Variation between samples of the Colorado potato beetle, Leptinotarsa decemlineata (Say), and between mortalities from some factors, on potato, were determined in long-term study plots at Merivale, Ontario. For each of six age intervals (spring adults; egg masses; larvae, Periods 1 and 2; pupal cells; and summer adults), inter-hill variance was the major source of sampling variance. Intra-hill and block differences were rarely significant. The most appropriate sample unit for the above-ground stages was the potato stalk and for pupal cells, the soil quadrant. Optimum allocation procedures indicated that not more than one sample unit per hill need be taken for the immature stages. For adults, the whole hill should be sampled. To estimate population means with acceptable limits of precision (10% standard error), it is recommended that 50 to 200 hills be sampled for the various age intervals.

In direct contact toxicity tests with four pyrethroid and three standard insecticides, using 24–48 h old crickets, Acheta pennsylvanicus (Burmeister), as test insects, carbofuran was most toxic > cypermethrin > fensulfothion > chlorpyrifos > fenvalerate > fenpropanate > permethrin. In moist (5% water) Plainfield sand, using the same test insect, chlorpyrifos was most toxic > carbofuran > fenpropanate > cypermethrin > permethrin > fenvalerate > fensulfothion, i.e. the pyrethroids, although quite strongly adsorbed by soil, were still moderately active as soil insecticides. All pyrethroids were less toxic in muck soil as compared with Plainfield sand, and in air-dry (0.5% water) as compared with moist (5% water) Plainfield sand, with the effects being less on cypermethrin and fenvalerate and greater on permethrin and fenpropanate. None of the pyrethroids was affected by soil type and moisture to the same extent as was carbofuran. Permethrin, fenvalerate, and cypermethrin showed a negative temperature coefficient of toxicity in moist Plainfield sand, being from 1.4 to 1.9× more toxic at 15° than at 32°C. Fenpropanate, like carbofuran, was slightly more toxic at 32° than at 15°C. Generally, soil type, moisture, and temperature had minimal effects on the toxicity of the four pyrethroid insecticides. In persistence studies over 48 weeks, using Plainfield sand, the pyrethroids were more persistent than chlorpyrifos, but less persistent than dieldrin. Under these laboratory conditions, permethrin and fenvalerate were slightly more persistent, while fenpropanate and cypermethrin were as persistent as carbofuran. Trans-isomers of permethrin and cypermethrin declined more quickly in the sand than did the cis-isomers and of the trans-isomers the 1S,trans declined much faster than the 1R,trans while little difference was observed for the corresponding 1S- and 1R,cis-isomers.

The author has frequently been asked why he did not make a key for the families of spiders. He has answered that a correct key was impossible.But as such questions are getting more numerous, and connected with a desire to know something about spiders, the author has decided to put together what he could as a contribution to the classification of our spiders, principally for the use of those who are unable to obtain the costly works necessary for study.

Natural and artificial reforestation, which basically depend on an abundance of sound seed, are adversely affected when insects destroy large numbers of cones, seeds, and cone-bearing shoots. Other factors, such as unfavourable weather, incomplete seed development, and damage by birds and mammals also reduce seed production, but they are rarely of such widespread importance as insects, whose damage often results in the failure of seed crops over large areas. Cone and seed insects sometimes restrict the natural regeneration of trees for a few years at a time, as, for example, in conifers on the Pacific coast (16), loblolly pines in Virginia (13), and oak in Michigan (5), but they become particularly important when the seeds they destroy are required for use in artificial reforestation. The future success of much reforestation, which is inclining more and more toward the use of seed obtained from trees cultivated especially for that purpose, may largely depend on a thorough understanding of cone and seed insects and their effect on seed production.

Managed and wild colonies of common eastern bumble bee (Bombus impatiens Cresson) (Hymenoptera: Apidae) are effective pollinators of wild blueberry (Vaccinium angustifolium Aiton) (Ericaceae) in Atlantic Canada. Because insecticides are used during bloom to manage insect pests, bumble bees may be at risk of exposure. We therefore assessed the susceptibility of B. impatiens to some insecticides used or projected for use in blueberry pest management. Workers were killed by topical applications of spinosad, spinetoram, deltamethrin, and phosmet, but not flubendiamide. Similarly, when ingested in honey solution, spinetoram and deltamethrin were toxic, whereas flubendiamide did not cause mortality up to double its recommended label rate. In another experiment, workers were fed one sublethal dose of contaminated honey solution and placed in microcolonies to assess impacts on feeding, life span, and reproduction. The highest concentration of deltamethrin (17 mg a.i./L) reduced feeding. Workers treated with deltamethrin had shortened life spans and produced fewer males. Flubendiamide (2000 mg a.i./L) and spinetoram (0.8 mg a.i./L) caused no sublethal effects. These results indicate that flubendiamide should be safe to apply to blueberries where B. impatiens is foraging, while some other insecticides we tested may be hazardous under different exposure scenarios.

