The term “biological control” is sometimes used very broadly to cover all methods of encouraging the action of biotic factors. For the purposes of this discussion I will use it to refer solely to the introduction of parasites, predators, or microorganisms. I will also confine my remarks to the control of introduced pests. That is the purpose for which it has most promise and has been chiefly used. In my experience the most pressing forest insect problems of the Maritime Provinces–with the notable exception of the spruce budworm–have been with foreign species of European origin. It is logical to assess the value of biological control against exotic species before turning attention to its possibilities against indigenous pests (see Rawlings, 1958).

In the spring, spruce budworm (Choristoneura fumiferana (Clem)), emerge as second-instar larvae from hibernacula. This emergence may be sudden and is readily detectable in the field. In northwestern Ontario, the sudden appearance of larvae in large numbers was especially spectacular in 1948; that year, very few insects were observed on May 11, but on the following two days, countless larvae could be seen on strands of silk streaming out from trees. Many of the insects were carried away by air currents. The surface of Big Canon Lake, a body of water close to four square miles in area, was covered with larvae, at an estimated density of 100 larvae per square foot of surface. At other times, however, emergence may be gradual or there may be two distinct periods of abundant emergence. Furthermore, the time of abundant larval emergence through six years has varied by as much as four weeks. Because of such differences, prevailing spring temperatures were examined to determine what relationship might exist between temperature and the time and character of emergence. This paper points out a relationship between emergence and April and May temperatures, and an apparent temperature threshold for emergence.

Adults of predatory carabid beetles (Coleoptera: Carabidae) of the species Stenolophus comma Fabricius field-collected from light traps were bioassayed against several soil insecticides along with laboratory reared larvae of the predatory carabid Pterostichus melanarius Illiger. Adult S. comma beetles were exposed to serial dilutions of insecticides using a Potter spray tower; larvae of P. melanarius were exposed to insecticidally treated Plainfield sand. Fensulfothion, phorate, methomyl, carbofuran, and O,O-diethyl-S(tertbutylthio) methyl phosphorodithioate (Counter®) proved to be highly toxic to adult S. comma with a 0.01% solution causing mortalities > 65%. In the bioassay of P. melanarius larvae, Counter®, phorate, heptachlor, aldrin, and O-(2-chloro-1-(2,5-dichlorophenyl)vinyl) O-methyl ethylphosphonothioate (WL 24073) produced mortalities > 75% at 0.1 p.p.m. in Plainfield sand. The Pterostichus larvae which are probably important as predators of pest insects appear quite susceptible to several important soil insecticides. Chlorfenvinphos, leptophos, and p,p′-DDT were fairly innocuous to both adults and larvae.

There are 16 species of Trichoclinocera Collin recognized from the Nearctic region, including eight new species. Four of six species-groups of Trichoclinocera are recognized in the Nearctic region, with the following included species: (1) T. comata group — T. cascadensis sp.nov. (type-locality Starvation Creek, Oregon, U.S.A.), T. comata (Melander) comb.nov., and T. rupestris sp.nov. (type-locality Newton Creek, Wyoming, U.S.A.); (2) T. dolicheretma group — T. dolicheretma (Melander); (3) T. lapponica group — T. lapponica (Ringdahl) comb.nov.; (4) T. longipes group — T. agilis sp.nov. (type-locality Fall Creek Falls, Tennessee, U.S.A.), T. ctenistes (Melander), T. dasycoxa sp.nov. (type-locality Ottawa, Ontario, Canada), T. falcata sp.nov. (type-locality Gatineau Park, Quebec, Canada), T. fumosa (Vaillant) comb.nov., T. hamifera (Melander), T. longipes (Walker). T. minor (Melander), T. ozarkensis sp.nov. (type-locality Haw Creek Falls, Arkansas, U.S.A.), and T. pectinifemur sp.nov. (type-locality Phoenixville, Pennsylvania, U.S.A.). The following new synonyms are proposed: T. brunnipennis (Melander) = T. dolicheretma; and Seguyella saltans (Vaillant) = T. hamifera. Lectotypes are designated for T. comata, T. ctenistes, T. dolicheretma, T. brunnipennis, T. hamifera, T. lapponica, and T. stackelbergi Collin. Seguyella Vaillant and Acanthoclinocera Saigusa are newly synonymized with Trichoclinocera and all species formerly placed in these genera are transferred to Trichoclinocera, except Acanthoclinocera glaucescens (Brunetti) which is transferred as Wiedemannia glaucescens (Brunetti) comb.nov.This revision includes a key to Nearctic species, a description of each species, and maps of species distributions. Homologies of male terminalia of Clinocerinae are summarized and the first descriptions of the immature stages of species of Trichoclinocera also are provided. A world list of described species of Trichoclinocera is provided and all species are assigned to one of six species-groups, except T. cummingi sp.nov. (type-locality Robber’s Cave, Oklahoma. U.S.A.), T. fluviatilis (Brunetti) comb.nov., T. fuscipennis Saigusa, and T. maewa Smith, which remain unplaced. The monophyly of Trichoclinocera is justified and phylogenetic relationships to the remaining Clinocerinae and among species-groups are discussed.

