Studies on non-treated plots at Harrow, Ontario, in 1967 and 1968 and at Kentville, Nova Scotia, from 1963 to 1968 inclusive showed that residues of viruses of the cabbage looper, Trichoplusia ni (Hübner), found in soil were related qualitatively and quantitatively to the virus residues on leaves of cruciferous plants grown in the plots and to mortality by viruses in the host populations. At Harrow where the cabbage looper is common and where virus diseases occur naturally in field populations, the viruses that occurred in the populations of the host built up in soil as the season progressed. At Kentville where the host is rare, virus was rarely found in soil or on foliage. The typical nuclear-polyhedrosis virus, an atypical nuclear-polyhedrosis virus that formed abnormally large polyhedra, and a granulosis virus were found at Harrow, with the typical nuclear-polyhedrosis virus predominating. Only the typical nuclear-polyhedrosis virus was detected at Kentville.

The morphology and fine structure of the stylets, labial clamp, and crumena of the balsam woolly aphid, Adelges piceae (Ratz.), are described from sections studied in the electron microscope.

Adults of Melanoplus bilituratus (Walker) were reared in the laboratory as groups of pairs, as groups in association with mature and immature males, as single pairs, and as groups of unmated females. Females of grouped pairs produced a larger number of eggs per pod and laid a greater total number of eggs that were more viable and hatched at least one day earlier than those of other groupings. Hatchlings of grouped pairs were more robust, 29% reaching the adult stage, whereas only 12% of nymphs from eggs of single pairs reached adulthood. Eleven per cent of the eggs of unmated females were viable, although only one hatchling lived to become an adult. Females of grouped pairs, of single pairs, and of those that were unmated reached their peak egg production in four, five and seven weeks respectively, after becoming adult. Young females matured three days earlier when mated with old males than when mated with males of their own age.

The long-held belief that grasshoppers are to a large extent omnivorous and, as Wolcott (1936) states, “like cows, feed on any kind of vegetation”, is slowly giving place to the view that they are much more restricted feeders. Their habit of nibbling at almost anything, particularly when they are present in large numbers, probably led to this erroneous concept. More recent work such as that of Rubtzov (1931), Criddle (1933), and Isely (1938, 1944, 1916) stresses the fact that many species of grasshopper confine their feeding to a group of related plants, and a few species to a single plant.

Acrolepiopsis assectella (Zeller), leek moth, is a widespread and common pest of species of Allium L. (Liliaceae) in the western Palaearctic subregion. The establishment of A. assectella in eastern North America has resulted in economic losses to garlic (Allium sativum L.), leek (Allium porrum L.), and onion (Allium cepa L.) growers, especially to organic producers in eastern Ontario and southern Quebec. Acrolepiopsis assectella was first recorded in the Ottawa area in 1993. By 2010, A. assectella had expanded its range into eastern Ontario, southwestern Quebec, Prince Edward Island, and New York. A bioclimate model, using CLIMEX simulation software, was developed to produce mapped results that closely approximated known distributions for A. assectella in central Europe. This model was then validated with recorded distribution records in eastern Europe, Asia, and North America. Model output predicted that A. assectella will readily survive in southeastern Canada and the eastern United States of America. Other areas potentially suitable for A. assectella include coastal regions of the Pacific Northwest, the interior of southern British Columbia, and north-central Mexico. The continued range expansion of A. assectella into other Allium-growing areas of eastern North America appears to be inevitable. Establishment in these areas presents the risk of substantial production losses to Allium spp. producers.

Laboratory tests showed that a Colorado potato beetle (CPB), Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae), strain collected from potatoes on a farm near Sherbrooke, Quebec, and known in 1979 to be resistant to most recommended organochlorine, organophosphorus, and carbamate insecticides, also had developed 23- to 38-fold levels of resistance to the pyrethroid insecticides permethrin, fenvalerate, and cypermethrin by 1982. Piperonyl butoxide (PB) had only a minor effect on fenvalerate and deltamethrin toxicity to insecticide-susceptible CPB and on deltamethrin toxicity to pyrethroid-resistant CPB. However, PB effectively synergized fenvalerate in pyrethroid-resistant CPB, e.g. a 1:8 fenvalerate:PB mixture was 12-fold more toxic than fenvalerate alone.

