What is Frass and How Can I Identify It?

Frass: The Facts

Property owners often miss the telltale signs of frass—tiny piles or dustings of substances that resemble sawdust, powder, granules, or mud. Closer inspection above or immediately at the site may reveal, however, a single hole, dozens of holes, or decay that is more difficult to detect—each type of damage evidence of a nest, a colony, and a potential infestation. The frass present at each site is often the key to identifying what type of pest might be at fault.

What Is Frass?

In the strictest, most technical use of the word, frass is the excrement of insects and their larvae. In some cases, frass leavings alone is present while in other cases, frass may be mixed with sawdust that the insects have chewed or reused to appear like mud, for example.

How To Identify Frass

Many insect pests have distinctive frass. Here are some of the most common ones.

Carpenter Ants: Cone-shaped piles of debris consisting of frass, shredded wood bits and pieces of insects near soft, moist wood are signs of carpenter ants. The ants kick frass from their nests, which may be tucked behind wall voids, hidden under attic insulation, or concealed in any other protective space or layer of construction.

Carpenter Bees: Carpenter bees will leave yellowish, fan-shaped accumulations of excrement beneath the entrance to their tunnel nest. This frass may become moldy or appear dirty. Beneath the dime-sized hole will be small piles of wood bits and sawdust. Behind the hole, tunnels may extend at a right angle up to eight inches. Larvae developing inside often attract woodpeckers.

Carpet Beetles: Frass typically resembles a finely powdered version of whatever textile the beetles have been consuming. Carpet beetle frass is granular, sandlike, and typically located under or near infested items. As larvae molt, they shed hairy skins known as husks, which are additional identifying signs of an infestation.

Bed Bugs: A diet of blood means these tiny frass stains are often reddish-brown. Shed skins may also be present as well as egg casings or tiny, sticky white eggs. Bedbug frass may be readily visible beneath mattress corners or along seams. On furniture, stains may be beneath cushions or in spots giving bedbugs both daytime concealment and access to their next nocturnal blood meal.

Cockroaches: The smaller, darker German cockroaches noted for invading homes will leave frass pellets resembling bits of cracked black pepper near their areas of harborage. Outdoor varieties—often recognized as palmetto bugs—may leave trails of slightly larger pellets.

Powderpost Beetles: Tiny, powderpost beetles and related wood borers create extensive damage often mistakenly attributed to termites. However, these insects fit their eggs into the pores of wood surfaces. When the larvae hatch, they bore into the wood, eating until they emerge as mature adults ready to reproduce. As the cycle continues, they leave behind sprays of tiny holes and accumulations of fine powder the consistency of flour.

Termites: Florida boasts 21 different termite species, but as a rule, they fall into three types:

  • Subterranean termites use their frass to construct mud tubes many experts believe. They affix these tubes or tunnels to span construction features so that the termite nest has access to wood food sources. Mud tubes resemble free-form straws made of earth and can be found inside or outcrossing internal basement walls, for example, or climbing external foundations.
  • Drywood termites nest inside their food-source wood. Due to the limited space, they will expel piles of frass through kick-out holes. Drywood termite frass resembles fine, six-sided, rectangular grains of sand, with all moisture removed.
  • Dampwood termites do not construct mud tubes or use kick-out holes. Instead, fecal pellets remain clustered within galleries tunneled throughout the infested wood. Dampwood termites may attach frass to the sides of gallery tunnels or leave it to accumulate on the tunnel floors. Occasionally, advanced deterioration of infested wood may allow frass pellets to escape and be seen.

Safely Treating Hard-To-Identify Pests

Even when property owners are able to properly identify frass, the pests responsible can be challenging to treat and the damage advanced. If you are concerned about protecting your business or home from pest insects, B&B Exterminating wants to help. We offer environmentally safe solutions that won’t harm your family, your pets, or the environment. Contact us today and we’ll help you protect your investments safely and responsibly.