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NORTH FLORIDA EXPERIMENT STATION
Quincyj Florida

April 2, 1957
NFES Mimeo Rpt. 57-9'

BLUE MOLD CONTROL IN TOBACCO SHADES
by Randall R. Kincaid
Plant Pathologist

Blue mold will probably be more of a threat to tobacco in shades in
1957 than usual. Two conditions contribute to this threat. One is that blue
mold appeared two to three weeks earlier than usual and became widely dis-
tributed in beds. Another is that the crop was transplanted early, thus
exposing the crop to a longer season in April and May when the weather may be
favorable to blue mold development. Temperatures below about 60 degrees and
high humidity are most favorable. Four methods of blue mold control in shades
are discussed.

Destruction of infected plants in beds as soon as possible after the
transplanting season is recommended, in an attempt to reduce field infection.
The cooperation of flue-cured tobacco growers as well as shade tobacco growers
is needed to make this practice most effective.

Dusting for blue mold control in shades is recommended. Dust containing
6.5 per cent zineb is applied twice a week, at rates ranging from 8 to 15
pounds per acre at each application, depending on the size of the plants.
One application each week may be made in combination with insecticide. Zineb
in pyrophyllite has given better blue mold control in beds than zineb in
tobacco diluent. Dust with a pyrophyllite or other similar light colored
base may be used in shades until a few weeks before priming.

Some shades or portions of shades, where air drainage or water
drainage is poor and the crop is most subject to blue mold, should perhaps
be abandoned, if other areas are available for shade.

Breeding for blue mold resistance is in progress. Whenever resistance
is available in combination with good yield and quality,, new varieties will
be released to growers.





NFES
4/2/57
400 cc -..