The 11 genera of Nearctic Braconini are keyed: two of them, Myosoma Brullé with a wide pantropical range and Alienoclypeus Shenefelt, new genus, are found chiefly in the Chihuahuan desert and shrub fauna of northern Mexico and the southwestern U.S.A. and are recorded as Nearctic for the first time. Four new species are described in Myosoma: eumystax, impexum, longius, and durango. R. D. Shenefelt describes a new genus and species, Alienoclypeus insolitus. The genus Atanycolimorpha Viereck, 1913 is synonymized with Ipobracon Thomson, 1892. The genus Coeloides is revised for the Nearctic Region; 12 species are described and illustrated. Five of these are new: mexicanus, durangensis, sympitys, tsugatorus, and sonora. One species, C. rossicus (Kokujev), is Holarctic, a new subspecies, betulae, is described from Canada. The following are new synonyms: C. rufovariegatus (Provancher) = (dendroctoni Cushman), C. vancouverensis (Dalla Torre) = (brunneri Viereck), C. crocator (Kirby) = (promontorii Dalla Torre).

Mayflies (Ephemeroptera) were collected from 35 sites (streams and tundra ponds) across southern Nunavut in 2002–2005. Nine mayfly species were previously reported for Nunavut: Acentrella feropagus Alba-Tercedor and McCafferty, Acerpenna pygmaea (Hagen), Baetis bundyae Lehmkuhl, B. flavistriga McDunnough, B. foemina McDunnough, Diphetor hageni (Eaton) (Baetidae), Ephemerella aurivillii (Bengtsson) (Ephemerellidae), Leptophlebia nebulosa (Walker) (Leptophlebiidae), and Metretopus borealis (Eaton) (Metrotopidae). We add 7 species to this list, bringing the total to 16: Ameletus inopinatus Eaton (Ameletidae), Acentrella lapponica Bengtsson, Baetis hudsonicus Ide, B. tricaudatus Dodds, Heptagenia solitaria McDunnough (Heptageniidae), Rhithrogena jejuna Eaton (Heptageniidae), and Parameletus chelifer Bengtsson (Siphlonuridae). Based on numbers collected, the dominant mayfly family was Baetidae. Baetis bundyae was the most common mayfly collected, particularly in coastal areas, where larvae were found in permanent and temporary streams and in small or shallow tundra ponds. Larvae hatched 2–3 weeks after ice-out and developed rapidly in 2.5–4 weeks, emerging as adults by early August. All populations containing larvae that were large enough to sex showed female-biased sex ratios, suggesting parthenogenesis. A combination of freeze-tolerant eggs, good dispersal ability, and probable parthenogenesis is probably responsible for the success of Baetidae across the Arctic.

The effects of Panonychus ulmi (Koch) density on several yield components of Red Delicious apples in a Nova Scotia orchard were examined from 1967 to 1970. The same 96 trees were sampled in each of the 4 years, and from a peripheral sampling zone within each tree the number of dormant and blossom clusters and the eventual number of apples produced was determined. The other yield components — bloom, set, and crop — were computed from these counts. Applications of ryania, carbaryl, and animert on 6 June 1967 followed by supplementary applications of animert on 7 July (carbaryl plots) and 1 August (ryania plots) were used to induce varying densities of P. ulmi. Mites were sampled twice weekly from June to August and fortnightly in September. Chemical treatments in 1967 had significant effects on mite-days/leaf in each year from 1967 to 1970. Cumulative mite-days/leaf had a significant negative influence on the number of harvested apples/sampling zone in 1967 and 1969, the years of higher apple production and higher mean bloom, but not in 1968 and 1970. Mites in 1969 also had a significant negative effect on return bloom in 1970. These findings agree with other studies that suggest an interaction between fruit load and yield losses induced by mites.

