In the laboratory, diapause in adult Psylla pyricola Förster was induced by rearing nymphs with exposures to daily photoperiods of 13.5 h or less. The critical photoperiod that induced diapause was not influenced by temperature. Diapause was terminated in laboratory-reared adults and winter form adults collected from orchards in mid-October by exposure to photoperiods greater than 13.5 h. With adults collected from orchards during November, December, and January, diapause was terminated in the laboratory under both short and long photoperiods. With the earlier collections, long photoperiods markedly reduced preoviposition periods but with later collections the effect was not as pronounced because the preoviposition period under short photoperiods decreased markedly with the later collection dates. These results are discussed with relation to observations under natural orchard conditions.

The seasonal activity and infestation potential of the cabbage maggot, Delia radicum (L.) (Diptera: Anthomyiidae), attacking rutabaga was studied at two Manitoba locations over 4 years based on captures of females in yellow water traps baited with alryl isothiocyanate. The activity peak for the overwintering generation occurred on 8 June ± 4.1 days (mean ± SD), with degree-day accumulations, base 5°C, of 159 ± 6.2 for soil at 5 cm and 387 ± 69.4 for air for both locations combined. The activity peak for the first generation occurred on 12 August ± 11.7 days with degree-day accumulations of 981 ± 229.3 and 1295 ± 175.7 for soil and air temperatures, respectively.

Correlations between numbers of females trapped per week and of eggs in soil samples from around rutabaga plants for individual seasons at the two locations generally were not significant. A regression of numbers of eggs on females trapped based on all data was significant but had a low coefficient of determination (r2 = 0.289). The water traps are adequate for monitoring seasonal activity of adult flies but the captures are unreliable as quantitative indicators of potential infestation.

Species of the genus Tinotus Sharp of America north of Mexico are reviewed. Five species are recognized: T. caviceps Casey, T. imbricatus Casey, T. morion (Gravenhorst), T. parvicornis Casey, and T. trisectus Casey. The genus Tinotus is recorded from Canada for the first time and is represented in the country by two previously unrecorded species: T. morion (Gravenhorst), introduced from the Palearctic region, and T. caviceps Casey, described from Nevada and subsequently reported from California, Idaho, Indiana, Iowa, and Montana. Tinotus morion was previously listed in North America from Connecticut and Nevada (unverified records), but until now it was unknown from Canada. Here it is reported as new for New Brunswick, Quebec, Ontario, Alberta, and British Columbia. Tinotus caviceps is found for the first time in southern Quebec where it probably reaches its northern distribution limit. The following synonymies are established, with the first names being valid: T. caviceps Casey (= T. pallidus Casey), T. imbricatus Casey (= T. amplus Notman, T. brunnipes Notman), T. parvicornis Casey (= T. planulus Notman), and T. trisectus Casey (= T. binarius Casey, T. brunneus Casey, and T. lateralis Notman). A new lectotype is designated for T. brunnipes Notman. The lectotype specimens have been dissected and their genital features illustrated. Diagnoses, illustrations, and a key to identify species from America north of Mexico are provided.

Two, or possibly three, types of stimuli that may influence host selection by entomophagous insects are produced by movements of the host or the prey. Movement may provide visual or tactile stimuli. Vibration caused by host movement may stimulate some species.

Tactile stimuli are produced by a host if it moves when touched by a parasite and are usually provided by a host that is enclosed in a case or a cocoon. Ullyert (1936), working with Dahlbominus fuscipennis (Zett.), and Williams (1951) and Thorpe and Jones (1937), working with Idechthis canescens (Grav.), found tactile stimuli an important factor in host selection, but Simmonds (1943) and Thompson and Parker (1927) concluded it was of little importance in I. canescens and Melittobia acasta Walk. respectively. Movement of potential prey upon contact stimulates attack by foraging ants (Vowels, 1955). Tactile stimuli produced by movement of the host may indicate an unsuitable host to the egg parasite Trichogramma evanescens Westw. (Salt, 1938).

A temperature-dependent model for predicting green peach aphid population development in potato fields was devised and tested. A laboratory estimate of generation time was utilized to derive expected generation number from field accumulated degree days (1975–77). Different aphid populations were produced in replicated field plots (1975–77) with various application rates of the systemic insecticide, aldicarb. Density data from these plots were regressed on the expected number of generations to derive prediction equations. These equations were coupled in a Fortran computer program with a degree day algorithm. Weather forecasts, therefore, provide input for future aphid population predictions. The model is being used to evaluate various control strategies and to decide on spray dates from weather forecasts.

