• facebook
  • twitter
  • YouTube
  • RSS feed
  • 651-201-6000
  • 800-967-2474
  • 711 TTY
  • PARKING

Loading
NodeFire Save Document
Home > Plants, Pests & Pest Control > Insects & Pests > Brown Spruce Longhorned Beetle

Brown Spruce Longhorned Beetle


Printable Version (PDF: 53 KB / 1 page)

Common names: Brown Spruce Longhorned Beetle
Scientific name: Tetropium fuscum Fabricius

Description: Adults are 1 to 1.5 cm long with a somewhat flattened body. The head and pronotum are black, with elytra being tan, brown or reddish. The reddish-brown antennae are about half the body length and the legs are dark brown. Larvae, which tunnel in wood, are yellowish-white, somewhat flattened, and range from 14 to 28 mm long.

Impacts: BSLB invaded Halifax, Nova Scotia, Canada with earliest records dating back to 1990. Untreated wood and wood products are likely pathways for human-assisted spread of this pest. BSLB feeds primarily on spruce (Picea spp.), but can also attack firs (Aibes spp.), pines (Pinus spp.), and larches (Larix spp.). In the native European and Asian range, it is considered a secondary pest, attacking only stressed trees. However, in North America, it is attacking apparently healthy trees. Damage is a result of larval tunneling. BSLB has also been associated with a new wood stain fungus, Ophiostoma tetropii, in North America. As of August 2009, this pest is not known to occur in Minnesota.

Biology: In Canada, where one generation occurs per year, adults are active from June to August. Females lay eggs in bark. After hatching, larvae tunnel underneath bark. As larvae mature, they tunnel inward toward the heartwood to pupate. Larvae are the overwintering stage.

Symptoms of attack:

  1. Resin on bark
  2. Oval or round adult exit holes (4 mm in diameter)
  3. Frass-filled galleries underneath bark (up to 6 mm diameter)
  4. L-shaped galleries penetrating xylem (seen in spring when pupation occurs)
Female and male brown spruce longhorned beetle
Female (left) and male (right) adults

 

Resin oozing from tree infested with the brown spurce longhorned beetle
Resin oozing from infested tree
Brown spruce longhorned beetle larval tunnels
Larval galleries beneath bark
(G. Smith, forestryimages.org)

Contact the Minnesota Department of Agriculture via Arrest the Pest if you suspect an infestation of brown spruce longhorned beetle in Minnesota. 

Arrest the Pest icon, report sightings by emailing arrest.the.pest@state.mn.us or call 888-545-6684