(E)-11,13-Tetradecadienal (E11,13-14:Ald) is the major component of the sex pheromone of the western blackheaded budworm (WBB), Acleris gloverana Walsingham. The compound was identified in extracts of the female’s pheromone gland by coupled gas chromatographic - electroantennographic detection (GC-EAD) and coupled GC - mass spectrometry in selected ion monitoring mode. In field experiments, E11,13-14:Ald by itself was attractive, but addition of (Z)-11,13-tetradecadienal doubled trap catches of male WBB. (E)-11,13-Tetradecadienol or (E)-11,13-tetradecadienyl acetate in binary or ternary combination with E11,13-14:Ald did not enhance attractiveness of the bait. In comparative assessments of five different trap designs, Uni-traps appeared to be the most suitable for use in pheromone-based monitoring of populations of WBB.

Eggs of western blackheaded budworm, Acleris gloverana (Walsingham), were found on the underside of needles of western hemlock, Tsuga heterophylla (Raf.) Sarg., with higher densities in the mid-crown area toward the outer tips of branches. Fringe and dominant trees were preferred oviposition sites over trees in lower crown classes or shaded positions. Vertical differences in needle density were considerable and led to high variability in insect densities when expressed on a per branch basis. When densities of eggs were based on a fresh branch weight basis there was a significant decrease in sample bias caused by the uneven distribution of foliage over the crowns.

The effects of trap design, lure concentration, lure age, and trap maintenance on the catch of western spruce budworm moths, Choristoneura occidentalis Freeman, in pheromone traps were tested in light to moderate infestations near Ashcroft, B.C. High cumulative moth catches reduced the trapping efficiency of both the sticky traps and the non-sticky Uni-traps relative to traps from which the moths were removed every 2 days. Correlations between the total season’s catch and larval density per plot in the same and following generations were not significant (P>0.05) for any of the eight combinations of trap design, lure concentration, and maintenance regimen tested. However, by dividing the mean moth catch in Uni-traps by either the basal area or foliage biomass per hectare in each plot, correlations with the following year’s larval density were significant (r 2 = 0.77–0.98; P<0.05; n=5).

Eggs of western blackheaded budworm, Acleris gloverana (Walsingham), are laid on the lower surface of western hemlock, Tsuga heterophylla (Raf.) Sarg., needles. A comparison was made of the following measures of sample branch size as a basis for expressing egg density: fresh branch weight, branch area, total twig length, branch volume, and number of buds. The criteria for selection of these measures were as follows: correlations of branch size with dry needle weight, variances of egg density and their relative contribution to sample size, and ease of measurement. Fresh branch weight was the best choice. A sequential sampling system was developed on this basis and was related to a scale of predicted defoliation. In addition, a transformation was provided for use in data analysis.

The sex pheromone components of the black army cutworm, Actebia fennica (Tauscher), were identified in abdomen-tip extracts from calling female moths. The primary pheromone component was (Z)-7-dodecenyl acetate. Although (Z)-11-tetradecenyl acetate was detectable only in trace quantities in the extracts, it was the major component in the best synthetic blend for attraction of male moths. The most effective synthetic blend was (Z)-7-dodecenyl acetate and (Z)-11-tetradecenyl acetate at a ratio of 1:20. No other component detected in the extracts increased trap capture of males when added to the two-component blend; however, (Z)-5-dodecenyl acetate, (Z)-7-dodecenol, and (Z)-9-tetradecenyl acetate reduced catches. This two-component blend will be useful for studying the habits of the adults and for population monitoring.

Male moths of Choristoneura occidentalis Freeman, C. biennis Freeman, C. fumiferana (Clemens), and C. orae Freeman were caught in pheromone-baited traps. Ten traps were placed at each site, five baited with an aldehyde lure and five with an acetate lure. This procedure permitted separation of species based on the specific chemical lure and also provided specimens for further study of morphological and isozyme differences. The color of the forewings, presence or absence of spicules on the aedeagus, and a specific allozyme frequency were determined on selected specimens where these characteristics were useful in separating species at a particular site. Distributions of all species were more extensive than previously known, sometimes adding hundreds of kilometres to the recorded range. Areas of sympatry were identified and the fidelity and usefulness of characteristics for separating species in areas of overlap were discussed.

The numbers of Douglas-fir tussock moths (Orgyia pseudotsugata) (Lepidoptera: Lymantriidae) caught in sticky, delta-shaped pheromone traps baited with different concentrations of synthetic lures were compared with egg-mass densities and subsequent defoliation throughout a population cycle. A lure containing 0.01% pheromone by weight in the form of a 3 × 5-mm polyvinylchloride rod provided more consistent catches than pheromone concentrations of 0.0001, 0.001, 0.1, or 1.0%. Trap saturation occurred when >40 moths per trap were caught. To achieve a standard error of 30%, 6 traps were required at each site. There was a poor correlation between numbers of moths caught and egg-mass density or defoliation estimates in the following generation, but a threshold density was found that provides a warning of an incipient outbreak. Ground surveys for egg masses are recommended to confirm suspected infestations after continuous increases in moth catches for 2 to 3 years or if an average of 25 moths or more per trap has been caught.

Adults of Choristoneura fumiferana, C. biennis, and an unidentified species reared from larvae or caught in pheromone traps from British Columbia were used for isozyme analysis to confirm the species identity, and for morphological study to determine the percentage of individuals with spiculate aedeagi. About 82% of C. fumiferana and less than 3% of both C. biennis and C. unidentified species (CPG) have spicules on the left side of their aedeagi. The number of moths that need to be sampled to determine a species is presented, based on the presence or absence of spicules.

A sequential sampling system for early-instar Douglas-fir tussock moth larvae based on beating 3 lower branches from each of a number of trees is described. The relationship between lower- and mid-crown insect densities is given. The number of samples required to assess moderate insect densities using a fixed level of precision and at low insect densities using a critical density level is presented. The system is designed to be used during the early stages of an outbreak in stands not previously defoliated.