Twenty species of ground beetles (Family Carabidae) and one species of carrion beetle (Family Silphidae) were collected in six stations east of a kraft paper mill in Thunder Bay, Ontario, from May to August, 1971. The beetle population decreased markedly towards the mill. There was no apparent statistical difference in size variation of specimens near the mill and those further away.

Spruce budworm infested balsam fir trees were aerially sprayed with Bacillus thuringiensis – chitinase combinations at the rate of 4 Billion International Units of B.t. and 18 mg of enzyme in 0.5 gal/acre. Larvae were peak third instar at spray time. Deposit rates ranged from 1.07 to 3.26 BIU/acre. Efficacy of the treatments was assessed in the year of treatment and carry-over effects were assessed 1 year later.

Results in the year of treatment indicated that: (1) Residual activity of B. thuringiensis was drastically reduced after 15 days’ exposure to weathering. (2) Larval mortality alone is not a suitable criterion of efficacy. (3) Dipel and Dipel + chitinase (but not Thuricide 16B or Thuricide + chitinase) were highly effective in reducing budworm densities. (4) Thuricide + chitinase treatment resulted in significant foliage protection. The treatments inhibited feeding in the following order of efficiency: Thuricide + chitinase > Dipel + chitinase > Dipel alone > chitinase alone > Thuricide alone. (5) There was no direct relationship between larval mortality and foliage protection in any of the treatments, likely due to delayed mortality effects. (6) No direct relationship exists between viable spore deposits and deposit of active ingredient (IUs). (7) B.t. treatments retarded development of the spruce budworm and reduced pupal weights, oviposition rates, and egg viability.

Assessment of the plots 1 year after spray showed that the treatments apparently gave no long term protection from defoliation, but this was likely due in part to mass invasion of the test plots by moths from immediately surrounding untreated areas.

Insect aggregation pheromones are defined as chemical substances produced by members of one or both sexes that induce members of both sexes to form aggregations (Borden 1984). Aggregation pheromones are typically emitted by and attract adult insects. Interestingly, larvae of the codling moth, Cydia pomonella L. (Lepidoptera: Olethreutidae), seeking pupation sites will aggregate in response to pheromone produced by cocoon-spinning conspecific larvae (Duthie et al. 2003). Such aggregations may be part of a mating strategy in which protandrous males are arrested by sex pheromone emanating from mature female pupae, thus allowing mating to ensue as soon as a female moth ecloses (Duthie et al. 2003). The cocoon-derived pheromone also attracts the specialist prepupal parasitoid Mastrus ridibundus Gravenhorst (Hymenoptera: Ichneumonidae), which “eavesdrops” on pheromonal communication of cocoon-spinning larvae (Jumean et al. 2004).

Codling moth larvae seeking overwintering sites usually spin up during hours of darkness on the trunks and larger branches of apple trees rather than in the soil or in debris under the trees. The number on the ground depends on the suitability for cocooning sites of the bark on the tree and on the amount and type of debris on the ground. Gould and Geissler (1941) found that larvae did not spin up in bare and compact soil and Steiner (1929) observed that most larvae returned to the tree to spin cocoons when there was little or no litter beneaththe trees. Baker (1944) reported eight to nine per cent spun up on the ground beneath unscraped trees, and 18 per cent where the loose bark scales were removed. Others (Headlee (1929). Worthley (1932), Gnadinger et al. (1940), Woodside (1941), and Stultz (1946), found that under natural conditions from 0 to 14 per cent spun up in the soil, in the cover crop, or in the debris on the ground.

Pine oil, derived from pulp mill by-products, and oleic acid significantly delayed and reduced the attack by ambrosia beetles Trypodendron lineatum (Oliv.) and Gnathotrichus spp. on Douglas-fir logs. Pine oil also appeared to interfere with the attack by bark beetles. The possibility of combining the use of repellents with a pheromone-based diversion scheme is suggested as an effective protection strategy.

Bio-assay showed that the pheromone of attractive female Trypodendron lineatum (Oliv.) must be produced in the posterior part of the ileum. Histological studies revealed a layer of secretory cells in the rear part of the ileum and the rectal valve which occur only in feeding adults. The attractive material is produced only when bark and wood particles are present at the site of pheromone production, and the actual production is initiated probably by activity of a female hormone or enzyme.