Thirty-two species of Pediobius (Hymenoptera: Chalcidoidea) are reviewed, 9 newly noted from both Europe and North America. New Nearctic species include P. adelphae, disparis, geshnae, liocephalatus, louisianae, magniclavatus, ni, ocellatus, pseudotsugatae, and strobilicola. Pediobius rugosithorax (Cwfd.) and kansensis (Grlt.) are newly noted as junior synonyms of acantha (Wlk.); lithocolletidis (Ashm.) of albipes (Prov.); longfellowi (Grlt), of alcaeus (Wlk.); wilderi (How.) of brachycerus (Thoms.); (Asecodes) P. albitarsis (Ashm.), tarsalis (Ashm.), and ashmeadi (Cwfd.) of crassicornis (Thoms.); utahensis (Cwfd.), longus (Grlt.), and perdubius (Grlt.) of eubius (Wlk.); (Entedon) P. albitarsis (Ashm.) and sexdentatus (Grlt.) of facialis (Giraud); splendens (C. & D.) of foliorum (Geoffr.); glabrata Blck. of phyllotretae (Ril.). Pediobius termerus (Wlk.) is recorded for the first time in Nearctic. A key to species and a host–parasite list are included.

The "secondary" attraction occurring after log attack by the female ambrosia beetle, Trypodendron lineatum (Oliv.), and the reduction in attractiveness after males arrive on the log are not dependent directly on mating. The reduction seems to be associated with the males’ presence, which suggests that they produce a masking substance.

Studies on the biology and control of biting flies in the Canadian north have been described by Hocking et al. (1950), Twinn et al. (1948), and Twinn (1950). The biological investigations have been directed largely toward the economic control of biting flies in isolated military areas. In the subarctic regions of North America so many factors influence the rate of development of mosquitoes that simple relations of time and temperature cannot be used to estimate adequately the periods of infestation. Casual field observations of mosquito larvae and pupae suggested that behaviour patterns peculiar to northern species modify the effect of environmental conditions on the rate of development.

The morphology and histology of the internal reproductive system of the male spruce budworm moth, Choristoneura fumiferana (Clemens), is described and discussed.

This paper describes a successful attempt to tag adult females of the European pine shoot, Rhyacionia buoliuna (Schiff.) with Co60, chosen as a tagging agent because it is a gamma emitter with a sufficiently long half-life (5.3 years). Emphasis is placed on the preparation and application of the tracer material, the absence of immediately harmful effects of radiation on the insects, and the ability of the insects to behave normally with the tags in place. This work was undertaken in order so develop techniques for following the movements of large numbers of these insects.

Field trials of the synthetic bark-beetle pheromone frontalin demonstrated that lines of single, baited spruce trees, in or near Dendroctonus rufipennis infestations, resulted in concentrated beetle attacks on trees in a strip 2 chains (40 m) wide on either side of the lines of baited trees. Pre-flight insecticide (Lindane) application killed the beetles and prevented tree mortality. Post-attack arboricide (Silvisar) treatment killed most parent beetles and brood under the bark. A predator, Thanasimus undatulus, also was aggregated at frontalin-baited trees. This application of pheromone shows promise of becoming a forest management tool to concentrate beetle attacks in partly infested stands prior to logging.

Shortly after the discovery of the introduction of balsam woolly adelgid, Adelges piceae (Ratzeburg), to the south coast of British Columbia, a predator release program was initiated to establish a complex of European and Asian adelgid predators to supplement existing native predators. Between 1960 and 1969, eight species of exotic predators, Aphidoletes thompsoni Mohn (Diptera: Cecidomyiidae), Cremifania nigrocellulata Czerny and Leucopis hennigrata McAlpine [=Leucopis sp. nr. melanopus Tanas. (McAlpine 1978)] (Diptera: Chamaemyiidae), Laricobius erichsonii Rosenhauer (Coleoptera: Derodontidae), Aphidecta obliterata (L.), Scymnus (Pullus) impexus Mulsant, and Scymnus (S.) pumilio (Weise) (Coleoptera: Coccinellidae), and Tetraphleps abdulghani Ghauri (Heteroptera: Anthocoridae), were released (Clark et al. 1971; Schooley et al. 1984).

Forty-nine 0.1 m2 emergence traps positioned over several substrate types and a range of water depths 0.9 to 5.5 m, from 2 June to 7 September 1967, collected 979 caddisflies and 195 mayflies. The caddisfly emergence was restricted to the period 24 June −27 August, and mayfly emergence to the period 2–30 July.The sex ratio for the caddisflies showed, in almost every case, a preponderance of females and no male Neureclipsis bimaculatus (Linn.) and N. validus Walk, were collected. Most of the caddisflies showed preference for a particular depth and/or substrate type. The few caddisflies which were present both in large numbers and distributed over a fairly wide depth range indicated that there is a relationship between depth distribution (temperature) and emergence time, heat perhaps being involved both in control of rate of maturation and as a releasing agent for the actual emergence.Male Stenonema interpunctatum canadense (Walker) showed peak emergence about 5 days before the females and also outnumbered the females by about 3:1. No relationship seemed to exist between depth distribution and emergence time for any of the mayfly species. However, the emergence of one species, Caenis forcipata (McD.) may be related to weather conditions.

