In nature, termites function as decomposers that breakdown dead or live wood that accumulates in and on the soil. Termites are social insects and the makeup of the colony can be somewhat complex. The beneficial products of this breakdown process are returned to the soil as humus. We will discuss two different types of termites, the drywood and subterranean termites. These insects are the most destructive pests of wood, causing more than $1.7 billion in damages and cost of control each year in the U.S. alone. Their presence in structures is seldom noticed until damage is discovered or the termites swarm within the building. About 46 species of termites occur in the continental United States.
Differences Between Drywood and Subterranean Termites
- Nest in soil a connection with soil is usually necessary.
- Generally smaller insects; therefore, tunnels and chambers usually smaller.
- Galleries usually run parallel to grain in the softer “spring wood.”
- Frequently build free shelter tubes or covered runways of mud and fecal material.
- Fecal material is soft and used in constructing nest and shelter tubes.
- Larger, rapidly-growing colonies work faster, damage often more severe.
- Flights occur day or evening, more often associated with rain.
- Nest in wood, ground contact is unnecessary.
- Larger insects with tunnels and chambers usually larger.
- Galleries often cut across grain of wood; attack both softer “spring” wood and harder “summer” wood.
- Do not commonly build exposed shelter tubes.
- Fecal material in form of hard, dry pellets–appearing like sawdust in galleries or in piles outside.
- Smaller, slower-growing colonies.
- Work more slowly, damage generally less severe.
- Flights more often occur evening or night, usually not closely associated with rain.
- When choosing a new house ask questions about its construction. A floating slab is quite susceptible to termite attack. Termites enter where the slabs meet the walls and through hidden expansion joints. Monolithic slab construction contains no joints and is therefore more resistant to termite entry. However, it is not termite proof. Some settling will occur regardless of how the slab is laid, and over time cracks may appear.
- Currently most new homes are treated with a continuous chemical barrier (termiticide) beneath and next to the slab that is guaranteed to protect a home from subterranean termites for five years.
- Wood-to-ground contact should be eliminated, i.e. wooden porches should be separated from the building proper and wooden steps should rest on a concrete base at least 6 inches above grade. Wood partitions and posts should be installed in basements after the concrete floor is poured and should never extend into or through concrete. Keep soil or mulch away from wood siding. Remove all wood scraps and do not bury them in soil near the house foundation.
- Keep wooden planters, trellises and raised beds away from foundations.
- Keep firewood away from the house and elevated off the ground.
- Make sure termite barriers are applied under new additions.
- Promptly repair leaks and faulty drainage.
- Fill any cracks in your foundation and seal any openings, particularly where utility pipes and wires enter from the outside.
- Eliminate standing water, which pools against the foundation. Re-grade the ground so that water drains away from the house.
- Avoid putting landscape plants or trees close to the building and make sure turf sprinklers and drip irrigation emitters are not soaking the home walls or foundation.
The homeowner should be encouraged to inspect their homes at least once or twice a year for signs of termite activity. Pay particular attention to additions such as porches or patios, and any area where wood contacts the ground. All additions to the house should have foundations that are pre-treated with a termiticide. Look for mud tubes, holes in wood with clean galleries cut across the grain, pellets or sawdust, piles of wings and swarming insects. If there are indications of an infestation, the homeowner can also request a professional inspection. Check with friends or neighbors and/or the Better Business Bureau for recommendations on what company to choose.