Mold/Mildew on Exterior Vertical Surfaces

I have a screened in porch that is only 5 years old. All of the posts are covered with mold (maybe algae because it is green). I’m thinking the contractor never primed the wood.
What is the best product to kill/remove the mold? Is sanding it down a good idea?
After I kill/remove the mold, I’m thinking of priming it with Zinsser Mold Killing Primer and then a top coat with Benjamin Moore Aura as it is supposed to be good at preventing mold.

Please HELP ! The Mrs. will not stop nagging me until she has a clean/white porch !!!