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.

Resorption of terminal oocytes was investigated in 3 species of grasshoppers, Melanoplus femurrubrum femurrubrum (DeGeer), M. scudderi (Uhler), and Hippiscus ocelote (Saussure). Significant differences in percentage resorption were found between species. Anterior ovarioles resorbed terminal oocytes more frequently than ovarioles in the middle and posterior regions of the ovaries. Resorption of terminal oocytes due to differences in relative ovariole age does not appear to be a factor in percentage resorption based on the lengths of developing terminal oocytes. There was no difference in percentage resorption of terminal oocytes between ovaries.

The relative density of corn-rootworm larvae was estimated in two field plots with 4 different plant spacings and with up to 4 plants clumped per location. In both fields the relationship between plant spacing and the number of corn rootworms per sample was similar with the maximum number of larvae occurring when plants were 46 or 50 cm apart. The number of plants clumped per location affected the numbers of corn rootworm in only one field. The relationship between clumping of plants and number of corn rootworms was curvilinear in this field with the most corn rootworms occurring at 3 plants per location.

Optimum size of a sample unit and within-branch distribution of overwintering spruce budworm were determined for black spruce in northern Maine. No significant differences in sample reliability were found between whole-branch and 45-cm branch-tip samples. Larval distribution on branches varied with total branch length and a model was developed to estimate the whole-branch population from a 45-cm branch tip. Use of a 45-cm branch-tip sample unit is recommended because it is biologically and statistically valid and reduces sampling costs.

The larva and pupa of Cardiocladius albiplumus Saether are described and compared with other members of Cardiocladius and the genus Eukiefferiella. The male adult is typically Cardiocladius, whereas the immature stages have many characteristics of Eukiefferiella. The traits of this species indicate a need to redefine the generic limits for Cardiocladius and Eukiefferiella.

Metatarsonemus simplicissimus Attiah, type-species of the nominal genus Metatarsonemus Attiah, 1970, was previously based on the adult male only. The adult female of this species is described herein, and descriptive notes further to those given by Attiah are included for the adult male. Characteristic structures useful for correlating females with males of this species, and the synonymy of Metatarsonemus under Tarsonemus, are discussed.

Relationships between mean egg weight and overwintering survival in the laboratory were explored in selected large- and small-egg lines and also in first laboratory generations from 5 widely separated locations. Overwintering stress was provided by prolonged storage or above average storage temperature. Under stress large eggs were shown to have greater survival than small eggs in both stocks of insects. The results explain why spruce budworm from higher latitudes (longer winters) have heavier (larger) eggs. Other effects of prolonged storage and storage selection on subsequent size and development rates in both the treatment and the F1 generations are reported.

A key, based on morphological characters of adult males, separating six traditionally recognized conifer-feeding Choristoneura species, C. pinus Freeman, C. lambertiana (Busck), C. fumiferana (Clemens), C. occidentalis Freeman, C. biennis Freeman, and C. orae Freeman occurring in Canada and Alaska is provided and illustrated. The newly discovered morphological features, the aedeagus of C. fumiferana and C. pinus with a short apical spine and with many microscopic spicules on the distal half, are used to separate these two species from their western allies C. occidentalis, C. biennis and.C. orae.

Nosema acridophagus Henry was shown to be more virulent than N. cuneatum Henry to 3rd-instar nymphs of Melanoplus sanguinipes (Fab.) following peroral inoculation with 1.0 × 106, 105, 104, or 103 spores/individual. The lethal time was dose dependent and significantly shorter and the lethal dose (LD50) was significantly lower in grasshoppers inoculated with N. acridophagus than for those inoculated with N. cuneatum. Grasshoppers inoculated with N. acridophagus died earlier and a smaller proportion survived to the adult stage compared with those inoculated with N. cuneatum. Nosema acridophagus was more infectious at the lower doses than was N. cuneatum; however, N. cuneatum reached an intensity of infection in host tissues which was 2–10 times higher. Both microsporidians appeared to have similar pathogenicity for both individually and group-reared M. sanguinipes.