A study was made of the poplar-and-willow borer, Sternochetus (= Cryptorhynchus) lapathi (L.) (Coleoptera: Curculionidae), in British Columbia between 1959 and 1964. The borer occurred principally south of 52 degrees north latitude. Willows were the preferred hosts. Ornamentals, hybrids in commercial plantings, and natural growing trees were attacked. The life cycle of the insect on southern Vancouver Island lasted up to 3 years; overwintering took place in early instar and adult stages. Eggs were laid in the bark; larvae mined first in the bark and then in the wood, where pupation took place. Few parasites and predators were found. DDT, dieldrin, and BHC killed adults; lindane (0.5% water emulsion), applied in the spring, caused larval mortality up to 96%.

An account is given of host acceptance, the influence of temperature on fecundity and longevity, and searching capacity of Chrysocharis laricinellae (Raczeburg), a parasite of the larch casebearer, Coleophora laricella (Hübner).

Fourth-instar case-bearing larvae were the preferred stages for attack. The size of the parasite progeny varied directly with the size of the host. Fecundity of progeny reared from small hosts was significantly less than that of progeny reared from large hosts. Not all parasite adults could successfully oviposit through the tough skin of the host pupa. C. laricinellae showed poor searching capacity. Superparasitism was common at low host densities of the casebearer and resulted in either one parasite emerging or in total parasite mortality. A sex ratio where females predominated resulted when sufficient numbers of preferred stages of the host were presented to mated C. laricinellae. The temperature threshold for attacking hosts was 55°F, and for development of the parasite 40°F. At 50°F the adults lived 4 months on the average.

Therefore C. laricinellae is able to survive in the field without alternate hosts and at very low host densities. The parasite seems to depend on a continuing supply of suitable instars of host species in sufficient numbers to be effective. If C. laricella is the only available host species in the ecosystem the biological control value of this chalcid must be rated as poor.

Species replacement is most commonly observed among the parasitic Hymenoptera because of their dominance in biological control. Such replacement is necessarily a reproduction phenomenon involving interspecific competition in population-saturated areas. The competitive interactions of parasitic populations are differentiated into two types, “intrinsic” and “extrinsic”, with characteristic conditions and mechanisms.

Intrinsic competition consists of interference between individuals of the interacting populations, being manifested by such factors as cannibalism, mutilation, starvation, suffocation, production of toxic or repellent excretions and secretions, and the differential susceptibility of individual hosts to parasitic attack.

Extrinsic competition concerns the interaction of populations as groups and is manifested largely by host-habitat finding, host-finding, and host acceptance.

Replacement through intrinsic competition takes place regardless of host abundance; replacement by extrinsic competition is an effect of decreased host abundance.

This paper is intended as an assessment of the state of knowledge and development of semiochemical methods for control of bark beetles (Coleoptera: Curculionidae) in western North America and as a roadmap for future research and development in this field. It is based on a keynote presentation given at the symposium Managing Bark and Ambrosia Beetles with Semiochemicals, held in 2018 in Vancouver, British Columbia, Canada, at the Joint Meeting of the Entomological Society of America, the Entomological Society of Canada, and the Entomological Society of British Columbia. We describe currently available active ingredients, formulations, and release devices. Furthermore, we describe the most urgently needed new products and techniques, and constraints to their further development. Finally, we speculate about opportunities afforded by new advances in microbial synthesis of semiochemicals, streamlining of regulatory processing, and aerial application using unmanned aerial vehicles.

Pupae and 3rd-instar larvae of Pseudaletia unipuncta (Haw.) survived longer at 0 and −2°C than other immature stages, and insects reared at 15°C were more cold tolerant than those reared at 20°C. Egg survival at 0°C varied greatly among replicates suggesting genetic differences among females. No adults survived 2 weeks at 0°C. Peridroma saucia (Hub.) would not rear satisfactorily at 15°C and, other than eggs, all stages tested were from rearings at 20°C. Eggs from adults at 15°C were more cold tolerant than those from adults at 20°C. There were no differences in survival among any of the larval stages or pupae. Some adults survived 6 weeks at 0°C. No stage of either species survived over 8 weeks at 0°C nor 4 weeks at −2°C indicating that overwintering on the Canadian prairies is unlikely.

