We describe the morphology of the alimentary canal in adult Acalymma vittata (F.), the vector of Erwinia tracheiphila (Smith) Bergey et al. emend. Hauben et al. (Enterobacteriaceae), the causal agent of bacterial wilt in cucurbits (Cucurbitaceae). The foregut includes a pre-oral cavity, pharynx, oesophagus, and crop but lacks a well-developed proventriculus. The midgut occupies approximately 65% of the length of the gut, has distinctive ventricular crypts throughout its length, and is lined with a peritrophic membrane, but lacks caeca for harboring symbionts. The hindgut comprises the colon and rectum and four Malpighian tubules. The cuticular intima of both foregut and hindgut bears rows of spines and is thrown into numerous folds. Transmission electron microscopy showed bacteria resembling E. tracheiphila within the hindgut 1 and 30 d after the beetles fed on E. tracheiphila spread between cotyledons of cucumber, Cucumis sativus L. (Cucurbitaceae). Our observations suggest that the midgut is not appropriate for long-term retention of E. tracheiphila because of the absence of caeca and the presence of a peritrophic membrane. Temporary and long-term pathogen retention may be associated with rows of spines and numerous folds within the foregut and hindgut.

The preferred host of the cluster fly, Pollenia rudis Fab., in Ontario is reported to be the earthworm Eisenia rosea Sav. Periodic field digging revealed the immature stages of P. rudis feeding, or in close association with, E. rosea. In addition P. rudis was reared in the laboratory on E. rosea but could not be reared on any of the other species of earthworm found in the field.For the first time in North America the complete life history, along with each of the immature stages of P. rudis, is described. The differences between P. rudis from North America and those from France are indicated.Finally, the authors speculate that there are two strains, or species, of P. rudis in France: one is host-specific to the earthworm Allolobophora chlorotica Sav. and the other to E. rosea. Only the strain with E. rosea as its preferred host has as yet been reported from Canada.

In a survey of predaceous phytoseiid mites from 65 apple blocks in the Hood River Valley, Oregon, Metaseiulus occidentalis (Nesbitt) and Typhlodromus pyri Scheuten were the principal species present. Metaseiulus occidentalis predominated over T. pyri by a ratio of about 2:1 in 1984 mites collected during 1985. In experimental, commercial, and integrated pest management blocks, M. occidentalis was present alone or predominated over T. pyri in up to 88% of the blocks, whereas T. pyri occurred alone or predominated in up to 20% of the blocks. Both species occurred in near equal proportions in a maximum of 20% of blocks. An analysis of nine factors influencing the relative abundance of M. occidentalis and T. pyri indicated that vegetation in the habitat surrounding the block and the pesticides used were most important. In 1986, seasonal distributions and proportions of predatory mites found in individual blocks were similar to those found in 1985. The feasibility of managing mixed populations of T. pyri and M. occidentalis in Hood River orchards is discussed.

The gall fly Urophora cardui (L.) (Diptera: Tephritidae), native to Europe, was released at 24 locations across Canada beginning in 1974. It became established in Ontario, Quebec, and New Brunswick but died out in all but one location in western Canada. Evidence for winter mortality in the west does not explain the failure of these colonies. Although galls, in particular those on the main shoot, reduce the height of Canada thistle, so far the impact on the host weed, Canada thistle (Cirsium arvense) (L.) Scop., is slight.

Ceutorhynchus litura (F.) laid an average of 123 eggs per female. Development from egg to adult took about 6 weeks at room temperature, followed by an obligatory diapause of 3–4 months. In laboratory rearings a maximum of only an 8-fold increase over the original breeding stock was achieved in one generation. The weevil was released against the weed Canada thistle (Cirsium arvense (L.) Scop.) near Belleville, Ont., in 1967. Near the centre of the release site on about 400 m2, thistle shoots have decreased to 4% of their former density of about 3–7 shoots per 0.25 m2. Circumstantial evidence indicates that the weevil aided in the spread of thistle rust Puccinia punctiformis (Str.) Rohl.

Adult Trichoptera of 39 species representing 11 families were collected from 4 emergence traps in Oak Creek, Corvallis, Ore., between May 1968 and December 1970. Glossosomatidae and Limnephilidae were the most abundant families, but Rhyacophilidae was represented by the most species. Relative abundance, seasonal occurrence, sex ratios, and ecological segregation of related species are discussed.

Adelges cooleyi (Gill.) causes galls on spruce in the forests and on shelter-belt and shade-tree plantings in Alberta. The alternate host is Douglas fir, on which the injury is less conspicuous. The tree species affected are white spruce, Picea glauca (Moench) Voss, Engelmann spruce, P. engelmanni Parry, and blue Douglas fir, Pseudotsuga menziesii (Mirb.) Franco. A. cooleyi is indigenous to North America.

