Hello, I built a new mantle last summer using new oak crown molding to support the granite shelf. The wood was sanded, sealed with Bin spray primer and given three topcoats of hammertone paint. All has been well until the last three weeks. Noticed a white spot on the dark bronze paint , looked like toothpaste, wiped this off, would reappear, now as weeks have passed this turned into a hole big enough to stick a good sized safety pin in about a 1/4 inch and I find a small pile of white dust. Could this be a worm ? Or does some one know what this is and what will kill this intruder , befor I have to replace more than this shelf ! Thanks in advance , David