Is a humidity control such as a thermidistat necessary with a 13 SEER air conditioner in an 1800 square foot 1 story home in Florida?

The first question you need to answer this is are you occupying the home year round? If you are NO. If you are a snowbird, then you should have a Humidistat installed to keep the moisture level down as to not grow mold. If you are there year round, then normal use of your A/C will keep the humidity at acceptable levels.