The mullein bug, Campylomma verbasci (Meyer) (Heteroptera: Miridae), was studied in and around 17 apple orchards in the Okanagan Valley during 1982–1984. Apple and pear were overwintering hosts and the principal perennial hosts during summer months. Campylomma verbasci was the most abundant mirid on apple and occurred in 16 orchards, with two or three generations per year. Nymphs first emerged from overwintered eggs near full bloom, but variation in timing occurred between orchards and years. Population densities of C. verbasci were higher (P<0.05) in unsprayed than in sprayed orchards, but no differences were observed between commercial and “organic” orchards. In June, some adults moved onto herbaceous plant hosts, primarily common mullein, Verbascum thapsus L. Two generations of C. verbasci were found on mullein and the bugs were distributed in an aggregated pattern. Significant associations occurred among height, raceme length, or flower number of mullein plants and the number of C. verbasci on them. From mid-August to October, adult numbers declined on mullein and increased on apple. The number of mullein plants per orchard was not always associated with the density of overwintered C. verbasci in the following year.

In Nova Scotia, a spray program that integrates chemical and natural control of apple pests has been evolved which is both economical and satisfactory. Among the natural enemies of injurious arthropods that have been favoured by this program are a number of general predators. Further investigation of the ecological principles on which integration is based requires a more intensive knowledge of the factors that influence the densities of these predators. Because of the difficulties of investigating these factors in the orchard, methods of simplifying the predator-prey systems have been sought (Lord, 1956, 1962). These attempts assessed the effects of low dosages of DDT on the interrelationships of phytophagous mites and their natural enemies.

Nine species of the gall-associated doryctine genus Allorhogas Gahan (Hymenoptera: Braconidae) are described from Brazil (A. clidemiae Martínez and Zaldívar-Riverón new species, A. granivorus Zaldívar-Riverón and Martínez new species, A. mineiro Zaldívar-Riverón and Martínez new species, and A. vulgaris Zaldívar-Riverón and Martínez new species) and Costa Rica (A. brevithorax Zaldívar-Riverón and Martínez new species, A. pallidus Martínez and Zaldívar-Riverón new species, A. psychotria Zaldívar-Riverón and Martínez new species, A. punctatus Martínez and Zaldívar-Riverón new species, and A. tico Martínez and Zaldívar-Riverón new species). We provide host plant records for the described species, including information that reveals that at least three of them feed on seeds. Allorhogas granivorus had previously been confirmed to represent a natural enemy of the invasive weed Miconia calvescens de Candolle (Melastomataceae). Updated keys to the species of Allorhogas from Brazil and Costa Rica are provided.

The study of insect pathogens became established as a distinct discipline in the late 1940s. In the ~65 years that followed, forest pest management was the main theatre for the development and practice of insect pathology in Canada. Researchers from the federal government and academic institutions contributed to the growing discipline by acquiring foundational knowledge on taxonomy, mode of action, natural occurrence, and ecological role of key pathogens infecting forest pest insects, covering an array of fungi, Microsporidia, viruses, and bacteria. The ultimate goal was to develop pathogen-based alternatives to synthetic insecticides used in large-scale forest protection programmes throughout eastern Canada. That goal was achieved through the development of baculovirus-based products for control of gypsy moths (Lepidoptera: Erebidae), tussock moths (Lepidoptera: Erebidae), and various sawfly (Hymenoptera) species, which are now in the hands of private industry and poised for growing operational use. The second success was the development of products based on Bacillus thuringiensis Berliner (Bacillaceae), which have almost entirely replaced synthetic insecticides in forest protection. We review those successes and other key Canadian contributions to forest insect pathology within the context of emerging digital, molecular, and other technologies, and show how they have altered today’s face of forest pest management in Canada.

The subject of this paper was selected with enthusiasm. The law of natural compensations seemed most intriguing and the part played by forest insects in its enforcement appeared to afford unusual opportunity for discussion. Now that the time has arrived for its presentation there is a sense of trepidation, because the drawing of generalizations is always dangerous. However, without generalizations we should inevitably be confused by the mass of information concerning populations of insects, their parasites, predators, and host plants, and the responses of these organisms to their habitat. Therefore, it may be appropriate to present this somewhat old story from a different angle to illustrate the viewpoint of one forest entomologist, using some old and some hitherto unreported examples. Most of the examples that will be cited, whether old or new, have been observed first hand.

European corn borer moths were caught in an ultraviolet light trap from early June to late October at Harrow, Ont. Two conspicuous peaks of light trap catches occurred each year, corresponding to two generations, but a third generation was deduced from three peaks of occurrence of virgin females. The number of moths which could be caught with nets in the day time correlated with the light trap catch of the previous night (r = 0.7). Most of the moths caught in the light trap or in nets were females but males predominated in the early June, September, and October catches. The shortage of males in the second generation was shown to influence the proportion of females mating, but not the number of spermatophores per female. Most females mated once and the number of matings per female did not differ enough between years to account for differences in adult populations.

