The weevils Hylobius radicis Buchanan and Hylobius pales (Herbst) survived to adulthood more frequently, developed more rapidly, and weighed more as adults when reared on diet containing ground phloem from Scots pine, Pinus sylvestris L., or red pine, Pinus resinosa Aiton, than from jack pine, Pinus banksiana Lamb., or eastern white pine, Pinus strobus L. In feeding tests, both weevils preferred Scots pine, although jack pine was preferred over red and white pine. When reared on diets containing phloem from red pines which had received various amounts of nitrogenous fertilizer, H. radicis and H. pales performed significantly better at elevated concentrations of nitrogen. Hylobius radicis adults exhibited a feeding preference for twigs from red pines containing elevated nitrogen concentrations.

A systematic review was conducted for the Cicindela sexguttata group taxa. Comparative methods of examination were applied to adult structural and ecological characters for purposes of taxa diagnoses, and to establish a basis for the derivation of the group’s history.Based on 13 adult exoskeletal characters and 25 tests on populations throughout the group’s geographical range, a discriminant analysis identifies the most significant characters as being elytral maculation, body size, pilosity of the stipes, and number of sensory setae on the antennal scape. In addition, selected characters of the male and female genitalia are shown to identify all taxa within the group. Among biological comparisons the different number of mature eggs found in adult females of C. sexguttata Fabricius and C. denikei Brown indicates that their fecundity differs; and the larval burrow of C. denikei opens directly beneath rocks and stones, a habit unique in Cicindela. Seasonality profiles of taxa appear to be dictated by geographical location, and by phylogeny to a smaller degree. Species–soils associations indicate that C. sexguttata has a strong affinity to warm, moist and loamy soils, but C. denikei is correlated with sandy, silty till. For all species of the group, habitats occupied and limits of distribution to eastern Canada and the United States appear to be governed by soil and forest types.Three species of the group are recognized: C. sexguttata consisting of geographical populations varying considerably in adult characteristics and the problematic form C. harrisii Leng which may be considered a cryptic species; C. denikei; and C. patruela Dejean consisting of two subspecies C. p. patruela and C. p. consentanea Dejean.A reconstructed phylogeny of the C. sexguttata group based on methods of Hennig (1966) allies C. sexguttata and C. denikei as sister species, and C. patruela as an earlier lineage. Recognized as a stem group of the C. purpurea complex, the C. sexguttata group is postulated to have had its origins in forested eastern North America during the Late Miocene. Speciations of C. patruela and lineage C. sexguttata – C. denikei are perceived to have occurred in the Pliocene, followed by speciations of C. sexguttata and C. denikei in the Late Pleistocene effected by continental ice mass advances and recessions.

Use of gerrids (Hemiptera: Gerridae) as primary hosts by the solitary egg parasitoid Lathromeroidea sp.nov. is established and parasitoid reproductive behaviour is described. Four species of Limnoporus (L. dissortis Drake and Harris, L. notabilis Drake and Hottes, L. rufoscutellatus Latreille, and L. esakii Miyamoto) and two of Gerris (G. buenoi Kirkaldy and G. pingreensis Drake and Hottes) were successfully parasitized in the laboratory. A greater proportion of wasps eclosed successfully from eggs of Gerris than from Limnoporus. Host size was directly proportional to both weight and body length of adult parasitoids. Sex ratios were female-biased, with males emerging before females.

A simple, inexpensive, permanent method for individually marking Colorado potato beetle is presented. The method consists of puncturing the elytra within the cream-colored longitudinal bands using a minuten nadeln; the wound response produces intense melanization at the point of puncture. Division of a band into three zones, each potentially receiving a dot, produces an octal digit. If all eight bands are employed, more than 16 million beetles can be uniquely marked. No significant survival effects of marking were seen in teneral, post-teneral, or post-diapause adult beetles. Propensity to fly in mid-summer beetles was generally unaffected by marking. Probabilities of mismarking and misreading are negligible if sufficient care is employed.

The variation in response to fungal inoculation and sterile wounding within and among Pinus taeda L. was evaluated. The mean fungal-induced lesion size among the 20 trees sampled was 105.8 mm (coefficient of variation of 49.19), compared with a mean lesion size of 19.4 mm (coefficient of variation of 36.40) for the sterile control treatment. Mean lesion size for the fungal inoculation of individual trees ranged from 61 to 192 mm with a range in variances from 10 368.48 to 166.64, and the mean lesion size produced in response to sterile wounding varied from 16 to 26 mm with a range in variances from 254.28 to 0.35. The variance in response to the fungal treatment was on average 16.39-fold greater than the mean compared with only 1.97-fold greater than the mean for the control. There was no relationship between size of responses to either treatment and the position of the sample site on the tree. We suggest that intra-tree variation of the kind demonstrated in earlier studies for the chemical constituents and for physical size of the tree response to invasion may make it very difficult for arriving beetles to assess actual tree susceptibility or suitability for colonization. This may be critical as a component of tree defense in this system where successful reproduction by the insect is dependent on death of the host tree.