Thirty-five species of Latridiidae are reported in Atlantic Canada as a whole, 17 in New Brunswick, 14 in Newfoundland, 31 in Nova Scotia, and 14 on Prince Edward Island. Fifty-six new provincial records are reported (11 in New Brunswick, 9 in Newfoundland, 23 in Nova Scotia, 13 in Prince Edward Island). Twenty-two species are newly recorded for Atlantic Canada. Of these, Cartodere (Aridius) bifasciata (Reitter), Enicmus histrio Joy and Tomlin, Latridius consimilis (Mannerheim), Corticaria elongata (Gyllenhal), C. impressa (Olivier), C. saginata Mannerheim, Corticarina longipennis (LeConte), Melanophthalma helvola Motschulsky, and M. inermis Motschulsky are newly recorded in Canada, and C. bifasciata, E. histrio, and C. saginata are newly recorded in North America. Dienerella filiformis (Gyllenhal) is removed from the New Brunswick and Prince Edward Island lists. Corticaria dentigera LeConte is removed from the Labrador and Atlantic Provinces lists. Melanophthalma inculta Motschulsky syn. nov. and M. signata Belon syn. nov. are designated as a junior synonyms of M. inermis Motschulsky and M. picta (LeConte), respectively. Melanophthalma helvola Motschulsky is reinstated as a valid species. Lectotypes and paralectotypes of M. helvola and M. americana (Mannerheim) are designated. Approximately half of the species are adventive (16 Palaearctic, 1 Australian) and half are native (13 Nearctic, 3 Holarctic). Two species are of uncertain zoogeographic status. Although some species are synanthropic, several have colonized native habitats. Nova Scotia has the largest number of adventive species, probably as a result of trans-Atlantic shipping. New Brunswick has the fewest, at least in part because of insufficient collecting there. Early detection dates and introduction processes are discussed. The native faunas on Prince Edward Island, Cape Breton Island, and Newfoundland appear diminished (33%–40%) compared with those of the neighbouring mainland. Although all latridiids are mycetophagous, many in the region show clear habitat preferences; however, the ecological role of those species requires further investigation.

The dogwood borer, Synanthedon scitula (Harris), is a relatively new pest problem on apples. Larvae feed principally in burr knots on the above-ground portion of clonal rootstocks. According to a survey of 33 orchards on dwarf or semidwarf apple root-stocks, about 70% of the trees had burr knots. The tendency to develop burr knots was similar among the rootstocks examined in this survey. The proportion of trees infested with dogwood borer in an orchard ranged from 0 to 100% and averaged 30%. The dogwood borer overwinters in the larval stage (2nd to 6th instar) and pupates in the feeding tunnel. Emergence and pheromone-trap records indicate 1 generation a year. In western New York, adults begin to emerge in mid-June, peak in mid-July, and continue to emerge through September. In several tests conducted over a 3-year period, chlorpyrifos at 180 g/100 L provided the most consistent control. At this rate a single spray timed to first or peak egg hatch was as effective as 2 sprays. Latex paint applied by brush to the trunk at the beginning of the oviposition period also reduced the infestation. In established plantings, dogwood borer can also be controlled by berming with soil up to the graft union to prevent access to burr knots. Destroying burr knots chemically with naphthalene acetic acid will not eliminate an infestation and may invite other borer problems.

The prey of adult dragonflies has been studied by the analysis of gut contents and was found to consist mainly of small Diptera. Most of the prey is very small but large dragonflies, such as aeshnids, occasionally take larger prey, such as caddis flies and other dragonflies. Relatively little diminution in the numbers of adult mosquitoes can be expected to occur as a result of dragonfly predation, because of the different conditions required for flight by dragonflies and mosquitoes.

The mechanics of coupling in Melanoplus sanguinipes (Fabr.) are described and differences between some species of Acrididae discussed. A high level of coupling activity was revealed with the most active male and female mating 56 and 46 times, respectively. In addition, multiple daily matings, to a maximum of five, were common. The majority of copulations occurred during the morning in both laboratory and field; however, in the latter, unfavourable weather restricted sexual activity. Coupling did not appear to occur at random; significant preferences were shown by certain males for certain females.

In recent years, the obliquebanded leafroller, Choristoneura rosaceana (Harris) (Lepidoptera: Tortricidae), has become a major pest of raspberries in the Fraser Valley, British Columbia (Anonymous 1994). Overwintering C. rosaceana larvae begin feeding on raspberry leaf buds in early April. Heavy infestation causes serious damage to raspberry plants. Larvae of the first generation hatch in late June to early July, and feed on growth terminals and berries. The occurrence of this generation usually coincides with berry harvesting time. Because the larvae are shaken from the plants by the harvesting machine, C. rosaceana can be a major contaminant of machine-harvested berries.

Twenty-nine species and named subspecies of Calligrapha Chev., including eight species previously undescribed, are listed below with notes on food-plant, distribution, and variability. New names are offered for the hamonyms elegans (Olivier) and similis (Rogers). The records and notes, except those credited to authors, are based almost entirely on material in the Canadian National Collection.