The male meiotic karyotypic formula of Conophthorus coniperda (Schwarz) (Coleoptera: Scolytidae) is 9AA + XY. This karyotype differs from C. resinosae Hopkins and C. banksianae McPherson, both of which have the karyotypic formula of 8AA + XY. Supernumerary chromosomes were found in different populations of C. resinosae and C. banksianae but were absent in C. coniperda. No geographic variation in the karyotypes of the three species was observed. The karyotypic formulae confirm the designations of C. coniperda and C. resinosae by morphological characters, but do not support the designation of C. banksianae as a distinct species.

Two braconids, Opius lectus Gah. and O. alloeus Mues., are being reported for the first time in Quebec as parasites of the apple maggot, Rhagoletis pomonella (Walsh).

The impact of canopy dieback on the activity and diversity of epigeal Carabidae was studied during the summers of 1987 and 1988 in 18 maple stands in southeastern Québec, using pitfall traps. A canopy thinning index (CTI) based on severity and incidence of dieback, and on tree basal area was calculated for each of the 72 stations sampled. An analysis of variance shows that canopy dieback had a significant effect on carabid beetle activity in 1988. The CTI was negatively correlated with the carabid species richness and diversity in 1988. The number of individuals caught per station was negatively correlated with the CTI for all species combined, except for the dominant Pterostichus coracinus Newm. in 1988. These results indicate a negative response of carabid beetles to canopy dieback in 1988; the climate may have tempered the effects of dieback in 1987.

Irradiation of specific regions of 5- to 20-h-old housefly pupae with X-rays shows that exposure of anterior seven segments alone to 1200 r prevents adult emergence, whereas irradiation of posterior region with doses up to 10,000 r has no effect on this phenomenon. It is evident that the target organ, damage to which results in the failure of adult emergence, lies in the anterior seven segments. It is suggested that failure to emerge is due to a direct effect of radiation on the differentiating myoblasts leading to dystrophy of the muscles.

The density and spatial relationship between the wasp parasite, Nasonia vitripennis, and the housefly host, Musca domestica, were investigated. As parasite dispersion decreased in a defined space, parasitism increased from 30 to 76% and host survival decreased from an average of 65.0 to 18.9%. The number of host pupae producing parasite progeny and the survival of host pupae decreased as the proportion of small host pupae increased. With host numbers increasing and parasite numbers constant, the mean number of eggs deposited per host increased significantly from 31.25 to 87.25 and the number of stings increased from 2.25 to 8.00. As parasite density increased and host number remained constant, the number of hosts which were nor attacked declined from a mean of 2.2 with 1 parasite to none with 32 parasites. Host survival declined from about 50% at the 1:8 ratio of female parasites to hosts to no survival at the 2:1 ratio.

Granary trials to determine the efficacy of an enhanced diatomaceous earth (DE) formulation (Protect-It™) at 0.15 kg DE/t grain to control grain-feeding beetles in barley, Hordeum vulgare L. (Poaceae), were conducted at Glenlea, Manitoba. During the test, the grain moisture content ranged from 11 to 13%, and grain temperature ranged from 27 to 2 °C. The bulk density of barley was reduced 10–20 kg/m3 by the addition of diatomaceous earth. Adults of the rusty grain beetle, Cryptolestes ferrugineus (Stephens), were released onto the top surface of the grain of each granary, producing an average density of approximately 4 insects/kg grain. Using Berlese funnels to extract insects from grain samples there was a 95% reduction in adults and an 80% reduction in larvae found in treated grain compared with untreated grain, 1 month after releasing insects into the grain. There was a 95% or greater decrease in the total number of insects caught with probe pitfall traps in the treated barley compared with the untreated barley for all sampling dates. For the confined populations, 200 adult C. ferrugineus or Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) (red flour beetle) were held in screened jars in the grain until the end of October, and there was over a 99% reduction in both insect species, compared with insects held on untreated grain. These results indicate that this diatomaceous earth formulation can control C. ferrugineus in barley in granaries at 0.15 kg DE/t grain.

The study examined quantitatively the effects of embryonic development in the preceding fall and cumulative heat units from 1 April to 31 July in the current year on density trends of three major grasshopper species (Melanoplus sanguinipes (Fabr.), M. bivittatus (Say), and Camnula pellucida (Scudder)) in Saskatchewan. The influence of adult density of the previous year, embryonic development, heat units, and their interactions were examined by multiple regression analyses for each of the three species to determine their contribution to next year’s adult populations. The models tended to underestimate density during a population increase and to overestimate during a population decline. Combined heat units during the preceding fall and following spring indicated that a general increase in density should occur when heat units were equal to or greater than 1600 °D50.