Five trap designs were evaluated for their efficiency in capturing overwintering adults of the carrot weevil, Listronotus oregonensis (Le Conte). Trap catches were compared with counts of oviposition and nutrition cavities found in carrots placed on the ground. A trap consisting of 22 wooden plates, separated by metal washers and placed over a carrot which was used as bait, proved to be the most efficient. The weevils crawl between the plates, feed on the carrot, and are collected by dismantling the trap over a pan. This technique provided a seasonal record of carrot-weevil activity comparable to that obtained with carrot sections and can be used to issue insecticide-treatment recommendations prior to the beginning of the carrot-weevil oviposition period.

The relationship between the density of insect holes in the bark (X1) and the density of emerged mountain pine beetles (Y) was investigated in naturally infested lodgepole pine in south-central British Columbia. The density of exit and ventilation holes (Ho) that were present in the bark prior to emergence by mountain pine beetle averaged 10% of all holes present following the emergence period. There was a weak but significant inverse relationship between Ho and both phloem thickness and density of emerged mountain pine beetles. Painting the bark with light-color latex paint did not affect survival or the temporal pattern of emergence by mountain pine beetle but ensured identification and greatly enhanced counting of fresh exit holes. Of the several regression models investigated, the relation between Y and both X1 and X2 (= X1 – Ho) was best fitted by a log-log linear model. A method is suggested for setting limits on the size of exit holes cut by mountain pine beetle in order to exclude from X2 much of the variation caused by exit holes cut by associated insects. A simple mathematical model was developed of the relationship between mean density of exit holes and the density of emerged mountain pine beetles.

The solitary, pupal parasitoids Spalangia spp. Muscidifurax raptor oviposited supernumerary eggs on house-fly pupae exposed at 3 poultry farms in north central Florida. The percentage total parasitoidism at the 3 sites was 23.7%, 33.6%, and 77.5%, while the percentage of the hosts containing supernumerary parasitoids was 6.2%, 10.7%, and 55.8%, respectively. The average number of parasitoids found per parasitoidized pupa ranged from 1.45 to 2.96. The parasitoids did not show a density-dependent response to spatial variation in host density. Among aggregates of hosts that contained at least 1 parasitoid, percentage total parasitoidism either decreased as host density increased or was unrelated to host density. When total parasitoidism was low, females tended to avoid already parasitoidized hosts. When total parasitoidism was high, more of the hosts contained multiple parasitoids than a single parasitoid.

Post-harvest grain temperature and moisture were consistently higher at the center than at the edge roof openings of steel granaries in Manitoba in 1982 and 1983. In 1982, temperatures at the center were significantly higher in infested than in uninfested granaries and declined only slowly during a 2-week period. Several kinds of insects were found in grain samples or in beetle-detection traps inserted into grain at the center location but none was found in grain or in traps at the edge. The heaviest infestations coincided with the temperatures and moistures at the center. In 1983, initial temperatures at the center and edge roof openings were high when the granaries were filled but declined rapidly, particularly at the edge, during the next 2 months. Between late August when the granaries were filled and early November, moisture content increased at the center and edge roof openings. It was significantly greater at the surface than at a depth of 20–130 cm. Insects were found in traps inserted 1 m into the grain at the center location. The results indicate that the most likely place to find insects in filled granaries is at the center near the surface and the most opportune time to begin checking the grain is 2 months after the granaries have been filled.

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.

Both Petrova albicapitana (Busck) and P. metallica (Busck) attack Pinus contorta Dougl. in Alberta. The similarity of their larvae and of the pitch-blister nodules that they construct make it difficult to identify the 2 species in the field; however, they can be separated on the basis of their feeding damage. The abundance of males caught in pheromone traps indicates that P. metallica was more common than P. albicapitana in 1981–1984, and more widely distributed than previously recorded in Alberta. The examination of the feeding damage and the pheromone trapping of males indicate P. metallica occur only in stands of P. contorta in Alberta. Petrova albicapitana, however, was collected in stands of P. contorta, P. banksiana Lamb., and a mixture of P. contorta and P. banksiana. The 2 species differed in seasonal occurrence and abundance at different elevations.

