Burlington weekly free press. [volume] (Burlington, Vt.) 1866-1928, 1917-02-01
NEW POTATO DISEASE
Application Of Potash or Manure to
Soil Recommended.

y potato disease. appearing on certain
SOILS and apparently associated with the
lack or potash in the commercial fertiliz-
ers used, was prevalent last summer in
various sections of the East. According
to specialists of the bureau Of plant in
dustry United States Department of Agri-
culture. the trouble was largely control
ed 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
considerable areas. Last year the dis
ease was first observed late in June in
| Maryland and Virginia, and during the
I latter part Of July in Maine. The af-
| fected plants first develop a downward
rolling of the leaf margins, accompanied
10y a peculiar bronzins Of the surface
sometimes mistaken for spray injury
Since it occurs on unsprayed as well as
on sprayed plants. it can not be due to
the corrosive action of sprays. The foil
age gradually turns brown-not yellow
and the plants ripen pre-maturely
Death of the leaves and sudden collapse
of the stems at the ground level follow
The yield. of course. is much reduced.
Tie disease il found more commonly on
fields Of carly-maturing varieties, but is
not restricted to them. II also appears
first on early planted fields.
What is more striking is the very ap-
parent association of the trouble with
certain soil types AZ least in Maine.
where this relation. az well rs other fea-
lures Of the trouble. are being Investigate
| ed by the department experts in cooper
alton with the Maine Agricultural Expert
ment station.
! Soils which originally supported the
growth Of soft woods, or mixed growth
lands" developed the diseased condition
in its most severe tyne. while the hard
wood ridges showed II least or not at all.
! The trouble appeared first in the swales
/ or loWlands, where the natural drain
! age was not so good as on the higher
| ridge land. When the disease appeared
: at all on the higher ground, it was of n
/ less severe tyne.
Specific fungi are frequently found on
the stems Of the collapsng plants, and
! some of these most constantly seen be-
| long to disease prod groups. Their
/ relation to the trouble is being investi-
gated. but the present indications sug-
cest that they are not the primary cause
but have attacked the plants already
/ StiloHSlN Ntdhefltu DN OtHtf tE'iiNI'S'
Fertilizer experiments in progress on
affected fields demonstrated that the
plots receiving potash showed little 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 de-
partment are incomplete. but the present
indications are that it is due to insunclent
potash, or, perhaps, in some soils AT least,
to an excess Of ntrates in the presence
of a minimum potash supply. Farmers
who are unable to secure potash fertilizer
for their potato fields but who have stable
manure may insure their crops against
attack by its use. In sections Where GER
tain types of soil have been observed &c
suffer from the disease under discussion
and it IS advisable to plant potatoes on
these types next year. it is strongly rec
commended that potash fer'il'Zcrs or
stable manure he applied If either are
| obtainable,