Chemical insecticides have been an important tool in the management of forest insect pests in Canadian forests. Aerial application of insecticides began in the 1920s and expanded greatly after World War II with the widespread adoption of DDT primarily for the suppression of spruce budworm, Choristoneura fumiferana Clemens (Lepidoptera: Tortricidae), and other defoliating insects. Significant progress was made in the development of new chemical insecticides and formulations including fenitrothion and tebufenozide, as well as technology for the application of insecticides against various insect pests. However, widespread opposition to the use of chemical insecticides in forest management has led to significant reductions in the number of insecticides registered for use in Canadian forests. Developments in the past 20 years have focussed on new insecticides, formulations, and technologies that seek to limit the impacts on non-target organisms and subsequent ecosystem effects. These developments have resulted in significant improvements in the management of traditional management targets, such as the spruce budworm (Choristoneura fumiferana (Clemens); Lepidoptera: Tortricidae) but also the management of invasive species, especially wood-boring beetles (Coleoptera: Buprestidae, Cerambycidae).

The mating behavior of spruce budworm [Choristoneura fumiferana (Clem.)] moths was studied in a wind tunnel. Of 88 contacts between male and female moths, 64 (73%) resulted in successful copulation. Failures were a result of males losing contact during courtship (11%), and females walking or flying, either when first contacted (7%) or when males attempted copulation (9%). Females showed no overt behavior other than moving away. Removal of the male labial palps had no effect on responses, which indicates that these structures have no role in courtship. Males with antennae completely removed did not respond to airborne pheromone and, therefore, none copulated. Removal of one antenna or half of both antennae of the males did not reduce the numbers of males that located females, but did result in slower responses and fewer matings. It also resulted in changes in male courtship behavior, which suggest that males depend upon their antennae to position themselves appropriately alongside the female when attempting to copulate. Analyses of male response to models of female moths constructed from glass rods with wings of male spruce budworm or male white-marked tussock moth [Orgyia leucostigma (J.E. Smith)] attached showed that males position themselves approximately halfway along me wing length of the model, with no dependance on its wing size or the length of the male’s antennae. Responses were equally high to both spruce budworm and to tussock moth wings, but no males responded to glass rods in the absence of wings.

We describe a method for identifying conifer-feeding species and lineages of Choristoneura Lederer in Canada and Alaska. The method relies on amplification of mitochondrial (mt) DNA by the polymerase chain reaction (PCR); amplified DNA is then digested with restriction enzymes to give characteristic DNA fragment patterns. We used the cytochrome oxidase I and II genes of mtDNA, which were previously shown to contain numerous nucleotide differences at the level of species. Ten restriction enzymes were surveyed and a combination of two of these (EcoR V + Hinf I) was sufficient to distinguish the major mtDNA lineages. Choristoneura fumiferana (Clemens), C. pinus Freeman, and C. rosaceana (Harris) were readily distinguished from each other and from an assemblage of three putative western species (C. occidentalis Freeman. C. orae Freeman, and C. biennis Freeman). The three western species have the same mtDNA marker pattern in most individuals and, although ecologically differentiated, their populations may actually be conspecific. At one locality in Alaska, pheromone traps bailed with lures for C. fumiferana attract moths with C. fumiferana mtDNA, and lures for C. orae attract moths with mtDNA that is characteristic of the western assemblage. This demonstrates geographic overlap of genetically distinct species in Alaska. The same two separate mtDNA lineages co-occur at two localities in Alberta, but pheromone attraction is unknown. In British Columbia, populations identified as C. biennis and C. occidentalis contain a few individuals with divergent mtDNA genotypes, the significance of which remains unclear. Amplified mtDNA thus provides a convenient, reliable marker for surveying genetic variation within species and for studying interactions among species of the C. fumiferana group.

The sex-pheromone-producing gland of the eastern spruce budworm, in addition to producing the sex attractant (E)-11-tetradecenal, has been shown by gas chromatographic and mass spectral data to contain (E)-11-tetradecen-1-ol, a known inhibitor to the sex attractant.