The responses of Ips latidens (LeConte) to multiple-funnel traps baited with various monoterpenes were determined in stands of lodgepole pine in British Columbia. β-Phellandrene was attractive to I. latidens in the absence of the pheromone ipsenol. β-Phellandrene increased the attraction of I. latidens to ipsenol-baited traps while α-pinene, 3-carene, terpinolene, and myrcene reduced trap catches. Differential responses by males and females to sources of ipsenol with or without β-phellandrene suggest that the information conveyed to males differs from that conveyed to females. Species-specific responses to monoterpenes by I. latidens and three sympatric species of scolytids suggest that unique combinations of kairomones could be important in facilitating matings with conspecifics. Pheromones need not be the sole constituent of species-specific chemical messages.

Soaking shredded moss and birch bark samples in a 2% bleach solution for 45 minutes will release attached hemlock looper eggs. Soaking has no deleterious effect on the hatching of larvae or the emergence of parasites. This technique, in contrast to direct examination, results in a significant increase in the number of eggs obtained and a decrease in counting time. It also permits the development of egg sampling techniques for use over extensive areas and the collection of eggs in large numbers.

Our review highlights research during the past century focussed on the population ecology of outbreak-prone insect defoliators in Canadian forests. Based on reports from national and provincial surveys that began in the 1930s, there have been at least 106 insect defoliators reported to outbreak, most of which are native Lepidoptera, Hymenoptera (sawflies), or Coleoptera (in order of frequency from most to least). Studies comparing life-history traits of outbreak versus non-outbreak species to better understand why certain species are more outbreak-prone indicate several traits especially common among outbreak species, including egg clustering and aggregative larval feeding. There have been at least 50 time-series studies examining the spatiotemporal population behaviour of 12 major defoliator species. These studies provide evidence for both regular periodicity and spatial synchrony of outbreaks for most major species. Life-table studies seeking to understand the agents causing populations to fluctuate have been carried out for at least seven outbreak species, with the majority identifying natural enemies (usually parasitoids) as the major driver of outbreak collapse. Our review concludes with several case studies highlighting the impact and historical underpinnings of population studies for major defoliator species and a discussion of potential avenues for future research.

Five new species, Apometriocnemus beringensis, Cricotopus (Cricotopus) bifurcatus, Doithrix dillonae, Hydrobaenus piloculus, and Paratrissocladius lawrencensis, are described. The following new combinations are established: Bryophaenocladius astis (Roback 1951b); Compterosmittia nerius (Curran 1930); Parakiefferiella subaterrima (Malloch 1915); Paratrichocladius nitidus (Malloch 1915); Pseudosmittia nanseni (Kieffer 1926); and Zalutschia sivertseni (Aagard 1979). New genus name synonymies are Maricladius Sublette, 1970 with Parakiefferiella Thienemann, 1936; and Prosmittia Brundin, 1956 with Pseudosmittia Goetghebuer, 1932. New species name synonymies are Spaniotoma (Trichocladius) senex Johannsen, 1937 with Trichocladius nitidellus Malloch, 1915 (= Acricotopus nitidellus); Hydrobaenus traenis Roback, 1957b with Hydrobaenus astis Roback, 1957b (= Bryophaenocladius astis); Compterosmittia clavigera Saether, 1982 with Camptocladius nerius Curran, 1930 (= Compterosmittia nerius); Cricotopus flannagani Saether, 1971 with Cricotopus macraei Saether, 1971; Gymnometriocnemus marionensis Saether, 1969 with Metriocnemus subnudus Edwards, 1929 (= Gymnometriocnemus (Gymnometriocnemus) subnudus); Gymnometriocnemus (Raphidocladius) acigus Saether, 1983 with Metriocnemus brumalis Edwards, 1929 (= Gymnometriocnemus (Raphidocladius) brumalis); Limnophyes spatulosus Saether, 1975 with Limnophyes borealis Goetghebuer, 1933; Limnophyes cristatissimus Saether, 1975 with Camptocladius fumosus Johannsen, 1905 (= Limnophyes fumosus); Limnophyes hudsoni Saether, 1975 with Limnophyes immucronatus Saether, 1969; Hydrobaenus hudsoni Saether, 1977 with Chaetocladius (Parachaetocladius) abnobaeus Wülker, 1959 (= Parachaetocladius abnobaeus); Parakiefferiella torulata Saether, 1969 with Camptocladius subaterrimus Malloch, 1915 (= Parakiefferiella subaterrima); Trichocladius helis Roback, 1957b with Orthocladius nitidus Malloch, 1915 (= Paratrichocladius nitidus); Syncricotopus fontinalis Saether, 1969 with Chironomus rufiventris Meigen, 1830 (= Paratrichocladius rufiventris); Pseudorthocladius (Lordella) comans Saether and Sublette, 1983 with Pseudorthocladius (Lordella) wingoi Saether and Sublette, 1983; Smittia triappendiculata Goetghebuer, 1931 with Camptocladius forcipatus Goetghebuer, 1921 (= Pseudosmittia forcipatus); and Psilometriocnemus cristatus Saether, 1982 with Psilometriocnemus triannulatus Saether, 1969. Major new distribution records are given for 49 species including 8 Nearctic and 32 Canadian. A key to adult males of Nearctic Limnophyes is given.

