Concentration:response regressions were established for male and female Panonychus ulmi from dicofol resistant and susceptible laboratory colonies using a rapid assay technique which utilizes pesticide residues in enclosed Petri dishes. Modification of the technique, which was developed for females, allowed reproducible results with males. Males and females from the resistant population showed similar levels of resistance compared with the susceptible population (ca. 4-fold). Within populations, males were approximately 3-fold more sensitive than females. Implications of these differences for field populations and the usefulness of males in inheritance studies are discussed.

These first North American records for Polymerus cognatus (Fieber) from across Canada and the northeast United States, and P. vulneratus (Wolff) from northwest North America, indicate that the two species are naturally Holarctic. Diagnoses and dorsal habitus illustrations are provided to distinguish the taxa from other North American Polymerus species. An argument for considering P. balli Knight, P. cognatus, P. elegans (Reuter), P. flaviloris Knight, P. froeschneri Knight, and P. vulneratus a monophyletic species-group is presented.

Rhinocyllus conicus Froelich was introduced into Wyoming in 1975 for the biological control of musk thistle, Carduus nutans L. A survey of 15 release sites was conducted in 1986 to determine parasitism of R. conicus. Eight species of parasitic Hymenoptera were identified. Parasitism of R. conicus infecting the flower heads of musk thistle was low (0.6%), but greater for weevils within the peduncles (17%). Parasitism varied among release sites, ranging from 0.0 to 1.3%, but was not significantly correlated with the duration of weevil establishment.

Three subspecies of the migratory grasshopper Melanoplus sanguinipes (F.) are recognized by Gurney and Brooks (1959) who, on the basis of morphology and presence of intergrades in collections, do not consider the taxa sufficiently different to warrant according them species status. Present experiments show that members of distant populations, when crossed, readily produce viable and fertile hybrids of both sexes. It is, however, premature to claim that the groups are conspecific without confirmatory information on, for instance, genetic distances and mating discrimination indices. Nonetheless, it is hypothesized that these parameters are expected to have low values given the hybridization results.

The European bark beetle, Ips sexdentatus Boerner, carries fungi in puncture pits located on the proximal part of each mandible, the sides of the pronotum, and the elytra.

On the pronotum, each mycangium corresponds to the cup-shaped depression surrounding each seta. Several type III gland cells are associated with each mycangium. The general organization of these cells, commonly found in the epidermis, corresponds to those described by other authors. Their finely granular secretions probably protect the fungi, assure spore adhesion, and also may temporarily inhibit their germination. Similar gland cells were scattered under unspecialized pronotal integument where fungi were not detected.

Thus, it appears that this beetle has evolved a mechanism for the protection or dissemination, or both, of yeasts and fungi such as Ceratocystis sp. This relatively simple system seems to be as efficient as the more evolved mycangia of other species.

Ixodes cookei Packard required ca. 14 weeks to complete development under laboratory conditions, using groundhogs [Marmota monax (L.)] as the blood meal source and off-host conditions of 25–29°C and 93–100% relative humidity. All three post-embryonic instars engorged in ca. 6–8 days. Larvae and nymphs maintained at 25°C moulted to the next instar ca. 18–20 days after detachment. Moult occurred under conditions of either a 0L:24D or a 16L:8D photoperiod. Adult females increased in weight ca. 49-fold from the unfed to the engorged state, attaining a weight of 194.1 ± 15.0 (mean ± SE) mg and producing 1281.5 ± 139.1 (mean ± SE) eggs at 29°C. The pre-ovipositional and ovipositional periods were 4.7 ± 0.3 and 20.2 ± 1.7(mean ± SE) days, respectively, at 29°C. Fifty percent of eggs were deposited within the 1st week of the ovipositional period at 29°C. First egg hatch at 29°C occurred ca. 31 days after oviposition was started. Eggs maintained at 10°C did not hatch, and the thermal threshold for egg development was calculated to be 11.2°C.

Removal sampling, sweepnet sampling, and visual count sampling conducted while walking at constant velocity through a field were used to sample populations of adults of five coccinellid species in plots established in spring wheat fields, Triticum aestivum L. Estimates of absolute population density obtained from two 20-min removal samples taken from each of six 5- by 5-m sub-plots per plot proved reliable and were used to convert estimates obtained from sweepnet sampling (180 sweeps per plot) and visual counts (36 min per plot walking at 10 m/min) into absolute estimates of population density. Population density estimates obtained by removal sampling were quite precise except for species with low capture efficiencies and low population densities.

