Welcome to the site: it does look like it might be termite damage or some other creature or fungi you don't want in the house. You will need to do or have done a complete inspection of the wood in that area and the sill plates or any wood in contact with the foundation. You will also want to look at the moisture level in the crawl space and the ventulation there.
There are two kinds of Termites in Florida. Drywood and Subterranean. The Drywood don't eat through the wood, they eat right up until they see light then move on. You can easily put your finger through the thin wood left where they have been. Subterranean's come up from the ground and do pretty much the same damage. Problem is they are both treated differently for removal. Best thing is have a pest control come out and at least tell you which one you have.
I noticed this wood at the entrance of my crawlspace.is this a sign of termites ?
Nematodes have recently gained popularity for organic pest control treatments. These are small microscopic insects that can be bought online from any garden supply store and works effectively over pest infestations.