The susceptibility of 31 species of agricultural insect pests representing 7 families of Lepidoptera, 3 of Diptera, and 3 of Coleoptera to the entomogenous nematodes Steinernema feltiae Filipjev and Heterorhabditis bacteriophora Poinar, were investigated in the laboratory. Of the 27 species found susceptible to S. feltiae, 19 are reported for the first time. Of the 21 species killed by H. bacteriophora, 15 are reported for the first time. The Lepidoptera as a group were highly susceptible to the nematodes. On the basis of larval mortality caused by the nematodes, of nematode reproduction in insect cadavers, and of the known economic importance and life histories of the test insects, S. feltiae was judged to warrant further research as a possible biological-control agent against Euxoa ochrogaster (Guenée), E. auxiliaris (Grote), Agrotis orthogonia (Morr.), Actebia fennica (Tauscher), Mamestra configurata Walker, Delia radicum (L.), D. antiqua (Meig.), and Zygogramma exclamationis (F.).

The Ceratozetidae of arctic western North America, represented by 12 species in 9 genera, are discussed. A new genus, Cyrtozetes, and species, Cyrtozetes denaliensis, are proposed, and Trichoribates copperminensis Hammer, T. polaris Hammer, Svalbardia paludicola Thor, Iugoribates gracilis Sellnick, Diapterobates notatus (Thorell) both adults and immatures, D. variabilis Hammer, Sphaerozetes arcticus Hammer, Fuscozetes sellnicki Hammer, Melanozetes longisetosus Hammer, and Ceratozetes spitsbergensis Thor and C. parvulus Sellnick are redescribed. Immatures of T. polaris, S. paludicola, F. sellnicki, and M. longisetosus are described. Distribution records of Ceratozetes gracilis (Michael) in the western North American arctic are listed. The new combination, Cyrtozetes shiranensis (Aoki and Fujikawa), is proposed.

Three native species of parasites and 3 hyperparasites were reared from pupae of the European winter moth, Operophtera brumata (L.), and the Bruce spanworm, O. bruceata (Hulst), collected in the Victoria area of Vancouver Island, British Columbia, in 1981. Two of the pupal parasites also attacked other species of Geometridae. Two species of hyperparasites attacked Cyzenis sp., and the third parasitized ichneumonid primary parasites of Operophtera spp. The hyperparasites may have a negative impact on the biological-control agents, Cyzenis albicans (Fall.) and Agrypon flaveolatum (Grav.). Total parasitism by pupal parasites of the Operophtera host complex was about 4%. Descriptions and illustrations of cephalic structures of final-instar larvae of the parasites and a key for their separation are given.

Residue analysis of apple foliage obtained from an orchard treated with the insecticides cypermethrin, fenvalerate, deltamethrin, permethrin, and azinphos-methyl revealed detectable residues on the leaves 8–9 weeks after the last treatment. Laboratory studies of foliage showed that of the synthetic pyrethroids, permethrin was initially as toxic as the other synthetic pyrethroids; however, its toxicity decreased considerably by the 5th and 6th week post-treatment. Azinphos-methyl was the least persistent and toxic insecticide evaluated. Unless new pest-management strategies are developed, the use of synthetic pyrethroids post-bloom in an integrated-pest-management program would not be desirable where Amblyseius fallacis (Garman) is the principal predator of phytophagous mites.

Nine species of Epidamaeus of subarctic western North America and extreme northeastern USSR are discussed. Six new species, Epidamaeus aborigensis, E. chukchi, E. floccosus, E. gilyarovi, E. koyukon and E. nasutus, are proposed; E. gibbofemoratus, E. hastatus and E. tenuissimus, previously described by Hammer, are redescribed.