Question
Hi Jim,
I have a shadow box fence and noticed that there are 3 or 4 of  these black roundish looking bees.  I dont know if they have any yellow on them and they might.  They dont fly very fast and tend to hover around my fence.  I can pretty much trace their pattern.  They start on one of the fence then slowly weave in and out of the fence. Make its way around towards the front of the house and since there isn't a fence in the front it goes across my driveway and then starts the whole fence dancing on the other side.  Was wondering if you knew what this was?  How can I stop them from coming?

Thanks,

Answer
This sound like carpenter bees. Carpenter bees are so named because they excavate galleries in wood to create nest sites. They do not consume wood. Rather, they feed on pollen and nectar. Carpenter bees are important pollinators of flowers and trees. Carpenter bees typically are just nuisance pests that cause cosmetic rather than structural damage to wood. Nonetheless, considerable wood damage can result from many generations of carpenter bees enlarging existing galleries in wood.

Carpenter bees somewhat resemble bumble bees, except bumble bees have dense yellow hairs on the abdomen and large pollen baskets on the hind legs. Various species of bumble bees and carpenter bees are similar in size. Bumble bees typically nest in the ground whereas carpenter bees nest in wood.

Carpenter bees are solitary insects that do not form colonies. Male and female carpenter bees overwinter as adults within their old nest gallery. Adults emerge in the spring (April and early May) and mate. There is one generation per year.

Carpenter bees nest in a wide range of softwoods and hardwoods, particularly if the wood is weathered. Eastern species of carpenter bees prefer softwoods such as cedar, redwood, cypress, pine, and fir. The bees can more easily tunnel through woods that are soft and that have a straight grain.

Carpenter bees attack structural timbers and other wood products, including fence posts, utility poles, firewood, arbors, and lawn furniture. In buildings, carpenter bees nest in bare wood near roof eaves and gables, fascia boards, porch ceilings, decks, railings, siding, shingles, shutters, and other weathered wood. These bees avoid wood that is well painted or covered with bark.

Despite their beneficial aspect of being important pollinators of many trees and flowers, carpenter bees also may be nuisance pests around structures. Carpenter bees are noisy, which may be bothersome. These large bees create alarm when they dive-bomb or fly erratically around humans. In actuality, these are male bees, which are territorial but harmless because they lack a stinger. Only females have a stinger. Female carpenter bees are docile and are reported to sting only if handled.

Prevention
Keep all exposed wood surfaces well painted with a -polyurethane or oil-base paint to deter attack by carpenter bees. Periodically inspect painted surfaces, because the coatings will begin to deteriorate due to weathering, leaving exposed wood that the bees then can easily attack.

I would not really worry about the bees near the fence just make sure they are not able to enter the wood on the house by keeping it painted. Over time they may cause parts of the fence to be damaged but this will take some time.

If you really want to control the bees on the fence and do not want the wood painted you can spray the fence with an insecticide. For use as a preventive, an insecticide should be applied to wood in early spring before carpenter bees begin excavating nests. The insecticide kills the bees that contact it on the wood抯 surface.
Such insecticides usually degrade in a matter of weeks or months so repeated applications are needed to maintain a lethal dose of the insecticide. Some pest management companies report good results against carpenter bees by spraying wood with a microencapsulated pyrethroid, Demand?CS insecticide (registered for use only by licensed professional applicators), which contains the active ingredient lambda-cyhalothrin. A number of other pyrethroids (bifenthrin, cyfluthrin, deltamethrin, permethrin, etc.) also are labeled for use against carpenter bees.