The cabbage root maggot, Delia radicum (L.), was introduced to North America in the mid-1800s, likely from northwestern Europe, and probably reached Quebec and British Columbia before 1885 and Manitoba by 1922. The mean temperature of crystallization (Tc) for overwintering pupae was −22.8 ± 1.2 °C for the St-Jean-sur-Richelieu, Quebec, population and −23.8 ± 0.7 °C for the Vancouver, British Columbia, population. The mean Tc for these two populations and for Winnipeg, Manitoba (−24.4 °C), Ascot, England (−22.8 °C), Tallinn, Estonia (−25.2 °C), and St. Petersburg, Russia (ca. −20 °C), did not show any relation to mean January temperatures. These locations represent both temperate oceanic and temperate continental climates and a range of mean January temperatures from +4.6 to −17.7 °C. Survival of puparia from St-Jean-sur-Richelieu exposed to nonfreezing temperatures decreased as temperature decreased and exposure time lengthened. The parameters for the regression equations describing this relationship were similar to those describing the Winnipeg population, and both were more coldhardy than the Ascot population. The upper limit of the cold injury zone (ULCIZ) for the St-Jean-sur-Richelieu population was −12.7 °C and the lower limit of this zone (LLCIZ) was −27.6 °C. Coldhardy populations from temperate continental climates (St-Jean-sur-Richelieu, Winnipeg) showed a rate of decrease in survival with increased cold stress (lower temperature, longer exposure) within the cold injury zone which was much slower than in the less coldhardy population (Ascot). Thus, some individuals from the coldhardy populations would be physiologically capable of surviving exposure to temperatures below Tc, whereas in the Ascot population nonfreezing injury would kill all the overwintering puparia at a temperature (−19.6 °C) well above Tc (−22.8 °C). The observed survival of puparia from Vancouver, following various nonfreezing exposures, resembled more closely the calculated survival for these exposures when the equations describing the Ascot population were used than when the equations for Winnipeg or St-Jean-sur-Richelieu were used. The Ascot and Vancouver populations, both from temperate oceanic climates, are less coldhardy than the populations from St-Jean-sur-Richelieu and Winnipeg (temperate continental climates). The founder populations of D. radicum in North America, which probably originated in the temperate oceanic climates of northwestern Europe, have adapted to the colder temperate continental climates by increasing their ability to survive longer exposures to all temperatures within the cold injury zone and not by lowering Tc. Therefore, selection for coldhardiness in D. radicum must have operated on structures, processes, or physiological-biochemical mechanisms that help the organism to avoid or repair nonfreezing cold injury but not on those that determine Tc.

Dung beetles (Scarabaeidae) were pitfall trapped at two sites in southern Alberta from 1993 to 1995. A 3-year total of 156 500 specimens representing 17 species was collected. Local assemblages were dominated, in descending order, by the exotic species Onthophagus nuchicornis (Linné), Aphodius prodromus (Brahm), Aphodius distinctus (O.F. Müller), and Aphodius fimetarius (Linné). Aphodius vittatus Say was the most common native species. Although adults were collected from mid-March to mid-November, the activity of individual species either peaked in the spring and again in the fall, or peaked once in spring to midsummer. Maps showing the Canadian distributions for 15 of these species were compiled from examination of collections and published records and identify 10 new provincial records. Most distributions are transcontinental, with the distribution of O. nuchicornis likely expanding only in the last 20–30 years to include Alberta and Saskatchewan. Aphodius erraticus (Linné) and Aphodius ruricola Melsheimer have not been previously reported from British Columbia. Aphodius pinguellus W.J. Brown, Canthon praticola LeConte, and Aphodius coloradensis Horn are restricted to western Canada.

A specially constructed fence was developed to exclude cabbage flies, Delia radicum (L.), from plantings of rutabaga. The number of first-flight female D. radicum caught on traps inside fenced enclosures declined linearly with fence height from 0 to 90 cm. Females caught in plots surrounded by a 90 cm high fence were 80.6 and 82.8% fewer than in open check plots in 1991 and 1992, respectively. The percentage of transplanted rutabagas killed by cabbage maggot in the 90 cm high enclosures was 1.4% in 1991 and 25.5% in 1992, compared with 11.8 and 84.5% in the open check plots, respectively. The mean damage index rating for rutabagas was severe in the open check plots but slight in the 90 cm high enclosures in 1991. Only 1.2% of rutabagas in the open check plots would have been of marketable grade in 1991, compared with 54% in the 90-cm enclosures. The mean damage rating was highest in the open check plots in 1992, but damage was also severe in all fenced plots due to the heavy infestation levels that year. The potential of exclusion fences for use in pest-management programs for rutabagas and other brassica crops is discussed.