Synchrony of insect and host tree phenologies has often been suggested as an important factor influencing the susceptibility of white spruce, Picea glauca (Moench) Voss, and other hosts to the spruce budworm, Choristoneura fumiferana (Clemens) (Lepidoptera: Tortricidae). We evaluated this hypothesis by caging several cohorts of spruce budworm larvae on three white spruce populations at different phenological stages of the host trees, and then comparing budworm performance with host phenology and variation of 13 foliar traits. The beginning of the phenological window of susceptibility in white spruce occurs several weeks prior to budbreak, and the end of the window is sharply defined by the end of shoot growth. Performance was high for the earliest budworm cohorts that we tested. These larvae began feeding 3–4 weeks prior to budbreak and completed their larval development prior to the end of shoot elongation. Optimal synchrony occurred when emergence preceded budbreak by about 2 weeks. Larval survival was greater than 60% for individuals starting development 1–3 weeks prior to budbreak, but decreased to less than 10% for those starting development 2 or more weeks after budbreak and thus completing development after shoot elongation ceased. High performance by the budworm was most strongly correlated with high levels of foliar nitrogen, phosphorous, potassium, copper, sugars, and water and low levels of foliar calcium, phenolics, and toughness. These results suggest that advancing the usual phenological window of white spruce (i.e. advancing budbreak prior to larval emergence) or retarding budworm phenology can have a large negative effect on the spruce budworm’s population dynamics.

Results of previous research revealed that the effect of Bacillus thuringiensis on spruce budworm was a septicemia enterotoxicosis dependent on the ability of spores to penetrate to the insect hemolymph. Some scientists still maintain that the role of B. thuringiensis crystals (endotoxin) is primordial and is by itself responsible, by toxemia, for mortality in Choristoneura fumiferana. Consequently, new studies were undertaken to confirm the role of spores in B. thuringiensis infection of this insect. Infection tests were carried out with normal, irradiated, acrystalliferous and non-sporogenous strains of B. thuringiensis, with purified and semi-purified crystals, with pure spore preparations of B. thuringiensis and with enomopathogenic Bacillus cereus. The results of these tests revealed that acrystalliferous strains of B. thuringiensis and B. cereus infected larvae of C. fumiferana more successfully than purified or semi-purified crystals.

Five formulations of the primary sex pheromone components of the spruce budworm (Choristoneura fumiferana [Clem.]) were evaluated as lures for monitoring spruce budworm populations: Biolures (Consep Membranes Inc.), Luretape plastic flakes (Hercon, Healthchem Corp.), polyethylene vials (International Pheromone Systems), hollow fibers (Albany International), and polyvinyl chloride (PVC) pellets. PVC pellets showed significant loss in attractiveness over the required 6-week period. Also, different batches of PVC pellets had very different rates of pheromone release and attraction; the oldest lures, stored for the longest period, were the most attractive. Luretape caught fewer moths than anticipated from the release-rate data and showed wide variation in catch among individual lures. Fibers were inconsistent. Biolures and polyethylene vials showed the lowest decline in attractiveness over time and the lowest variation in catch among individual lures, but their capture rates were higher than necessary.

An individual-based phenology model for western spruce budworm, Choristoneura occidentalis Freeman (Lepidoptera: Tortricidae), was developed using stage-specific rates of development, oviposition, and egg hatch observed under controlled conditions at several temperatures. Model output was compared with age distributions estimated by sampling field populations of budworm at several locations in British Columbia, Canada, over many years. The fit of the model was very good for the entire life cycle of the insect. We further validate the model by comparing output with independent observations of moth flight phenology of C. occidentalis and Choristoneura fumiferana (Clemens) in populations of Cypress Hills, Canada and illustrate spatial variation in the seasonal occurrence of early-stage feeding western spruce budworm over most of its range in western Canada. In addition to serving as the underlying structure for the modelling of population dynamics at the seasonal level, the model can be used to predict the time of occurrence of different life stages for precise timing of pest management operations.

Survey counts of spruce budworm, Choristoneura fumiferana (Clem.), female pupae, and eggs recorded annually at about 1000 sample points in New Brunswick from 1960 to 1975 provided ratios of eggs to females (E/F ratios) which are a measure of apparent reproduction. The 10-fold variation in the ratios was inversely associated with the frequency of July storm tracks. A positive relationship between E/F ratios and changes in the area of the budworm infestation in the province was also shown.

