The sweetpotato whitefly, Bemisia tabaci (Gennadius), was accidentally imported into Canada on poinsettia, Euphorbia pulcherrima Willd., cuttings from the United States in 1987 and in 1988. The biology and population dynamics of B. tabaci were reviewed by Butler et al. (1986). It is a worldwide pest of more than 500 plant species in 74 families. Prior to 1986, there was only one report of this insect as a greenhouse pest, on vegetables in Turkey (Lopez-Avila and Cock 1986). Bemisia tabaci was first reported on poinsettia in Florida greenhouses in November 1986 (Price et al. 1987). In 1987, this insect was reported as a pest on field tomatoes in Florida (Schuster and Price 1987).

Micrempis anatolica Chillcott is considered a junior subjective synonym of M. bomboxynon Chillcott, based on re-examination of purported differences in the female terminalia given by Chillcott and Teskey (1983), as well as examination of a number of additional specimens collected from eastern North America. As a result of its new broader concept, M. bomboxynon is redescribed, a distribution map of the species is provided, and separation from other Nearctic species of Micrempis is discussed.

Two bioassay methods using leaf discs and Petri dishes as the treated medium were compared. Resistance levels were approximately 11-fold with the leaf disc method and 7-fold using the Petri dish assay. Comparisons of the two methods on six wild populations indicated that the Petri dish assay was more sensitive in identifying low frequencies of resistance. Advantages of the Petri dish assay over the previously used leaf disc method for rapid, field-type surveys are discussed.

Surveys of populations from the Simcoe and Niagara areas, using the Petri dish assay, indicated resistance to dicofol in 11 of 22 samples. Resistance was generally correlated with sites where dicofol had been used at least once a year for 2–3 consecutive years. The data indicate a resurgence of dicofol resistance since 1984 when resistance was detected at 4% of the surveyed sites.

Sticky stovepipe traps, flight interception traps, and Lindgren multiple-funnel traps were baited with conifer monoterpenes and ethanol to capture conifer-feeding beetles and their associates. Of the more than 6000 beetles captured, 74.6% were caught by stovepipe traps, 14.8% by interception traps, and 10.7% by multiple-funnel traps. Dominant families were the Scolytidae (14.5% of all beetles captured), Elateridae (14.4%), Lampyridae (12.1%), Cerambycidae (12.0%), Cleridae (10.5%), Curculionidae (9.3%), Staphylinidae (4.0%), and Buprestidae (3.4%), with other families accounting for 19.8% of specimens captured. Conifer-feeding species in the families Buprestidae, Melandryidae, Cerambycidae, Scolytidae, and Curculionidae and their predators (Cleridae) were captured in greatest numbers by the sticky stovepipe traps; the interception traps generally captured the fewest specimens. The sticky stovepipe traps may be superior because they offer a distinct vertical silhouette to approaching insects.

Oil-based formulations of Bacillus thuringiensis Berliner var. kurstaki, Dipel 132, Dipel 176, and Dipel 264, were aerially applied at rates of 1.18–2.36 L/ha over five 30-ha plots in a balsam fir, Abies balsamea (L.) Mill., forest in efficacy tests against the eastern hemlock looper, Lambdina fiscellaria fiscellaria (Guen.), in Newfoundland. Double applications of 30 Billion International Units (BIU) per hectare of each formulation and single applications of 40 BIU per hectare of Dipel 176 and Dipel 264 were tested. Larval population reductions of more than 95% and no defoliation of old or new foliage were observed in the plots receiving double applications and in the plot treated with a single application of Dipel 264. Larval numbers were reduced by 85% and defoliation was 4% in the plot treated once with Dipel 176.

These treatments were applied against low to moderate larval populations, and their success was attributed to excellent spray coverage and early application when 50% or more of the larvae were still in their first instar.

