You can use beforeShowDay to do this
The following example disables dates 14 March 2013 thru 16 March 2013
var array = ["2013-03-14","2013-03-15","2013-03-16"]
$('input').datepicker({
beforeShowDay: function(date){
var string = jQuery.datepicker.formatDate('yy-mm-dd', date);
return [ array.indexOf(string) == -1 ]
}
});
Demo: Fiddle