The possibilities of using genetic principles to improve biotic agents used in biological control are discussed, and a number of examples quoted where possibly useful racial differences between parasites occur.

However, the main conclusion is that in introductions of biotic agents the principal aim should be to have as much genetic variability as possible in the material released, rather than to try and select a priori certain apparently suitable strains.

Nutritional studies on plant sucking insects have not made outstanding progress in the past decade. The information on the rearing of aphids on prepared liquid foods is rather scanty. Carter (1927, 1928, 1945) developed techniques for the artificial feeding of homopterous insects, particularly leafhoppers and mealybugs. Fife (1932) and Severin et al. (1928) devised cages for the artificial feeding of leafhoppers. These authors suggested many excellent ideas on the use of membranes, but the works of Hamilton (1930, 1935) on the green peach aphid, Myzus persicae (Sulz.). appear to be the most thorough source of informarinn on the artificial feeding of aphids. Pletsch (1937) also developed a device for the artificial feeding of aphids and his apparatus presents several advantages over previously described devices. Various types of cages and membranes were used by the above workers with limited success. They have all succeeded in getting homopterous insects to feed temporarily on special diets through different types of membranes, but they were unable to maintain the development of these insects and have them reproduce under artificial conditions.

We tested six behavioral chemicals, pityol, conophthorin, 4-allylanisole, verbenone, 2-hexenol, and α-pinene, in a series of field trials directed at six combinations of Conophthorus Hopkins – Pinus L. spp. (Pinaceae) in sites distributed across North America. Beetle – host tree combinations included Conophthorus ponderosae Hopkins on Pinus ponderosa Laws., C. ponderosae on Pinus monticola Dougl., Conophthorus conicolens Wood on Pinus pseudostrobus Lindl., Conophthorus teocotum Wood on Pinus teocote Schl. & Cham., Conophthorus coniperda (Schwarz) on Pinus strobus L., and Conophthorus resinosae Hopkins on Pinus resinosa Ait. trans-Verbenol was tested only on C. resinosae on P. resinosa. Traps baited with pityol caught more beetles than unbaited traps in nearly all of the assays, and conophthorin consistently inhibited male beetle response to pityol for all species tested. Behavioral responses of species of Conophthorus to α-pinene appeared to parallel host phylogeny, inasmuch as beetles using Haploxylon pines as hosts utilized α-pinene as a synergist for the beetle-produced pityol, whereas beetles using Diploxylon pines as hosts did not. α-Pinene was a synergist for pityol in C. ponderosae on P. monticola and C. coniperda on P. strobus, but not for species of Conophthorus on any other pines tested. Conophthorus ponderosae on P. ponderosa was the only beetle–host combination tested where verbenone was a synergist for pityol, but this effect was not consistent in all years of testing. It was also the only beetle–host combination in which 4-allylanisole was a repellent. For all other beetle–host combinations, verbenone was neutral to slightly repellent and 4-allylanisole was either synergistic or neutral in pityol-baited traps. Promising synergists and interruptants/repellents were identified for implementation in pest-management regimes, including conophthorin as an interruptant for all species of Conophthorus tested, 4-allylanisole as an interruptant for C. ponderosae on P. ponderosa, α-pinene as a synergist for pityol in all species tested on Haploxylon pines, and 4-allylanisole as a synergist for pityol in C. conicolens and C. coniperda.

Protein fed to adults of the carrot rust fly, Psila rosae F., enhanced oviposition: the addition of yeast hydrolysate to the sugar diet resulted in a 50% increase in oviposition, giving an average of 75 eggs per female.A description is given of a simple oviposition device, which allows normal oviposition (compared with sand).Carrots planted in sand gave best rearing results when inoculated with eggs 14 days after insertion. Germinating carrot seeds placed on top of the sand improved the rate of development of the eggs to pupae from 40% to 62%.

