Controling Carpenter bees how to recognize, kill and prevent them

 The most common species of carpenter bee in the eastern US. is Xylocopa virginica. It is a large black and yellow, bumble bee sized insect with amber, reddish colored wings. It has a shiny, blue/black abdomen that is bare not fuzzy like a bumble bee's and it is a solitary bee not living in hives or groups. In the early spring the males and females emerge from the wood cavities they over winter in, to mate and find nesting sites. The males are stingless and hover around the nesting area buzzing any one that comes close. The females have stings but are not aggressive unless provoked. The females drill holes in any unprotected wood surfaces large enough to house their broods. These 1/2 inch hole are a sure sign of carpenter bees. The bees do not eat wood, they chew out cavities that extend from a few inches to several feet into the wood and lay their eggs inside. The female will provision each egg with a food supply of pollen and nectar and then seals it up before laying another and repeating the process several times in each cavity. Each grub upon hatching will eat and develop into an adult within 5 to 7 weeks. They then emerge and depending on how long the summer season is in the area, may start reproducing themselves or in short summer areas, seek out holes to hibernate in. The same holes may be used for several years by succeeding generations of bees. You will see these large bees hovering around the eaves and overhangs of your house in the early spring. They will also attack outside furniture and fences weakening the wood and opening it up to moisture, fungus, and other pests.

Prevention is the best way to deal with carpenter bees, but it can be almost impossible if you use wood trim. Using metal flashing to cover wood trim is one solution and being sure to use treated wood for all exposed wood surfaces is another way to guard against these pests. For untreated wood surfaces the only defense shown to last over several seasons is several coats of oil based enamel paint. You can get paints with insecticides added but these do not hold up for long and because the bees don't eat the painted wood it is unlikely to control them. The same goes for spray on insecticides. They must be reapplied every few weeks to be strong enough to deter the bees. Stains and varnishes will not fully protect wood from attacts and neither will Borate treatments of the wood surface.

Killing the adult bees is not difficult, as any wasp or flying insect spray will bring them down, but this is not the best way to control the main problem. You need to kill not only the adult bees but their offspring also, to keep future generations from developing. The best products for this use are insecticidal powders that you dust into the breeding holes. Carbaryl based products such as Sevin, Boric acid products such as Borid, and the chemicals - cyfluthrin, and resmethrin, are useful poisons to treat the holes. Read all instructions and follow all safety measures when using poisonous insecticides. It is best to treat the entrance holes after dark when the bees are inactive. Wear eye protection and dust masks and a flashlight will be helpful. Use a dust applicator with a long nozzle to puff the dust into the holes and then leave them alone for a week to give the bees a chance to spread the poison to all their brood. The bees will not recognise these poisons and will get them all over their body as they enter the holes. They then will carry the toxins into the nest and contaminate the food supply of the future grubs causing their deaths. After about a week, close the now inactive holes up, using caulk, wood putty, or plugs.

One of the newer ways to kill the bees is the use of traps. These traps consist of hollow wood or plastic structures with pre-existing holes for the bees to enter. Once inside the bees are either poisoned, ensnared in adhesive, or simply not able to get back out and die. You put the traps up around your house where ever the bees are nesting. In order to be the most useful you need to put these traps up before the bees become active in the spring and you need to poison and close off all the pre-existing holes. This will help to get the bees to enter the traps and once some have entered others will follow as they are attracted to the smells and sounds of other carpenter bees. Because the bees are attracted to the odors left by other bees, it is important that you seal up any holes thay have left after treating them and before painting over them.