Low temperature is a major factor regulating diapause development in Holcothorax testaceipes Ratzeburg. Diapausing pupae required a cold period of 0°C, 5°C, or outdoor (≤0°C) for ca. 15 weeks to terminate diapause. The pupae required a further 21–27 days at 21°C for 50% emergence. Longer periods and higher temperatures of storage often were associated with shorter times of morphogenesis and duration of emergence. Percentage emergence of H. testaceipes was constant after various periods of cold storage at low temperatures. After storage at 0°C, pupae held at 21°C and a 16-h photophase reached 50% emergence sooner than those held at the same temperature but at a 12-h photophase. Photoperiod did not affect percentage or duration of emergence of the parasitoid. The threshold temperature for development of pupal H. testaceipes was estimated to be 9°C regardless of sex or host species. The thermal constant did not vary with sex of the parasitoids but differed significantly for H. testaceipes reared on Phyllonorycter ringoniella Matsumura (237 DD) and on Phyllonorycter blancardella (F.) (202 DD). Temperatures from 11 to 29°C did not affect percentage and duration of emergence from overwintered pupae, which were 75.5% and 2.4 days respectively, when reared on P. ringoniella, and 86.2% and 1.7 days respectively, on P. blancardella. These results suggest that H. testaceipes accepts P. blancardella as a host and will be synchronized with its development in Ontario.

The saltatorial orthopteroid insects did not originate in North America. Five avenues of entry were utilized in migration from other parts of the world. These were: (1) ancestral forms migrated to this region in Pangaean times when all continents formed a single land mass; (2) later in time, taxa migrated from Europe when Eurasia and North America were still joined, or later via an Atlantic land bridge; (3) ancestral forms migrated northward from the Neotropical region before the separation of the two continents or, much later, when the two continents became rejoined; (4) later arriving taxa entered North America during the Pleistocene via a Beringian land bridge; (5) some species are very recent immigrants, either because of the activities of man or by migration into Canadian territory from the south.

The fossil record is very incomplete. It indicates past climatic conditions, but is of limited assistance concerning extant taxa.

Pleistocene glaciation had a profound effect upon the distribution of extant species. Many species were forced to move southward to escape the advancing ice. Some species probably were eliminated. It is clear that most of the extant species have migrated northward since the recession of the Wisconsin glacier.

The spatial and frequency distributions of Douglas-fir cone moth, Barbara colfaxiana (Kearfott), eggs in Douglas-fir trees and stands were determined by dissecting 13 262 conelets collected from 81 trees in three sites and 2 years. There were no consistent trends in egg density associated with crown level or aspect. The frequency distribution of eggs per conelet fitted the negative binomial in three of five site-years but a common k for the negative binomial could not be calculated. Green’s index of aggregation suggested that the cone moth egg distribution was significantly aggregated in each site-year.

The optimal number of conelets per tree to sample was determined to be four in forest stands and three in seed orchards. The number of sample trees required for estimating mean egg density with 10% and 20% precision and 90% confidence was calculated for a range of mean egg densities using the method of Kuno. The sample sizes required to estimate a control threshold density of 0.6 eggs per conelet with 10% precision and 90% confidence were very large and would be impractical for operational use. Therefore, a sequential sampling plan was developed for use in seed orchards that would classify cone moth egg densities as either above or below a critical density at which 10% seed loss would be expected.

Based on field and laboratory research, a simulation model was developed that describes the within-season population dynamics and oviposition of adult northern corn rootworm beetles, Diabrotica barberi Smith and Lawrence, in field corn, Zea mays L. Particular emphasis was placed on the role of host plant phenology. Overall goals were to examine the contribution of insect dispersal to the dynamics of single fields, and provide a means of examining the factors influencing insect/plant synchrony and the relationship between adult abundance, oviposition, and crop phenology. The model is process-oriented and integrates component models for corn phenology, and adult emergence, mortality, dispersal, reproductive development, and oviposition.

Comparison of field data with simulations excluding dispersal generally indicated a net emigration of beetles from corn fields on a season-long basis; however, the timing and magnitude of dispersal from fields were strongly influenced by the relative timing of corn flowering, beetle sex, and the reproductive maturity of females. Simulation and field data were used to describe and estimate the parameters of a component model for dispersal incorporating these features. Various component models and the overall system model were validated against independent field data. The model provided adequate prediction of adult emergence and crop phenology for three varieties on which it was based, but consistently underpredicted total oviposition and poorly predicted the phenology of two different corn varieties. Overall, the model accurately predicted seasonal population trends, the relative abundance of mature females, and the relationship between adult abundance and oviposition.

Adults of Arrenurus (?Micruracarus) kitchingi sp.nov. are described. This is the first species of Arrenurus to be reported from a tree-hole habitat. Problems with the currently used subgeneric classification of Arrenurus are discussed.