Variability in vectoring efficiency among six clones of Rhopalosiphum padi L. and five clones of Sitobion avenae Fabr. in transmission of three French PAV isolates (PAV-RG, PAV-2t, and PAV-13t) of barley yellow dwarf viruses (BYDVs) on seedlings of barley (Hordeum vulgare L.) cv. Plaisant was determined. All the clones could transmit these three isolates, but their vectoring efficiency was significantly different: 91% and 56% transmission efficiencies were obtained from the most efficient clones (Rp-M and Sa-R1) but only 21% and 9% from the least efficient clones (Rp-R26 and Sa-V) with 5-day acquisition and inoculation access periods (AAP, IAP). A significant difference in overall transmission between apterous adults and winged aphids of the tested clones was also found. In most cases, apterous adults were more efficient than were winged aphids. The overall transmission efficiency of apterous adults was 1.5 and 1.7 times that of winged ones for R. padi and S. avenae, respectively. The transmissibility of PAV-RG and PAV-2t isolates was similar within each of the tested aphid clones, but that of the PAV-13t isolate differed, particularly for the poorly efficient vector clones of S. avenae. Temperature could significantly influence the vectoring efficiency of the tested clones of R. padi, but the influence was greater on Rp-R26. High temperature (25 °C) facilitated more transmission than did low temperature (14 °C), and high temperature for AAP played a more important role than it did for IAP.

The diel pattern of drifting adults, pupae, pupal exuviae, and larvae of Chironomidae in a stream was established. Emergence was trimodal for the common species (Cricotopus sp. and Psectrocladius sp.), and larval drift-rates increased almost two-fold in darkness. The concurrent diel consumption of Chironomidae by coho fry was examined. The fish appeared not to make use of the peak drift-rates of larvae. Closest temporal correspondence between drift and diet was shown by adults. Forage ratios demonstrated greater consumption of chironomids than would be expected from their proportions in the drift. The order of acceptance was pupae, adults, larvae, and exuviae. High degree of utilization of an item is attributed to flotation and visibility. The major determinants of how much food is taken from the stream are identified as: marginal residence of the fish, the occupation by the fish of slow-water feeding stations, and the visibility of food items.

The phenologies and distributions of pea aphid (Acyrthosiphon pisum (Harris)), blue alfalfa aphid (A. kondoi (Shinji)), and spotted alfalfa aphid (Therioaphis maculata (Buckton)) were intensively studied in California alfalfa. The results showed, as expected, that aphid populations across all densities were aggregated; but that ladybird beetle (Hippodamia convergens (G.-M.)) predation increased the degree of aggregation. The distribution parameters of the aphids were estimated using methods developed by Iwao and Kuno (1971).

Research into the feasibility of growing peach [Prunus persica (L.) Batsch] in a protected environment structure (PES) was initiated in 1981 by the Ontario Ministry of Agriculture and Food at the Horticultural Research Institute, Vineland Station (Leuty and Miles 1983).

The 0.2-ha PES comprised seven gutter-connected greenhouses, each 5.3 by 58.5 m, with 3.4-m gutter height fibreglass walls and a double polyethylene roof. Temperatures suitable for plant growth were obtained by capturing solar energy beneath the plastic enclosure. Diurnal temperatures ranged between 6 and 27°C. Relative humidity varied between 40 and 95% and remained above 90% within the covered structure for greater than 50% of the time period between bloom (March 20) and roof removal sometime in May.

Average duration of the larval stage of Syrphus corollae Fab. reared at 20 ± 1 °C decreased linearly with increase in amount consumed from 9.2 days with 40.9 cal consumed/larva to 7.9 days at 78.1 cal/larva. Mean weight of pupae and percentage emergence of adults increased with calories consumed. No eggs were laid by flies developed from larvae which consumed less than 54.6 cal of energy, equivalent to 38 aphids. Average fecundity increased linearly with consumption up to 81.6 cal/larva (= 58 aphids). Mean reproductive output was 3.2% of larval consumption above 55 cal but decreased as larval consumption increased. When food was scarce, fecundity decreased because pupae, and therefore ovaries, were smaller. Larvae consumed as much as possible in the time available rather than pupating after consuming a minimal amount.

A review and analysis of the literature showed that precipitation, or its absence, can regulate the numbers of or the damage by insect pests of annual crops in Canada in essentially four main ways: as soil moisture, when the insects are in the ground; as a mechanical factor that impinges directly on them when they are exposed; through its effects on foodplants; and through its effects on natural enemies of the pests. Though any one pest species may be influenced by two or more of these processes and in different ways by each depending on the stage of its life cycle that is affected, usually only one way is significant. Precipitation is so far of little value in forecasting pest situations reliably, but water in various forms has much potential for use as a pest control agent.

This study was originally undertaken so as to provide information on the life history and ecology of Tarsonemoides truncatus (Ewing), to describe for the first time the developmental instars and male, and to redescribe the female of this species. Research soon indicated, however, that a group of closely related species of mites, including T. truncatus, was involved and that the problems to be investigated were more complex and extensive than anticipated.