What is the powdery refuse produced by borer tunneling known as?

The term used to describe the powdery refuse produced by the tunneling of borers is "frass." This material consists of the excrement and the finely shredded wood or plant material that results from the feeding activity of wood-boring insects. Frass is indicative of an infestation, as it can often be found around the entry and exit holes made by these pests in trees or wooden structures. Understanding frass is important for identifying the presence of insects, which can aid in pest management and treatment strategies.

The other terms do not apply in this specific context: debris generally refers to scattered pieces of waste or remains, mold pertains to fungi growth, and detritus refers to decomposing organic matter in various environments. Thus, frass is the most accurate and specific term for the powdery refuse produced by borer tunneling.