WDO stands for wood-destroying organisms.  Wood may be rotted by fungi or eaten by insects.

Molds, some stains, and decay in wood are caused by low forms of plant life called fungi. Not all damaging fungi destroy wood.  Some fungi stain wood without damaging it’s structure or decreasing its strength.  Fungi have four basic requirements to grow and reproduce: moisture, oxygen, adequate temperature and food.  If you deny the organisms one of these four, then the wood does not decay.

Wood can also be destroyed by insects such as termites or carpenter ants.    In Florida, the most common termites are drywood or subterranean.  Drywood termites infest dry wood and do not require contact with the soil.  Subterranean species must nest in the soil or near a water soure to survive. 

It is always a good idea to have a complete termite/WDO inspection done before purchasing a home.  Make sure you hire a qualified inspector and get a detailed report.    If you are acquiring a mortgage loan, your lender may require to see a copy of the report.   If the report shows evidence of termite damage or WDO fungi, that may have to be repaired prior to purchasing the house.