Bivariate Pheromone-based Monitoring of Spruce Budworm Larvae (Lepidoptera: Tortricidae).

A bivariate approach to pheromone-based monitoring is developed for the spruce budworm, Choristoneura fumiferana (Clem.) (Lepidoptera: Tortricidae). The approach uses captures of males at pheromone traps for generation t (♂t) as a transitive term between densities of overwintering larvae in consecutive generations (L2t, L2t+1), based on a large data set including >2,000 observations in the province of Quebec (QC) between the interval 1992 and 2010. Although estimates of L2t and ♂t are autocorrelated to some extent, multi-year assessments of larval densities combined with pheromone trapping are justified by the complementarity (statistical significance) of both L2t and ♂t in predicting L2t+1 for 15 of 18 pairs of 2-yr intervals. Bivariate pheromone-based thresholds (number of males corresponding to specific transitions in larval densities between L2t and L2t+1) are reported for each year. As expected, thresholds for stable populations (L2t = L2t+1) were lower than for populations with positive growth rate (L2t < L2t+1). The thresholds derived in this study have limited heuristic value; however, because they vary greatly from year to year.

Pheromone-Based Monitoring of Spruce Budworm (Lepidoptera: Tortricidae) Larvae in Relation to Trap Position.

The local abundance of male spruce budworm, Choristoneura fumiferana (Clemens) (Lepidoptera: Tortricidae), was evaluated in the province of Quebec at 112 locations between 2002­2012 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.

Occurrence of species of the genus Pityophthorus Eichhoff (Coleoptera, Curculionidae, Scolytinae) in the province of Quebec, Canada.

Twig beetles in the genus Pityophthorus Eichhoff, 1864 include more than 300 species worldwide, with maximum diversity in tropical and subtropical regions. To date, approximately 50 species of Pityophthorus have been recorded in Canada, and these species are associated mainly with coniferous trees. Since 1981, no comprehensive study on this difficult taxonomic group has been conducted in Quebec, Canada, most likely due to their limited significance as forest pests. Based on data gathered from five years of field sampling in conifer seed orchards and compiled from various entomological collections, the distribution of Pityophthorus species in Quebec is presented. Approximately 291 new localities were recorded for the Pityophthorus species. Five species-group taxa, namely Pityophthorus puberulus (LeConte, 1868), Pityophthorus pulchellus pulchellus Eichhoff, 1869, Pityophthorus pulicarius (Zimmermann, 1868), Pityophthorus nitidus Swaine, 1917,and Pityophthorus cariniceps LeConte&Horn, 1876 were the most widespread. In contrast, Pityophthorus consimilis LeConte, 1878, Pityophthorus intextus Swaine, 1917, Pityophthorus dentifrons Blackman, 1922, Pityophthorus ramiperda Swaine, 1917, and Pityophthorus concavus Blackman, 1928 display a notably limited distribution. In addition, the first distribution records of Pityophthorus intextus and Pityophthorus biovalis Blackman, 1922 are furnished, and the subspecies Pityophthorus murrayanae murrayanae Blackman, 1922is reported from Quebec for the second time. Moreover, distribution maps are provided for all Pityophthorus species recorded in the province of Quebec.