South
Florida
Beef -
Forage
Program
"Article of the Month"
April 2003
Keeping an Eye on Tropical Soda Apple Infestation on Your Pasture
Dr. Martin Adjei
UF/IFAS Range Cattle REC, Ona
Tropical soda apple (TSA) has invaded pastures in south Florida since 1990. Serious efforts were made to
control TSA in Florida in the mid 1990s but the enthusiasm eventually waned. Currently, there are more
than 500,000 acres of TSA infestation in Florida.
Tropical soda apple is spread to new locations by cattle movement, wildlife, contaminated hay, grass
seed and sod. It is on the list of Florida State's Noxious Weed according to Florida Law (Fla Admin.
Code 5B-57-007) and as such it is unlawful to introduce, possess, or move TSA plants deliberately except
under permit issued by Florida DACS or the USDA. Recently, some southern states including Georgia,
Mississippi, and Alabama have considered passing legislation to regulate the movement of cattle from
Florida to their states in order to stop the spread of TSA in southeastern USA. Such legislation, if adopted,
would require the quarantine of Florida cattle at specified locations for up to one week during/prior
to shipment. The expense of such confinement will be charged to the cattle owner and will
increase cattle production costs in Florida.
Therefore, South Florida cattlemen need to pay greater attention to TSA infestation on their pasture and
engage in renewed efforts at preventing, monitoring and controlling TSA as follows:
Sparse Stand:
For sparse stands in south Florida, spot spray individual TSA plants in November with a 0.5% solution of
Remedy (tryclopyr) + 0.1% non ionic surfactant. Wet foliage completely to the point of dripping with
solution and use a color maker in the spray mix to ensure all plants are treated. Monitor the weed
problem through winter and spot-spray new/regrowth TSA plants on that pasture again in February of
the following year. Monitor plants through spring and if there are still some live TSA plants on
the pasture, spot-spray a third time in May followed by continued monitoring through summer. Monitoring
and repeated spot-spraying at about 60 d intervals over 2 years will prevent TSA fruits form maturing
seed and help clean up a sparse stand of TSA on a pasture unless pasture is re-infested with seed
introduced from outside.
Dense Stand:
Dense stands of TSA on pasture in south Florida must be mowed repeatedly to a 3-inch stubble in November,
February and April to prevent fruit setting/seed maturation. Repeated mowing every 50-60 days can in itself
cause 50-60 % mortality in mature TSA plants. After the April mowing, allow the TSA plants to regrow for
about 60 days and broadcast spray 1 qt /A of Remedy + 0.1% non-ionic surfactant in June. Next, monitor
TSA plants through September and spot-spray remaining plants in October with a 0.5% Remedy solution + the
non-ionic surfactant and the color marker. Continue monitoring TSA for at least another year and spot
spray emerging plants every 60 days as described for sparse stands until pasture is completely cleaned up.
There are hopeful signs that a variety of biological agents (insects, virus) for TSA control will soon
become available to increase our arsenals on this noxious pasture weed. But for the meantime, prevention,
monitoring and repeated spraying with Remedy provide the key to successful tropical soda apple control in
south Florida.
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