Larvae of Phanocelia canadensis (Banks) were found inhabiting the floating sphagnum fringe of acidic bog ponds. Phanocelia canadensis has a 1-year life cycle with autumnal emergence. This is the first morphological and biological information available for immature stages of this genus.

Drift of aquatic insects was compared at three sites downstream (21, 38, and 107 km) from methoxychlor treatment (0.3 mg. L−1 for 15 min) of the North Saskatchewan River, relative to an upstream untreated site. Species of Diptera (Simuliidae), Ephemeroptera (Baetidae, Heptageniidae, Ephemerellidae, Ametropodidae, Metretopodidae, and Tricorythidae), Plecoptera (Perlodidae and Chloroperlidae), Trichoptera (Hydropsychidae and Hydroptilidae), and Hemiptera (Corixidae) were studied. Drift responses differed depending on species, distance from the injection site, and time after methoxychlor injection. Exposure to methoxychlor initiated catastrophic drift of aquatic insects at all downstream sites. Of 22 species compared before treatment and following methoxychlor injection, post-treatment drift of 17, 21, and 13 species significantly exceeded pre-treatment drift at the km 21, 38, and 107 sites, respectively. Methoxychlor treatment initiated or increased drift of several normally non-drifting species. Similar drift patterns were observed among closely related taxa during the catastrophic phase. For all species studied, comparisons of 24-h drift densities between days preceding and following the catastrophic phase of treatment indicated significant post-treatment drift density increases or decreases at one or more of the downstream sites, but not at the untreated site. Species were classified according to their drift responses to methoxychlor treatment. Factors that may have caused different drift responses among species are discussed.

Larval performance and adult size of Chrysomela knabi Brown varied with host quality and species. Beetles reared on a low moisture diet of Salix humilis Marsh. or a novel host, S. nigra Marsh., showed reduced growth rates, survival, and adult size compared with performance on the local host, S. humilis, at high moisture. For all performance variables, beetles were least successful on the novel host. Development (hatch to pupation) was 1.2 and 3.9 days faster on the high moisture diet than on the low moisture diet or novel host, respectively. Survival (hatch to pupation) was 8 and 20% higher on the local host (high moisture) than on the low moisture diet and novel host, respectively. Weight and elytral length of newly eclosed adults showed these same trends.

Stage survival is typically calculated from estimates of numbers entering two successive life stages. We present a method that estimates stage survival by reference to the difference between directly measured recruitment to the stage and the estimate of recruitment obtained from Southwood and Jepson’s graphical technique. The method assumes mortality is constant within the stage. The method is applied to two generations (at two sites) of the egg stage of the Colorado potato beetle, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae), and the predicted stage survivals are compared, for two generations, with direct field measurements of egg mortality.

Four benzoylphenyl ureas (BPU’S) were tested on the four feeding larval instars of western spruce budworm, Choristoneura occidentalis Freeman, from a nondiapausing laboratory colony. BPU’s compared were chlorfluazuron, penfluron, triflumuron, and XRD-473 (N-(((3,5-dichloro-4-(1,1,2,2-tetrafluoroethoxy)phenyl-amino)carbonyl)-2, 6-difluorobenzymide). Although previous evidence suggested that BPU’S were generally most active on younger instars, last-instar western spruce budworm larvae were most susceptible to three of the four tested. Contour plots of estimated effectiveness during development of a western spruce budworm laboratory population indicated that the optimal time of application (lowest LC90) for XRD-473 would be ca. 16 days after the first group of larvae hatched, but the optimal time for the other three BPU’s would be between 40 and 50 days after hatch began. However, chronological age of insects in natural populations is difficult to estimate because of the influence of factors such as climatic conditions (e.g. temperature) and other ecological factors. The need to estimate optimal timing for application of BPU’s and other chemicals in terms of physiological time during population development is discussed.

The mountain pine beetle, Dendroctonus ponderosae Hopk., causes extensive mortality of lodgepole pine, Pinus contorta var. latifolia Engelm., throughout western North America (Van Sickle 1982). The Prince Rupert Forest Region, in the northwest of British Columbia, initiated an aggressive beetle management program in 1981. Logging of infested stands, and winter felling and burning of individual infested trees are the most common direct control techniques.

