Brown Spruce Longhorn Beetle
Tetropium fuscum (Fabr.)

This Web page summarizes what is known about the biology
of a potentially devastating exotic pest, and the issues surrounding
its discovery in Point Pleasant Park in Halifax, Nova Scotia.


Frames Version

Table of Contents

Male Brown Spruce Longhorn Beetle
Male Brown Spruce Longhorn Beetle
(Source:  Canadian Food Inspection Agency )

Page prepared by
Stephen Locke
Student, Dalhousie University
Posted Dec 24, 2002
                 Terms presented in brown are found in the glossary.

1. Introduction

 In 1999, the Brown Spruce Longhorn Beetle (BSLB) (Tetropium fuscum ) was been found in the Halifax Regional Municipality in Nova Scotia, Canada. The site of "infestation" is Point Pleasant Park, an urban forest and popular park.

A relatively innocuous pest throughout much of its native Eurasia, Canadian authorities are blaming the beetle for the deteriorating condition and death of apparently healthy trees within the park. Fear that the BSLB might establish itself in Nova Scotia and then spread accross Canada and into the U.S. has authorities destroying thousands of trees within the Park in an attempt to eradicate the beetle. The cutting of trees has put government, environmental groups, scientists and citizens at loggerheads.

2. Point Pleasant Park

(Sources: Anonymous, 2000d; Freedman, 2000)

Location: south end of Peninsula Halifax, Nova Scotia, Canada
Designation: "natural area" urban park
Forest type: mature (more than half the trees are older than 100 years)
Park size: 75 hectares
Most common tree species:
Visitors: over 1.3 million people per year
Ownership: Federal Government (leased to HRM since 1997)
Comments: Point Pleasant Park is the city's premiere park
red spruce, the most abundance tree species is main host of the BSLB at this site

LAND CLASSIFICATION OF PARK
Forest Land Area
(ha)		 Percent
Total Area
Softwood 58.5 78.0
Mixedwood 4.5 6.0
Hardwood 0.0 0.0
Total 63.0 84.0
Non Forest Land
Total		 12.0 16.0
TOTAL PARK 75.0 100.0
Location of Point Pleasant Park

Location of Point Pleasant Park
Click on image for larger display

(Source:  CFIA )


The health of the trees within the Park has been questioned for more than a decade.

3. Brown Spruce Longhorn Beetle (BSLB)

 A. Background  (sources: Anonymous, 2000c; Anonymous, 2000d)
In March 1999, The BSLB was found in dying red spruce trees in Point Pleasant Park. The following summer, the Canadian Forest Service (CFS) reared over 40 T. fuscum adults from red spruce bolts collected in the park. In its native Europe and Asia, the BSLB is recognized mainly as a secondary forest insect, normally attacking weakened, stressed, and dead or felled conifers. Governmental agencies here believe there is strong evidence that the BSLB is attacking apparently healthy trees and killing them.

The BSLB has been present in Nova Scotia since at least 1990, when the first specimens were collected in the Park. They were originally misidentified as a related native species of Tetropium but have subsequently been identified as Tetropium fuscum.

It is believed solid wood packing material provided the entry pathway for this pest via the port of Halifax. The beetle has been found in 47 other locations in the Halifax area, all within a 15 km radius of the Park. There are currently no registered insecticides known to be effective against Tetropium spp.


There are four other Tetropium species in Nova Scotia:
Native
  • Tetropium cinnamopterum Kirby
    		•
  • Tetropium parvulum Casey
    		•
  • Tetropium schwarzianum Casey
    		•
    Non-native
  • Tetropium castaneum Casey
    		•


    B. Distribution  (source: Anonymous, 2000c)
    The BSLB is native to northern and central Europe, where it can be found from Scandinavia to Turkey, and western Siberia. It is also found in Japan. This is the first established population of the BSLB discovered in North America.

    C. Biology  (sources: Anonymous, 2000c; Freedman, 2000)
    The published scientific literature on the BSLB is not extensive or recent. There are aspects to the lifecycle of the BSLB in Halifax that are still not well understood. It has not been determined whether there are one or two generations of the beetle per season. The beetle likely has one generation per year but in the warmer regions of southern Ontario, southern Quebec, and interior parts of B.C., the beetle could have two generations per year.