The development of gypsy moth larvae was monitored in the laboratory on the foliage of 39 species belonging to 18 genera in the Araucaraceae, Cupressaceae, Ginkgoaceae, Pinaceae, Taxaceae, and Taxodiaceae. Larval survival through successive molts, time of larval development, live female pupal weights, and adult female production of ova were measured as indicators of host plant suitability for the gypsy moth. The criteria for distinguishing the most suitable hosts were as follows: (1) greater than 80% survival of first-instar larvae, (2) development to pupation in less than 41 days, (3) female pupal weights over 1099 mg, and (4) the production of more than 350 ova. The most suitable species were in the Pinaceae, in particular, Cedrus deodara (Roxb. ex Lamb.) G. Don, Larix decidua Mill., and Picea pungens Engelm. The least suitable species were in the Cupressaceae, Ginkgoaceae, and Taxaceae. First-, second-, and third-instar larvae often differed in their ability to survive on new foliage compared with foliage from the previous year. Overall, first-instar larvae successfully developed into adults on 20 of the species tested but second-instar larvae developed into adults on 29 of the species tested. First- through fourth- or fifth-instar larvae failed to develop into adults on eight of the species tested.

The tribe Ipini (sub-tribe Ipina) contains the genera Pityokteines Fuchs, Ips De Geer, Orthotomicus Ferrari (Balachowsky, 1949) and Orthotomides Wood. Some of the characters used in previous keys in this group are not constant within a genus but are useful when combined with other characters and when exceptions are specified. This article presents a key to the genera, with a discussion of some characters that have been used in previous keys. A new species is described and new synonymy and a new combination are established.

The field population dynamics of pea aphid (Acyrthosiphon pisum) and blue alfalfa aphid (A. kondoi) in alfalfa (Medicago sativa), as influenced by weather, competitors (Egyptian alfalfa weevil = EAW, Hypera brunneipennis), predation from coccinellids (Hippodamia convergens) and harvesting practices, are examined with a stochastic multitrophic level simulation model. The model incorporates a demand-driven functional-response model to estimate prey consumption, and a metabolic pool model to determine the rates and priorities of food allocation to respiration, growth, reproduction, and egestion.

The model results compare favorably with field data, and are used to examine the effects of removal of each of the above factors on the dynamics of the aphids. The model shows that the observed density of EAW did not affect the aphid dynamics, but did reduce the standing crop of alfalfa. The predator H. convergens had a significant effect on the population dynamics of the aphids and the plant. Harvesting greatly affected the aphid population dynamics, as well as the dynamics of plant growth and reserve accumulation. However, high temperatures mediated through species-specific respiration costs and possibly a fungal pathogen were responsible for the observed dominance of blue aphid populations in the cool parts of the year and pea aphid populations during warmer parts of the year.

The Canadian insect fauna is too inadequately understood to support well-informed assessments about its conservation status; however, the foregoing collection of synthetic papers illustrates potential threats from industrial forestry. Loss of forest species and dramatic changes in forest insect assemblages driven by forestry activities are well illustrated by studies from places where industrial forest management has been more intensive or of longer duration. Improved understanding of how arthropod species are coupled to habitats, especially microhabitats, appears to be central to progress toward their conservation. Studies of arthropods conducted at the species level are most relevant for applied conservation purposes, because only species-level work that is well documented with voucher specimens provides adequate comparative data to document faunal change. Although taxonomic infrastructure required to support such work is seriously under-resourced in Canada, entomologists can help themselves by producing useful modern resources for species identification, by undertaking collaborative biodiversity work that minimizes the split between taxonomists and ecologists, and by supporting incentives for work at the species level. Securing the future of arthropod diversity in Canadian forests through effective policy will require sound regionally defined bases for whole-fauna conservation that mesh with broader land-use planning. Building these will require a practical understanding of how “ecosite”-classification systems relate to arthropod diversity, accurate inventories of the predisturbance forest fauna in all regions, and development of sound monitoring plans designed to both detect faunal change efficiently and identify its drivers. Such monitoring plans should include both baseline inventories and monitoring of designated control areas. In addition, effective biomonitoring efforts will facilitate the development of suites of arthropod indicators, accommodate both seasonal (especially phenological) and annual variation, clarify the relationship between cost-effective samples and reality, and ensure adequate consideration of “rare” species. Return on investment in monitoring will depend on effective preplanned linkage to policy development that can respond to drivers of faunal change in a way that effectively addresses undesired changes.

