El Paso herald. (El Paso, Tex.) 1901-1931, 1916-01-14
POTATO BLIGHT
CAN Be HALTED
State College Bulletin Ex-
plains How Early and Late
Blight Can be Controlled.

State College, \. N, Jan. IA bull
ietin on potato blight. issued by the
State college experiment station as
sistant biologist Fred c. Workenthin.
says there are two distinct fungi
which produce the blight In potato, one
known botanically as macrosporium
solani, causes the early blight, the
other. known as phytOphthora infes-
tans causes the late blight and rot.
Late Blight.
Symptoms Of the disease It usually
makes its first appearance when the
vines OF the later varieties are in full
growth Upon the leaves of the potato
spots which cannot be easily confused
y with other potato diseases. These
spots may appear at the margin. at the
tip, or even at the center Of the leaves
and spread until the whole leaf may be
involved A fine mildewy growth ap-
pears over the diseased area on the
underside Of the leaf, especially at the
margins Of the spots The affected it's
sue softens and decays and gives off
characteristic potato blight Odor. On
the tuber, the disease appears as dis
colored areas that later are somewhat
Sunken ana dry, known as dry rot.
These areas may be small or may eX-
tend over the entire tuber- The flesh
at such places has a reddish brown
color If the infection comes late in
the season, the tuber may show no
indication of rot when dug. but it may
appear after they are stored
Method OF Control.
As the fungus Is carried over winter
largely, or perhaps entirely, by hiber-
mating fungal threads in the tubers,
every effort should be used TO secure
seed potatoes from field in which
no blight or rot has occurred. Bor-
deaux mixture, when applied TO the in
fected vines, destroys the vitality Of
the spores with which IL comes in con-
tact and thus prevents the infection Of
healthy plants It is ordinarily advis-
able TO begin spraying with Bordeaux
mixture when the plants are about six
TO eight inches high and follow BY at
least three TO five thorough applica-
tons at intervals of from ten days 10
Two weeks apart The amount Of mix
ture to be applied TO an acre varies
with the size OF the vines. Usually so
gallons viii be sufficient when the
vines are small but 75 gallons or more
viii be needed as they become larger.
If the bordeaux cannot be purchased
readily. IL may be made as follows: Put
TOUR pounds OF copper sulphate in a
in i've gallons Of water until II is COM
pletely dissolved. Stake four pounds
OF stone lime and dilute TO a milky So
luton Let it cool Then dilute with
half OF the remaining water Dilute
the copper sumaIe now with the other
half OF the water left. Pour the two
mixtures slowly together and stir wen
IN the meanwhile. Apply with a ptrmp
hat has brass or porcelain lining. Fol-
low the directions exactly Ldme-sul-
phur solutions must not be used for
spraying potato vines, as they cause
dwarfing OF the plants to such an ex-
tent that the yield Of tubers is less
than from those not sprayed
Early Blight Symptoms.
The early blight may be distin-
euished from the late blight bva its
sence Of the mold-iike fuzz. BY its
earlier appearance and slower growth.
and from the fact that it does not. af-
rect the tubers Applications of bor-
deaux mixture is as effective a rem
edy Tor the early blight as for the late