The Barre daily times. (Barre, Vt.) 1897-1959, 1917-01-20
POTATO DISEASES.
Show Tendency to Spread in Various
Parts Of Country.

Parts of Country.
Potato diseases, which are showing a
tendency to become established or to
spread in various parts of the country,
can best be controlled in most cases
through the adoption by farmers of the
seed. bed method OF control, according to
DIR. IL. A. Edison, truck-crop disease spe-
cialist of the u. S. department of agri-
culture. In discussing the potato disease
situation and possible control measures
in recent address, DIR. Edison said:
"A disease of the potato which is max
ing its appearance in several sections OF
the country is the one designated by Or
ton as streak. The cause of this dis
ease is unknown. 1t is characterized by
the appearance of angular spots on the
leaves, which have tendency to run
down the veins through the stems of the
leaflets to the main petiole, or leafstalk,
producing a streaked appearance. The
affected portions of the plant wither and
die, the leafstalk breaks over at the axil
of the leaves-that is, their junction
points with the branches--with the re-
suit that leaves hang directly down,
swinging in the wind and attached only
by portion of the epidermis. In severe
cases the plants are eventually entirely
killed. The trouble is apparently trans
mtted from generation to generation by
means of the seed tubers, and there is
some indication that it is transmitted
from plant to plant in the field. In the
absence of more definite knowledge of
the disease, it is recommended that rogu-
ing be practiced as precautionary meas |
ure wherever it appears.
Heavy Loss from Mosaic.
Mosaic is assuming great Importance
as potato disease in certain sections of |
the country. 1t is characterized by a I
nothing in the green of the leaves, some. I
times accompanied also by crinkling |
but not rolling of the foliage. The dis
ease should not be confused with the UNI
even yellowing which results from the
application of excessive water in irri
gated regions nor with the somewhat
different yellowing and rolling associated
with excessive alkali content in soils nor
should it be confused with the condition
of partial absence of coloring matter,
possibly chim9ra, seen occasionally in
fields, more particularly in certain Sec
tons of the west. The cause of mosaic
has never been determined, but it is
known that the disease is reproduced
when tubers from affected plants are
used for seed. The experimental data
which have been secured both in the Unit
ID States and abroad show that the yield
rom mosaic plants is less than that from
healthy plants of the same variety grown
Under the same conditions or in the
'ame field. The average reduction in
yield in trials made by the department
With various varieties and in several
lifferent sections of the country is APP
fortunately 80 per cent. Roguing out ,
Elected plants in the seed plot affords a ,
PRACTICAL though perhaps not complete
ontrol of the trouble
"The late blight of the potato caused
" Phytophthora infestans and the rot
f tubers which follows in the winter are
90 well known to call for description. 1
t has recently been shown, however ,
hat the planting of tubers affected with 7
decay affords means for !
affection of the growing crop, The devel- q
pment OF the disease, however, is en- !
rely dependent upon weather condi !,
ions. In. dry seasons one may plant
ffected tubers without insuring the de-
elopment of the late blight, but it has :
cen shown that the original infections !
blow up the stems from the seed tubers )
the weather conditions are favorable /,
, the development of the fungus. 1t is, c
lerefore, advisable to avoid infected seed b
hen possible in addition TO employing ?
he usual control by Bordeaux mixture, !.
hich is a weIl-known established prac- =
ce.
Recent studies upon the powdery scab
ave demonstrated the fact that this =
sease is less serious in its character in q
he United States than was at first a
AIRED. 1t is apparently unable to sur b
We except in the more northern sections q
the country, and the damage done
Iere is, in many years, not serious. The
sease is correlated with heavy, rather "
ct soils, or more particularly with sub NJ
ills of this character, The damage done
to large extent dependent upon 10
Gather conditions even in these unfa- I
'rable types of soil.