The North American members of the genus Operophtera Hübner (Lepidoptera: Geometridae) are revised to include three species: O. brumata (L.), O. bruceata (Hulst), and O. danbyi (Hulst). Operophtera occidentalis (Hulst) is now treated as a subspecies of O. bruceata. All species are illustrated and characters to distinguish the species are given. The most useful characters for separating O. brumata from O. bruceata include the following: (1) hindwing dorsal surface with discal dot, which is almost always visible on O. bruceata but absent from O. brumata; (2) forewing colour, which is grey-brown or light brown in O. bruceata but reddish-brown in O. brumata; (3) abdomen colour, which is golden-brown to brown in western O. bruceata but brown in O. brumata; and (4) the costa of the forewing ventral surface, which is usually golden-brown in O. bruceata but brown in O. brumata. The structure of the genitalia of these two species allows hybridization between O. bruceata males and O. brumata females, but not vice versa.Hypothesized species interrelationships between palaearctic and nearctic Operophtera are illustrated in a cladogram. Maps for the distribution of each species are also included.

Predatory insects and spiders were collected from apple orchards in two geographic regions of Central Washington State, United States of America to assess seasonal phenology and diversity of the generalist predator community. Arthropods were collected from orchard canopy every 3–7 days over two growing seasons (March–October) at seven organically managed and two insecticide-free orchards. Over 35 000 specimens and 80 species of spiders (Araneae), ladybeetles (Coleoptera: Coccinellidae), lacewings (Neuroptera), and predatory true bugs (Hemiptera) were collected. Composition of insect and spider communities differed between the two geographic regions. Indicator species analysis identified several species that had a significant association with one of the two regions. Counts of the most common taxa were examined in detail on a calendar date basis to determine seasonal phenology of adult and immature stages. We observed substantial differences among taxa in number of generations, seasonal timing of first appearance in orchards, overwintering stages, and seasonal occurrence of the adult and immature life stages in orchards. Understanding seasonal phenology of natural enemies in orchards is a core requirement in integrated pest management programs for apple pests, and results of this study provide this information for the generalist predator community of orchards in the Pacific Northwest.

The within-cone distribution of Megastigmus spermotrophus Wachtl (Hymenoptera: Torymidae), the Douglas-fir seed chalcid, infesting Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] cones from north-central France was compared with that in samples from California. Results indicate that the mid-region of cones was more intensively utilized by seed chalcids in France than in California, whereas in the northwestern United States the mid-region is characteristically occupied by dipteran and lepidopteran species. This difference in distribution may explain the large discrepancy in infestation rates on the two continents. The potential impact of this finding on pest management strategies is discussed.

Cones were measured and dissected or X-rayed to determine seed chalcid infestation levels. Analysis of covariance performed on data from cones that were collected in 1986 and dissected showed cone diameter at maturity to be a highly significant factor in attack rate, although slopes were different among clones. Between-tree variation was also significant, but clonal source was not. Cone diameter, clonal source, and between-tree variation constituted 87.1% of the variation in rate of attack by the seed chalcid. Although clone was not a significant factor in data from dissected cones, X-rayed cones showed significant differences in attack rates for some clones.

It is unrealistic to achieve high-resolution biodiversity inventories required to support local conservation strategies over large areas; however, benchmark associations between arthropods and ecosystem classification can support landscape scale biomonitoring. We investigated habitat associations of ground-dwelling spiders (Araneae), staphylinid beetles (Coleoptera: Staphylinidae), and carabid beetles (Coleoptera: Carabidae) in three forest ecosystems in northwestern Alberta, Canada and also studied the effect of variation in depth of pitfall trap installation on catch. Composition and diversity of all three taxa were correlated with the ecosystem classification map, and 20 species were strong indicators of particular habitats. The black spruce (Picea mariana (Miller) Britton, Sterns, and Poggenburg; Pinaceae) bog supported fewer species and individuals of beetles but this trend was not observed for spiders because of natural history traits associated with their performance in this environment. Pitfall trapping biases were constant among habitats enabling proper comparison of ground-dwelling invertebrate assemblages. Three species of beetles (Agonum retractum LeConte (Coleoptera: Carabidae), Pterostichus brevicornis (Kirby) (Coleoptera: Carabidae), and Quedius velox Smetana (Coleoptera: Staphylinidae)) were disproportionally active beneath the soil surface, as catches were greater in pitfall traps with the lip situated 15–25 cm below the soil surface. Thus, even highly standardised trap placement will influence the concept of biodiversity achieved through pitfall trapping, because some target organisms are disproportionately active in subterranean zones.

All stages of the spruce budworm parasite Glypta fumiferanae (Viereck) are described in this paper. Illustrations of all stages are presented.

