Mud tubes are covered highways that subterranean termites build from soil moisture up to the wood they are eating — pencil-thick tunnels of dirt and saliva, most often found rising from the soil line up a foundation stem wall, in the garage, or along an exterior corner. In the East Valley, finding them means the desert subterranean termite is working your house, because our dominant species builds them prolifically.
The good news buried in that sentence: tubes are evidence, and evidence found early is cheap. Desert subterranean termites work slowly compared to their cousins in wetter states, and a colony discovered at the stem-wall stage has usually done little real damage yet.
What you do in the next week matters more than what the termites do. Here is how to check whether tubes are active, what not to do, and what treatment actually looks like.
What you are looking at
Look for tubes in the classic spots: the exterior stem wall (especially behind shrubs and where soil or gravel sits high), inside the garage along the base of drywall, in the corners of closets on exterior walls, and hanging from ceilings or eaves in heavy infestations — this species also builds distinctive drop tubes that dangle like dirty stalactites.
Width matters for identification: desert subterranean tubes are narrow, often the width of a pencil lead to a pencil. Mud dauber wasps and swallows also leave mud on walls, but only termite tubes run in continuous lines from the soil upward.
The active-or-abandoned test
Abandoned is not the same as safe. Colonies routinely retreat during dry, hot stretches and return when soil moisture improves, and an abandoned tube proves a colony has already found your house once. It is a reason for an inspection, just not an emergency.
What not to do
Do not spray the tubes with over-the-counter insecticide. You will kill the few dozen workers present and push the colony to reroute, while the thousands of termites in the soil colony are untouched. Surface spray on a tube is the most common DIY mistake we see, and it makes infestations harder to trace.
What real treatment looks like
The job is trenching around the stem wall, drilling patio and garage slabs where they abut the foundation, and treating the soil beneath — the thoroughness of that perimeter is most of what separates a good termite job from a cheap one. Expect a warranty measured in years, and expect the applicator to be licensed by the Arizona Department of Agriculture's Pest Management Division; termite work in Arizona legally requires it. Our reviews and service details are on the NEARPEST Google Business Profile if you want to check us out before we ever set foot on your property.
Monsoon season is when swarms and new tube-building peak, which makes late summer and fall the most common discovery window. There is no wrong season to treat — soil treatment works year-round.
