The carpenter bee normally attracts a lot of attention in Georgia in late spring and early summer. Adult carpenter bees are large, one inch or slightly longer, robust insects. They are blackish in color and possess yellowish hairs mostly on the thorax. The abdomen is shiny black and is bare of hairs on top.
Carpenter bees burrow into the dry wood of buildings, telephone poles and fence posts, causing an unsightly appearance to the wood and structural weakness.
They usually choose wood that is soft and easy to work. Carpenter bees usually avoid well-painted wood and wood with bark on it. Wood with a stain or light coat of paint can be attacked.
Also, wood that has been lightly pressure treated with metallic salts for above-ground use could become infested.
Female carpenter bees seldom sting but when disturbed or handled they can inflict a painful sting. Male carpenter bees cannot sting but they often become aggressive.
In the late spring and early summer, adult carpenter bees emerge from protected overwintering sites. These fertilized females soon begin boring into susceptible wood.
After a gallery has been constructed, an egg is deposited with a mass of pollen and nectar. Then the egg with provisions is sealed off with a plug of wood pulp and saliva. The process is continued at the rate of one cell each day until approximately six cells are constructed. Adults then soon die.
The larval period extends 30-45 days and the pupal period 14 days. Development form egg to adult requires five to seven weeks or longer depending on temperatures.
Here are three methods that could be used to control carpenter bees:
1. Aerosol insecticide sprays labeled for use to control flying insects and bees can be applied directly to carpenter bees. The oil-based carrier and the insecticide will kill carpenter bees. A few aerosols are available which have long-range capabilities.
2. Residual applications of insecticides such as permethrin and cyfluthrin sprays can be applied to outdoor wooden surfaces.
An unsightly insecticide deposit could occur on treated wood so be careful. Nests or galleries can be treated directly with these insecticides or with others such as carbaryl or deltamethrin dusts that are labeled for carpenter bee control. Carpenter bees will be controlled when they contact the residual insecticide deposit.
Several days following treatment, after carpenter bee activity has ceased, holes can be plugged with dowel rods, plastic wood or with other materials.
If carpenter bees continue to attack the wood, additional residual insecticide treatments may be required at weekly or twice weekly intervals.
3. Wood which has been recently painted with oil based or latex paint will not normally be attacked by carpenter bees.
Pressure treated wood is often resistant to attacks until it has weathered for several years.
There are only a couple of options for organic control. Boric acid can be used to control carpenter bees by placing this powder in the area or in the holes they make.
Secondly, spraying pyrethrins, these chemicals are derived from chrysanthemums and are generally not considered to be dangerous.
Professional pest control operators can be especially helpful when carpenter bees are a problem.
As always, the Forsyth County Extension Office is here to help. Call 770-887-2418, email firstname.lastname@example.org. Visit the website at www.ugaextension.org/forsyth or Facebook.