My Pygmy enclosure has several branches that have fallen off a silver maple in my yard. After 2 months this began to grow. Is this a fungus I should worry about?
I would take them all out, wash them really well and put them in the oven for a few hours. You do not want any more fungus growing. Even if you can't see the fungus, there could still be alot of harmful bacteria on the branches.
IMHO, as someone who has always used natural branches in all my setups, you don't really need to make your cage furniture sterile and you will never accomplish that anyway. I usually scrub my new branches with a bleach hot water solution (1 part bleach to 10 parts water) just enough to get rid of rotting bark, remove obvious mosses and lichens and surface dirt. Rinse until you can't smell the bleach, let dry. I'd cut off the piece with the fungus, scrub the rest and dry everything. I've never baked anything.
I've only used live cut branches from trees in my yard. (I didn't bake the branches but I used a bleach hot water mix as Carlton mentioned). Baking the branches is a bit extreme. Mine were too big to fit in oven anyway.