Tobacco Blue Mold Update for North Central Florida


Dr. Amanda Gevens (via email)

May 16, 2008

Since my initial report of tobacco blue mold in Alachua
County FL on March 17, 2008, we have had no new
reports in other areas of Alachua County or
additional FL counties.  I have been scouting tobacco
fields in Alachua County on a weekly basis and have
observed the following situation.  After destroying a
large percentage of his plant/seedling bed, the
producer placed his remaining plant bed on a 5 to 7
day spray program which included alternation of
azoxystrobin (Quadris) (minor phytoxicity noted on
lower leaves in plant bed only) with dimethomorph
(Acrobat or Forum) tank mixed with mancozeb.  Plants
that were set out into the field were placed on a 7
day spray program using the same fungicide program
as indicated above for the plant bed.  North central FL
has experienced a very dry spring, with little to no
rainfall in the past month or two.  The dry weather
conditions coupled with the tight fungicide program
have kept blue mold at bay on this one farm in Alachua
County.  During our scouting, we observed that new
foliage was consistently free of infection.  Older,
lower leaves that had exhibited blue mold lesions were
dried up. On few occasions we noted that older lesions
contained some active sporulation. After these
findings, the producer would tighten up his spray
program from 7 to 5 days and invariably, the following
week we would not find active sporulation.  The
producer is only irrigating his tobacco fields when
it becomes apparent that the plants are at risk of
wilting and death.  Fortunately, the blue mold did not
appear to go systemic in these plants and the producer
has been able to manage this diseasein his crop
at this time.

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