Robert Lavallée and Jon Sweeney
Natural Resources Canada, Canadian Forest Service

SERG Project #2005/03
Year of Project: 2005
Report Received: 2006

Over the last several years, mainly with the support of the SCF-EPMM program, we managed to develop and improve techniques in fungal isolation, manipulation, and production. In addition, we screened different isolates of Beauveria bassiana for control of the white pine weevil (Pissodes strobi; WPW), the pine shoot beetle (Tomicus piniperda; PSB) and the brown spruce longhorn beetle (Tetropium fuscum; BSLB), in laboratory and field trials to identify the most virulent isolates.

Two potential strategies for the control of the WPW with B. bassiana were tested in laboratory trials: direct application to the terminal leader and soil applications.

To demonstrate the efficacy of B. bassiana against the PSB several isolates were tested to identify the most efficient strain and application of B. bassiana to bait logs was tested as a potential control strategy. Efficacy of treatments was determined from the length of parental galleries and the number of emergence holes per log.

Field trials were conducted in 2004 and 2005 on McNabs Island, Halifax, Nova Scotia, to test the efficacy of B. bassiana for infecting foraging adult BSLB. Two methods were used: 1) application of concentrated conidiospores suspensions directly to spruce bait logs once per week for four weeks during the peak flight season (June); and 2) polyester bands impregnated with B. bassiana conidiospores wrapped around the stems of live spruce trees. Direct application of B. bassiana conidia to spruce bait logs did not significantly reduced BSLB brood production in the logs. The polyester bands were effective at trapping large numbers of T. fuscum on spruce trunks, with a total of more than 570 beetles recorded on 180 trees. Mean (± SE) percent infection of T. fuscum adults was significantly greater on Beauveria-treated bands (65.6 ± 2.5%) than on untreated bands (13.9 ± 2.4%) but did not differ between formulations or between replaced vs. non-replaced bands.

Finally, with SERG International support a special survey was made to find new isolate of entomopathogen fungi on the PSB and the larch beetle (Dendroctonus simplex).