Survey of parasitoids and hyperparasitoids (Hymenoptera) of the green peach aphid, Myzus persicae and the foxglove aphid, Aulacorthum solani (Hemiptera: Aphididae) in British Columbia

We surveyed the parasitoids and hyperparasitoids of the green peach aphid, Myzus persicae, and the foxglove aphid, Aulacorthum solani in the lower Fraser Valley of British Columbia, Canada. Field surveys were conducted using isolated pepper plants, with aphids, as trap plants. Primary parasitoids recorded from field surveys were Aphidius ervi, A. matricariae, Praon gallicum, P. unicum, P. humulaphidis, Ephedrus californicus, Diaeretiella rapae, Monoctonus paulensis, Aphelinus abdominalis and A. asychis. Diaretiella rapae only emerged from green peach aphids, and Ephedrus californicus only emerged from foxglove aphids. Aphidius matricariae was the most abundant primary parasitoid species reared from both aphid species. Hyperparasitoid species collected belonged to the genera Dendrocerus, Asaphes, Alloxysta, Pachyneuron and Syrphophagous. In greenhouses, Dendrocerus carpenteri was the dominant hyperparasitoid species. Aphidius and Aphelinus spp. were attacked by hyperparasitoids at similar rates. In the field, Aphidius spp. were attacked by five species of hyperparasitoid, and Aphelinus spp. were attacked by one, Alloxysta ramulifera. In general, the rate of attack by hyperparasitoids was much lower in field surveys than in our collections from greenhouses

Variation in levels of acceptance, developmental success, and abortion of Halyomorpha halys eggs by native North American parasitoids

Using native North American parasitoid species (Hymenoptera: Scelionidae) that often unsuccessfully attack the eggs of the invasive brown marmorated stink bug Halyomorpha halys (Hemiptera: Pentatomidae), we assessed variation in traits that may determine the parasitoids’ ability to adapt to the invasive host by either exploiting or avoiding H. halys eggs (acceptance, developmental success). We also assessed variation in the parasitoids’ ability to induce H. halys host egg abortion, which may contribute to biological control of H. halys in invaded areas. The first set of experiments evaluated intra- and interspecific variation using standardized laboratory tests with iso-female lines of Telenomus podisi and Trissolcus euschisti that included matching of detailed behavioural observations of acceptance with developmental outcomes. In a second set of experiments, we assessed how variation in developmental ability and abortion induction may affect levels of biological control by indigenous parasitoid species. We examined a broader sample of parasitoids that emerged from field collections of egg masses of an indigenous north American stink bug Podisus maculiventris in a region newly invaded by H. halys. Results from the first set of experiments showed high levels of acceptance of H. halys eggs among iso-female lines of parasitoids, but offspring development success was almost zero. H. halys egg abortion due to unsuccessful parasitism was often very low and varied among iso-female lines only for T. podisi. In the second set of experiments we never observed increases in abortion levels of Halyomorpha halys eggs above natural levels, even for the two species (T. euschisti and T. podisi) that were observed to oviposit in and abort H. halys eggs in the first set of experiments. We conclude that while there may be some variation in behavioural and physiological parameters mediating acceptance and abortion of H. halys eggs by native North American egg parasitoids, there does not appear to be significant variation in developmental success. Moreover, current biological control impact of H. halys eggs via host egg abortion is likely very low

Evidence of established brown marmorated stink bug populations in British Columbia, Canada

We report four new detections of invasive agricultural pest Halyomorpha halys (Stål) (Hempitera: Pentatomidae), the brown marmorated stink bug, in the Lower Mainland and Okanagan Valley regions of British Columbia (BC), Canada, in 2015 and 2016. These finds include two confirmed breeding populations, as well as homeowner collections at the same residence in two consecutive years. Preliminary comparisons of mitochondrial DNA haplotypes from these collections suggest that H. halys populations in BC are the result of movement and spread of existing populations in North America, likely from the Pacific Northwest USA

Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study

Background: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods: This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings: This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (74·0%) had emergency surgery and 280 (24·8%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (26·1%) patients. 30-day mortality was 23·8% (268 of 1128). Pulmonary complications occurred in 577 (51·2%) of 1128 patients; 30-day mortality in these patients was 38·0% (219 of 577), accounting for 81·7% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 1·75 [95% CI 1·28–2·40], p\textless0·0001), age 70 years or older versus younger than 70 years (2·30 [1·65–3·22], p\textless0·0001), American Society of Anesthesiologists grades 3–5 versus grades 1–2 (2·35 [1·57–3·53], p\textless0·0001), malignant versus benign or obstetric diagnosis (1·55 [1·01–2·39], p=0·046), emergency versus elective surgery (1·67 [1·06–2·63], p=0·026), and major versus minor surgery (1·52 [1·01–2·31], p=0·047). Interpretation: Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding: National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research

