Eagle River review. [volume] (Eagle River, Wis.) 1890-1927, 1925-03-12
Tomato Blight
Cause Of Loss
Good Results Have Been
Obtained by Setting Out
Hardened Plants.

prepared by the United States Department
of Agriculture.)
Tomato growers in the Middle At
lantic and Middle Western states may
greatly reduce their losses from leaf
spot, or blight, by following the prac-
tees recommended in Department Bull
letin 1888, The Control of Tomato
Leaf Spot by Fred j. Pritchard and
United States Department Of Agricul-
ture The disease, which, In the
United States, causes the commercial
growers an estimated annual loss Of
100000 tons of tomatoes, is widely dis
tributed east Of the Rocky mountains.
Because spore formation of this
fungus takes place only at tempera-
lures between SO and 8O5 degrees f.,
and because the disease develops best
only within temperature range Of
70 to 70 degrees f., it is relatively
unimportant in the northern states and
in the far South. Because it thrives
best in moist atmosphere, it is more
abundant in Maryland, Virginia, and
the adjoining coast states than in the
inland parts of the same temperature
belt
Mixtures Too Expensive.
In the past bordeaux or other copper
spray mixtures have given the best
control Of leaf-spot but profits have
not always been increased enough to
justify the expense. The bulletin sug-
gests that a more effective and eco
nomical method of control lies in the
use of modified field practices. Good
results have been obtained by setting
out large, stocky, well-hardened plants
early in the spring. Since the fungus
does not produce spores at low tenn
peratures the disease will not begin
to do damage in this region before the
latter half of June and for that rea-
son these early plants escape more
leaf-spot than the small ones that are
commonly set late. Plants of the de-
sirable kind at least six weeks old can
be produced cheaply outdoors in the
South and shipped north at the right
time for planting. In 1923 more than
100000 southern grown tomato
plants were shipped into Indiana and
a considerable number into the East
ern states Some Of the larger north
ern companies manufacturing tomato
products are growing their own plants
in the South, In order to obtain
healthy plants Of suitable size and
age. The indiscriminate purchase Of
southern stock of unknown history
cannot be recommended, because of
the attendant danger Of introducing
wilt and root-knot. There is need of
a system Of plant certifcation to pro-
tect the careful southern grower and
the northern purchaser against this
danger.
Fungus Prevented.
The fungus can be largely prevented
from -wintering by blowing under
the old tomato vines in the fall. The
vines must be thoroughly covered to
kill all the fungus on them and this
can be accomplished by first cutting
them with disk and by using weed
hook on the pillow or weed hook and
jointer The fungus also grows and
produces spores on dead weeds,
grasses, and remains of various crops,
especially cornstalks. BY keeping
these dead materials covered with soil
and by destroying such plants as the
horsenettle, groundcherry, jimsonweed
and nightshade and by burning dead
weeds and grasses along the fence
rows and other waste places, the dis
ease can be well controlled.
Copies of the bulletin may be OBJ
tanned free as long as the supply lasts
by addressing the United State De
partment Of Agriculture, Washington,
D. G.