Press Bulletin No. 54. Dec. 15, 1904.
HORTICULTURE AND BOTANY.
By F. M. ROLFS.
A careful study of the potato plants and tubers from vari-
ous parts of this State shows that dry rot (Fusarium oxyspo-
rium, Schl,) causes considerable less to our potato industry.
The purpose of this paper is simply to give a short discussion
of dry rot, and also to give the results obtained from a series
of experiments with seed potatoes.
DRY ROT-Infected tubers appear to be the principal
means of spreading this disease. It is quite difficult to find a
lot of seed which does not contain at least a few tubers infect-
ed with this malady. Thoroughly washing all sound tubers
which have come in contact with infected ones gives fairly
good results. All seed which is washed must be carefully dried
before it is placed in a sack or barrel. Tubers showing any
signs of dry rot are worthless for seed. Diseased seed produces
plants which do poorly, and many of them die before the crop
is harvested. Some, however, live throughout the entire sea-
son, but remain small, and usually take on a lighter color and
produce small, inferior tubers, The black lines frequently ob-
served in tubers are clue to the work of the dry rot organism,
and such seed is apt to produce weak plants.
CUTTING THE SEED TunERS-In cutting the seed, care
should be taken to have as small an injured surface as
possible. The work ought to be done about two days be-
fore planting, and the seed must be placed on a dry floor, so as
to allow the injured surface to form a callous before the seed is
planted. This callous formation serves, in a measure, to pro-
tect the injured side from unfavorable conditions and from the
invasion of various organisms. Carelessness in not allowing
this formation of callous before planting may cause serious
loss. This is especially true if the planting is followed by a
spell of wet weather.
OLD POTATO LAND.-Poor stands are most likely to
occur on old potato land. This is due to the work of the vari-
ous diseases which remain in the field from year to year, and
as the young plants push through the infected soil, many of
them are killed before they reach the surface of the ground,
and those which reach the surface and become established,
frequently suffer more or less "from the diseases during the
Burning all diseased tubers and vines after harvest is an
excellent practice. The time will soon come when our most
successful growers will abandon the present methods and take
up a systematic rotation of crops.
CORROSIVE SUBLIMATE AND FORMALIN SOLUTION.-Seed
treated with the standard corrosive sublimate and formalin
solutions gave marked gains, and also improved the appear-
ance of the crop, when the treated seed was planted on land
which had not been cropped in potatoes for a number of years.
However, when the treated seed was planted on old land, the
yield was invariably cut short.
SEED SELECTION.-Carefully selected clean smooth, round,
well-developed tubers, especially those with well-formed ends,
usually produce stronger and more productive plants than the
flat, or long, slender tubers, with pointed ends.
EXPOSING THE SEED TUBERS TO THE LIGHT.-Placing
the tubers to the light (not in the direct rays of the sun) for
five or six weeks before planting, gives good results. Such
treatment tends to produce stronger and harder sprouts, which
grow rapidly and develop plants which are apparently better
able to overcome the attacks of most of our diseases.
Success and failure depend much upon the quality of seed
tubers used. However, the care in handling of the tubers is
also important as a factor to be considered in selecting seed.
It will be far cheaper in the end to pay a good price for seed,
and to buy only from men who you know will give the most
careful attention to the selection and care of their seed. Deal
with honest men.
Those who care to test the value of corrosive sublimate
and formalin seed treatments will find a full explanation for
the preparation of these solutions and their use in Bulletin 76
of this Station.
STATE PAPERS PLEASE COPY.