The beetle fauna of conventional, organic, and abandoned apple orchards was monitored in the Annapolis Valley, Nova Scotia, between May and September 1991. Treatment in the three types of orchards differed with respect to weed control, disease control, fertilization, and general care. The most commonly captured beetles in all three types of orchards were carabids, in particular, Carabus nemoralis Müller, Carabus granulatus Linné, Harpalus rufipes (DeGeer), and Pterostichus coracinus (Newman). In general, abundance of predaceous beetles was highest in the conventional orchards and lowest in the abandoned orchards. Generic composition of predaceous beetles was similar among orchards, although the abandoned orchards were characterized by high proportions of the larger carabids, C. nemoralis and C. granulatus, whereas the organic and conventional orchards were dominated by the smaller carabids, H. rufipes and P. coracinus. Although there were no significant differences among orchard type in the total abundance of non-predaceous beetles, the abandoned orchards displayed the greatest diversity of non-predaceous beetles, with the lowest diversity found in the organic orchards.

Cyanobacterial mats of Oscillatoria spp., found in the habitat of Bembidion obtusidens, a halophilic carabid beetle, emit metabolites that act as allelochemic attractants to these insects. In a wind tunnel designed for use with small, fast-running carabid beetles, B. obtusidens adults responded to a homogeneously dispersed wind-borne mixture of these allelochemics by walking upwind. These results suggest that wind-borne metabolites of Oscillatoria spp. could act as distant chemical cues that invoke positive, odor-mediated anemotaxis in migrant B. obtusidens, enabling them to locate their habitat.

Diets of fresh wheat foliage, rye, or lettuce had to be supplemented with dried wheat leaves, bran, or a dry alfalfa mix to obtain adequate growth and reproduction in the grasshopper Melanoplus sanguinipes (Fabr.). It was concluded that the high water content of fresh plant material makes it necessary for this insect to supplement its diet with dry vegetable material and that this may account for the success of toxic bran baits under field conditions.

DDT, carbaryl, Dursban® (0,0-diethyl 0-3,5,6-trichloro-2-pyridyl phosphorothioate), and AC-47031 (cyclic ethylene (diethoxyphosphinyl) dithioimidocarbonate) were applied at different rates on rye and/or soil for control of the dark-sided cutworm, Euxoa messoria (Harris), attacking flue-cured tobacco in Ontario. All insecticides tested caused significant reductions in cutworm damage in comparison with the untreated check. Dursban at 1/2 lb/ac on rye, or 1 lb/ac incorporated in the soil tended to give better control than DDT at 4 lb/ac on soil and showed a significant difference from split applications of DDT at 11/4 lb/ac on rye and 4 lb/ac on soil in the large scale test. Carbaryl and AC-47031 showed less effect than DDT. There was no advantage in the split application of DDT or Dursban on rye and on soil since each treatment singly could provide effective control of this pest. Rye treatment is more economic than soil treatment and could apparently provide adequate control. Dursban showed promise as a substitute for DDT for control of the dark-sided cutworm in tobacco fields.

Adult emergence of Simulium verecundum S. and J. and S. decorum Walk. was reduced 58–94% by exposure of late instar larvae to 0.1 ppm Altosid or Altosid SR-10 for 1 h. Pupae were not affected by the presence of 0.1 ppm Altosid SR-10 in the rearing water. Adult emergence of S. verecundum was reduced 95% when mixed larval instars were reared in the presence of 0.001 ppm Dimilin. Last instar larvae died as a result of abnormal metamorphosis. Black fly mortality was 86–100% with 1-h exposures to 0 1–0.2 ppm Dimilin, and 100% with a 15-min exposure to 1 ppm at 22 ± 2 °C, lower temperatures giving similar results.