The “Bristol Lake” infestation developed in the Bulkley Forest District, approximately 55 km northwest of Smithers, B.C., on a steep rocky ridge within the valley of Harold Price Creek. The area contained large volumes of mature lodgepole pine, and control of the infestation was therefore considered critical to the local beetle management plan, but the size (50 ha) and rough topography of the infested area precluded normal direct control measures.

Analyses were performed on a simulation model describing the population dynamics of adult Diabrotica barberi Smith and Lawrence in field corn. Overall goals were to gain a better understanding of the dynamics of this insect/plant system and explore possibilities for improved population management. Parametric sensitivity analyses revealed that model behavior was moderately sensitive to changes in the timing of female emergence, rates of immature female dispersal at peak flower, fecundity, and rates of reproductive development. Model behavior was highly sensitive to changes in age-specific oviposition rates, and to factors determining the seasonal timing and duration of the flowering period of corn. Alteration of planting dates, variations in seasonal temperature patterns, and year-to-year variation in beetle dispersal patterns greatly affected the simulated relationship between adult abundance, oviposition, and crop phenology, and the synchronization of beetle populations with flowering corn. Factorial analyses indicated that manipulation of planting dates, variety, and the duration of the flowering period represent equivalent alternatives for reducing site-specific oviposition. Factorial analyses further suggested that the timing of emergence and dispersal, relative to flowering, are the major factors contributing to the presence of beetles during the flowering period, but their relative contributions depend on the seasonal time of flowering. The timing of emergence is more important in early-flowering fields but dispersal becomes more important for fields flowering later in the season. Simulation was used to examine the relationship between adult abundance, oviposition, and crop phenology and to formalize hypothetical improvements in current action thresholds for making recommendations for corn rootworm control based on adult sampling. Overall, analyses have allowed important insights into the behavior of this insect/plant system.

Aspects of the biology of Cystiphora sonchi (Bremi) (Diptera: Cecidomyiidae) were investigated and releases were made on perennial sow-thistle (Sonchus arvensis L.) (Compositae) in six provinces of Canada. Fecundity, determined by dissection of newly emerged females, averaged 86.2 eggs. Cystiphora sonchi became established in Alberta, Saskatchewan, Manitoba, and Nova Scotia, and produced three generations at Vegreville, Alberta. In fall, mature larvae enter the soil, and most can pupate in temperatures of 4 °C. The gall fly thrives in shady and sunny locations. Cattle caused considerable fly mortality by feeding on galled leaves of perennial sow-thistle. Extremely dry or moist soils reduced the number of adults that emerged from pupation and extremely moist soils increased the lengths of the pupation periods. Flooding caused greater mortality of pupae than of larvae but 2% of the larvae survived flooding up to 8 weeks.

Analysis of 10 years of grasshopper survey data (1978–1987) indicated that grasshopper populations in fields can be reliably predicted from roadside survey counts. Direct estimation of grasshopper densities in crop fields is no longer required for summaries of infestation levels or forecasts. Spatial autocorrelation was significant and positive for both roadside and field counts. The coefficient of variation of the field counts was greater than that of the roadside counts in each of the last 10 years. Population density was summarized by crop type and sampling method for the last 10 years. Linear regressions fitted to the 1978–1984 grasshopper survey data were used to estimate field population density from crop type and roadside counts in 1985–1987. Maps of population density were generated from the predicted and observed field counts with SPANS, a microcomputer-based geographic information system. Large coefficients of association (73–79%) between the predicted and observed maps attested to the sufficiency of road-side counts as the basis for production of population density maps.

The spatial distribution of spring and summer populations of the potato flea beetle, Epitrix cucumeris (Harris) (Coleoptera: Chrysomelidae), on potatoes (“Superior” variety) was studied in 1987 and 1988. Slopes of the regression of mean crowding on the mean number of adults per plant were not significantly different from 1.0 except for summer populations in 1988. The y-intercepts of these regression equations were not significantly different from 0, suggesting that adults of the potato flea beetle are not aggregated. The ratios of mean crowding to mean number of adults per plant were 0.81 for spring populations and 1.02 for summer populations, also indicating that the populations were not highly aggregated. With a level of precision of 0.25, 10 samples per plot were appropriate when more than 2.8 adults per plant were present in the spring and when more than 7.2 adults per plant were present in the summer.