The Blackfoot optimist. [volume] (Blackfoot, Idaho) 1907-1918, 1913-08-14
POTATO SITUA-
TON in DETAIL
FEDERAL PATHOLOGIsT At IDA.
Ho EXPERIMENT STATION
MAKES REPORT
PLANTING AND CARE
Disease Conditions Which Exist En-.
tireIy PreventabIe by Careful
Study Of Situation

Study OF Situation
Paper read before meeting of DO
tato growers Of the Idaho Falls, Idaho,
district in the Club of Commerce
pathOlogist in charge of federal ex-
pertinent station, Jerome, Idaho.
Potato Diseases Prevalent in Cellars
A tour over the principal po-
tato growing districts of Idaho and in
inspection of potato cellars and pits
during early spring Of the present
season revealed the presence of an
amount of diseased potatoes Outlines
alarming. The most serious and preva
lent disease was the powdery dry rot
About equally prevalent, but less de-
structive, was Rhizoctonia scab. The
common potato scab was nowhere
found to be abundant.
Suggestions for Selecting and Planting
Seed Potatoes
At the close of this tour suggestions
were offered for the selection and
treatment of seed potatoes prior to
planting; hints were also given for
the choice and preparation of ground
in which to plant selected tubers. The
potato growers were cautioned TO Sc
lect only seed potatoes entirely free
from symptoms of disease, most care
fully culling out any showing rotted
areas, not even using the apparently
sound portions of such tubers.
Diseased Potatoes Infect the Soil
This advice was given because the
planting of potatoes thus diseased
would inevitably infect the ground in
which they were planted and, although
cuttings affected with dry rot might
in many cases terminate end bear
sound potatoes, a pocket of infected
soil would be created, and the germs
or spores of tie disease-producin
fungus would probably come in CON
tact with, and remain upon, the sur
face OF any potatoes obtained from
diseased cuttings. Should conditions
be favorable these spores would GER
inmate in bruised places on potatoes
in storage.
The Powdery Dry-Rot a Storage
Disease
The powdery dry-rCt is caused by a
fungus which attacks potatoes in stor-
age. Although the spores Of this fun
gus may be present upon the tubers
when harvested, they have net at that
time produced any rot. This fungus
attacks the potatoes during storage,
chiefly through wounds in the skin,
whence under favorable moisture and
temperature conditions it may develop
rapidly until the infected potato be-
comes wholly or in part rotten and
conveys the disease to other potatoes.
Unfortunately for us, this fungus,
which, like other plants, requires
certain amount of heat and moisture
for it's development, is capable of
growing at the comparatively low
temperature of 81 degrees F. and is
generally able to obtain moisture
enough from the mass of stored pc
tatoes, especially if the cellar be not
we'll ventilated.
Rotation Necessary to Rid the Soil
Of Disease
Once infected with this and some
other fungus diseases, the soil re-
quires several years to become rid of
the disease germs; and then only when
no crops susceptible to these particu-
lar germs are grown there. Therefore
a rotation of four or five years should
always be practiced There is land
enough available to do this even
where potatoes. are most extensively
grown. 1t is safe to predict that if
this and careful seed selection be not
practised a fate similar to that now
so greatly reducing the yields of one
of COlorado's great potato districts
will overtake the potato districts of
Idaho.
Treatment to Prevent the Spread of
Scab
AS for the common and RhZoctonia
scabs: 1t was recommended that seed
potatoes be treated with solution o.
formaldehyde, l pint Gao per cent? to
30 gallons of water, for 2 hours, or
fumigated with formic acid gas-gen-
Grated by pouring 40 per cent formal
dehyde upon permanganate of potas-
SUM in the following proportions:
Formaldehyde GAO per cent 8 pints
PermanSanate of potassium 90 o.
This amount to be used for every
1000 cubic feet of space in the cellar,
which should be closed for at least
than 60 degrees F.
AAAO "AAeSA 40 PISe>oCo " OIdtS llldJ
q number of growers accepted and
followed the advice offered at that
time. He personally fumieated a
large cellar at the owners request.
while another extensive potato grower
constructed fumigating chamber
within his cellar, in which 800 to 500
sacks of potatoes could be fumigated
at once. Many growers soaked their
seei potatoes in formaldehyde solu-
ton.
Formaldehyde Treatment Of Seed Po-
tatoes Will Not Destroy the Dry
Rot Infections
Unfortunately for themselves, how
ever, many growers neglected both the |
culling out of diseased seed stock and
the treatment of the seed before plant
ing, still others treated their seed with |