Populations of the lesser clover leaf weevil, Hypera nigrirostris (Fabr.), on red clover, Trifolium pratense L., in northeastern Saskatchewan were sampled weekly from May to August 1986 and 1987. Adults overwintered in red clover fields, and began to feed, mate, and oviposit in late April and early May. Eggs were laid subepidermally in stipules, shoots, and leaves from early May to mid-July. Larvae were located on red clover stipules, buds, and fiowerheads and developed through four instars Larvae were collected from early June until mid-August. Spatial distributions of eggs and larvae were aggregated, though the degree of aggregation decreased with succeeding developmental stages. Pupae were collected on shoots and in debris from late June until August. New-season adults first occurred in mid-July; large increases in adult densities corresponded to the appearance of these adults.

Five cycles of single-plant and progeny-row selection in lines derived from Brassica rapa L. "Tobin" were used to identify plants with incomplete resistance to flea beetles, Phyllotreta cruciferae (Goeze). This line, called C8711, had higher survival, grew larger, and yielded more seed than Tobin when the two lines were compared in field plots at Glenlea, Manitoba, unprotected by insecticide. C8711 without insecticide yielded more seed than Tobin treated with a lindane seed dressing, but less than Tobin treated with carbofuran granules. With carbofuran, which prevents most flea beetle damage, the yield of C8711 was 35% higher than for Tobin. At Saskatoon, Saskatchewan, the differences between C8711 and Tobin were not statistically significant, although the trends were similar to those at Glenlea. C8711 was late maturing, produced small seed, and was not of canola quality. The resistance in C8711 is attributed to a low level of antixenosis, rapid growth at the cotyledon stage, and tolerance to damage during the first 3–4 weeks of growth.

A seasonal light-trapping study of Culicoides species, in particular C. obsoletus Meigen, was conducted in the Fraser Valley of British Columbia to determine seasonal peaks and first and last appearance of these insects. Culicoides obsoletus is the causal agent of Culicoides Hypersensitivity (CH), an allergic dermatitis in horses, in British Columbia. Trapping at two sites in 1987 showed that C. obsoletus was first trapped in late March, and peaked in early May and again in late June. Small numbers were collected into mid-November. This coincided with the appearance and regression of clinical signs associated with CH in horses in the area. Stabling horses during the peak activity of Culicoides spp. has been recommended to prevent the development of CH. Light-trapping Culicoides both inside and outside stables showed that although fewer insects were caught inside, some (6%) were trapped indoors. A horse kept in an unscreened stable will not be protected from being bitten.

Rhyzopertha dominica (F.) (lesser grain borer, Coleoptera: Bostrichidae) is a major pest of stored grain in the United States, Australia, and most other warm regions of the world. It has rarely been detected in Canadian grain, until recently. To determine the distribution of/R. dominica in western Canada, Lindgren multiple-funnel traps baited with R. dominica aggregation pheromones were placed near grain elevators, feed mills, and farms. Rhyzopertha dominica was found flying outside grain-handling facilities in all Prairie Provinces in 1990 and 1991, with thousands collected in Manitoba, hundreds in Alberta, and less than 100 in Saskatchewan. A few R. dominica were caught in Vancouver and Thunder Bay. None were caught in the traps placed beside two grain elevators in southern Ontario. In Alberta and Saskatchewan, the locations with R. dominica were mainly in the south. In Manitoba, the total number of R. dominica caught at each location was higher in the south than in the north. Rhyzopertha dominica were caught as early as 15 May and as late as 18 September, with the peak numbers for a given location occurring between July and September. No difference in the total number of R. dominica caught per year was found among farms, feed mills, or grain elevators in 1990 or 1991. Sampling of stored grain on three farms showed that two of the eight bins sampled had R. dominica. The possible origins of the R. dominica (importation of infested grain, wind-borne migration from the United States, or an established Canadian population) are discussed.

