The Glenwood post., 1906-04-28
POTATO PROBLEMS.
Bulletin of the Colorado Agricultural
Experiment Station.
(By Prof. Wendell Paddock.)

| ~ 'ci- W thutll duuoCh.D
A Poor Stand of Potatoes.-A poor
stand of potatoes is usually due to the
attacks of plant diseases of various
kinds. Two of these minute plants are
quite common; one of them causes the
seed potato to rot in the ground, and
the other attacks the young shoots,
often rotting them OFF before they
reach the surface of the ground. In
the former instance it will usually be
found that the seed potatoes have been
injured by improper storage, thus CIV
ing certain fungi an opportunity to de-
velop. With the latter instance, fun
gus which is associated with heavy,
poorly-drained soil is responsible.
Such soils should commonly be
avoided for potato growing. Potato
soil contains more or less sand of
gravel and is well under-drained.
Vines and No Tubers-This condition
Is common one in many parts of the
state, and is largely due to the attacks
of fungus which thrives best in
heavy, damp soil. This condition may
not appear every year, but usually it
will not pay to try to grow potatoes in
soil where this condition is at all
noticeable.
Potato Scab.-True potato scab is al
ways caused by the attacks of minute
plants, or fungi and, curiously enough,
| scab is more common in the best po-
tato soils than it is in localities where
the crop is more precarious. Good po-
tato soils, when first brought under
cultivation, often give large per cent.
of scabby potatoes, but after one or
more crops of alfalfa have been plowed
under this tendency is partially cor
rected.
In former publications we have ad-
vocated the treating of seed potatoes
as means of preventing potato scab
Some of our experiments with treated
seed gave good results but the major
ity gave negative results. These eN-
periments extended through four sea
sons at Fort Collins and at Greeley.
Our conclusions are, that in these To-,
calities it will not only pay to treat
seed potatoes for scab, but that such
treatment may positively be detri-
mental to the crop. Growers on the
western slope have reported good re-
suits from seed treatment; for this rea-
son formulas are given below.
Potato Blight.-POtato blight, or the
dying of the leaves and vines before
the crop is mature, is commonly
thought to be entirely due to diseases
which attack the top of the potato
plant. We have not found it so in
Colorado. Spraying experiments with
Bordeaux mixture did not materially
lessen the blight, and the microscopic
plants which cause these leaf diseases
are not commonly found associated with
this trouble. We concluded, therefore,
that the premature dying of the potato
vines is usually an evidence. that the
underground portion of the plants is
diseased. Water applied at the wrong
time often so favors the development
of this disease that the vines may be
seriously damaged in short time.
Internal Brown Spot.-A disease
which appears to be identical with
what is known as internal brown spot
has made its appearance in some por-
tions of the state. This trouble APP
= pears to be the result of certain condi-
tions, rather than to the attack of any
specific plant disease. All that is
known on the subject is summed up in
the following paragraph, which was
taken from Bulletin No. 81 of the Bu
reau of Plant Industry, United States
Department of Agriculture:
1t is considered not to be parasitic
disease, and no remedy is known and
no suggestions are made except the
doubtful one of avoiding the use of dis
eased tubers for seed. In England and
Scotland several potato specialists of
wide experience gave evidence of like
purport. The trouble is frequently OBJ
served, and is most commonly called
'sprain.' 1t is not propagated
| tn coil iS
parasitic. 1t is considered to
be the direct result of NAL
nutrition associated with unfavorable
soil conditions resulting either from
too dry conditions or from the lack of
potash or lime. 1t is frequent in light,
dry soils during dry seasons, and is
never seen on heavy, strong moist
soils. The remedy, in the judgment of
the specialists cited, lies wholly in at
tention to cultural conditions and the
choice of varieties"
While the conditions described above
do not apply to irrigated land, 1t will
do doubt be found that our trouble
Is due to some condition of soil or cul-
ture, or both, which is unfavorable to
the proper development of the potato
plant.
Seed Selection.-Too much emphasis
cannot be given to the importance of
seed selection. 1t should be possible
by this means to build up strain of
potatoes which would be adapted to
our conditions and which should be-
come better year after year. The fol
lowing extract is quoted from former
bulletin of this station:
Another method which gives evil
dence of considerable practical value
is to set aside each year five or ten
acres of land for the growing of seed
potatoes The soil of such tract ought
to be fertile and free from the various
diseases which attack the potato plant.
The tubers used in planting the seed
tract are carefully selected each year
from the seed plot of the previous
year. The surplus seed is used for
planting the general crop, and in this
way'a strain of pedigree potatoes Is