This beetle has been found in North Kona

A tiny, wood-boring beetle has been causing problems for residents in North Kona. Xylobiops parilis Lesne, or horned powder post beetle, bore into untreated wood, which can include furniture, cabinets, and other wood products – similar to termites, but larger! Larvae burrow into the wood, making lots of little tunnels. While they chew, the larvae are kicking out fine sawdust, or frass. When the adult emerges, they leave behind pinholes in the wood surface, which can reduce the attractiveness of the item. The time it takes this beetle to go from egg to adult varies – sometimes it can be more than a year before the adults emerge! This allows the beetle to go undetected in wood for a long time before any signs of infestation appears.

This beetle was first detected on the Big Island in Kona in 2020. It was found at an illegal green waste dump site, emerging from cut mango branches. In 2022, Kona residents began to notice beetle damage to their cabinets. The beetle is now very likely established in the environment. They prefer to stay outdoors, and it is uncommon for them to attack cabinets and other furniture, but it can happen. In nature, these insects serve the purpose of breaking down wood, and go after stressed or dying trees. There are also other species of powder post beetles that are established in Hawaii.

It is estimated that one insect species per day is accidentally introduced to Hawai’i. Of these, at least 17 species will naturalize (that is, they survive, make offspring, and become established). We generally do not know what these species are, or if they will be invasive, until they begin to cause noticeable harm. This is one of the reasons it is so critical that Hawai’i improve its biosecurity and work to prevent new species from arriving.