The distribution of feeding damage by adult Phyllotreta cruciferae (Goeze) was examined on the cotyledons, first true leaves, stems, and petioles of four crop species of Brassicaceae (Brassica juncea L. "Cutlass", B. napus L. "Westar", B. rapa L. "Tobin", and Sinapis alba L. "Ochre"). Previous studies showed that B. napus and B. rapa are susceptible, B. juncea is partially resistant, and S. alba is highly resistant to P. cruciferae. Flea beetles usually fed more on the upper surfaces, bases, and edges of cotyledons and first true leaves, but the feeding patterns were not identical on the four species. Phyllotreta cruciferae had a greater preference for the upper surface of S. alba cotyledons than for the upper surfaces of Brassica species. First true leaves of B. napus had over 90% of the feeding damage along the edge, compared with < 70% for the other species. The size of feeding pits did not differ on the upper and lower surfaces of the cotyledons and first true leaves for the Brassica species, but S. alba had smaller feeding pits on the lower surface. Sinapis alba also had the smallest feeding pits on the upper surface of its cotyledons, and S. alba and B. juncea first true leaves had feeding pits about one-half the size of the feeding pits on the other species. There was no significant difference in the amount of stem damage for the four species, but B. juncea had significantly less petiole damage than S. alba. Although there were differences in the way P. cruciferae exploited the seedling tissues of these Brassicaceae, the differences were not consistent with, or were too small to account for, the different levels of resistance of the four crops.

During an outbreak of army cutworm in southern Alberta in the spring of 1990, the overall incidence of parasitism by the polyembryonic parasitoid, Copidosoma bakeri (Howard), was 61% in samples from seven fields. The incidence of parasitism in samples of army cutworms collected on five dates from a single location, during the spring of 1991, increased from about 20% in the early samples to about 50% in the later samples. Cutworms parasitized by C. bakeri feed for a longer time than unparasitized ones; therefore estimates of the incidence of parasitism by C. bakeri, based on samples of late-instar cutworms, are misleadingly high. Parasitized cutworms also grow considerably larger than unparasitized ones and may have a supernumerary instar. Larger hosts support larger broods of C. bakeri and apparently a successful strategy of C. bakeri is to prolong host development so as to maximize an acquired resource. Because cutworms parasitized by C. bakeri feed more and longer than unparasitized cutworms, a high rate of parasitism can exacerbate crop damage and complicate control recommendations. The life cycles of army cutworm and C. bakeri are asynchronous and it is likely that high rates of parasitism are dependent on the presence of intermediary hosts.

Three emergence trap designs were evaluated for effectiveness in collecting adult Frankliniella bispinosa (Morgan) (Thysanoptera: Thripidae) from beneath and between citrus trees in Florida. Trap A [a wooden-frame 30- by 30-cm (= 900 cm2) square trap with removable Plexiglas® lid coated with Tangle-Trap® adhesive] was effective in trapping F. bispinosa adults whereas trap B [a polyvinylchloride (PVC) round trap with a centered 3.7-mL capacity shell vial] was ineffective. Trap A was as effective in collecting emerging F. bispinosa adults as trap C [a PVC round trap with a 30-cm-diameter (= 706.5 cm2) removable adhesive-coated Plexiglas lid]. Comparative costs for trap construction, maintenance, and insect counting are all higher for trap A compared with trap C. Trap placement beneath citrus trees 15 cm from the trunk or just inside the dripline of the canopy provided similar thrips catches in two citrus grove sites. Both interior and dripline trap positions beneath "navel" orange trees had significantly higher numbers of F. bispinosa than did traps exposed within rows between these trees.

The ambrosia beetle Gnathotrichus retusus (LeConte) (Coleoptera: Scolytidae) is primarily univoltine. The development of brood from eggs to adult took a minimum of 40 days in Douglas-fir logs. Brood production was proportional to gallery length. Boring activities shifted from shallow sapwood to deep sapwood over time. Gallery abandonments were mainly made by females on warm days in June and July.Gnathotrichus retusus can use both Douglas-fir and western hemlock stumps equally well for brood production. Brood emergence began in late April, peaked in late May, and ceased, with rare exceptions, in late June. The seasonal flight began in late April and had one major peak in June, with occasional catches through October when the weekly mean maximum temperature dropped below 15 °C. Brood emergence, seasonal flight, and the sex ratios of captured beetles varied with temperature. Diurnal flight showed a small peak in morning and a large peak at dusk, probably entrained mainly by light intensity and also influenced by temperature and relative humidity.

Initially, fenvalerate and permethrin tags at two tags per animal and one tag for every other animal nearly eliminated horn flies [Haematobia irritons (L.)] at Glenlea Research Station, Manitoba. However, fly numbers increased 8 weeks post-treatment in 1987 and 6 weeks post-treatment in 1988. LC50 values of the flies to fenvalerate and permethrin increased toward the end of each season but the slope of regression lines decreased in 1987. In 1988, initial LC50 values were lower compared with those observed at the end of the 1987 season. When tags were applied in 1988, LC50 values increased from 0.42 to 3.14 μg per cm2 for fenvalerate and from 2.06 to 10.76 μg per cm2 for permethrin. Mortality observed at discriminating concentrations of fenvalerate (0.625 μg per cm2) and permethrin (5 μg per cm2) during the season decreased from 67.9 to 2.8% and from 66.8 to 5.7%, respectively. Cattle at Glenlea and in a second herd at Libau were not treated in 1989; susceptibility of flies resistant to pyrethroids did not change significantly during the season in these herds. Discontinuing use of pyrethroid-impregnated ear tags for one season was not long enough for substantial reduction in resistance to occur.