Effects of soil moisture, texture, and temperature on larval and pupal survival and development of the bean leaf beetle, Cerotoma trifurcata (Forster), were investigated in laboratory and greenhouse studies. In both cases, mortality rates were highest during the first instar, decreased during subsequent larval instars, then increased during the pupal stage. Under constant laboratory conditions, survival and adult weights were highest in wet and organic soils and lowest in dry and loamy sand soils. In wet and organic soils, developmental time was shorter than in other soils.

Although survival/plant in the greenhouse was greatest in sandy clay loam, survival/nodule was greatest in organic soil.

These studies, together with oviposition preference, egg survival, and larval movement experiments agree with field observations and provide some explanations for observed patterns of local and regional abundance of the bean leaf beetle in North Carolina.

Anti-attractants, defined as substances with little or no intrinsic repellency but with the property of diminishing the attractiveness of a lure, are predicted on spectroscopic grounds and their existence demonstrated in experiments with Ceratitis capitata (Wiedemann), and Dacus cucurbitae (Coquillett).

The tribe Xyloterini is widely distributed in the Holarctic realm. It is comprised of three rather small but well known genera. The largest of these, Trypodendron Stephens, consists of about a dozen species and occurs throughout the Holarctic realm; five of these species occur in North America. Dendrotrypum Schedl contains six species that are known only from eastern Asia. Xyloterinus Swaine contains one species from eastern North America.

Single aerial applications of Bacillus thuringiensis Berliner (Bt) to control infestations of the eastern spruce budworm (Choristoneura fumiferana Clemens) have had varied operational success. Double applications are too expensive for general use, but might prove useful if directed to areas where the initial application was unsuccessful. This requires forecasts of the efficacy of the initial application in operational spray blocks within 4–5 days.

Data were collected in 30 spray blocks in 1989 in a feasibility study to determine if such forecasts of spray efficacy could be made from the prespray budworm population density, N0, and from the proportion of the population that had ingested a lethal dose Bt within 2 days of application, M. A mathematical model forecasting the postspray budworm population density, NF, was derived from population-dynamic considerations and fitted (r2 = 0.48, p < 0.0001):

The proportion of current foliage defoliated, D, depended (r = 0.81) on N0 and on whether the block was sprayed (I = 0) or not (I = 1):

Only one measure of defoliation involved M in any statistically significant way. The predicted (from values of N0) proportion of defoliation prevented by Bt application, dD, was weakly (r2 = 0.25, p = 0.002) related to M:

The large proportion of the variation in efficacy that remains unexplained by the models involving M limits the operational utility of this approach as it now stands for specific sites. The potential for further development of these models as decision support tools for fairly large spray blocks is discussed in terms of improving the sampling plan and including additional predictor variables.

Methods are also presented that reduce bias in calculations of population reduction (Abbott 1925) and foliage protection when data are available from few control and many treatment blocks.

The species of Macroneura Walker are revised for America north of Mexico. Seven species are recognized, of which M. camptoptera, M. cerasma, M. chrysosinamora, and M. tanyaris are described as new; M. meteori (Gahan) is removed from synonymy with M. epicaste (Walker) and accorded specific status. Eupelmus melanderi Brues is synonymized with Eupelmus dryorhizoxeni Ashmead and the taxa are reassigned to Eupelmus Dalman from Macroneura. Diagnostic features are given to distinguish females and males of Macroneura from members of other eupelmine genera; putative phylogenetic relationships of Macroneura are discussed, and a key is presented to distinguish females and known males of the North American species.

The two cruciferous plants Thlaspi arvense and Lunaria annua are largely unacceptable to the striped flea beetle, Phyllotreta striolata, which normally feeds on cruciferous plants. Results suggest that these plants contain chemical compounds that act as feeding deterrents to the beetles. Methanol fractions of the leaves of both plants deterred feeding when added to the surface of acceptable radish leaves. An alkaloid fraction of Lunaria annua was, surprisingly, not deterrent. Evidence suggests that saponins in both Lunaria annua and Thlaspi arvense may be a major reason for the low acceptability of these plants as food for Phyllotreta striolata. Commercial saponins are highly deterrent at concentrations of 0.05% and above.

The eggs and oviposition sites of six species of predatory mirids from Nova Scotia apple orchards are described. These species are Hyaliodes harti Knight, Atractotomus mali (Meyer), Deraeocoris fasciolus Knight, Diaphnidia pellucida Uhler, Blepharidopterus angulatus (Fall), and Pilophorus perplexus D. & S. The differences between the eggs of each species are great enough to identify them in situ.