The influence of topical applications of fluorescent dyes or rubidium chloride (RbCl) solution, or both, on adult male spruce budworm longevity and attraction to and capture by pheromone-baited traps was investigated. Both marks persisted for at least 8 days in the field (duration of tests) and for at least 3 weeks in the laboratory. Recoveries of marked moths were similar to unmarked moths with respect to total recovery and timing and location (within the canopy) of recovery. The results validate the assumption implicit in previous mark–release–recapture studies on spruce budworm males that fluorescent dyes have no measurable effect on male trapping. A 0.41 M RbCl solution topically applied to laboratory-reared adult males is an efficient mass-marking technique for the spruce budworm.

Optical brighteners were recently discovered to function as UV protectants for baculoviruses of insects (Shapiro 1992) and, also, to enhance entomopathogenic activity of these viruses (Hamm and Shapiro 1992; Li and Otvos 1999a). Enhancement of viral activity by brighteners varied greatly from one virus–host system to another: for example, from 1500-fold in LdMNPV against Lymantria dispar (L.) (Lepidoptera: Lymantriidae) (Argauer and Shapiro 1997) to 2- to 13-fold in a multicapsid nuclear polyhedrosis virus of Choristoneura fumiferana (Clemens) (Lepidoptera: Tortricidae) (CfMNPV) against Choristoneura occidentalis Freeman (Li and Otvos 1999a). The reason for this variation in enhancement of viral activity is still unknown. In this study, we used CfMNPV to compare the levels of viral enhancement by an optical brightener between C. occidentalis and C. fumiferana.

Relationships between temperature and development rates of eggs and larvae of Winthemia fumiferanae Toth. were experimentally determined, using the spruce budworm as host. Hatching of parasitoid eggs was triggered by host pupation. The median time required to complete egg development at different temperatures was estimated from distributions of percentage development success of the parasitoid over time between egg deposition and host pupation. For parasitoid eggs that had sufficient time to hatch, detachment from the host before pupation was the most important cause of mortality at 15 °C or higher, but was negligible below this temperature. A curvilinear model describing egg development rate as a function of temperature was used to simulate the development of W. fumiferanae eggs in the field. The relationship between larval development rate and temperature also was modelled, and the variability described. Simulations initiated by host pupation-driven egg hatching, and terminated with prepupal drop to the ground, are presented and discussed with respect to the appropriateness of using host pupation as an indicator of parasitoid egg hatching in the field.

The disruption of insect mating with sex pheromones by the air permeation technique is a complex problem influenced by a number of variables. Not least among these is the actual atmospheric concentration of pheromone during the course of the experiment. While closely related to the measured release rate from a formulation, the atmospheric concentration should be regarded separately since a number of other factors may intervene, e.g., chemical instability, foliage adsorption, and the differential effects of formulation weathering in the laboratory and the field.

The present study was conducted in conjunction with small scale field trials involving an aerially applied hollow fiber formulation of the sex pheromone of the spruce budworm, Choristoneura fumiferanu (Clem.), I1 -tetradecenal (97:3::E:Z). (Hereafter referred to as pheromone.)

A process-oriented model was recently developed to simulate the efficacy of spray products containing Bacillus thuringiensis Berliner subsp. kurstaki (Bacillaceae) against the spruce budworm, Choristoneura fumiferana Clemens (Cooke and Régnière 1996). The model accurately predicted foliage protection and larval population reduction during validation spray trials (Régnière and Cooke 1998; Cooke and Régnière 1999). The impact of treatment on budworm generation survival was generally well mimicked by the model except for a consistent overestimation of survival at the end of immature development in the treated plots. Régnière and Cooke (1998) speculated that residual mortality due to treatment may be occurring during the pupal stage. Carry-over of B. thuringiensis from larvae to pupae has been documented for spruce budworm (Klein and Lewis 1966) and several other Lepidoptera (Legner and Oatman 1962; Angus 1965). Although we recently investigated the response of spruce budworm larvae to ingestion of sublethal doses of B. thuringiensis (Pedersen et al. 1997), effects on pupal survival or adult emergence were not examined. In this note, we report the results of an experiment designed to assess such effects.

