Wood-Destroying Organisms

Wood-destroying organisms (WDOs) are so-called because of their harm to wooden structures and products. Below is a summary of the biology and control of these pest organisms, which include insects and fungi. The common name of each organism is followed by its scientific name in parentheses.

Knowledge of WDO biology and control provides security on the health of wooden products.

Termites

Subterranean termites

Drywood termites

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Formosan termites

Formosan termites

Pest biology

Eastern subterranean termites (Reticulitermes flavipes, Kollar) are the world’s most destructive insects, causing $2B in damage/year by some estimates.  These termites are more common than the light southeastern subterranean termite (Reticulitermes hageni)  and dark subterranean termites (Reticulitermes virginicus, Banks). Subterranean termites feed along the grain on softer springwood versus the harder summerwood.


Drywood termites (Cryptotermes brevis), which are found near coastal and south Georgia. Drywood termites feed against the grain on springwood and summerwood.  Drywood colonies are smaller and do not include mud tubes. Frass is pellet shaped.

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Formosan termites (Coptotermes formosanus) swarmers are yellowish to brown in color and larger than the subterranean termite.

  • Order Isoptera (which means, "same wing," referring to the similar size of the fore- and hind wings on reproductives) represents several families of termites.
  • Termites range in length from ¼ and ½ of an inch long.
  • Develops through three-stage, simple/incomplete metamorphosis, including egg, nymph and adult.
  • Termites need moisture and are prone to dehydration due to thin cuticle.
  • Key words:  trophallaxis, which is the exchange of food and body secretions between colony member, which passes on beneficial gut symbionts. Trophallaxis can be via mouth to mouth or anus to mouth; frass is shavings of wood and excrement left behind by wood-destroying organisms.
  • King and queen are wingless swarmers. Swarmers or alates are reproductive, adult, winged termites; can be male or female.
  • Workers are wingless, blind and make up about 75-95% of the colony.
  • Soldiers are blind and make up about 5-10% of the colony. Soldiers are feed by workers.
  • Pest control

    • Wood that is termite-infested sounds hollow. Swarming activity, sawdust-like frass, shelter tubes, infested wood, and wood-to-soil/ground contact, where high moisture content, is favorable to termite infestation.
    • Control of termites includes termiticides as directed sprays (spot treatments). Common chemicals that can be used to manage termites include creosote, pentachlorophenol, and inorganic arsenicals. In Ground bait stations have also proven to be effective.

    Carpenter ants

    Pest biology

    Black carpenter ant  (Camponotus pennsylvanicus) is common to inland and central GA, and one of the largest of pest ant species in Georgia at just under ¼ inch, along with Florida carpenter ant (Camponotus floridanus), which is common to southern and Southeast GA.  The Florida carpenter ant is rare.

    Termites live in caste systems which make up a colony containing workers, soldiers, swarmers, a king and a queen.

    Photo by Erin Daniels (UGA Special Bulletin 1241). Used by permission.

    Carpenter ants and termites appear similar to the untrained eye. However, carpenter ants can be distinguished from termites by having bent antennae, wings of different sizes and constricted spaced between the thorax and abdomen. Conversely, termites have straight antennae, broad waist, and fore- and hindwings of similar size.

    Carpenter ants don’t incorporate mud into galleries and don’t consume wood like termites, but these pests cause damage to wood.

    Pest control

    Treatment of carpenter ants infestation includes dusts, which are very effective. Aerosols are also best for indoor infestations.

    Carpenter bees

    Comparison of carpenter bee (left) and bumble bee (right).

    Wood-boring beetles

    From L-RCigarette beetle, drugstore beetle, and powderpost beetle

    Pest biology

    Power-post beetles are Anobiid beetles, which include the cigarette beetle (Lasioderma serricorne) whose larvae or grubs leave behind frass and ⅛ inch exit holes during feeding on wood; drugstore beetle (Stegobium paniceum) fakes death when disturbed; and powderpost beetle (Euvrilletta peltata), which is the most common wood-destroying beetle that leaves behind frass near the infestation.

    Wood-destroying fungi

    Pest biology

    Destruction of wood by fungi (several species) occurs when the moisture content is greater than 28%. This is caused by frequent rain, leaks, condensation, or moist soil. Infested wood appears brown and crumbly or white and stripped.

    Pest control

    Treatment with boric acid is recommended in this case, however, the ideal control method is the reduction of moisture through cultural controls, which include facilitating proper drainage, eliminating contact between wood and soil, increasing airflow and decreasing vapor movement. The use of treated lumber is also recommended.

    Shown here at the top of this image is a support beam where dry rot caused by a fungus, which created cracks and distortions in wood left untreated. Photo: Creative Commons.

    Pest biology

    Adult carpenter bees (left above) are robust (1” or longer), with black and yellowish hairs on the thorax. The abdomen is shiny, black and hairless on top. Carpenter bees damage wood, especially cedar, but don’t ingest wood as do termites. This type of bee can be distinguished from bumble bees (right below), which are similar in size and coloration, but bumble bees possess yellowish hairs atop their abdomen. 

    Carpenters bees nest near wood, where they build ½ inch holes into wood, while bumble bees nest outside near the ground. Bumble bees are similar in appearance to the heel or grub (bomb) fly.

    Pest control

    Control methods of this type of pest include the use of aerosol insecticides as contact applications, residual surface and gallery treatments with insecticides. Prophylactic treatments, such as painting wood with thick coats of oil-based or latex paints to prevent reinfestation, is done by a carpenter or contractor.

    Old-House Borer

    Long-horned beetles, such as the old house borer is 1/2 to 3 inches long and damages wood in the larval stage; these beetles prefer pine sapwood.

    The old house borer prefers pine sapwood can be identified with a pair of lustrous spots on its thorax.

    Pest control

    To control these types of insect pests, moisture content less than 10% is best. Wood that is dry does not promote infestations. Insecticides, such as Bora-Care® with Mold-Care®, used according to the label rates are effective. Lastly, removal of infested wood is recommended


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