Crop plant growth stage influenced the numbers of beetles caught in sweepnet samples and was incorporated in regression models for converting sweepnet catch to absolute density. Values of R2 of regressions ranged from 0.51 to 0.90, depending on species. Visual counts were influenced by temperature and aphid density, and these variables were incorporated in regression models. Values of R2 for regressions relating visual counts to population densities ranged from 0.63 to 0.94, depending on species.

Eight species of the siphonine genus Actia Robineau-Desvoidy are recognized in the Nearctic Region, including four that are new: A. dasymyia sp.nov. (type-locality 21 mi. east Tuktoyaktuk, North West Territories, Canada), A. dimorpha sp.nov. (type-locality Sapelo Island, Georgia, USA), A. radialis sp.nov. (type-locality Gatineau Park, Quebec, Canada), and A. sternalis sp.nov. (type-locality mi. 51 Dempster Highway, Yukon, Canada). Adults of the eight species are keyed, described, illustrated (heads, wings, and male terminalia), and their distributions mapped. The species are arranged into three species groups: the autumnalis-group with Nearctic members A. autumnalis (Townsend), A. rufescens (Greene), A. diffidens Curran, and A. dimorpha sp.nov.; the lamia-group with Nearctic members A. interrupta Curran, A. dasymyia sp.nov., and A. radialis sp.nov.; and the crassicornis-group with the single Nearctic member A. sternalis sp.nov. Nearctic Actia are inferred to be of relatively recent origin because only the A. autumnalis/A. rufescens species pair seems to have speciated within the Nearctic Region. Actia autumnalis/A. rufescens, A. diffidens, and A. dimorpha are each hypothesized to have their closest phylogenetic affinities with Neotropical species, and A. sternalis, A. interrupta, A. dasymyia, and questionably A. radialis are each hypothesized to have their closest affinities with Palearctic species.

Five species of Berytidae are reported to occur in Canada, Acanthophysa echinata Uhler being recorded for the first time. A key for identification, descriptions, a summary of the distribution, and notes on the biology are given.

Analysis of structural features of adults (legs, proportions of prothorax, male genitalia, and ovipositor) establishes the hypothesis that Anisocnemus Chaudoir, Trichopselaphus Chaudoir, and Stenomorphus Dejean comprise a monophyletic assemblage, named the Stenomorphus genus-group, with Anisocnemus the adelphotaxon of Trichopselaphus + Stenomorphus. Analysis of form of median lobe, armature of the internal sac, allometric trends in proportions of the prothorax and hind tibia, and chorological considerations, provide the basis for recognition of six species of Stenomorphus and postulation of their phylogenetic relationships, as follows: S. convexior Notman {[S. penicillatus Darlington + S. sinaloae Darlington] + [S. cubanus Darlington + (S. angustatus Dejean + S. californicus Ménétries)]}. Three monophyletic species-groups are recognized: S. convexior, including S. convexior; S. sinaloae, including S. penicillatus and S. sinaloae; and S. angustatus, including S. cubanus, S. angustatus, and S. californicus. The names Stenomorphus dentifemoratus Chaudoir, 1844 and Stenomorphus alius Darlington, 1936 are synonymized, and S. dentifemoratus Darlington, 1936 (not Chaudoir) is renamed S. darlingtoni. Morphometric and chorological features provide evidence for subspecific recognition, each taxon representing a new combination: for S. angustatus, S. a. angustatus, S. a. braziliensis Darlington, and S. a. dentifemoratus Chaudoir; for S. californicus, S. c. californicus, S. c. rufipes LeConte, S. c. manni Darlington, and S. c. darlingtoni Ball and Shpeley. Evolutionary trends postulated include development of allometry with respect to form of the prothorax and hind tibiae, correlated with sexual dimorphism. Driving forces are postulated to be associated with sexual selection and burrowing. The geographical history of Stenomorphus is reconstructed as follows, using the reconstructed phylogeny and chorological affinities interpreted against a background of geological and climatic events in Middle America, during the Late Cretaceous, and Tertiary and Quaternary Epochs: isolation in Middle America from its South American adelphotaxon of the ancestral stock of Stenomorphus; specialization for life in drier tropical forests and savannas; isolation and differentiation of taxa in response to cyclical climatic changes and mountain building; and over-water dispersal to, and isolation and differentiation in, the Greater Antilles. A key, figures of diagnostic features, descriptions of structural features and of geographical ranges (supplemented with maps) provide means of recognition of taxa.

