Bumble bees living under porch behind steps
My sister has a 1950's ranch home that has a cement slab porch supported by a brick under-structure with two built-in stairs. The mortar has deteriorated and a few bricks have fallen into the hole underneath this porch. This Spring, I have witnessed a few huge bumblebees going into these holes where the bricks are missing. I suspect that a nest exists. A member of the house is allergic to bees, but I have read that you shouldn't kill bumblebees due to declining numbers. Suggestions for getting them to move? I have removed all flowers from around the house.
Secondly, there are also different bees that are drilling perfectly circular holes in the mortar between the bricks of the house. What is the best type of insecticide to kill these?
Oakland County Michigan