There should be no problem this spring using Apistan strips you bought in
August.  Fluvalinate is a contact pesticide so does not work by evaporation and
fumes.  It is probably best to seal any unused strips in the packet they come
in and tape the open end closed airtight as a precaution to keep their greatest
efficacy.  It will also probably help to keep them cool and out of humidity
and they will last longer.  I can't see waiting from August until now as being
any problem at all.  They should work just fine.

Layne Westover
College Station, Texas