Apanteles fumiferanae Vier. and Glylpta fumiferanae (Vier.) are two well known hymenopterous parasites of the spruce budworm in Canada. While studying a microsporidian disease of the budworm caused by Perezia fumiferanae Thom. (Thomson, 1955) it was observed that occasionally the microsporidian and one of the hymenopterous parasites occurred together in the same host. This paper is a report of a study of the effect of the microsporidian on the hymenopterous parasites.

We investigated the impact of different fluorescent marking powders on both survivorship and daily body condition, measured as mass/volume ratio, using adult mountain pine beetles, Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae: Scolytinae), in a laboratory study. Initial condition of the marked beetle groups did not differ from that of an unmarked group. However, beetles in better initial condition survived longer, thus validating our condition index. The condition but not the survivorship of mountain pine beetles was affected by the marking treatment. Overall, the condition of beetles declined over time. The condition of marked beetles decreased at a higher rate than that of unmarked beetles while alive but at a lower rate after death. This pattern of decreasing condition suggests that marked beetles lost water faster than unmarked beetles while alive, so unmarked beetles had more water to lose after death. Because reduced condition may affect optimal dispersal behaviour, we suggest that these effects be routinely examined and minimized in mark-recapture studies.

The distribution and adult flight activity of obliquebanded leafroller, Choristoneura rosaceana (Harris) and threelined leafroller, Pandemis limitata (Rob.) were studied in the Okanagan and Similkameen valleys of British Columbia using traps baited with the sex pheromone of each species. Adult activity began in early June and continued through September and the two species were distributed throughout the apple-growing region of the Okanagan and Similkameen valleys. In the northern Okanagan and in uncultivated areas at higher elevation, the trap captures indicated that both species are univoltine. In the southern Okanagan and the Similkameen Valley, large numbers of both species were captured throughout the season which may indicate more than one generation. Traps captured similar numbers of adults in orchards with known infestations and in orchards lacking infestations, suggesting that males are attracted to traps in orchards from native hosts in uncultivated sites.

Thermoregulation in nests of two colonies of Vespula arenaria and two colonies of V. maculata was studied in relationship to seasonal changes in colony biomass. The colonies achieved maximum ability to resist ambient temperatures of 5 °C and maintained high nest temperatures on or within a week of achieving maximum biomass. During this period the colonies were capable of producing about.20 to.35 cal per gram of biomass per minute. The caloric production per gram required to maintain the normal nest temperatures of 30 °C and 32 °C in an ambient temperature of 25 °C was much less, but was greater for the V. maculata colonies than for the V. arenaria colonies. The greater efficiency in thermoregulation by V. arenaria is largely due to the fact that nests of this species have a greater biomass of wasps than approximately equal sized nests of V. maculata.

The last-instar larvae of 22 species of Spilomelini are described and illustrated. Diagnostic characters are given, and a key included, for North American species.

No research has previously been conducted on gall aphids on poplar in Alberta. Strickland (1953) published records of some of these aphids in his list of Hemiptera of Alberta. Manson (1931) mentioned that noctuids fed in galls of Pemphigus populitransversus Riley.

In the United States, several workers have reported on these aphids. Palmcr (1952, pp. 358-372) published a key to and some bioiogical notes on several species of the genus Pemphigus and related genera. Maxson and Knowlton (1929) gave considerable information on the life-history and classification of the tribe Pemphigini. Maxson (1923) and Hottes and Frison (1931) published keys to the same tribe. Essig (1926, pp. 259-261), Gillette (1913). Gillette and Bragg (1915), Jackson (1908), Oestlund and Hottes (1926), Patch (1913), Swaine (1919), and Williams (1910) also reported on some of the gall aphids on poplar.

Codling moth eggs were very sensitive to diflubenzuron (Dimilin), particularly when treated topically shortly after oviposition. Regression analysis showed a linear relationship between % hatch and the age at which the eggs were treated with diflubenzuron. The LC50 values for 0- to 21/2- and 3-day-old eggs were 1.1 and 17.2 ppm, respectively. Egg hatch was also inversely related to the length of time the chorion was in contact with the diflubenzuron solution. When the compound had dried on fruit or foliage, residual activity against the eggs was excellent and did not decrease markedly over a 10-day period. The surfactant, Tween 20, enhanced the contact ovicidal activity of diflubenzuron especially on older eggs. Tween 20 also improved the residual activity of diflubenzuron on foliage and immature apples but not waxy mature apples.

Diflubenzuron incorporated into artificial diet was toxic to 1st- and 2nd-instar larvae. The LC50s for the two instars were 48.2 and 8.1 ppm, respectively. When 1st instars fed on diflubenzuron + Tween 20-treated foliage for 2 days, larval entry into apples was not impaired but subsequent larval survival was reduced significantly. However, neither fruit entry nor larval survival was affected when 1st instars were reared on apples which had been dipped in 500 ppm diflubenzuron - Tween 20. Adult codling moths dipped in or fed diflubenzuron solutions showed no marked adverse effects although marginal reductions in egg viability were observed.