Korscheltellus gracilis (Grote) is a pest of red spruce and balsam fir roots in the forests of the northeastern United States and southeastern Canada. The larvae feed below ground on woody and non-woody plant tissues for 2 years before maturing. It was found at 18 localities across New England and Nova Scotia during the summers of 1987 and 1988. On Whiteface Mt., New York, and Mt. Moosilauke, New Hampshire, larvae were absent to uncommon at low (500 m) and high (1300 m) altitudes, but common to abundant in red spruce – balsam fir associations at 700, 900, and 1100 m. During September 1987, larval populations were estimated at 56 000 and 312 000 per hectare in soils at 900 m on Whiteface and Moosilauke, respectively. Dense populations occurred locally, e.g. 27 larvae were recovered from a single 0.25-m2 soil pit at 900 m on Moosilauke. By June 1988, larval numbers on Whiteface and Moosilauke had declined by 51% and 72%, respectively. Seedlings and mature trees of both spruce and fir were damaged by larval feeding on bark and cambium. Seedlings were girdled; mature trees had wounds paralleling the root axes.

Leaves were collected between 28 July and 10 September from 36 (1986) and 85 (1987) apple orchards, and examined for mites. Twelve species of Phytoseiidae were found: Amblyseius fallacis (Garman), Typhlodromus longipilus Nesbitt, A. andersoni (Chant), T. caudiglans Schuster, T. pyri Scheuten, T. pomi (Parrott), Phytoseius macropilis (Banks), T. herbertae Chant, A. driggeri Specht, A. finlandicus (Oudemans), T. conspicuus (Garman), and A. pusillus (Kennett), in order of frequency. The stigmaeid mites Zetzellia mali (Ewing) and Agistemus fleschneri Summers, a complex of erythraeid mites of Balaustium spp. and Hauptmannia spp., and tydeid mites, primarily Tydeus spp., were other common predatory species. Species of Tetranychidae, Bdellidae, Eriophyidae, Winterschmidtiidae, and Tarsonemidae, also were collected.

Predatory mites were present each season in all abandoned orchards and in 43–74% of the commercial orchards. Their abundance in commercial orchards was compared with the use of insecticides applied only for control of the spotted tentiform leafminer, Phyllonorycter blancardella (Fabr.). Fewer (P < 0.05) phytoseiids occurred where pyrethroids were employed than in sites without pyrethroids, but differences were not found for similar use of the carbamoyl oxime, methomyl. Fewer (P < 0.05) stigmaeids occurred in sites treated with methomyl than in sites without methomyl, whereas such differences were not found for pyrethroid use.

The efficacy of alpha-terthienyl (α-T) for reducing larval populations of black flies was determined in two streams in southeastern Ontario. By 24 h post-treatment, larval black fly population reductions greater than 90% resulted from exposure to calculated dosages of 0.04 and 0.10 mg-L−1 α-T emulsifiable concentrate over distances of 1.0 and 1.5 km, respectively. Significant population reductions were not observed 2.3 km downstream from injection of the 0.10 mg·L−1 dosage, probably because a marshy area upstream from this sampling site slowed the transport and enhanced photodegradation of α-T. Alpha-terthienyl initiated catastrophic drift of benthic invertebrates that was not selective for any functional feeding group. Significant increases in post-treatment drift, relative to pre-treatment densities, were observed downstream from treatment for eight of 10 taxa studied and included filter-feeders, grazers, and predators. Upstream from treatment, significant increases between sampling days were observed for only two taxa. The catastrophic and nonselective impact of α-T on invertebrate drift preclude its usefulness as an alternative to black fly larvicides used currently, although specialized applications for α-T may exist in integrated black fly control programs.

The structure and temporal control of insect life cycles can best be understood by viewing them as pathways along which various options (e.g. develop or enter diapause; grow rapidly or grow slowly) are chosen in response to environmental controls such as photoperiod and temperature. Simple life cycles include small numbers of such options. The combination of several successive simple elements, however, can produce remarkably complex life cycle patterns, which are more prevalent than most entomologists have recognized. The ways in which these simple elements contribute to life cycle pathways are outlined and illustrated schematically. Flow charts showing the successive decision points in the life cycle then are constructed for selected species. This approach confirms the different simple elements, and shows how they are used in combination to control seasonal life cycles in nature.

Intra- and inter-plant spatial patterns were determined for adult and immature western flower thrips, Frankliniella occidentalis (Pergande), on greenhouse sweet pepper at two commercial greenhouses using five sampling methods. The population density of the thrips was monitored biweekly for 4 months from May to August using blue sticky-traps, plant tappings, blossoms, plant leaves, and whole plants. The intra-plant spatial patterns of adult and immature populations of F. occidentalis were aggregated with the majority of the thrips collected from the top one-third of the plant. The inter-plant spatial patterns also were aggregated. The aggregation cluster for the adult thrips was at least three plants in size, although it was surmised to be at the individual plant level for immature F. occidentalis. The accuracy of the blue sticky-trap, plant tapping, blossom, and leaf samples was determined for monitoring the population densities of adult and immature thrips throughout the growing season. It was shown that leaves should be sampled from the middle section of the sweet pepper plant when using this sampling method. A precision-level sampling program was proposed for monitoring adult F. occidentalis on greenhouse sweet pepper. Sampling blossoms was the most cost-effective sampling method based upon time and number of samples for a specific precision level.

