Masonry bees are similar in coloration to the honey bee.They do not swarm, they are not aggressive and will only sting under provocation, their stings do not penetrate the skin and they are beneficial in promoting plant pollination. They can, however, cause damage to buildings, which can be quite severe over several seasons.
The bees tend to bore holes in lawns, flowerbeds, rockeries or any soft suitable material in order to lay eggs. They sometimes bore into perished or friable mortar of brickwork or stonework where the joints are sufficiently soft (sound hard mortar is unaffected). The walls concerned tend to be south facing, as they receive more hours of sunlight, which enhances germination of any eggs which are laid. After laying the eggs the hole is left until the larvae hatch the following spring.
The only effective treatment for masonry bees is for the mortar joints in the affected area of the property to be raked out and repointed. The joint should be raked out to a depth of 15 mm and repointed with an appropriate mortar that is not too strong for the bricks, but hard enough to discourage the bees (4:1 sand/cement is a typical industry standard). This work should, if possible, be carried out in late summer after the bees have ceased their activities, but before frost becomes a problem. Proprietary insecticides may be used, but the degree of success is limited and cannot be guaranteed. It is also recommend that the whole of the property is surveyed for further penetration, and further treatment carried out if necessary.
THE ONLY SURE REMEDY IS
TO HAVE THE MORTAR JOINTS RAKED OUT AND REPOINTED AS THIS WILL PREVENT EITHER THE LARVAE BORING OUT OR ADULTS BORING IN.
Honey bees have a banded orange and brown abdomen. The thorax is brown and furry, unlike the wasp which is black. The honey bee can sting humans, but this is normally only under extreme provocation. They are useful creatures, promoting the pollination of plants. As bees travel from blossom to blossom in search of nectar, they transfer pollen from plant to plant, thus fertilising the plants and enabling them to bear fruit. Far from eradicating pollinating bees, they should be encouraged by providing nesting habitats, stopping the use of harmful pesticides and allowing plants to grow on which they can forage. Honey bees are social insects that cannot survive alone. To start a new colony, a new queen needs to be produced and when this happens, the old queen leaves with some of the workers resulting in a swarm. Swarming mainly occurs during fine weather in May and June, but honey bees are normally harmless, provided that they are not interfered with. If you think a swarm of honey bees has arrived on your property, it is likely that they are just resting, usually on a tree branch, before they move on to form the new colony. They should move on within 24-48 hours, so unless they are causing a problem-leave them alone. If they have decided to make a new nest site, often in chimney-breasts, then you will need to contact a beekeeper for professional help.
Treatment with insecticides should only be considered as a last resort.