Henderson daily dispatch., 1937-01-25
IW|LDF|RE, M|LDEW
CAN Be: CONTROLLED
Two Tobacco Seeded Dis
eases Possible To Over
come, Experts Say

Washington, Jan. 25.-Wildfire and
downy mildew, two diseases of tobac-
co which attack the plants while still
in the seedbed, have been controlled
effectively in spray experiments car
ried out by scientists of the Bureau
of Plant Industry, U. S. Department
of Agriculture
Tests carried on for the past five
years, show that bordeaux mixture
will prevent wildfire infection, and
copper-oxide oil has shown surprising
results in the control of downy mil
dew, also known as blue mold. Cop
per oxide may be purchased CONNER
cially and mixed with cottonseed oil.
Wildfire is common in Maryland
and Pennsylvania and to lesser ex-
tent in western Tennessee and Ken
lucky, while the downy mildew on
blue mold disease is prevalent in seed
beds throughout Maryland, Virginia,
North and South Carolina and Geor-
CD Dr.. E. Clayton, who has charge
of the raying Investigations, says
tobacco mowers have been using Dor
deaux 4sporadically in plant bed
stances, 5however, they waited until
the wildffTe had infected the beds and
it was toDsslate to be of any benefit,
resulting HI. the general opinion that
spraying does not control the disease
Growers4were not plagued with mil
dew generally until 1882 when the
first severe epidemic occurred over
the area extending from Georgia to
Maryland. Bordeaux mixture was
first tried for this disease, but this
spray treatment was worse than use
less. 1t checked the wildfire but SEEM
ed to make the plants more sus-
ceptible to mildew. From 1882 through
1885 systematic spraying experiments
were conducted in Georgia, North
Carolina, South Carolina and Mary
land in cooperation with the State ex-
pertinent stations This led to the dis
covery of the copper-oxide oil treat
ment
In Maryland, where both wildfire
and mildew were prevalent, the COM
bination of early bordeaux sprays fol-
lowed by applications Of cooper-oxide
oil gave good results in the control
of both diseases during the 1885 and
1886 seasons. Many field paintings,
says DR.. Clayton, showed that in all
tests the sprayed plants lived as we'll
and grew as vigorously after trans
planting as they unsprayed plants. In
some instances the stand percentage
was increased by spraying.
The first bordeaux spray was ap-
piled in the Maryland tests as soon
as the seedlings had begun to break
!, r1-I, I,
about the middle of April The spray
ing was continued once a week until
three or four applications had been
made. Immediately following the Dor
deaux spray schedule the plants were
sprayed twice a week with copper
oxide oil. This was continued through
transplanting- usually from May Is
to June 10.
Progress made in the spraying stud
les is reflected in the attitude of sew
eral of the grower-cooperators Dr.
Clayton reports. During the first three
years none of the growers indicated
any confidence in the spray program.
During the past two years, however,
number of the cooperators have
shown an enthusiastic interest and
are convinced that it is a profitable
practice.
Wildfire Infection was prevented in
some instances where the spraying
was virtually the only precaution. AS
rule growers try to prevent infec-
ton Ky locating the beds away from
the curing barns, by treating the seed
and sterling the soil, and by boiling
all old plant bed covers.
After three years of observation the
scientists also found that the whole
bed had to be sprayed for effective
control of the diseases. For the first
three years only part of each bed