Release of Altosid over a 48-h period from formulated blocks gave a concentration of 0.002–0.006 ppm in a small stream. Emergence of adults was completely suppressed for 23 days 18 m downstream and 17 days 43 m downstream. Applications of 1 ppm Dimilin for 15 min to two streams resulted in the gradual elimination of black fly larvae from artificial substrates, a high reduction in adult emergence, and the formation of abnormal larvae following the tests. The maximum concentration of Dimilin detected in the water was 0.31 ppm during application; however, submerged vegetation residues as high as 18.9 ppm were found 1 h following the second application, decreasing to less than 0.05 ppm 14 days later.

Characters of male genitalia and sternal coloration are used to supplement the variable characters of head shape and tegminal colour pattern in determining the species of the world Prosapia. Five new species are described: chiapana, hemelytra, ignifera, and isobar from Mexico, and fortior from Panama. One new combination is created: Prosapia miles (Fowler). Four subspecies are considered valid species: ignipectus (Fitch), inferens (Walker), ripalis Fennah (new status), and teapana Fennah (new status). P. simulons (Walker) (1858) is synonymized with fasciaticollis (Stål) (1864), and bicincta (Say) (1830) is synonymized with fraterna (Uhler) (1864). An illustrated key to males of the 14 world species is provided.

Only soil temperatures below −7°C are likely to cause significant pupal mortality of M. configurata in the field, and only if exposure periods are sufficiently prolonged. At −17°C, a temperature not uncommonly encountered in the soil at 10 cm during the prairie winter, near total mortality occurred within 1 week in laboratory tests and significant mortality (20–30%) occurred within 1 day. The survival time at −12°C was considerably longer, and 50% mortality occurred after about 6 weeks of exposure. Pupal mortality caused by cold might thus vary from 0 to 100% depending on local climatic and field conditions and therefore is an essential component of a survival model for the species.

Exposure to cold accelerates diapause development by as much as four orders of magnitude for the lowest temperature tested (−17°C). However, the acceleration of diapause development by sub-zero temperatures appears to be of limited phenological significance, since in western Canada the pupae spend at least 40 weeks in the soil and can easily complete diapause development within this time at 0° to 5°C. Further evidence for a major reorganization of the endocrine system of M. configurata pupae during stage 2 of diapause development is presented.

Sections of stem galls induced by Diplolepis triforma Shorthouse and Ritchie obtained by plant histological techniques were used to examine anatomical features of immature stages of the insect found in situ. First-instar larvae feed over the entire surface of larval chambers, whereas maturing larvae feed only at one end of the chambers. Last-instar larvae undergo two phases of development: feeding occurs in the first phase, whereas in the second, or prepupal phase, feeding has ceased, the mid- and hind-guts become joined, contents of the gut are voided, and compound eyes, gonads, and internal ovipositional apparatus begin to differentiate. The prepupal phase also consists of two phases: the first occurs in the fall and winter, and the second occurs in the spring prior to pupation. The spring phase exhibits external adult features within the integument of the last-instar and moults to the pupa. Sections of some maturing larvae contained endoparasitoid larvae of the genus Orthopelma Taschenberg (Hymenoptera: Ichneumonidae).

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.

Pissodes strobi (Peck) and P. approximatus Hopkins are sibling species that can produce fertile hybrids in the laboratory, but in nature they are isolated by differences in their breeding habits. In a laboratory assay for feeding preference, these species exhibited similar patterns of acceptance of most conifer hosts in the fall, but differed distinctly in their preferences for certain conifers in the spring. Both species had high levels of feeding on white spruce in the fall and spring tests, hut these data apparently do not reflect host preference in nature. In field tests, P. strobi males and females confined on 1-year-old terminal leaders of eastern white pine (their usual breeding sites) produced abundant progeny, whereas P. approximatus pairs confined on leaders produced few progeny. Mixed species pairs were successful in killing and breeding in white pine leaders when the females were P. strobi, but not when the females were P. approximatus. Laboratory-reared hybrids were unsuccessful when forced to breed in leaders. When confined on red pine bolts (the usual breeding sites of P. approximatus), P. strobi and hybrids produced substantially fewer progeny than did P. approximatus. Breeding site separation provides compelling evidence of reproductive isolation between these sympatric species.