Sex attraction studies were carried out to investigate the mate-finding behaviour of invasive Vespula vulgaris (Linnaeus) (Hymenoptera: Vespidae) wasps. Delta traps were baited with live, caged males, and gynes (virgin queens) of V. vulgaris to determine whether either sex produced a long-range sex attractant. Traps baited with gynes caught 71 males, while the controls and live-male wasp baited traps did not catch gynes. Wind tunnel trials were performed to verify if the signal produced by the gynes was chemical in nature. First, V. vulgaris males were flown to live caged gynes, where more than half of the males tested flew upwind in a zigzagging pattern and made contact with caged gynes. Males were also flown to hexane rinses of gynes and flew upwind in a zigzagging pattern towards the gyne extract, although none made contact with the cotton roll stimulus. The results presented here demonstrate conclusively that V. vulgaris gynes produce a sex pheromone.

Laboratory studies of seven North American Choristoneura species and two subspecies from widely distributed locations demonstrate the low level of genetic separation among them. No differences were found in numbers (n = 30) or morphology of chromosomes among members of the group or in any of the hybrids examined. High levels of mating success were obtained in all inter se matings as well as in crosses and back-crosses. However, mating success was greater for crosses within host type and within pheromone type than for crosses between types. Viability and fertility were similar in all the hybrids and close to those of the inter se progenies. Mean weights of initial eggs varied by a factor of 2 from the lowest (C. pinus Freeman) to the highest (C. lambertiana ponderosana Obraztsov). Mean weights of initial eggs produced by hybrids were generally close to those of the parental species. However, when one parent was C. fumiferana (Clem.), mean weights of initial eggs were either much larger (male C. fumiferana) or much smaller (female C. fumiferana) than either parental type. These differences could affect survival of some progeny under harsh conditions. This evidence supports other studies in indicating that C. fumiferana is genetically distinct from other species in this group.

Three body dimensions (body length, head width, and abdomen width) were used to determine size differences between laboratory-reared and wild populations of Trichogramma minutum Riley. Six separate groups of T. minutum were measured: three groups were from Sitotroga cerealella (Olivier) eggs, two from spruce budworm Choristoneura fumiferana (Clemens) eggs, and one from wild populations of spruce budworm.

Female T. minutum from spruce budworm (large host) eggs were significantly larger for all body dimensions than T. minutum from S. cerealella (small host) eggs. Male T. minutum from field-collected spruce budworm eggs were significantly larger for all body dimensions than T. minutum reared for more than one generation in S. cerealella eggs.

A significant reduction in female parasitoid size was observed during the initial generations of T. minutum reared in the smaller host (S. cerealella). However, this size reduction was not permanent. Following numerous generations in the S. cerealella host eggs, a significant increase in female parasitoid size was noted within the first generation of T. minutum reared in the spruce budworm host eggs.

A field trial was conducted to evaluate a spunbonded polyester row cover (Reemay) as a means of protecting cauliflower plants from insect pests. Total yield variables (curd weight, size, and color) did not differ significantly between plants under the row covers and those treated with insecticides, although plants under the row covers did produce a greater yield at an early harvest date. Plants in control plots failed to produce any marketable heads, owing to attack by cabbage maggots, Delia radicum (L.). Row covers may be a useful alternative to insecticides for pest control via physical exclusion of the key pest(s) from the crop plant.

Sperm transfer in the desert locust, Schistocerca gregaria (Forsk.), is accomplished by means of small (1.5 mm) spermatophores, formation of the first of which begins almost immediately after coupling. A normal copulation, which lasts 4 hours or longer, results in the production of about 6 spermatophores and a maximum of at least 14. Some details of the process of spermatophore formation are presented and differences among certain groups of acridoids are discussed.

The fourteen species of the subgenus Eurylophella are reviewed with accounts of each species including complete synonymies, synoptic descriptions of nymphs and adults, and distribution. Illustrated keys for nymphs and adults and distribution maps are presented for each species. Ephemerella bieoloroides McDunnough is regarded as a synonym of E. verisimilis McDunnough. Ephemerella doris and E. trilineata Berner are of questionable status, being either closely allied to or identical with E. temporalis; and the relationship of E. lithuanica Kazlauskas to E. karelica is uncertain.