Pathogenicity of the microsporidium Nosema fumiferanae (Thomson) in the obliquebanded leafroller, Choristoneura rosaceana (Harris), was evaluated in laboratory bio-assays. When consumed by first-, fourth-, or fifth-instar obliquebanded leafroller larvae, Nosema spores primarily infected the gut and Malpighian tubules. When 2000 spores per square millimetre diet surface were consumed by neonate, fourth-, or fifth-instar larvae, the N. fumiferanae caused 91, 24, and 5% mortality, respectively. Infection by N. fumiferanae had a delayed impact on the older larvae. Large numbers of spores were retained to the adult stage by obliquebanded leafrollers treated as fourth- or fifth-instar larvae.

The toxicity of the insecticides permethrin, azinphosmethyl, and methomyl to adult Pholetesor ornigis (Weed) and P. pedias Nixon was evaluated in laboratory bioassays. Older P. pedias (2 and 3 days old) were more susceptible than younger parasites (1 day old) to permethrin. Azinphosmethyl was slightly more toxic to female P. ornigis than to male P. ornigis or to P. pedias. There was no consistent difference in the response of adult P. ornigis compared with P. pedias exposed to permethrin or methomyl on treated paper disks. Methomyl was twice as toxic as either azinphosmethyl or permethrin. Male P. ornigis were less susceptible than female P. ornigis to permethrin, but the difference was significant in only one of four populations tested. Male P. ornigis were less susceptible than females to azinphosmethyl. In 1986, populations of P. ornigis which had been exposed previously to pyrethroid insecticides were less susceptible to permethrin than P. ornigis from orchards where pyrethroids had never been applied. The response of both Pholetesor spp. to permethrin varied significantly from 1986 to 1987.

The Nearctic species of the genus Duta are revised. Two new species are described: D. foveolata (Canada, USA) and D. policeps (Canada, USA). Duta virginiensis (Ashmead), new combination, is shown to be widely distributed in the Western Hemisphere, extending to the New World tropics. A diagnosis of Duta and a key to the Nearctic species are given. The impact of environmental degradation on the frequency of Duta species in North America is discussed.

Metzneria paucipunctella Zeller is a seed head moth introduced for biological control of spotted knapweed, Centaurea maculosa Lamarck, in the Pacific Northwest. A cage study was conducted in Montana in 1987 and 1988 to assess the feeding strategy of the M. paucipunctella larva and its impact on two seed head flies, Urophora spp., also introduced on spotted knapweed. Each moth larva destroyed an average of 8.13 knapweed seeds. Most of the seeds were destroyed prior to seed dispersal in early September but the remaining seeds were attacked in the spring of the following year. Each larva tied an average of 7.0 seeds with silk webbing which allowed for feeding long after normal seed dispersal. Seed survival in cages containing both the moth and the two fly species (4.71 seeds per head) was significantly less than in fly-only cages (9.75 seeds per head). The moth larvae caused extensive mortality to the two Urophora species, especially during the spring months. Moth-caused mortality to U. affinis larvae increased from 19% during June through October to 67% in May of the following year. Mortality to U. quadrifasciata also occurred but did not increase significantly in the spring. Data from 10 field sites showed very little association between M. paucipunctella and the two Urophora species which suggests that the unnatural conditions associated with the cages did not increase the incidence of joint moth and fly attack to individual seed heads. The moth is a valuable biocontrol agent as it is contributing significantly to the overall consumer pressure on spotted knapweed seed heads.

The efficacy of mating disruption for controlling the grape berry moth, Endopiza viteana (Clemens) (Lepidoptera: Tortricidae), was evaluated from 1987 to 1989 in the Niagara peninsula, Ont. Mating disruption was tested in commercial vineyards with high-, moderate-, and low-density grape berry moth populations using the Biocontrol Ltd. tape-type and wire-type pheromone dispensers. Pheromone-baited trap catches were reduced by 92% or more in plots treated with pheromone. Treatment with pheromone significantly reduced damage (percentage infested clusters) compared with an untreated control in each of two tests, and provided control as good as or better than an insecticide control programme in two of four tests. Damage increased from 1.3- to 12.8-fold between successive generations in plots treated with pheromone, and was greater on the borders of some plots treated with pheromone or insecticide. It is concluded that mating disruption may have potential as a control method for use in the integrated management of E. viteana.