Termite Swarm Season

25 March 2005

Virginia Cooperative Extension, Charlottesville/Albemarle County Office
460 Stagecoach Road, Charlottesville, Virginia 22902
phone: 434.872.4580   fax: 434.872.4578

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Swarming is the termite method of dispersal and establishing new colonies. Subterranean swarmers emerge from the colonies at certain times of the year when conditions are suitable. Peak swarming season for the subterranean termites in Virginia is from March through June. The eastern subterranean termite, Reticulitermes flavipes, usually swarms in the spring (March-May) during the daylight hours on warm days following a rain. Subterranean termite swarmers are attracted to light so if they emerge indoors they will be seen flying to windowsills and open doors. Usually, termite swarming either indoors or outside is the first indication to the homeowner that they have a subterranean termite infestation.

Subterranean termites usually invade a structure from the soil along the foundation. They commonly enter through cracks in the slab, utility conduits, and expansion joints and plumbing connections. A common problem in Virginia is subterranean termites entering a structure between brick veneer, stucco or expandable foam insulation (EFIS) that is below the grade level and the foundation. This is a major problem because there is no external evidence of the termite presence until the damage becomes obvious. Also, wood structures in direct contact with the ground such as decks or porches invite termite entrance.

The source of most of subterranean termite infestations is a colony living in the soil. However, some infestations originate from above ground (aerial infestations). Above ground infestations occur either when a termite king and queen begin a new nest within a structure or when foraging termite workers become isolated and cannot return to the parent colony. Such infestations are rare in most of Virginia because they require extremely moist conditions year round. However, homes with flat roofs or chronic leaks are sometimes at risk because enough moisture is retained within the structure to allow the termites to become established. The constant moisture allows the termite colony to survive with no connection to the soil. In such cases the structural moisture problems may be as damaging to the home as the termite activity.

A subterranean termite infestation is usually recognized by the following three indicators:

1. Mud tubes: The termite foraging tubes extend from the ground to the infested wood providing shelter for the foraging termites. The tubes are muddy looking in appearance, flattened and about the width of a pencil. They are most obvious when they extend over concrete foundations and other exposed surfaces. However, the tubes are often less visible, running along cracks, underneath flooring or behind siding.
2. Swarmers: Winged termites emerging indoors or from swarming tubes immediately outside the structure are often the first sign of a subterranean infestation. Indoors, swarmers are often found around lighting fixtures, windows, doors and vents. Also, large numbers of discarded termite wings on windowsills, floors, or in spider webs are a sure sign of infestation.
3. Wood Damage: A common indication of subterranean infestation is the presence of dark areas or blisters in wood flooring. However, subterranean termite damage can go unnoticed because the termites only eat the springwood leaving the grain and exterior surface intact. However, the galleries can be detected by tapping the wood every few inches with the handle of a screwdriver. The damaged wood sounds hollow and the screwdriver may even break through the wood into the galleries. If the galleries are active the worker termites will be observed inside.

Subterranean termites feed exclusively on wood materials and have strict moisture requirements. With these characteristics in mind a lot can be done to prevent infestation by eliminating the food and moisture resources in their environment. Listed below are a few practical ways to prevent termite infestation by modifying their habitat.

1. Repair structural and plumbing leaks.
2. Pull all mulch and landscaping back at least 6 inches from the foundation.
3. Remove piles of trash and debris from around the home.
4. Keep firewood stacked away from the structure.
5. Make sure downspouts are long enough to direct water away from the foundation.
6. Keep gutters clean.
7. Avoid direct wood to ground contact when building porches or decks.

Subterranean termites are widespread throughout the United States. Because they are so abundant prevention alone may not always protect a structure from infestation. If a structure has become infested additional action must be taken. Over the past few years the number of subterranean termite treatment methods has increased dramatically. The most commonly sold methods of termite treatment in Virginia fall into two categories: liquid termiticide applications and termite baiting systems. The life span for most of these treatments is approximately five years. More information on termites and methods of controlling them including product brand names, active ingredients, and how the products are applied is available.

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If you believe you have a termite infestation and you want more information, either about the insects you find or about termite treatment options, contact your local Virginia Cooperative Extension office. The local Virginia Cooperative Extension office numbers are Albemarle 872-4580, Fluvanna 591-1950, Greene 985-5236, Louisa 540-967-3422, and Nelson 263-4035.