Maggots of Pegohylemyia sp. have been found inhabiting the cones of white spruce, Picea glauca (Moench.) Voss, in southern Ontario. The species was identified from a single male specimen as probably Pegohylemyia anthracina Czerny by the Swedish authority Dr. O. Ringdahl. Difficulty in rearing the maggots to the adult stage has delayed confirmation of this identification but it is expected that a good series of adults will be available shortly. In this paper, however, the emphasis is placed on the instars with an outline of the life cycle. It is shown that the second- and third-instar larvae are free-living, but the first-instar larvae moult to the second within the egg chorion.

Application of petroleum oils prior to oviposition by overwintering pear psylla, Psylla pyricola Foerster, reduced oviposition by 98% for up to 5 weeks. The delay of oviposition and reduction in subsequent egg and nymph densities were inversely proportional to the rate of oil used. The reduced oviposition rate was due primarily to inhibition of oviposition by oil deposits on the host, not adult mortality. No commercially important deleterious effects of oil treatments were detected on several pear varieties.

An energy budget was evaluated for the bertha army worm, Mamestra configurata (Walker), over its life cycle. Cumulative values for the budget at the end of larval development were: ingestion, 2124 cal; respiration, 372 cal; production, 485 cal; and egestion, 1266 cal. The sixth instar larva accounted for 80.1, 83.2, 81.3, and 78.8% of the total energy in ingestion, respiration, production, and egestion, respectively, during its development. Assimilation efficiency varied from 35.5 to 44.4% with a mean of 40.6%, gross production efficiency varied from 16.6 to 23.8% with a mean of 21.3%, and net production efficiency varied from 37.5 to 61.3% with a mean of 52.7%.

The diet of the common shrew contained significant proportions of lepidopterous remains, and these were mostly of winter moth. The least shrew also at times preys heavily upon winter moth. Calculations indicate that predation by mammals, especially common shrews, could have important consequences on the population dynamics of the winter moth. It was concluded that there is only slight interaction between winter moth predation by shrews and predacious beetles.

Rangeland grasshopper species richness was monitored at 10 sites in Montana, U.S.A., during 1986 through 1992, which included an extreme drought year (1988). We observed significant post-1988 drought reductions in rangeland grasshopper species richness in the eastern and south-central region of Montana where drought intensity has been increasing during the past 20 years. In the north-central region, which also experienced the 1988 drought but showed no long-term drought trend, we did not observe a post-drought reduction in overall rangeland grasshopper species richness. Thus, in terms of rangeland grasshopper species richness, the potential impact of a severe drought in a given year may depend on the timing of such an event within longer-term climatic cycles. Our findings suggest that as regional drought intensity increases temporally, there may be an increased likelihood that a single extreme drought year will not only have a profound impact on abundance but may also result in significant long-term reduction of grasshopper species richness. Our results support the hypothesis that resource limitation is a very important factor in structuring rangeland grasshopper communities in space and time.

Eggs of Sepedon fuscipennis (Diptera: Sciomyzidae) < 1, 1–2, 2–3, and 3–4 days old were offered to inexperienced female Trichogramma sp. near californicum in a laboratory experiment. Exposure period (2 h) and number of host eggs offered at one time (10) were held constant. Percentage of hosts parasitized, total number of parasitoid progeny found in a group of hosts, percentage of parasitized hosts yielding adult parasitoids, and survivorship of parasitoid progeny to adulthood all decreased significantly with increased host age. Younger hosts yielded more than one adult parasitoid more often than did older hosts. Over 50% of the adult parasitoids emerging from hosts < 1, or 1–2 days old were female. Hosts 2–3 days old produced only males. The data show a somewhat different relationship of host age to host acceptance and suitability than do some published data on lepidopteran hosts of Trichogramma.

Experiments were done in fields of potato in Fredericton, New Brunswick, in 1981, 1982, and 1984 to determine the effect of native predators on the abundance of aphids. The populations of predators were altered by pitfall trapping within plots enclosed by polythene barriers and by applying a selective insecticide. The abundance of aphids was monitored in the enclosed plots and in unenclosed areas serving as control. The experimental design was successful at significantly reducing the numbers of Carabidae in the enclosures compared with the open plots. Aphid populations tended to be larger in the plots with depleted populations of Carabidae than in the control areas and were significantly larger in the plots where the insecticide depleted the populations of canopy level predators. These results suggest that the Carabidae play a relatively minor role in aphid control on the potato crop compared with specific predators.