Thirty-two species of Pediobius (Hymenoptera: Chalcidoidea) are reviewed, 9 newly noted from both Europe and North America. New Nearctic species include P. adelphae, disparis, geshnae, liocephalatus, louisianae, magniclavatus, ni, ocellatus, pseudotsugatae, and strobilicola. Pediobius rugosithorax (Cwfd.) and kansensis (Grlt.) are newly noted as junior synonyms of acantha (Wlk.); lithocolletidis (Ashm.) of albipes (Prov.); longfellowi (Grlt), of alcaeus (Wlk.); wilderi (How.) of brachycerus (Thoms.); (Asecodes) P. albitarsis (Ashm.), tarsalis (Ashm.), and ashmeadi (Cwfd.) of crassicornis (Thoms.); utahensis (Cwfd.), longus (Grlt.), and perdubius (Grlt.) of eubius (Wlk.); (Entedon) P. albitarsis (Ashm.) and sexdentatus (Grlt.) of facialis (Giraud); splendens (C. & D.) of foliorum (Geoffr.); glabrata Blck. of phyllotretae (Ril.). Pediobius termerus (Wlk.) is recorded for the first time in Nearctic. A key to species and a host–parasite list are included.

Several host–parasitoid models were examined to assess the feasibility of parasitoid inundation as a means of pest control or eradication. The approach is comparative, to assess independently the effects of various ecological factors on the ease of control by this means. For most of the models, there exists a critical inundation rate, I*, above which the host population is eradicated, provided inundative releases continue beyond the time of eradication. The existence of density-dependent mortality in the hosts reduces the time to eradication but does not affect I*. Density dependence in the parasitoids, however, usually increases I*. The existence of hyperparasitoids appears to have no effect on the ease of host eradication.

A method of rearing Paraphlepsius irroratus (Say) under artificial conditions was developed by using a leguminous plant species as the oviposition host and a gramineous species as the food plant for nymphs. Nymphs completed their development on all 10 gramineous species tested. Total time for completion of the 5 nymphal instars ranged from 31.8 to 59.2 days, depending on the plant species used. With the exception of Alopecurus pratensis, all monocotyledonous species tested were found to be suitable food plants for nymphs, allowing 50% or more of the insects to survive for 3 weeks or more. Only 5 dicotyledonous species supported a similar survival level of nymphs. Adult survival remained above the 50% level on Apium graveolans var. dulce, 6 members of the Leguminosae, and all members of Composite with the exception of Callistephus chinensis. Survival of adult leafhoppers on monocotyledons was relatively high after 1 week but considerable mortality followed longer confinement. Although nymphs emerged from eggs laid on a wide range of plant species, the numbers recorded on monocotyledons suggest that monocots are important as oviposition hosts for P. irroratus in nature.

The winter survival of artificial and natural infestations of pupae of the bertha armyworm, Mamestra configurata Walker, are assessed in relation to soil temperature and snow depth. The results are discussed in relation to the hypothesis that winter mortality affects the spatial distribution and timing of outbreaks of this pest. Pupae did not survive a Manitoba winter in snow-free field plots, but 55% survived in plots with 5 or 10 cm of snow. Pupal survival in the plots was estimated accurately from daily soil temperatures using a computer simulation model, confirming that natural soil-temperature regimes can affect pupal survival. Based on the model, an equation was derived to relate pupal survival to the number of winter days with soil temperatures of −10°C or less. For natural populations in canola fields, the model, in conjunction with a model that estimated soil temperatures from standard meteorological data, could estimate the observed survivals. However, the estimates were sensitive to estimated snow cover and the measurements of snow cover in the fields were incomplete. There was a significant negative relationship between mortality and snow depth measured at the end of January up to about 20 cm. The sensitivity of soil temperature and therefore pupal survival to small changes in snow depth makes it difficult to predict pupal survival for large areas. Although the distribution of outbreaks of bertha armyworm coincided with the areas of the canola-growing region where winter soil temperatures were highest, the summers when outbreaks occurred were not preceded by winters with high soil temperatures, nor were summers without outbreaks associated with low soil temperatures during the preceding winters. Winter soil temperatures apparently affected the spatial distribution of outbreaks, but variation in pupal survival due to winter soil temperatures did not, by itself, initiate or terminate bertha-army worm outbreaks.