    The larvae kill trees by tunneling into the cambium, phloem , and outer layer of wood, forming extensive networks of wide irregular tunnels which disrupt the essential transfer of nutrients.


    Natural enemies of T. fuscum that occur in Canada:
  • Rhyssa persuasoria L.
    		•
  • Xylonomus irrigator F.
    		•
  • Atanycolus denigrator L.
    		•
  • Clisopyga sauberi Brauns
    		•
  • predatory wasps
    		•
  • birds (primarily woodpeckers)
    		•
  • amphibians
    		•


    D. Identification   (sources: Anonymous, 2000c; Smith and Humble, 2000)

    Adult:
  • 8 - 18 mm long
  • head and neck dark brown to black
  • antennae red-brown, approx. half body length
  • body tanned, brown or reddish brown, flattened
  • legs dark brown
  • wing covers with 2 - 3 longitudinal stripes
  • flying insects
  • difficult to distinguish from similar small flying beetles

    Click on image
    BSLB Larva
    Larva
    (Source:  CFIA )
    Larva:
  • 14 - 28 mm long
  • head reddish brown, approx. 3mm wide
  • body yellow - white, slightly flattened
  • thorax with conspicuous legs

    Pupa:
  • approx. 17 mm long and 3.8 mm wide
  • white

    Egg:
  • 1.0 - 1.2 mm long
  • 0.2 - 0.3 mm wide
  • white with a tinge of green
  • oblong - oval

    • E. Detection   (sources: Anonymous, 2000a; Smith and Humble, 2000)

    Click on image
    BSLB Larval Galleries
    Larval Galleries
    (Source:  CFIA )
    Preferred hosts:
  • spruce (Picea spp.)
  • firs (Abies spp.)
  • pines (Pinus spp.)
  • larches (Larix spp.)
  • occasionally hardwoods

    Symptoms of attacked trees:
  • excessive resin flow along trunk
  • oval to round holes in bark, approx. 4 mm across
  • networks of feeding tunnels just under the bark, up to 6 mm across, filled with frass
  • tunnels in the wood approx. 4 cm deep and 6 mm wide, appear L-shaped in cross section.
  • browning of foliage


    • 4. Economics

     Canada's forests are central to its:
  • economic
  • environmental
  • social well-being
    • Red spruce, the provincial tree of Nova Scotia, is an extremely valuable resource for pulp and paper and lumber production. It is the mainstay of the maritime lumber industry (Anonymous, 2000c). The spread and establishment of the BSLB could cause significant loss to Canada's forest sector and prompt Canada's major trading partners to impose quarantine restrictions on Canadian forest products. Canada is obligated under legislation and international agreements to take appropriate measures to eradicate introduced insect pests (Freedman, 2000). It is suggested that the CFIA's response is motivated more by concerns that US authorities could threaten sanctions against softwood lumber exports if Nova Scotia does not seem to be moving forcefully against this perceived threat.



    		NOVA SCOTIA CANADA
    Spruce Trees % of Total Forest Land 60% 33%
    Jobs Provided by Forest Industry 11,000 880,000
    Annual Export of Conifer Lumber $161 million $11.1 billion
    (Anonymous, 2000d)


    Despite detection efforts at Canada's points of entry, the number of alien species are increasing. This is the result of the increased volume of trade and the broadening of trading partners (Anonymous, 1999).


    5. Task Force

     The Task Force, a multi-agency and multi-disciplinary group, was formed in the spring of 2000 to provide scientific support and research information to the Canadian Food Inspection Agency (CFIA).

    The CFIA conducted a pest risk assessment (PRA) for Tetropium fuscum . Their assessment rated the BSLB as a potentially high risk species requiring an immediate eradication program:

    LIKELIHOOD OF INTRODUCTION POTENTIAL INTRODUCTION IMPACTS OVERALL RISK RATING LEVEL OF UNCERTAINTY
    high high high high
    (Anonymous, 2000c)

    The BSLB has been identified by the Task Force as the causal agent of red spruce mortality in Point Pleasant Park. All Task Force members support the efforts of the CFIA to eradicate this invasive forest pest and believe that success is possible considering the small number of sites the beetle is found (Anonymous, 2001).


