Identification of Wood-Destroying Organisms

Drywood Termites

Drywood termites are small, wood-destroying insects and are very common in Southern California. Workers, the most numerous members of the colony, are cream-colored and about 1/8 inch long. Soldiers are similar in size with larger heads and bigger mandibles. Swarmers, or reproductives, are dark and reddish brown with translucent wings and about 1/2 inch long. During warm weather, particularly on sunny days, swarmers leave the colony in search of new nesting sites. Most swarmers die relatively quickly due to environmental factors. However, a few manage to find suitable cracks or exposed wood, shed their wings, and establish a new colony.

Identifying Drywood Termite Frass

One of the key identifying features of drywood termites is their frass, or droppings. Unlike subterranean termites, drywood termites do not use their waste to construct mud tubes. Instead, they push their frass out of small kick-out holes near the nest. Drywood termite frass is often found in small piles and resembles sawdust or tiny pellets. These pellets are hard, oval-shaped, and have ridges along their sides. The presence of frass is a clear indicator of a drywood termite infestation and is often one of the first signs noticed by homeowners.

Drywood termites and their frass inside a damaged wood structure. The termites remain hidden within the wood, potentially creating extensive internal damage.

Drywood termites alongside their distinct frass, which resembles tiny, ridged pellets. These termites, with their cream-colored bodies, are rarely seen outside of their wooden habitats.

Shed wings and deceased swarmers on a windowsill, a common sign of a termite infestation. Swarmers, or reproductive termites, are often drawn to light sources where they shed their wings. However, once separated from the colony, they typically perish quickly.

Frass left behind by drywood termites, often mistaken for sawdust. Seen here on a windowsill, with a kick-out hole visible on the right.

Extensive damage caused by drywood termites, with visible frass accumulating within the hollowed wood. The termites burrow deep into the structure, weakening its integrity over time.

A slight bulge or wrinkled appearance, often caused by hollow voids just below the surface. Subtle signs like this can indicate underlying structural damage.

A pile of frass beneath a kick-out hole.

Frass scattered across a wooden floor.

Uncontrolled drywood termite infestations can lead to severe structural damage over time, as demonstrated by the extensive deterioration visible in the eaves shown here.

Subterranean Termites

Subterranean termites are a less common threat to homes in Southern California compared to drywood termites. While most homes in the region either have or will encounter drywood termites, this is not the case with subterranean termites. These termites live and thrive underground, constructing mud tubes to access wood and other cellulose-based materials above ground. Mud tubes are the primary sign of a subterranean termite infestation. Subterranean termites often incorporate mud into their galleries, which helps retain moisture and protects them from predators. This characteristic can be a key factor in identifying them. The subterranean termites most commonly seen locally are slightly smaller than drywood termites. Although most members of the colony share similar coloration and appearance with drywood termites, the swarmers of subterranean termites are distinguished by their black bodies.

Dryrot

Dryrot is a wood-destroying fungus that thrives in damp environments. Often mistaken for water damage, dryrot is caused by the fungus breaking down wood fibers, not by water itself. Water alone typically causes wood to swell and shrink, leading to visible problems like cracks, warping, joint separation, buckling, and damaged finishes. Outdoor wood is further affected by UV radiation and temperature changes, which accelerate surface wear and create entry points for moisture.

Cracks and unfinished wood surfaces trap moisture, creating the ideal conditions for fungal growth. Unlike water’s indirect effects, dryrot directly compromises the structural integrity of the wood, making early identification and prevention critical to avoiding extensive damage.

Signs of Dryrot

Identifying dryrot early can prevent costly repairs. Common signs of dryrot include:

• Soft wood: Wood should feel firm and solid to the touch. If it feels soft or spongy, it’s a clear indicator of dryrot.

• Cracking or crumbling: Wood may crack along the grain or crumble when pressure is applied.

• Shrunken wood: Uneven surfaces or distorted shapes may suggest underlying rot.

• Fungal growth: Visible fungal threads or fruiting bodies, such as white or gray mold-like formations, are a clear indication.

This image shows dryrot on a patio cover rafter, identifiable by its sunken and uneven appearance. Addressing dryrot early can prevent further structural deterioration.

Dryrot affecting the starter board beneath the roofline. Note the fungal growth on the right side.

Dryrot affecting a deck board, evident by its slightly shrunken appearance and deep cracks. In addition to this look, the wood will feel soft or spongy when pressed or probed.

Dryrot at the base of a door frame, showing crumbling and decayed wood.

Dryrot at the corner of fascia, showing decay and loss of material.

Dryrot at the base of a wooden post, revealing crumbling and decayed wood.

Dryrot at the end of a rafter. Note the fungal growths, which are a clear indication of the fungus causing the dryrot.