The Idaho Republican. [volume] (Blackfoot, Idaho) 1904-1932, 1913-08-15

QlSIrlcC III the CluD Oh COmmeTCt
rooms, Idaho Falls, by Harry B. Shaw
pathologist in charge of federal ex.
pertinent station Jerome, Idaho.
Potato Diseases Prevalent in Cellars
A tour over the principal potato
growing districts of Idaho and in in
spection 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-
4ent 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 Plant
ing Seed Potatoes
At the close of this tour suggestions
were offered for the selection and
treatment of seed potatoes prior to
planting; hints we're 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 and bear
sound potatoes, pocket of infected
soil would be created, and the germs
or spores of the disease-producing
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
This powdery dry-rot is caused by a
fungus which attacks potatoes in stor-
age. Although the spores of this fun
gus may be presented upon the tubers
when harvested, they have not 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 a
certain amount of heat and moisture
for its 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 DO
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 suspectible to these particu-
lar germs are grown there. Therefore
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
practiced 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 Rhizoctonia
scabs: 1t was recommended that seed
potatoes be treated with solution of
formaldehyde, pint go 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 GO pct.) 3 pints.
Permanganate of potassium 23 OF.
This amount to be used for every
1000 cubic feet of space in the cellar
which should be closed for at least
"a hours, at temperature of not less
than 60 degrees F.
The writer is pleased to state that
a numbers of growers accepted and
followed the advice offered at that
time. He personally fumigated a
arge cellar at the owners request