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.

Cultural practices (tillage, planting date) were examined for their effect on flea beetle, Phyllotreta cruciferae (Goeze), populations in three species of oilseed crucifers—Brassica napus L., B. rapa L., and Crambe abyssinica Hochst. No-till appeared to reduce flea beetle densities when compared with conventional tillage. The greater structural diversity of the no-till plots might be interfering with host plant location. Earlier plantings had significantly more flea beetles per plant than later plantings. The Brassica crops yielded higher densities of beetles compared with crambe, supporting earlier reports of crambe resistance.

Eight species and seven subspecies of costate Altica are described and illustrated. Lectotypes are designated for Altica alni Harris, A. ambiens LeConte, A. prasina LeConte, A. subplicata LeConte, and Graptodera plicipennis Mannerheim. A neotype is designated for Altica bimarginata Say. Two subspecies are recognized for A. ambiens, three for A. bimarginata, and two for A. prasina. Graptodera plicipennis is removed from synonymy and given a new subspecific status under Altica bimarginata, and A. populi Brown is given a new subspecific status under A. prasina. Altica latiplicata Blake is placed in synonymy with A. ambiens LeConte. Altica bimarginata labradorensis LeSage is described as a new subspecies of A. bimarginata. Keys are given for males and females, and data are provided on distribution, host plants, biology, parasites, predators, and economic importance of these species.

Volatile compounds were isolated and identified from a crude extract of garry oak, Quercus garryana, foliage which was known to be attractive to the tachinid fly Cyzenis albicans. Candidate compounds were identified by the combined use of gas chromatography–mass spectrometry, and infra-red spectroscopy. Specific oak-leaf volatiles were field-tested in 2 different years in an apple orchard. Compounds were applied singly or in combination to individual apple trees; the number of C. albicans entering the canopy of each tree was observed and the number of eggs they oviposited on foliage was estimated. Borneol was the only compound that attracted flies when compared with the other treatments, but this did not result in more fly eggs being oviposited on borneol-treated trees. None of the compounds tested resulted in a greater number of Cyzenis eggs being oviposited. A greater abundance of borneol in oak foliage than in apple foliage, and its attractiveness to C. albicans, may explain the aggregation of flies in response to feeding-damage among oak trees and the absence of this pattern among apple trees.

Many soil-inhabiting insects are susceptible to entomopathogenic nematodes but the degree of susceptibility ranges widely. Much is understood about the habitat of insect pests in relation to their susceptibility but little attention has been paid to the influence of physical deterrents. "Physical deterrents" is used here to include morphological barriers (passive deterrents) and behavioural responses to attack (active deterrents). The roles of both are reviewed and discussed, in particular with reference to wireworms (Elateridae), a group of insects generally resistant to the nematodes. Knowledge of insect morphology and behaviour as well as habitat is important in predicting susceptibility to entomopathogenic nematodes.

Damage by Hylobius congener, the seedling debarking weevil, to newly planted conifer seedlings was reduced to tolerable levels by treating the roots of the seedlings with the nematode Steinernema carpocapsae (Weiser) before planting. A practical treatment method was to apply a suspension of infective juveniles (IJs) in water to seedlings in multipots with a watering can. An application rate of 300 000 IJs per seedling is recommended. The plantation should be at least 500 m from recent clearcuts and the entire plantation should be treated to avoid negation of treatment effects by invading uninfected weevils. It is suggested that a similar method may also be effective against other species of weevils that damage conifers near the soil surface.

Hylobius congener, the seedling debarking weevil, is a pest of newly planted coniferous seedlings in clearcut forest in the Maritime provinces (Magasi 1988). Adult weevils feed on the bark of the seedlings, which are often girdled and killed. Pendrel (1990, pers. comm.) investigated the insect's life history and behavior, and a number of cultural and chemical controls. He developed combinations of control methods to match the variety of site types and cultural practices found, but recognized a need for a method that would be suitable across a variety of conditions.

Fleas (Siphonaptera: notably species of Ceratophyllidae) parasitize many species of birds. Although adult fleas rely on the birds as their principal means of dispersal, they are not commonly collected on the host itself. Most of these fleas spend the greatest portion of their life cycle in or near the host's nest. Colonial nesting habits facilitate transfer of fleas among hosts (Hoogland and Sherman 1976), and reuse of nests or nesting cavities in successive breeding seasons enhances transmission from one generation to the next (Hopla and Loye 1983). This stability of nest habitat and reliability of host presence favours fleas that are truly nest-bound. On the other hand, birds that defend exclusive breeding territories and construct new nests for each breeding attempt are usually host to vagabond, generalist species (Darskaya 1964).

The western flower thrips [Frankliniella occidentalis (Pergrande)] (Thysanoptera: Thripidae) is a major pest of greenhouse crops (Broadbent et al. 1987; van der Veire and Degheele 1992; Chambers et al. 1993). Chemical control of F. occidentalis is difficult because of its cryptic behaviour and widespread resistance to insecticides (Immaraju et al. 1992). The insidious flower bug, Orius insidiosus (Say), is widely promoted as an effective biological control agent for this pest (Chambers et al. 1993; van der Veire and Degheele 1992; Castane and Zalom 1994) and its use has increased steadily since their introduction in the late 1980s. When our project was initiated in 1989, O. insidiosus was a little known and largely unavailable biological control agent. Now there are several domestic and international commercial sources of Orius spp. and these predatory bugs have become a focus of research in Canada, the United States, and Europe. At first it was difficult and costly to maintain cultures of only 100 or 200 individuals but now we can rear 50000 — 100000 Orius per week for less than $0.03 (Canadian) each.