The influence of diet on oviposition and survival of Forficula senegalensis Serville was studied in laboratory conditions using four different regimens: millet leaves and stems, lepidopteran eggs and larvae, millet pollen, and no food at all. Four parameters were monitored: female weight, survival time, time to oviposition, and number of eggs produced. Starving females and females fed millet leaves and stems lost weight and survived for an average of 30–40 days without any of them laying eggs. Females fed millet pollen or lepidopteran eggs and larvae gained weight and survived for more than 60 days. Forty percent of the females fed pollen laid an average of 49 eggs the first time, and 50% of those fed lepidopteran eggs and larvae produced an average of 67.5 eggs. In both cases, less than 2% of the females oviposited a second time (average of 30 eggs). Earwigs fed lepidopteran eggs and larvae oviposited sooner. A diet of millet leaves is insufficient for oviposition in F. senegalensis; females need a richer diet based on pollen or animal preys in order to lay eggs.

The effects of various diets composed of millet leaves and stems, millet anthers, and animal prey on the development of Forficula senegalensis Serville were studied in the laboratory using mortality, duration of development, and weight at eclosion and at imaginal moult as comparative parameters. A diet of millet leaves and stems did not allow larvae to reach the adult stage. A diet of millet anthers allowed the production of adults, but with high mortality. When fed animal prey, the larvae developed adequately into adults, but with the mixed diet (prey and millet anthers) development was more rapid and the weight of the adults produced was greater. Millet leaves are probably not an important part of larval earwigs diet in their natural environment. They do, however, eat millet anthers and they may also feed on the insect fauna that lives on millet.

Eggs, larvae, and adults of diamondback moth, Plutella xylostella (L.), and imported cabbageworm, Artogeia rapae (L.), were monitored on cabbage, broccoli, and brussels sprouts [Brassica oleracea (L.) var. capitata, italica, and gemmifera] for 2 years in southwestern Quebec. The first eggs and adults of P. xylostella were observed during the first week of June, and the use of pheromone traps combined with plant sampling permitted detection of three to four generations on each cultivar type. However, adult counts in pheromone traps were not correlated with the number of eggs and larvae on plants. The date at which each generation appeared and their duration varied little between the three Brassica cultivars. An average of 352.7 degree-days (DD) above 7.3 °C were required to complete one generation, but the considerable overlap between generations reduced the usefulness of DD accumulations to predict P. xylostella occurrence. Visual counts of adult A. rapae and plant sampling of eggs and larvae permitted detection of three generations of this species on each cultivar type. The first A. rapae eggs were found during the last week of May, at least 2 weeks before adults were observed. However, butterfly counts were generally correlated with the number of larvae on plants. The dates at which each generation of A. rapae started were similar between cultivar types, and an average of 319.7 DD above 10.0 °C was required to complete one generation.

Residual and contact toxicities of several insecticides to larvae and adults of insecticide-susceptible (four insecticides) and insecticide-resistant (three insecticides) Colorado potato beetle, Leptinotarsa decemlineata (Say), were measured in laboratory studies. For both methods of exposure, azinphosmethyl was the least toxic to all life stages tested. The residual toxicity of deltamethrin was at least 4.4-fold higher than either cypermethrin or endosulfan. With the insecticide-susceptible strain, residual toxicities of azinphosmethyl, endosulfan, and deltamethrin were, respectively, 3.5, 5.9, and 4.1 times higher to first instars than to adults and 1.2, 8.1, and 1.6 times higher to third instars than to adults. Contact toxicities of azinphosmethyl, endosulfan, and deltamethrin were, respectively, 3.3, 2.9, and 1.4 times higher to insecticide-susceptible third instars than to adults. In most comparisons, susceptibilities of fourth and third instars were similar. With the insecticide-resistant strain, azinphosmethyl, endosulfan, and deltamethrin were, respectively, 3.2, 1.6, and 8.0 times more toxic to third instars than to adults. The importance of differential life stage toxicity to current control recommendations for Colorado potato beetle is discussed.

Two new species of Isotogastrura, one from the Pacific coast and one from the Atlantic coast, are described: Isotogastrura ahuizotli sp.nov. and Isotogastrura veracruzana sp.nov. A key for the five species known at present is included.

Reproductive processes in female Pissodes strobi (Peck) fed with a 5% ground bark artificial diet following summer emergence were studied. Females exposed to different temperature and photoperiod regimes were dissected every other week and their reproductive organs were observed to evaluate the maturation time according to the treatments. After 12 weeks, half the females were transferred onto lateral branch sections of white pine and the other half onto artificial diet supplemented with 10% ground bark of white pine, and their realized fecundity was determined. During the first 12 weeks, ovary development was detected but very few mature oocytes were found. No significant differences were observed for the maturation times between the different abiotic conditions used, but significant differences were observed in female egg-laying response on natural and artificial diets. Females that completed their sexual maturation at 24 °C and 16L: 8D laid over a 3-week period 14.4 ± 8.8 (mean ± SE) and 2.6 ± 2.6 eggs per female on white pine sections and artificial diet, respectively. Oviposition behaviour was compared with results from an earlier experiment conducted with spring-emerging white pine weevils on natural and artificial substrates. The egg-laying responses on white pine seedlings and on an artificial diet with a concentration of 15% ground white pine bark were 0.892 ± 0.124 and 0.171 ± 0.394 eggs per female per day, respectively.

