FOREST HEALTH: Brown Spruce Longhorn Beetle
by Don Cameron, RPF

Be on the lookout for this nasty imported beetle.

The saga of the Brown Spruce Longhorn Beetle (BSLB) continues. This little beetle has caused many problems since it was first positively identified in 1999 in Point Pleasant Park along the Halifax waterfront. 
This is the only known location where BSLB was found onland in North America although it has also been found in solid wood packaging at the ports of Montreal and Vancouver. 

It is believed that the pest was shipped to the area before 1990 via infested wood packaging materials brought from Europe through the port of Halifax. It is not difficult to imagine how the beetle would make its way to the nearby large potential feeding area - Point Pleasant Park - which is immediately next to the port. 

With all the fuss surrounding the beetle, one may wonder why it is such a problem. This woodboring beetle is native to northern and central Europe and western Siberia. It poses a potential serious problem to the forests of Nova Scotia and potentially the rest of North America as it has no known predator or natural mechanism to keep the population in check. This little beetle is able to kill large spruce trees over a single year.

It is known that the BSLB attacks healthy spruce trees, dying trees, and recently felled trees, such as those downed by strong winds. If a spruce tree is under some sort of stress such as insect infestation, over-maturity or drought, it is even more susceptible to BSLB attack. Research indicates that although any spruce tree of 10cm or more in diameter may be attacked, mature spruce trees in excess of 30cm diameter tend to be the favourite menu item of choice. 

Evidence indicates that our Halifax BSLB will make a meal out of a variety of spruce trees that grow in Nova Scotia. Along with the commonly found damage to red spruce, the pesky beetle has also attacked white spruce, which is also a favourite target for our native spruce bark beetle, black spruce, and the exotic and fast growing, Norway spruce. The wide-scale blowdown of spruce trees during Hurricane Juan, created additional prime feeding areas for the BLSB.

Because of established patterns in Europe, scientists believe that pine, fir, larch, and even some deciduous tree species may be at risk here as well. Due to the Canadian climate and nationwide coniferous forest, there is a possibility that the BSLB could create a widespread infestation westward toward the much more famous Mountain Pine Beetle, which is feeding its way eastward from BC and Alberta.

The actual tree damage caused by the BSLB is a result of the larvae feeding under the bark in the cambium and phloem, which is the growing tissue that transports nutrients. The larvae form meandering feeding tunnels through this critically important tissue. Once they make a complete circle around the tree, it effectively girdles it leading to a quick death. Trees can also be damaged over time by repeated attacks, which do not cause complete girdling. After feeding, the adult bores out through the bark, creating exit holes of about 4mm across. 

These holes soon are running with resin that streams down the bark, creating an obvious symptom of problems within. 

The Canadian Food Inspection Agency (CFIA) is the federal agency responsible for preventing pests of quarantine significance from entering Canada. 

Once the BLSB was found, in an attempt to eradicate the pest, the CFIA undertook a large survey and infested tree removal program. A Ministerial Order was issued in October 2000 that established an 828 square kilometre part of Halifax Regional Municipality as a regulated quarantine zone. Under legislation, this authorized the CFIA to restrict the movement of high infestation risk materials to be moved outside of the regulated area without the agency’s formal approval. 

Regulated materials included wood of all species, in the form of logs, trees, lumber, wood with bark attached, nursery stock, wood mulch, wood or bark chips, and firewood. Obviously, this situation caused many challenges for woodland owners and the forestry sector in and around HRM. 

In April 2007, the CFIA announced that it was extending the containment zone to include central Halifax County and smaller adjacent parts of Hants and Colchester counties. It also created new guidelines for handling and moving higher-risk products, such as spruce logs, bark and large wood chips. The new regulations were worked out in consultation with industry stakeholders. The expanded zone now includes several sawmills, which means that there are now more possible markets for woodlot owners and industry to direct their harvested timber within the zone.

It is practically impossible to accurately predict what long-term impact the BSLB will have on our forests. It is imperative that we make all efforts to slow the spread of this foreign pest.
For further information see www.gov.ns.ca/natr/protection/ipm/Sheets/bslbeetle.pdf or cfs.nrcan.gc.ca/index/bslb2.

Don Cameron, RPF, is Regional Forester for the Nova Scotia Department of Natural Resources, as well as Information Officer for the Nova Scotia Section of the Canadian Institute of Forestry.