The Challis messenger. (Challis, Idaho) 1912-current, 1922-04-19
seed Potato Treatment
, ~. Is. l.. richards, Associate
1'":anist, Experiment Sutton.
Utah Agricultural College

AAAAoAS It.)Us
Ctah Agricultural CoIl.vs
increased activity In seed potato
1ouuction and certificatien In tho
"es' together with a clearer daf,nL
s.'n OF standards has focused atteu.
'''n more definitely upon the potato
Us product free from disease and
upon seed treatment as an aid In
ciean seed production. In the process
o. seed treatment we are concerned
primarily with three disases az III.
p~'ato plant al Of which are serious
N Utah and throughout the 1ntar.
mountain region: scab, stem eanksr.
'"alzoctonia) and Black lsa. The
organisms which cause these disease,
are all tuber borne and al such ara
latFoouced each year into large areas
Of clean land rendering them unfit
for potato production. It is definite.
|! Known that these organisms when
planted with the seed result In 4 DE-
creased yield and In the production Of
suDers inferior both for the market
and for seed purposes. Further II
must be remembered that the scab
ana the stem canker organisms once
introduced into the soil may live there
Indefinitely and seriously damage 9th.
or and succeeding crops.
Inc disease organisms as they an
pear on the surface of the tubers arc
very resistant to the action of chem.
icals and rather severe methods are
necessary to destroy them.
For treating seed potatoes two stand
ard disinfectants have been used:
formafdehyde, one pint to thirty gal
Ions OF water. and mersurIc chloride.
ounces to thirty gallons Of water.
The formaldehyde treatment is not
effective against Rhizoctonla at ordin
airy temperatures and is therefore not
to be generally recommended. The
mercuric chloride method on the Other
hand when properly applied has given
INFORMALLY good results.
A number of precautions are neces
sary, however, in the application OF
mercuric chloride to the surface Of
the potato tuber. In the first place
1t must be recognized that the potato
tuber Is living structure and as such
is most resistant to the action Of
mercuric chloride when in a dormant
or resting state. With the earliest
signs Of sprouting the eyes Of thu
tubes becomes very liable to injury
from this chemical and considerable
damage may result in treatment at
this particular stage. Early treatment
Is therefore advisable.
Again it has been determined that
damage to the seed may result from
the continued action Of mereuric
chloride If the tubers are allowed to
remain wet for a considerable period
after treatment. Rapid drying Of the
tubers will eliminate this danger and
will further add to the effectiveness
of the treatment by depositing q
slight film Of the poison on the sur
face of the potatoes.
A further protective precaution
must be taken against too rapid re-
duction of strength Of the treating so.
luton. The surface Of the tubera
rather rapidly absorbs the mercuric
chloride in solution as do also the
sacks and any other organic materials
that may be introduced with the seed.
Where necessary to use sacks a few
should be previously treated for 2
hours in a solution Of mercuric chlor.
ide and then used repeatedly with sue
cessive lots of potatoes.
Details for treatment are as fol.
lows:
SELECT only those tubers for treat
ment which are free from burises,
decayed spots and internal browning
TREAT UNCUT SEED as early as
possible in the spring. at least ten
DAYS or two weeks before planting
Avoid the use Of sacks in treating
Keep seed in a clean place and IN
sterile sacks after treating and drying
PROPER STRENGTH, Mercuric
Chloride. ounces to 30 gallons OF
water. u: 1000.
TIME OF TREATMENT. Dormant
seed u hours. II tubers have started
to sprout and show but little disease
reduce the time. but in all cases soak
the seed for at least a hour. Soak
ing for "a hours in cold water before
treatment will greatly aid In destroy
ing the disease germs.
DRY POTATOES as rapidly as pos
sible after treatment. For early crop
where convenient green" the tubers
IN the sun for few days befor plant
ing.
KEEP UP STRENGTH OF soLu
TON by adding 3-S ounce OF mercurit
chloride after treating each foul
bushels of potatoes treated for one
and one half hours and restore the
Volume Of water to its original 30 gal
Ions.
DISCARD SOLUTION after the
third or fourth treatment where nc
chamical is added. 1t is also neces