Reports in the literature on the activities of adults of the cabbage maggot, Hylemya brassicae (Bouché), are scanty, sometimes not in agreement with one another, and usually recorded in conjunction with observations on field ecology. Now that individual insects are being used in studies of resistance in rutabagas (Swailes, 1960) a more detailed account of activities after adult emergence is available. This paper deals with the pre-oviposition, mating, and oviposition 'behaviour of the females and mating behaviour of the males.

Tick paralysis continues to be one of the most baffling and fascinating tickborne diseases in Canada. It was first reported in this country by Todd in 1912. Since then about 250 human cases, including 28 deaths, have been recorded from British Columbia. Outbreaks in cattle have affected up to 400 animals at a time, with losses in a herd as high as 65 head. Although the disease is most common in the Pacific northwest, where it is caused by the Rocky Mountain wood tick, Dermacentor andersoni Stiles, it has lately been reported as far south as Florida and has been produced by Dermacentor variabilis Say, Amblyomma maculatum Koch, and A. americanum (L.) (Gregson, 1953). The symptoms include a gradual ascending symmetrical flaccid paralysis. Apparently only man, sheep, cattle, dogs, and buffalo (one known instance) are susceptible, but even these may not necessarily be paralysed.

Descriptions of the larvae of Lancetes angusticollis (Curtis), L. lanceolatus (Clark), L. subseriatus Zimmermann, L. flavoscutatus Enderlein, L. delkeskampi Ríha, and L. nigriceps (Erichson) are provided. Characters from larval morphology are analyzed to infer the phylogenetic relationships of the genus Lancetes Sharp with other genera of Dytiscidae. A parsimony analysis based on 51 informative larval characteristics was conducted with the program NONA. The most parsimonious tree supports a sister-group relationship between the genus Lancetes and members of the subfamily Dytiscinae. The only unambiguous synapomorphy in support of this hypothesis is the secondary subdivision of some cephalic appendages. Other putative synapomorphies are the proximal articulation of the primary seta CO7 both on meso- and meta-coxa and the presence of additional primary setae on the ventral margin of the tibiae. Based on several character states including the presence of multifragmented urogomphi, the genus Lancetes is monophyletic.

The use of potato as a trap crop for the Colorado potato beetle, Leptinotarsa decemlineata (Say), in processing tomatoes was evaluated. The proportion of beetles counted on potato trap rows vs. the tomato crop on a per plant basis was 0.99, 1 week after transplanting, and never fell below 0.93 on any sampling date. In tomato plots that received no insecticides, potato trap rows placed as much as 16 tomato beds apart were effective in reducing beetle numbers on the tomatoes and producing crop yields 61–87% higher than plots without trap rows. Four of six pairs of plots had significantly fewer adult beetles and significantly higher tomato yields when a potato trap crop was present.

The woodwasp Sirex noctilio F. is invading North American forests, where it will interact with a large guild of pine-inhabiting beetles and their associated fungi. The woodwasp's obligate fungal symbiont, Amylostereum areolatum (Fries) Boidin (Stereaceae), plays an essential role in the wasp's larval development but is expected to be a poor competitor in the presence of fungi vectored by co-occurring insects. We examined the outcomes of competitive interactions between A. areolatum and two fungal species vectored by bark beetles, Leptographium wingfieldii Morelet (Ophiostomataceae) and Ophiostoma minus (Hedgcock) H. and P. Sydow (Ophiostomataceae), and the effect of temperature and substrate on these interactions. Beetle-associated fungi were usually able to capture more uncolonized resource than A. areolatum regardless of substrate or temperature. Amylostereum areolatum was able to colonize relatively more space in some cases but could not gain substrate already colonized by the ophiostomatoid competitor. These findings suggest that competitive interactions between beetle-vectored fungal species and A. areolatum could influence the reproductive fitness and distribution of S. noctilio within individual trees and also across a wide geographic area.