    6. Friends of Point Pleasant Park (FPPP)

     Friends of Point Pleasant Park (FPPP) was established in the spring of 2000 by a group of citizens alarmed at the continuing problems in Point Pleasant Park (*Friends of Point Pleasant Park).

    The FPPP are critical of the actions taken by the CFIA. They believe that the felling of trees is an overreaction as the beetles are feeding on dead and dying spruce trees, and are not the cause of the trees' malaise (LeBlanc, 2000).


    FPPP argue:
  • CFIA has refused to reveal any scientific data to support their actions
  • no evidence that the beetles are harming the trees
  • CFIA is engaged in an expensive media campaign which alleges the Park is overflowing with an infestation of beetles
  • there are natural predators of BSLB in Park
  • cutting of trees in midsummer, when BSLB are able to fly, might cause beetles into moving beyond the Park
  • waste of $2 million of taxpayers' money to cut trees in Park
    (*Friends of Point Pleasant Park)

    • 7. Conclusion

     Most scientific research indicates the presence of the BSLB in Point Pleasant Park but if the CFIA is saying there is an infestation in the Park, they should be capturing hundreds or thousands of the beetle, not only a few here and there. The data released by the CFIA often contradicts itself and works against their reasoning. The following is results from their current testing:


    No. of trees identified suspect 2030
    No. of trees removed 954
    Total returned reports 237
    Positive for BSLB 148
    Negative for BSLB 87
    Pending reports 2
    (Anonymous, 2001)

    If 37% of the trees that were suspected of being infected with BSLB have been confirmed as testing negative for their presence, it is possible that these beetles are inhabiting visibly stressed trees and are not responsible for the dying trees. This supports the need for further research in determining the causal agent(s) of the dying red spruce.




    It is expected that it will take several years of research, survey and eradication activities to determine the success of the Task Force's efforts. In the mean time, reasonable efforts should be made to eliminate such species if there is a chance to prevent such a potential catastrophe. Even if most invasions are not significantly harmful, the small fraction that can seriously affect our ecosystems, economics and health are sufficient reason to attempt to control them (MacIsaac and Ricciardi, 2000).

    "The expansion of world trade is dramatically escalating the risk of introducing new exotic pests, especially through wood packing materials used in international trade. If exotic pests are detected early, aggressive eradication programs can prevent large-scale infestations. If we are not prepared to extend the effort to safeguard our economy and ecosystems, North America will be poorer in terms of resources and biological diversity" (Haack et al., 1997). Point Pleasant Park is undoubtedly a beautiful urban forest, but is it worth risking the forests of North America?


    8. Glossary

    Biological control
    Introduction of natural enemies to reduce the density of the pest.
    Bolt
    A block of timber to be sawed or cut.
    Cambium
    Formative one-cell-thick layer of tissue in most vascular plants that is responsible for secondary growth.
    Entomology
    The scientific study of insects.
    Eradication
    The removal of every potentially reproducing individual of a species.
    Hardwood
    The wood of a tree with two embryonic seed leaves or cotyledons that usually appear at germination.
    Larva
    The newly hatched, wingless, often wormlike form of many insects before metamorphosis.
    Non-indigenous species
    Any species in an area or ecosystem to which it is not native.
    Phloem
    Tissue that conducts synthesized food substances (e.g., from leaves) to parts where needed; consists primarily of sieve tubes.
    Pupation
    The act of becoming a pupa.
    Quarantine
    A limiting or forbidding of movements of persons or goods that is designed to prevent the spread of disease or pests.
    Secondary forest insect
    An insect of minor importance; not primary causal factor for tree damage.
    Thorax
    The middle region of the body of an insect between the head and the abdomen; it bears the legs and wings.

    9. Useful Links

    10. Useful Literature

    11. Useful Journals

    12. Cited Literature and Links

    Male Brown Spruce Longhorn Beetle Resin Flow Resin Flow Close-up Female Brown Spruce Longhorn Beetle
    Resin flow on red spruce
    Adult male BSLB
    Click on photos for larger images
    (Sources:  Canadian Food Inspection Agency )
    Adult female BSLB



    Posted by Stephen Locke October 14, 2001
    Modified by Stephen Locke January 8, 2001

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