White Bluffs spokesman. [volume] (White Bluffs, Wash.) 1907-1938, 1926-05-28
What Kind of Potato Seed
Are You Going to Plant?
BY George L. ZundeI, Extension Spe-
ciaIist in Plant Diseases, State
College of Washington

At this season of the year the ques-
ton that is uppermost in the minds
Of Washington potato growers is,
what kind of seed shall / plant this
year? Too frequently farmers fail to
realize that it always pays to secure
the best seed available even though
they have to plant a smaller acreage.
In selecting seed the purchaser
wants to know what constitutes good
seed. Good potato seed is fairly true
to type of the specific variety, some
what smooth, not fully matured and
free from fungus diseases on the
exterior. The disease question is the
most important one to consider.
If potatoes have been grown in
rather clay soil and are therefore
somewhat misshapen it will not
necessarily exclude them from the
class of good seed. If potatoes are
raised in sand or other loose types
of soil and have a good variatel shape
they are not necessarily good seed if
very much disease is present. While
we do not want the fungus diseases,
portant thing for the seed grower to
determine is the presence or absence
such as rhizoctonia and scab, the i'm
of the virus diseases such as mosaic,
leaf roll, spindle tube, etc. These
diseases can only be determined by
field inspection and for this reason
it is necessary to use certified or
other high grade seed that has been
inspected by specialists in plant
disease control We are fast coming
to the idea that SO per cent of the
work of certified potatoes is patho-
logical /, rather than horticultural.
Virus diseases cause a decided reduc-
ton in yield which varies according
to the type of disease. One charac-
teristic which usually accompanies
virus diseased tubers is very fine
variatel type. Washington potato
growers should use care in buying
extra typey seed unless there is a
certification back of it, for within
that beautiful potato may be lurking
the virus Of disease. Beauty is only
skin deep" is true in this case, for
behind that fine skin on the nice type
potato usually turks the virus caus-
ing these diseases.
Let us examine some results where
good disease free seed is used as COM
pared with seed that is full of the
virus trouble. In 1921 the Extension
Service established a demonstration
in Walla Walla to compare the use Of
ordinary seed with disease free seed.
In 1925, the end of the fifth year, the
poor diseased seed had averaged 90
sacks per acre as compared with the
yield of 2O5 sacks per acre where
disease free seed was used. This is
an increase of 113 per cent. Not only
was the yield increased but the mar
reliability of the potato was increased
by the use of good seed.
In a two-year demonstration in the
southeastern part of Pacific County,
Washington, one of our cooperators
rogued part of his field in 1925. This
year a comparison was made in yield
between the local seed from which
the disease had not been removed,
the local seed in which the disease
had partly been removed and the
yield with certified seed where prac-
tically all of the disease had been re-
moved From one thousand foot
row the common seed produced 533
pounds as against 1913 pounds, or an
increase Of Sc per cent where the
disease had partly been removed;