In field and cage experiments in a Costa Rican oil palm plantation, the largest, most fecund female bagworms, Oiketicus kirbyi, had the greatest mating success. Differential mating success of small and large females may be attributed to mate choice by males or to competition between protogynous females for access to males.

The Douglas-fir beetle (Dendroctonus pseudotsugae) antiaggregation pheromone, 3-methylcyclohex-2-en-1-one (MCH), was applied to stands at high risk for infestation. The MCH was applied in a bubble capsule formulation to plots ranging from 2.1 to 2.6 ha in size at rates of 45–76 g/ha. Catches of Douglas-fir beetles in attractant-baited Lindgren funnel traps located at the plot centers were significantly lower on MCH-treated plots compared with untreated plots. In contrast, catches of the most abundant predator, Thanasimus undatulus (Say), were unaffected by the MCH treatment. The percentage of Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] trees ≥20 cm dbh that were mass attacked was significantly lower on treated plots (0.2%) compared with untreated plots (8.5%). MCH alone was effective in reducing the probability of Douglas-fir beetle infestations occurring in high risk stands.

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.

A simple, reliable feeding bioassay was developed for screening certain biorational insecticides with potential use against pine bark beetles. Adult Ips calligraphus and Dendroctonus frontalis were fed freeze-dried phloem fortified with Avermectin B1, Bacillus thuringiensis with known coleopteran activity, or a bacterial metabolite (R003). Avermectin B1 was toxic to adult I. calligraphus by 4 days at an LC50 of 0.36 μg AI/g of diet. R003 was active against both beetle species, yielding 85–100% mortality after 10 days exposure to a concentration of 360 μg/g of diet. No B. thuringiensis product was toxic at a discriminating concentration of 200 μg of spore/crystal preparation per gram of diet. Beetle mortality on untreated diet remained <10% over the 4–10 days duration of feeding trials. Unadulterated, lyophilized phloem diet did not spoil during bioassays, provided that tanned beetles were taken for bioassays before they emerged from their natal host bolts. Microbial products with scolytid activity, such as Avermectin B1 and R003, could have future value for limiting bark beetle infestations of individual trees or small stands in urban or ecologically sensitive forests. Innovative strategies for delivery would have to be developed, however, to circumvent the cryptic habits of these phloeophagous beetles.

Traps consisting of open, cylindrical tins containing moistened clay aggregates were evaluated as field oviposition sites for corn rootworm, Diabrotica spp. Six trap features were investigated: clay aggregate size, water saturation level, trap opening, trap cover, trap volume, and trap position relative to corn plants. More eggs were recovered in traps containing clay aggregates ranging from 0.5 to 3.5 mm diameter compared with aggregates from 2.5 to 8.0 mm diameter. Saturation of the trap to 2.5 cm from the opening resulted in greater egg recovery compared with traps saturated to 6.0 cm from the opening. Covering the exposed surface of the trap with a metal ring and/or a corn leaf increased egg recovery in the field.

Oviposition traps were placed in four commercial corn fields in 1990 and three in 1991 to monitor egg populations. Egg recovery from traps and estimates of the absolute egg population in the soil were compared with densities of adult corn rootworm to predict larval damage on roots of corn planted the next year. In five fields, adult populations were above the current economic threshold of one beetle per plant. However, economic damage to roots occurred only in the field in which the most eggs were recovered from traps (226.6 eggs per trap) and soil samples (30.2 eggs per litre). Mean egg recovery per trap per field was correlated with mean damage ratings from untreated corn.

The monoterpenes (±)-α-pinene, (1S)-(−)-β-pinene, (R)-(+)-limonene, and myrcene did not enhance the catch of red pine cone beetle, Conophthorus resinosae, in traps baited with the female sex pheromone, (±)-trans-pityol. Traps placed in the upper half of the tree’s crown caught significantly more beetles than those hung from the tree’s trunk 2 m above ground. No significant differences in trap catches were found among standard yellow Japanese beetle trap tops and those painted red, green, blue, white, black, or yellow.

Protopiophila litigata sp.nov. is described from Ontario and Nova Scotia. McAlpine’s (1977) key to the species of Protopiophila is modified to facilitate identification of the new species. Behaviours of P. litigata and P. latipes were studied in Algonquin Park, Ontario. Whereas P. latipes reproduces on corpses in advanced stages of decay, P. litigata mates and oviposits on discarded cervid antlers, ignoring other carrion. Unlike P. latipes, males of P. litigata engage in ’mate guarding’. These traits probably represent autapomorphies of P. litigata.