Estimating Susceptibility of Biological Control Agents to Pesticides: Influence of Life History Strategies and Population Structure

In this study we examined the influences that differing life history strategies and population structures at the time of pesticide exposure have on population susceptibility to pesticides. We used life table data and a matrix projection model to incorporate combinations of mortality (lethal effect) and reductions in fecundity (sublethal effect) into estimates of intrinsic population growth rates (r) for a predator, the seven-spot lady beetle, Coccinella septempunctata L., and its prey, the pea aphid, Acyrthosiphon pisum Harris, and an aphid parasitoid, Diaeretiella rapae (M\u27Intosh). All three species exhibited differences in key life history variables. The aphid had the highest r and shortest generation time, the ladybeetle had the lowest r and longest generation, while the parasitoid exhibited intermediate life history characteristics. When the model was run with populations started as neonates (aphids) or eggs (lady beetle, parasitoid) for each species, ladybeetle populations were much more susceptible than either aphid or parasitoid populations 30 days after simulated exposure to a pesticide. For example, 50% mortality and a 50% reduction in fecundity resulted in a population headed toward extinction (negative r) for the ladybeetle while the parasitoid population grew exponentially (positive r) even after sustaining 70% mortality and a 70% reduction in fecundity. The aphid species maintained exponential growth after sustaining 80% mortality and an 80% reduction in fecundity. Thus, differences in life history variables accounted for the greater susceptibility of the ladybeetle to a pesticide than its aphid prey or the parasitoid over a set time interval. These differences in susceptibility were greatly reduced when the model was run starting with a mixed age/stage population (the stable age distribution) for each species indicating that population structure at the time of pesticide exposure plays a critical role in population susceptibility. These results suggest that life history attributes as well as population structure at the time of pesticide exposure both play a major role in population susceptibility to pesticides, highlighting the need to explicitly consider differences in life history variables among species when calculating compatibility of pesticides and biological control agents as well as the population structure of beneficial species at the time of pesticide application. (C) 2003 Elsevier Inc. All rights reserved

First detection of the samurai wasp, Trissolcus japonicus (Ashmead) (Hymenoptera, Scelionidae), in Canada

We report the first detection of Trissolcus japonicus, an exotic Asian egg parasitoid and the primary candidate for classical biological control of the invasive brown marmorated stink bug, Halyomorpha halys, in Canada. Twenty-eight Trissolcus japonicus emerged from an H. halys egg mass from a site heavily infested by H. halys in Chilliwack, British Columbia, in 2018. This egg mass was deployed and retrieved as part of ongoing sentinel egg mass surveys for natural enemies of H. halys from 2017–2018 in coastal and interior British Columbia (total of 1,496 egg clusters at 16 sites). The identification of T. japonicus was based on biology (high levels of successful emergence from H. halys eggs), morphology, and mitochondrial DNA sequences. Trissolcus japonicus was not detected at any other survey sites in 2017–2018; however, three species of indigenous egg parasitoids were found attending or emerging from H. halys egg masses at low levels (<4%) at several sites. The origin of the detected T. japonicus, the extent of its establishment in British Columbia, and its ultimate impact on H. halys populations remain to be determined. Nonetheless, the detection of this exotic biological control agent in Canada concurrently with regulatory review of its intentional importation and release is emblematic of the current uncertainty around regulatory control on the movement of biological control agents across borders

Genetic relationships among laboratory lines of the egg parasitoid Trissolcus japonicus from native and adventive populations

Candidate biological control agents of invasive insect pests are increasingly being found in new geographic regions as a result of unintentional introductions. However, testing the degree of genetic differentiation among adventive and native-range populations of these agents is rarely done. We used reduced-representation sequencing of genomic DNA to investigate the relationships among laboratory lines of Trissolcus japonicus (Ashmead) (Hymenoptera, Scelionidae), an egg parasitoid and biological control agent of the brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera, Pentatomidae). We compared sequences from multiple adventive populations in North America (Canada, USA) and Europe (Switzerland) with populations sourced from part of its native range in China. We found considerably more genetic variation among lines sourced from adventive populations than among those within native populations. In the Pacific Northwest of North America (British Columbia, Canada and Washington State, USA), we found preliminary evidence of three distinct genetic clusters, two of which were highly dissimilar from all other lines we genotyped. In contrast, we found that other adventive lines with close geographic proximity (two from Ontario, Canada, three from Switzerland) had limited genetic variation. These findings provide a basis for testing biological differences among lines that will inform their use as biological control agents, and provide evidence to support a hypothesis of several independent introductions of T. japonicus in western North America from different source areas