Brown spruce longhorn beetle, Tetropium fuscum, is a member of the the longhorn beetle family, (Cerambycidae).
The brown spruce longhorn beetle (BSLB) is an invasive forest insect. It is native to Europe. The first occurrence in Canada was in Halifax in 1999, but it has been established in Nova Scotia since 1990. The beetle likely arrived in wood packaging brought over in container ships. (Natural Resources Canada)
Here are some key features that may help to positively identify the brown spruce longhorn beetle:
8-17 mm long
Flat body with dark brown-black head covered with light-coloured hairs
Wing covers vary in colour from tan to reddish brown
2-3 longitudinal grooves
Antennae are red-brown and about half of the body length
Adults lay eggs under bark scales and in bark crevices, larvae hatch 10-14 days later
White with a greenish tinge.
Up to 28mm long.
Head reddish-brown, up to 3mm in diameter.
Segmented like an intestine.
Segmented like an intestine, difficult to differentiate from larvae.
SYMPTOMS OF BSLB INFESTATION:
Holes in the tree bark, oval to round, ~4 mm across
Feeding galleries (networks of tunnels) underneath the tree bark, up to 6 mm across, filled with sawdust-like material
Coarse sawdust may be found in and around the tunnels or plugging the entrance/exit hole
BSLB infest spruce trees in North America. The larvae bore into the tree and feed on phloem, fluid that delivers nutrients to tree roots. Infestations occur in the same trees year after year until the tree dies – usually in 1-5 years. The BSLB usually target weak trees. It is present in NS, but has not been detected in PEI to date.
Infestations of BSLB negatively affect our native forests, a large component of which is spruce trees.
BSLB can be devastating to spruce populations under stress, as it reproduces best on damaged and stressed hosts.
BSLB can impact timber harvests both in terms of yield and salability.
Prevention and early detection are key in the management of this species.
Brown spruce longhorned beetles (BSLB) are not currently found on Prince Edward Island, so efforts must be made to keep our trees safe from this invasive pest.
When traveling long distances, avoid bringing firewood along. The beetles have historically spread through the transport of contaminated wood products, so not transporting and inspecting any transported wood is crucial in the fight against BSLB.
Regulatory control measures have been put in place to prohibit the movement of raw spruce products from infested areas. Be aware of the regulatory status of the area you are traveling in/to/from.
BSLB has a lower reproductive success rate when infested host trees are otherwise healthy, so maintaining a healthy Spruce population through proper silviculture is key to preventing establishment.
As the beetle prefers to infest unhealthy or damaged trees, clearing windfall trees and removing unhealthy or damaged trees from the area can help prevent infestation.