Intensive and systematic laboratory studies conducted under various experimental conditions (larval stage, physiological condition of the insect, temperature, formulation) revealed that non-crystalliferous strains of Bacillus thuringiensis Berliner and B. cereus Frankland and Frankland were equally pathogenic for larvae of Choristoneura fumiferana Clemens as the crystalliferous strain of B. thuringiensis tested. Also the addition of minute quantities of chitinase (10,000 UN/ha) considerably increased the efficiency of commercial preparation of B. thuringiensis against C. fumiferana.

At 20°C, B. thuringiensis var. kurstaki provoked a slow septicemia in 3rd instar larvae of C. fumiferana which resulted in 90% larval mortality in 27 days. Under the same experimental conditions, a non-crystalliferous strain of B. thuringiensis (No. 17) and two strains of B. cereus, entomopathogens isolated from C. fumiferana and from a Tachinidae, also caused a slow septicemia resulting in 90% mortality of 3rd instar larvae after 30 to 32 days.

Experiments revealed that the symptoms of infection (lethargy, loss of weight) caused by B. thuringiensis + chitinase were far more rapid and pronounced than those provoked by B. thuringiensis alone The commercial preparation 26B prepared by Sandoz-Wander, applied at a rate of 16.8 × 109 BIU/ha caused only 80% mortality of 3rd and 4th stage larvae, while the complex Sandoz + chitinase N.B.C. provoked 100% larval mortality between 9 and 27 days depending upon the experimental conditions used Similar results were obtained with Dipel 36B. For instance, at 20°C Dipel + chitinase N.B.C. provoked 100% mortality of 3rd stage larvae in 9 days, while with Dipel alone, the same level of mortality was reached after 24 days. Also, it was established that C. fumiferana larvae reared on Abies balsamea were far more susceptible to the action of the bacillus than those reared on artificial diet.

These results confirmed that addition of chitinase considerably increased the pathogenic properties of B. thuringiensis on C. fumiferana and the low efficiency of the bacillus alone. The addition of chitinase to commercial B. thuringiensis preparations is required and of prime importance in future use of B. thuringiensis for the control of this insect pest.

An absolute requirement for sugar could not be shown but laboratory rearing experiments using artificial diets have demonstrated a definite increase in weight of adult spruce budworm (Choristoneura fumiferana (Clem.) Freeman) with increasing dietary levels of certain sugars. Males exhibit a threshold of 0.9% soluble sugars above which higher sugar levels produce no further increases in size. Females respond with an increase in size up to 4.0%, the highest level tested. Generally, faster development rates accompany greater mature weights on diets with higher nutrient levels.

Maltose, raffinose, glucose, sorbitol, sucrose, and fructose are all good sugar sources. Galactose and trehalose are only slightly inferior. Lactose, ribose, melibiose, xylose, mannose, arabinose, and melezitose in the diet are little different from the sugarless control. Sorbose is somewhat inhibitory.

Results of transfer experiments confirm the importance of sugar particularly during late larval development. They also indicate that a high protein diet during early instars has a significant effect on development rates. These results suggest that departure from the normal synchrony of development in the insect and its host can affect both rate of development and mature size of the insect.

In 1956, the spruce budworm infestation which had been in progress in the Lower St. Lawrence and Gaspe Peninsula for about eight years, covered the whole territory from the Rimouski River to the eastern tip of the Peninsula (Fig. 1). In many localities throughout the region repeated defoliation had been severe enough to cause some trees to die (3) . Had it not been for the extensive aerial spraying operations practised in this region since 1954, tree mortality would undoubtedly have been even more widespread.

The head and neck muscles of the spruce budworm, Choristoneura fumiferana (Clem.), are reported. Thirty-nine muscles with their origins, insertions, and functions are described. This forms part of a study on the brain and suboesophageal ganglionic mass of the same species.

Spruce budworm, Choristoneura fumiferana (Clemens) (Lepidoptera: Tortricidae), is a destructive defoliator found throughout the Nearctic boreal forest. This pest has a broad geographic range and shows regional variation in key life history traits. These population differences may represent important adaptations to local environmental conditions and reflect underlying genetic diversity. Existing laboratory colonies of spruce budworm do not capture this regional variation, so we established five new spruce budworm colonies from across its range to explore regional adaptations among spruce budworm populations within common garden experiments. We present methods for establishing new spruce budworm laboratory colonies from wild populations. We describe the process of flushing, rearing, and disease screening used on these new populations to produce healthy disease-free laboratory stocks.