title: Pheromone-Based Monitoring of Spruce Budworm (Lepidoptera: Tortricidae) Larvae in Relation to Trap Position.
abstract: The local abundance of male spruce budworm, Choristoneura fumiferana (Clemens) (Lepidoptera: Tortricidae), was evaluated in the province of Quebec at 112 locations between 2002–2012 using pheromone-baited traps deployed on lower branches near the ground level (GL) or in the tree canopy (TC; three traps at GL and TC for each location); in addition, the presence of second instars (L2) was assessed at each location on three balsam fir branches. Numbers of moths captured at GL and TC were highly correlated, and the regression parameters did not vary between years. Consequently, estimates of L2 based on pheromone trap catches are precise independent of trap location, and deploying traps at ground level (rather than in the tree canopy) does not come with a loss of accuracy in L2 assessments. Relationships between moths (x) and L2 (y) exhibited strong nonlinearity and were most adequately described by exponential functions of the form: ln (y+1)=[ß0+ß1×k ln (x)]. A conservative threshold of 100 males per trap at GL (corresponding to one L2 per branch) may be used to guide forest managers in the transition from endemic to epidemic populations. Relationships between L2 and moths are likely influenced by the number of traps per site; hence, the tentative threshold above is only valid for jurisdictions relying on three traps per site. Considering the economic importance and rising populations of spruce budworm, rigorous quality control programs must be implemented promptly to ensure a steady supply of standardized pheromone lures across years.
authors.forename: Marc
authors.initials: M
authors.lastname: Rhainds
authors.forename: Pierre
authors.initials: P
authors.lastname: Therrien
authors.forename: Louis
authors.initials: L
authors.lastname: Morneau
mesh_terms: D000818:Animals; D007300:Insect Control / Q000379:methods*; D007814:Larva; D008297:Male; D009036:Moths; D010675:Pheromones; D028222:Picea
chemical_list: D010675:Pheromones