We have found that the products shown below are the best for controlling Carpenter Bees.
How to Control Carpenter Bees
During spring when the temperatures start to warm up we start getting calls from customers on how to control Carpenter Bees. When homeowners start to notice large, black bees hovering around the outside of their homes. These are probably carpenter bees searching for mates and favorable sites to construct their nests. Male carpenter bees are quite aggressive, often hovering in front of people who are around the nests. The males although aggressive are quite harmless since they lack stingers. Female carpenter bees can inflict a painful sting but seldom will unless they are handled.
The Carpenter Bee is more of a destructive insect versus honey bees who are more likely to sting in large numbers.
Carpenter bees resemble bumble bees, but the upper surface of their abdomen is bare and shiny black; bumble bees have a hairy abdomen with at least some yellow markings and much more of a waistline.
Carpenter and bumble bees might resemble each other but their nesting habits of the two types of bees are quite different. Bumble bees will usually nest in the ground; carpenter bees will tunnel into wood to lay their eggs. Bare, unpainted or weathered softwoods are preferred, especially redwood, cedar, cypress and pine. Painted or pressure-treated wood is much less susceptible to attack of carpenter bees. Common nesting sites include eaves, window trim, facia boards, siding, wooden shakes, decks and outdoor furniture.
The entrance hole and tunnels are perfectly round and about the diameter of your finger. Sawdust the color of fresh cut wood will often be present beneath the entry hole, and burrowing sounds may be heard from within the wood. Female carpenter bees may excavate new tunnels for egglaying, or enlarge and reuse old ones.
Carpenter Bee Control
Carpenter bees prefer to attack wood which is bare, weathered and unpainted. Therefore, the best way to deter the bees is to paint all exposed wood surfaces, especially those which have a history of being attacked. Wood stains and preservatives are less reliable than painting, but will provide some degree of repellency versus bare wood. To further discourage nesting, garages and outbuildings should be kept closed when carpenter bees are actively searching for nesting sites.
Using liquid insecticides to apply to areas that have become attractive to the carpenter bee can be used and retreatment applied every few weeks. Products like Tempo SC and Demand SC are both great choices as they are very effective.
Tunnels from Carpenter Bees which have already been excavated are best treated by puffing an insecticidal dust Tempo SC, and Delta Dust are great dust for use in the nest opening. Aerosol sprays labeled for wasp or bee control also are effective. Leave the hole open for a few days after treatment to allow the bees to contact and distribute the insecticide throughout the nest galleries. Plug the opening later with caulks, wood putty, wooden dole rounds, etc.