The amount of wax on leaf surfaces was determined for waxy and low-wax phenotypes of three Brassica crops: oilseed rape, kale, and collards. The effects of these phenotypes were assessed on the fecundity, settling time, and biomass increase of the mustard aphid, Lipaphis erysimi (Kaltenbach), a pest of oilseed rape. Leaves of the waxy phenotype of each Brassica had about twice as much wax as the low-wax phenotype, but the amount of wax had no effect on any of the three measures of aphid performance. Lipaphis erysimi was more fecund and produced a higher biomass on the rape than on the collards, but settled more quickly on the collards than on rape. If the waxiness of oilseed rape is altered to increase crop resistance to other pests, the pest status of L. erysimi is unlikely to be affected.

Mites of 10 genera and one undescribed taxon of Pyemotidae were found on specimens of 10 genera of beetles of farm-stored grain or grain residues. Four species of the mites are known to be associated with stored products. Almost 10% of beetles carried mites. Most of the mites were found on the abdominal tergites, under the wings of the beetles, but Tarsonemus spp. were found on external surfaces of beetles. Hypopi of Acarus farris (Ouds.) are recorded for the first time as subelytral phoronts of grain beetles. Mites can occasionally be found in fungal mycelia attached to beetles.

Epizootiological studies of a Nosema sp. in field populations of the grasshopper Chorthippus curtipennis (Harris) were conducted in Madison County, Montana. The average density and percentage prevalence for each modal stage are reported for two sites from 1986 through 1990. Alternating high and low densities of C. curtipennis were observed during even and odd years, respectively. Prevalence of Nosema in C. curtipennis during a high density year was characterized by an increase in prevalence during nymphal development. Furthermore, prevalence of Nosema in C. curtipennis was positively related to host density, suggesting some form of density-dependent transmission.

Lygus species were sampled from alfalfa and canola fields in Manitoba from 1988 to 1990. Lygus lineolaris (Palisot de Beauvois), L. borealis (Knight), and L. elisus (Van Duzee) were found consistently throughout the agricultural area. The relative abundance of these species varied among crops, physiographic regions, years, and date of collection. The most abundant species in alfalfa and canola fields tended to be L. borealis in the north and west, L. elisus in the south, and L. lineolaris in the east. Each of the species was the most abundant in some collections, however L. borealis tended to be more abundant in alfalfa and L. lineolaris and L. elisus in canola. First-generation nymphs of Lygus species were found on alfalfa and those of the second generation on canola.

North American members of the Oreodyies alaskanus clade are revised. The species O. productotruncatus (Hatch) and O. recticollis (Fall) are recognized as valid and those names are removed from junior synonymy with O. alaskanus (Fall.). Oreodytes leechi Zimmerman is considered a new junior subjective synonym of O. recticollis. Lectotype designations are provided for O. alaskanus and O. recticollis. Palaearctic O. dauricus (Motschulsky) is included within the O. alaskanus clade whose members are characterized by the protibia having the inner margin sinuate and strongly narrowed proximally, Oreodytes kanoi Kamiya, from Japan, is suggested as the sister-group of members of the O. alaskanus clade based on the shared presence in the female of a last abdominal sternite with an emargination at the apex.

Patterns of locomotion of arctiid caterpillars, Diacrisia virginica Fabr., deprived of all external chemosensory organs were recorded in a field where there was patchy distribution of two of the most favored food plants, Plantago major L. and Taraxacum officinale Walker, on a background of grass and mixed forbs. Each track traced in the field was retraced on a digitizing tablet from its point of origin in the center of a circle of 30 cm radius to the circumference. The length of the path was a measure of tortuosity. The patterns of paths followed by normal, antennectomized, maxillectomized, and antennectomized + maxillectomized larvae were compared. No differences in meander were found. The ability of larvae of each class to locate, discriminate among, and feed upon food plants was tested in field-plot tests and cafeteria tests. Different degrees of chemosensory deprivation did not affect ability to locate and begin feeding on plants but did impair ability to discriminate among species. Execution of normal patterns of meandering by chemosensorily deprived larvae and successful encounters with food plants support the hypothesis that food-related search behavior by this species of caterpillar is neither initiated nor steered by chemical stimuli provided by food plants.