How to Kill Mason Bee Larvae in a House Wall

Locate the bees’ entrance into the wall. Look for a small hole, caked with mud around the edges. Mason bees seal off their nests with a mixture of mud and saliva.

Watch the entrance for an hour or so and observe the number of bees coming in and out.

Count the bees coming in and out. Mason bees have individual nests, not hives. If only a few are using the wall as a nest, you are dealing with mason bees and can kill them and their larvae on your own.

Put on protective glasses, gloves and a bee veil to protect yourself from stings.

Clear away the mud blocking the hole with the end of the screwdriver to improve your access.

Spray the insecticide into the wall. Apply it a few times, waiting an hour in between each application. This increases your chances of killing any adults out gathering nectar. The insecticide will eliminate adult bees, neophytes and larvae.