Larvae of the black spruce cone maggot, Strobilomyia appalachensis, were infected and killed by Steinernema carpocapsae (Weiser) All and Umeå strains, S. feltiae (Filipjev) (= bibionis) strain 27, and S. glaseri Steiner strain 326, in laboratory tests. After formation of puparia, however, cone maggots were practically resistant to all species and strains tested. Very few or no maggots were infected when nematodes were sprayed on or injected into infested spruce cones. The survival, activity, and infectivity of infective juveniles held in an aerated infusion of black spruce cones were significantly lower compared with those held in aerated water. In peat–sand columns, the proportion of larvae infected with S. feltiae, but not S. carpocapsae Umeå strain, was significantly greater when larvae were dropped immediately or 1 day following nematode application compared with 1 day before or 3 days following nematode application. Our results suggest that, in field trials for cone maggot suppression, nematodes should be applied within a day prior to larval drop and that repeated applications may be required for persistence of sufficient infectivity.

Larval and pupal parasitoids were studied from collections made in endemic, outbreak, and post-outbreak populations of forest tent caterpillar (FTC), Malacosoma disstria, at 21 sites in Alberta, Canada, from 1989 to 1994. The parasitoid complex included 18 identified species. Aleiodes malacosomatos (Mason) (Hymenoptera: Braconidae) was common in low density populations and was the only species to attack FTC larvae prior to the fourth instar. Leschenaultia exul (Townsend) (Diptera: Tachinidae) was the most abundant larval parasitoid in endemic populations and after the 2nd year of outbreak. Although prevalent early in outbreaks, Patelloa pachypyga (Aldrich and Webber) (Diptera: Tachinidae) declined in older outbreaks possibly because it completes larval development later than other tachinids, leaving it vulnerable to competition from aggressive pupal parasitoids. I hypothesize that early initiation of oviposition allows L. exul to be more successful than P. pachypyga in low density populations because caterpillars have dispersed before the latter species initiates oviposition. I recorded lower pupal parasitism by Arachnidomyia aldrichi (Parker) (Diptera: Sarcophagidae) in Alberta than has been recorded in other regions, although it was still the most abundant parasitoid reared in this study. Parasitism by A. aldrichi was significantly higher in cocoons collected from undergrowth vegetation than from the forest canopy. Other pupal parasitoids contributed relatively little to FTC mortality.

Morphological, allozyme, and chromosomal characters and ecological traits have limited value for discriminating among four closely related Pissodes spp. known from western Canada. We amplified a 1585-bp segment of mitochondrial DNA (mtDNA), including half of the cytochrome oxidase I (COI) and all of the tRNA leucine and COII genes, using the polymerase chain reaction, and studied mtDNA variation within and among all four species of Pissodes with restriction enzymes. Twenty-four haplotypes were found among the 121 maternal lineages surveyed. Haplotype distributions suggest intermediate levels of gene flow for each species. Interspecific estimated sequence divergences ranged from 0 to 28.7%. Phylogenetic relationships among species were reconstructed using P. affinis Randall as an outgroup. Pissodes terminalis Hopping and P. nemorensis Germar were the most closely related species, and this clade was most closely related to P. strobi (Peck); P. schwarzi Hopkins branched off below these three. Restriction site variation is sufficient to discriminate unambiguously among most species. However, P. terminalis and P. nemorensis haplotypes were very similar, which may complicate discrimination between these two species, using mtDNA characters, where their ranges putatively overlap in Manitoba. A diagnostic protocol using three restriction enzymes, Bcl I, Dra I, and Hinf I, is recommended.

Through an analysis of the primary setae and pores (campaniform sensilla) of first-instar larvae of 32 species of Colymbetinae, 33 species belonging to other dytiscid subfamilies, and seven species belonging to other families of Hydradephaga, the ancestral system of primary setae and pores of the legs, the last abdominal segment, and the urogomphi of Colymbetinae is deduced. Seventy-four setae and 24 pores have been assigned to the generalized colymbetine larva: 51 setae and 18 pores on the legs, 15 setae and three pores on the last abdominal segment, and eight setae and three pores on each urogomphus. A comparison with the ground-plan pattern of the subfamily Hydroporinae is provided. Members of Colymbetinae differ from those of Hydroporinae by the presence of setae TR3, AB14, and AB15, the absence of pore ABd, and the presence of a variable number of additional setae on the femur. A tentative phylogenetic reconstruction of the colymbetine genera provided is based on 24 larval characteristics. The monophyletic origin of the subfamily Colymbetinae is confirmed based on the shared presence of seta AB14. Two monophyletic lineages unite basally: (1) [(Agabus Leach + Ilybius Erichson) + Agabinus Crotch], and (2) {[Colymbetes Clairville + (Rhantus Dejean + Neoscutopterus Balfour-Browne)] + Matus Aubé}. The genera Agabinus and Matus are postulated as a sister-group of (Agabus + Ilybius) and [(Colymbetes + (Rhantus + Neoscutopterus)], respectively. Compared with other Colymbetinae, both Neoscutopterus and Matus stand out by the presence of several strikingly peculiar features. The subgenus Rhantus (Nartus) is postulated to be the sister-group of Neoscutopterus based on the shared presence of additional setae on the dorsal margin of the femur.