Chrysopidae in Canada comprise 24 species in 9 genera and 2 subfamilies. Additional southern species are mentioned, 1 as a new combination, and other nomenclatorial changes are reviewed in relation to the Canadian fauna. Generic diagnosis of males employs sternum VIII + IX, the arcessus, gonapsis, pseudopenis, and tignum. Generic diagnosis of females is based on the dorsal furrow, ectoprocts, spermatheca, subgenitale, and a non-genitalic trait, the innermost gradate crossvein in the wings. The ecological implications and inherent difficulties in taxonomy are discussed for coloration in Chrysopidae, to develop a practical key to differentiate 26 species using color and other non-genitalic traits. A checklist summarizes maps of the geographic distribution in Canada and notes species in Alaska, based on specimens examined. Patterns of distribution for the Canadian chrysopid fauna are either Holarctic for 1 species or indigenously Nearctic, with eastern, western, or boreal foci. Disjunctions are apparent for species with a more southern, transcontinental distribution, which enter Canada primarily in Ontario and British Columbia. Life-history and bionomic notes are limited to 6 species in Canada, for which synonymies and figures are based on specimens examined. Most data originate from studies performed in Ontario. There are 5 species of parasites from 2 chrysopids. Hosts include 11 species of insects and mites, with 2 cases of hyperpredation. Three insecticides account for the more recent scarcity of chrysopids in the Niagara region. Conclusions relate the following: variable color in the 1 Holarctic species to post-glacial mingling in the northwest; gaps in temporal and spatial distribution to extinctions in progress; and renewed interest in Chrysopidae to earlier research on this group in Canada.

The western Nearctic genera Neothremma and Farula are assigned to the family Uenoidae, previously comprising only the type genus Uenoa from Asia; a new genus Sericostriata with S. surdickae n. sp. from western North America is also added to the family. Traditionally assigned to the Limnephilidae where they have been always anomalous, Neothremma and Farula are shown to share many synapomorphic larval characters with Uenoa; under close examination, characters of the adults support this relationship. Familial and generic diagnoses are provided, reflecting the revised composition of the Uenoidae. Generic keys to adults, larvae, and pupae are given; species are briefly reviewed and keys given to adults; Uenoa arcuata n. sp. is described from Assam, Uenoa janetscheki Botosaneanu is placed as a junior subjective synonym under U. hiberna Kimmins, and Neothremma laloukesi Schmid as a junior subjective synonym of N. alicia Dodds and Hisaw. Phylogenetic relationships among the genera are considered. This study is an instructive example of the importance of larvae in providing data for the systematics of Trichoptera.

The onion maggot, Delia antiqua (Meigen), is the most important pest of Allium spp. in temperate regions of the northern hemisphere (Loosjes 1976; Ellis and Eckenrode 1977). If left uncontrolled, the onion maggot can cause from 20 to 100% crop losses, especially in light organic soils. In the early 1950's, with the development of organochlorine insecticides, onion growers obtained good control of onion maggot populations (Finlayson et al. 1959), but the pest rapidly developed resistance to these toxicants (Harris 1977). The chlorinated hydrocarbons were replaced by the less persistent organophosphorus and carbarnate insecticides (Hanis et al. 1981), but the onion maggot was reported to become resistant to these compounds (Harris et al. 1981; Carroll et al. 1983). Among alternatives to the use of insecticides to control the onion maggot are the entomopathogenic fungi and their metabolites. The potential of mycotoxins as rnicrobially derived insecticides has been investigated by several researchers and reviewed recently by Roberts (1981).