We carried out a 2-year study to elucidate the biology of the gregarious, idiobiont ectoparasitoid Elachertus cacoeciae (Howard) by placing (implanting) laboratory-reared spruce budworm larvae [Choristoneura fumiferana (Clemens)] on current-year balsam fir (Abies balsamea L.) shoots in the field, simulating low (endemic) densities of the budworm. Spring female E. cacoeciae attacked fourth-, fifth-, and sixth-instar budworm larvae, beginning near the predicted peak of the fourth instar and ending about 10–12 days after the predicted peak of the pupal stage of the wild budworm population. The mean (±SE) brood size of spring females was 2.9 ± 0.3 E. cacoeciae pupae per host. The proportion of females increased during the season, with many broods consisting of 100% females late in the season. In 1994 and 1995, the mean proportion of females was 0.74 ± 0.05 and 0.79 ± 0.05, respectively. In the laboratory, development time from eggs to adults was approximately 20 days at 20.6 °C. Adult males provided with honey water lived 43.6 ± 3.2 days, whereas females provided with hosts and honey water lived 90.1 ± 6.6 days. Spring females had a pre-oviposition period of 11.5 ± 1.3 days, resulting in a generation time (egg to egg) of ~31 days. The oviposition period lasted 76.3 ± 7.7 days during which time spring females parasitized 19.2 ± 1.9 hosts, and produced a clutch size of 4.9 ± 0.4 eggs per host, for a lifetime fecundity of 96.8 ± 14.7 eggs. The post-oviposition period was 18.5 ± 3.7 days. Throughout their lifetime, spring females host fed only (host feeding without oviposition) on an additional 9.3 ± 1.9 hosts. Approximately 2% of pupae developing from spring females overwintered, whereas approximately 95% of pupae developing from summer females overwintered. Laboratory results for summer females suggest that they may be adapted to parasitizing alternate host(s) rather than spruce budworm.

The field attractivity of (E,Z)-2,13-octadecadienyl acetate (E,Z-2,13-18:OAc) (30 μg loaded on red rubber tubing) alone or in combination with (E,Z)-3,13-octadecadienyl acetate (E,Z-3,13-18:OAc) (0.9 μg added) towards the male currant borer, Synanthedon tipuliformis Cl., (Lepidoptora: Sesiidae), was compared in British Columbia (B.C.) and in Quebec (Canada) by means of trapping trial. The binary mixture attracted males in significantly higher numbers into sticky traps than E,Z-13-18:OAc alone [17.0 male captures/trap/inspection versus 1.7 in Langley (B.C.), 32.7 versus 11.9 in De Roche (B.C.), and 5.3 versus 0.2 in Ile d’Orleans (Que.), respectively]. These results suggest that the Canadian currant borer populations belong to the same strain as those in Europe and New Zealand, with E,Z-3,13-18:OAc remaining an important attractant-synergistic component.

Feeding damage by the crucifer flea beetle, Phyllotreta cruciferae (Goeze), was assessed on 51 accessions of false flax, Camelina sativa L., and compared with damage to seven other crucifer species. Three experiments were conducted on seedlings in laboratory arenas infested with field-collected beetles. Feeding damage was estimated visually at daily intervals for up to 7 days. Natural infestation of false flax and other crucifers was observed in the field. Flea beetles fed little (0–10% consumption) on cotyledons or true leaves of any of the false flax accessions, and fed more (59–100% consumption) on the other crucifers. Flea beetles were observed sitting on false flax in the field, sometimes in high numbers, but they did not feed. In the laboratory, beetles eventually fed on cotyledons and leaves and once feeding was initiated, it tended to continue. Resistance in false flax may result from the absence of cues that initiate feeding, rather than a feeding deterrent. The high level of resistance in false flax would likely be economically beneficial if this species is developed as an oilseed crop. False flax could also be useful experimentally for identifying the cues that attract flea beetles to plants and stimulate their feeding.

The crucifer flea beetle, Phyllotreta cruciferae (Goeze), feeds primarily on plants in the Brassicaceae (Cruciferae) (Feeny et al. 1970). Introduced from Europe, it is now a widespread pest of canola, Brassica napus L. and Brassica rapa L., in North America (Lamb and Turnock 1982; Weiss et al. 1991). Before canola occupied so much crop land in western Canada, flea beetles were present and presumably fed mostly on wild crucifers. These native and weedy crucifers are potential sources of resistance genes that might be transferred to canola. We examine feeding preferences of flea beetles among nine wild crucifers (Table 1) to determine which, if any, are avoided. The suitability of these plants has already been examined for another crucifer-feeding chrysomelid, the red turnip beetle, Entomoscelis americana Brown (Gerber and Obadofin 1981; Gerber 1984), and the feeding responses of the beetles are compared.

The eastern spruce budwonn, Choristoneuva fumiferana (Clem.) (Lepidoptera: Tortricidae), is subject to a variety of naturally occurring infectious diseases including nuclear polyhedrosis virus (NPV), granulosis virus (GV), cytoplasmic virus (CPV), and entomopox virus (EPV), of which the most intensively studied is NPV (CfMNPV) (Cunningham 1985). If CfMNPV is ever to be deemed an effective and economical alternative to chemical pesticides for spruce budworm control, additional research is required.