When I was trimming shrubs around the outside of my house, I found these strange mud tubes on the siding. Do you have any idea what made them? J. J., Stowe, MA

Mud tubes on an outside wall could be the nest of a mud dauber wasp or they could be travel tubes used by subterranean termites (or they could be the work of a 4-year old!). Size and location of the tubes would determine the correct answer.

(1) Tubes Made By Wasps – Organpipe mud dauber wasps construct mud tubes that are a few inches long, about 3/4 –inch wide, and stacked side by side. The tube nests are found in sheltered places on a home such as under porch roofs, on eaves, or on window frames. The tubes contain the wasp’s developing larvae and spiders provided for them to feed on (see Mud Dauber Wasps – Unsightly Nests But Little Threat)

Old Tubes or New Tubes? If the tubes have circular holes in them, that means that the wasp larvae have completed development and adult mud dauber wasps have already emerged from the nest. Adult wasps emerge in the spring and begin building their own nests. If the tubes are entire, wasps will still emerge, probably next spring. There is usually no control necessary other than removing the mud tubes with a putty knife.

(2) Tubes Made By Termites – Termite mud tubes, on the other hand, are much smaller in diameter and often much longer than a few inches. Termite tubes meander up a wall, usually from the ground, often branching as they are constructed and extended. Subterranean termites build these mud tubes to use as tunnels while looking for wood, or to reach wood already discovered. The tubes protect the soft-bodied termites from drying out once they leave the soil and also protect them from predators like ants (see What Do Termite Tubes Look Like?).

Old Tubes or New Tubes? Termite tubes are made from a combination of soil, wood, and a glue-like substance made from the saliva and fecal material of the termite. Old tubes are dry and brittle and break easily. Fresh, newly constructed tubes are moist and you might find worker termites inside when you break them open. If you have termite tubes, you need a professional termite inspection by an exterminator. Termites may already be feeding on the wood in your home. At the very least, they are trying to reach the wood in your home. Call Colonial today!