Which term describes the remnants of termite damage found in treated wood surfaces?

The term that describes the remnants of termite damage found in treated wood surfaces is "frass." Frass refers to the waste material produced by termites, which consists of small pellets of digested wood and cellulose. When termites consume wood, they break it down and excrete it in this pellet form, and this waste material is commonly found near areas where termite activity has occurred.

The presence of frass is often a key indicator of an active or previous termite infestation, as it not only signifies that termites have been feeding in that area but also helps in identifying the location of their activity. In a treated wood surface, finding frass suggests that the treatment may not have been fully effective or that termites were active before the treatment was applied.

Other terms provided in the question refer to different phenomena; for instance, fungal growth occurs when wood is decaying due to moisture, and larvae shells are the cast-off exoskeletons of insects, which do not specifically indicate termite activity. Fecal pellets can be a bit more ambiguous because they could refer to waste from various pests, not just termites. Therefore, frass is the most precise term among the options for describing the remnants specifically related to termite damage in treated wood.