Sweetclover, Melilotus Miller, was planted in a field near Saskatoon, Saskatchewan, to determine the effects of species and cultivars on early season feeding by the sweetclover weevil, Sitona cylindricollis. The wild annual species M. infesta Guss. was consumed less than were cultivars of M. alba (Desr.), which were generally consumed less than cultivars of M. officinalis (L.). The amount of feeding injury by the weevil among nine sweetclover entries was not significantly correlated with nitrate levels in cotyledons, unifoliolate, or first trifoliolate leaves. Weevils fed equally well on entries with high and low coumarin levels. Results from greenhouse cultivar trials generally paralleled those from the field. In an experiment in which different levels of ammonium nitrate fertilizer were broadcast prior to seeding of M. officinalis cultivar Norgold, levels of nitrate ion in the foliage were significantly correlated with fertilizer regime, but not with damage indices of the weevil. These experiments suggest that the nitrate ion in isolation is not the principal factor in the deterrence to sweetclover weevil feeding in M. infesta, and that elevating nitrate levels in sweetclover leaves would not confer resistance to this insect.

During the 1977–1986 outbreak of mountain pine beetle (Dendroctonus ponderosae) in southwestern Alberta and Saskatchewan, populations of this beetle developed in lodgepole pine and limber pine stands, and threatened to spread northeasterly to the extensive jack pine forests in the central parts of the two provinces. To assess jack pine as a potential new breeding host, I compare egg galleries, brood production, and adult characteristics of D. ponderosae reared in lodgepole, limber, and jack pine logs. Brood productivity, beetle size, sex ratios, and egg gallery characteristics are described for beetle populations reared from naturally infested limber pine logs from southwestern Alberta, and from artificially infested jack pine logs from east-central Alberta and central Saskatchewan. In a field experiment where logs of the three hosts were placed together, adult beetles and their gallery characteristics are described and compared on the three hosts. The results confirm that jack pine is a viable host, that D. ponderosae’s attack characteristics, survival, and progeny on jack pine all appear comparable to those characters observed for beetles reared on lodgepole pine, and that limber pine is highly productive of beetle brood.

Sequential decision plans based on aphid counts and binomial counts of infested plants (presence or absence of aphids) were developed to guide chemical control decisions for die potato aphid, Macrosiphum euphorbiae, on two growth stages of oilseed flax in western Canada. The plans were derived from studies of aphid dispersion among plants in field plots at two locations over 4 years, and verified in samples from 51 commercial fields, in Manitoba. The relationship between variance (s2) and mean aphid density () perplant was loges2 = 0.790 ± 0.050 + (1.649 ± 0.031) loge (n = 69, r2 = 0.98), for both crop growth stages. Neither sweep samples nor pan samples produced reliable estimates of the number of aphids per plant and, therefore, these sampling tools could not replace aphid counts on individual plants. Aphid counts and the binomial method gave similar control decisions with similar amounts of effort, but the aphid counting method required fewer plants to reach a decision. The same decisions were reached in 85–95% of fields by counting aphids on a minimum sample of 25 plants when the crop was in full bloom, or 20 plants at the green boll stage, as with samples of 50–100 plants.

Araniella proxima (Kulczyński, 1885) occurs in northern Europe (Blanke 1982) and northern Asia (Marusik et al. 1992), but has not been previously reported from North America. Our attention was drawn to this species when we identified as A. proxima a male Araniella collected by Keith Roney at Peter Pond Lake, Saskatchewan (55°55'N 108°36'W) on 10 July 1989.

Larvae of the leafminer Chromatomyia fuscula attack many wild and cultivated grass species, including cereals, in Europe (Spencer 1969, 1991; Griffiths 1980) and are considered a major pest in parts of Fennoscandia (Spencer 1973; Andersen 1989a). However, in North America this species has been reported only on non-cereal grasses (Spencer 1969, 1991; Griffiths 1980). Therefore in 1994 a survey was undertaken in the region around Quebec City to determine if C. fuscula was truly restricted to non-cereal grasses or if, as in Europe, it also attacked cereals.