Evening star., 1931-06-19
CROPS OF TOBACCO
RAvAGED BY FUNGI
Five Maryland Counties At
tackled by Blight of
Blue Mold.
ny THOMAS r. HENRY.

= blue mold is sweeping over the rich
Nohacco area of southern Maryland.
II is e wind-carried fungIs Icsclsely
%he Same in appearance, as the dreaded
hIIe mold disease that has caused enor-
NOUS damage in the tobacco heloS OF
Australia It does not, however, pc
have in quite the same way ana De-
parlment of Agricultire specialists s nope SIos
that it may be different ana less
Virulent strain.
The fungus practically defoliates
plants in a few DAYS and its raVages
are quite similar in appearance 10
those of the "wildfire disease" bac-
terial infection that spreads rapidly
over a countryside. 1t has been touno,
however that it does not entirely XIII
plant and thus far its effects have peen
confined to plants in seed beds betore
fhey are set out in the fields. The Aus
tralian fungus attacks the field plants.
Called Downy MiIdew.
The "blue mold" or downy 1nildew
as 1t has been named IN this country,
appeared suddenly and mysteriouSly in
one bed in Georgia early in April
Within a week it had spread to many
other beds in the neighborhood ana
then it spread very rapidly along the
Gulf Coast and northward through the
appearance in this country was in
Georgia 10 years ago. Then the out
break was slight and hardly any dam
age was done It Is not known Whether
the present outbreak was introduced
in some way from Australia or whether
it is a native fungus that has remained
quieScent. 1t might be the Australian
fungus. it is pointed out, whose raw
ages are checked by the types OF Soif
b fo
States.
The fungus attacks the lower sides
of the lower leaves of seeding and
causes the leaf tissue to break down.
"A great deal of damage can be done
in a single night but Department Of
Agriculture specialists believe Maryland
farmers are more frightened than the
present spread warrants, since the
seeding season is almost over and the
disease has shown no tendency TO go
into the fields.
The fungus apparently is specific for
Young tobacco plants, although the ex-
istence of some wild host is suspected.
In Australia it has practically made to-
bacco growing impossible in some areas,
but, it is pointed out, the country IS
not we'll suited to tobacco, anyway.
The first appearance In Maryland was
about June /.
Covers Entire Area.
Since then it has been reported from
all five counties of the tobacco area
and nearly every seed bed has shown
signs of 1t. Sprays adapted for fungus
diseases are being recommended. The
disease apparently is favored by few
damp, cold days. A slight breeze will
carry its millions of spores great dis
tances
TTShe ujIdfre dicease also has broken
out in Pennsylvania, Department of Ag-
riculture Investigators report, but has
not spread into Maryland. The danger
of both these plant diseases lies in the
speed with which they work once they
have gained foothold. Tobacco plants
are quite susceptible to infection.
The worries of the tobacco grower,
according to Department of Agriculture
specialists. are increasing because of
changing methods of cultivation. Seed
lings are raised IN a cold frame until
they are large enough to set out in the
fields Formerly it was the practice to
go into the woods and clear space of
trees and brush, which were burned on
the spot The seeds were then planted
soil had been sterilized by the fire and
by the wood ashes covering it.
Rotation ImpracticabIe.
But this practice. it was pointed out,
has become increasingly difficult and is
very wasteful. Experiments on the ster-
ilization of cold frames with steam have
had indifferent results. The old prac-
tice was to plant a field with tobacco
two years in succession and then turn
it over to other crops for 10 to is years,
but scarcity of land makes this difficult.
The result, it was pointed out, is that
the quality of tobacco may not be quite
so good and that the plants are more
subject to fungus and bacterial infes-
tations. Thus far none of these has
proved very serious to the Maryland and
Virginia tobacco growers, and their
product has occupied high place in
the world market.
Maryland farmers are referring to the
new infestation as the blight" and
comparing it to the dreaded chestnut
blight, which in few years has prac-
tically killed all the chestnut trees in
the Eastern United States. Actually,
the Department of Agriculture special
lists say. the effect is quite different on
the, tobacco plants, and they are conf
dent that the blue mold will not cause
any serious losses once the plants are
flourishing in the fields.