonly
on fields of early maturing varieties, but
is not restricted to them. 1t also APP
pears first on early planted fields.
What is more striking is the very APP
parent association of the trouble with
certain soil types, at least in Maine,
why're this relation, as well as other
features of the trouble, are being in
vestigated by the department experts in
cooperation with the Maine agricultural
experiment station.
Soils which originally supported the
growth of soft woods, or "mixed- growth
lands" developed the diseased condition
in its most severe type, while the hard
wood ridges showed il least or not at
all. The trouble appeared first in the
swales or loylands, where the natural
drainage was not so good as on the high
er ridge land. When the disease APP
peared at all on the higher ground, it
was of less severe type.
Specific fungi are frequently found on
the stems of the eollspsing plants, and
some of these most constantly seen be-
long to disease-producing groups. Their
relation TO the trouble is being investi- |
gated, but the present Indications sug- /
gest that they are not the primary cause |
but have attacked the plants already /
weakened by other agencies. |
Fertilizer experiments in progress on /
affected fields demonstrated that the /
plots receiving potash showed little OF no
signs OF the trouble, even where the |
other plots were entirely dead. Stable i
manure also held the disease in almost
complete control.
Investigations Of the trouble by the
apartment are incomplete, but the pres
mt Indications are that il is due 10 in.
potash, or, perhaps, in some
soils at least, 10 an excess Of nitrates in
he presence OF a minimum potash sup
Dly. Farmers who are unable To secure
potash fertilizer for their potato fields
lut who have stable manure nav insure
heir crops against attack by it, use
IN sections where certain types 81 soil
rave been observed 10 suffer from the
iiscase under discussion. and i IL advis.
,ble to plant potatoes on these types
text year. it = strongly recommended
hat potash fertilizers Or stable manure
e applied 4 either ere obiainsble.