The meiotic formula of the European spruce beetle, Dendroctonus micans (Kugelann), is 10 AA + Xyp in males and 10 AA + XX in females. This karyotype is different from the morphologically similar Dendroctonus punctatus LeConte (14 AA + Xyp), which is consistent with the taxonomic validity of both species. The chromosome number found in D. micans, added to karyological data from other species of the genus Dendroctonus Erichson, suggest that the karyological diversification within this genus may have occurred in two directions: one toward more southerly latitudes in North America and the other toward Europe and Asia.

The life cycle of Strobilomyia appalachensis Michelsen, a maggot exploiting black spruce seed cones, was studied in two plantations in northern Ontario in 1987 and 1988, and two seed orchards in New Brunswick in 1991 and 1992. Oviposition by S. appalachensis occurs slightly later than the white spruce cone maggot, S. neanthracina Michelsen, relative to seed cone development; otherwise the life cycles of the two species are similar. Adults were trapped near host foliage in May and early June. Eggs were laid between the scales of seed cones during early June, starting when the scales on most cones were closed and ending 1 week after cones were fully pendant. Up to five eggs per cone were observed but single eggs were most common. The first larval molt occurred within the egg chorion and second-instar larvae emerged from the egg. Second-instar larvae were found in the cones during the 2nd and 3rd week of June, and third instars from the 3rd week of June until mid to late July. Larvae tunneled around the cone axis and destroyed an average of 60% of the total seed per cone before exiting and dropping to the soil. Larval drop occurred from late June to late July and was significantly correlated with periods of rainfall. Mature larvae moved into the duff and overwintered in the soil as pupae. Aspects of the maggot’s life history are discussed in relation to pest management strategies.

Mitochondrial DNA cytochrome c oxidase subunit 1 (DNA barcode) and nuclear microsatellite flanking region sequences were used to analyse populations of putative “sugarbeet root aphid”, Pemphigus betae Doane, from sites in Alberta, Canada. Three sympatric genotypes were revealed, identified as P. betae, P. populivenae Fitch, and an undetermined third species. All three genotypes formed morphologically indistinguishable galls on the same set of cottonwood (Populus L., Salicaceae) host species, often on the same tree. Gall morphology is frequently used to identify Pemphigus species. Our results indicate that this practice may be unreliable for these three taxa at least.

The chemicals cis (Z) and trans (E)11-tetradecenyl acetate (11–14:Ac), trans 11-tetradecen-1-ol (E11–14:OH) and trans 11-tetradecenal (E11–14:Ald) were isolated from unmated female Choristoneura orae Freeman and shown to be highly attractive when used as lures in sticky traps. The identification of these components of the sex pheromone facilitates the separation of C. orae from other Pinaceae-feeding Choristoneura in the same area.

This author and others have previously proposed that causes of population fluctuations can be ascertained by regression analysis in which Nt+1/Nt is the dependent variable, and Nt is one of the independent variables. This procedure contains a bias, since the expected relationship between Nt+1/Nt and Nt is hyperbolic when there is no causal relationship. The simplest way of circumventing this difficulty is to use Nt+1, not Nt+1/Nt as the dependent variable.

The seasonal life history and mortality of the lodgepole terminal weevil, Pissodes terminalis Hopping (Coleoptera: Curculionidae), were investigated in young lodgepole pine, Pinus contorta Douglas var. latifolia Engelmann (Pinaceae), at three sites in west-central Alberta. Flight was monitored with traps. Development and mortality of all stages were investigated by dissecting infested leaders biweekly from late spring to early fall. Two years were required for P. terminalis to complete its life cycle, and generations overlapped. Overwintered adults emerged from the duff and commenced flight in late May, with a peak in mid-June. Eggs were present from mid-June to late July. There were four larval instars. The first two instars fed only in the phloem. Third and fourth larval instars eventually entered the pith to continue feeding, overwinter, and complete development the following spring. The new generation of adults emerged between mid-July and early August, fed on new shoots for several weeks, and overwintered in the duff. Adults have an obligatory diapause and did not reproduce until after winter. Fourth larval instars suffered the highest mortality. The major attributable cause of mortality was resinosis among eggs and young larvae and cold temperatures during the winter among mature larvae. Pathogens caused little mortality. Six species of parasitoids were collected.