Simulating the Potential Distribution and Abundance of the Brown Marmorated Stink Bug (Halyomorpha halys) under Future Climate Scenarios in Switzerland

The climate in Switzerland is changing. Depending on the emission scenario and time period, the projected increase in temperature is 2.7-4.8°C and the projected decrease in precipitation is 18-28%. There is scientific evidence that climate change will increase economic damage by agricultural pests. The prevention and management options of alien species are cost and time intensive. Climate change will improve the long-term suitability of potential new areas and amplify the need for action. Therefore it is highly important to assess the risk of alien species under future climate conditions and to plan an efficient monitoring and to develop management strategies. The brown marmorated stink bug (Halyomorpha halys) is an extremely polyphagous insect and has invaded North America and Europe around 2004. Especially in Italy it has become a relevant fruit pest. In Switzerland fruit damage have been reported from the canton Ticino and since 2017 also from the canton Zurich. Climate Impact studies are of great importance to develop adaptation strategies. In this work we used high-resolution, gridded climate change scenarios for Switzerland to simulate the distribution and abundance of H. halys under present and future climate conditions. The simulations were performed with the software package CLIMEX (© CSIRO), a process-based bioclimatic niche model that simulates the mechanisms that limits species’ geographical distributions and determine their seasonal phenology, and to some extend their relative abundance. A recently published CLIMEX model for H. halys (Kriticos et al. 2017, J Pest Sci) was validated and calibrated for Switzerland considering adult trap catch data. The potential distribution and abundance under present and future climates was compared by means of the number of generations per year and the annual growth index (suitability of the climate for the growth of insects). Today H. halys is univoltine in Switzerland. Our results indicate that under future climate conditions a multivoltine behavior will be possible. Furthermore our simulations demonstrate an enhancement of the overall suitability for the growth of H. halys. Our results help to define regions and time periods at greatest risk and to design management strategies for H. halys under future climate conditions

Studies on the ecology of European Peristenus spp. (Hymenoptera: Braconidae) and their potential for the biological control of Lygus spp. (Hemiptera: Miridae) in Canada

In Canada, native plant bugs of the genus Lygus (Heteroptera: Miridae) are serious pests of a wide variety of agricultural crops. Lygus spp. outbreaks in western Canada have renewed interest in introducing European Lygus parasitoids. The intention of this thesis was to provide information on the host specificity of Lygus parasitoids belonging to the genus Peristenus (Hymenoptera: Braconidae), in an effort to assess potential risks for introducing these European parasitoids as biological control agents of native Lygus species in Canada. Investigations were made on the distribution, seasonal abundance and synchronization of Lygus spp. and their associated nymphal parasitoids, P. stygicus and P. digoneutis. In addition, the physiological host range of the parasitoids was defined. The results were compared with data on the ecological host range of the parasitoids, obtained from field studies in Schleswig-Holstein. In addition, lifetime fecundity and cold-hardiness of the parasitoids were studied to guide the choice of parasitoid species for possible introduction

Dispersal and oviposition behaviour of Diabrotica virgifera virgifera in non-maize crops to improve advice and guidelines for crop rotation

Verbreitungs- und Eiablageverhalten von Diabrotica virgifera virgifera in Nicht-Mais-Kulturen zur Verbesserung von Beratung und Richtlinien für den Fruchtwechse

Halyomorpha halys (Hemiptera, Pentatomidae): ten years after in Europe

We describe the situation of the invasion of Halyomorpha halys (HH) in Europe, since its discovery in Switzerland in 2007, but with effective presence since 2004. After a relative stagnation for many years, the dispersal of H. halys seems to increase, probably due to growing populations and passive transport by human activities. We suppose that it is not possible to stop the invasion of this species in Europe due to global warming but mostly to ecological characteristics such as high dispersal capability especially with human assistance , a broad host spectrum, a high female fecundity, and a high overwintering survival. The particularly mild winter 2013-2014 in France and Western Europe may further contribute to its progressive dispersal. It is likely that H. halys is already much wider distributed than previously assumed because it is easily confused with the native species, Raphigaster nebulosa. Most recently H. halys was recorded from Hungary, which is nearly 1,000 km east of its centre of distribution in Switzerland. In France, H. halys was first recorded in the Alsace in 2012, but in fall 2013 it was also discovered 400 km further west in Paris and Ile de France. The ongoing dispersal in western France will be monitored and prevention methods will be investigated. After the first occurrence in 2012, a “citizen-science” type of survey allowed to detect many specimens of H. halys in different areas of Northern Italy, with a bigger nucleus centred in the territory of first detection, in the Emilia Romagna region. As this region has extended areas cultivated with high value fruit crops, field monitoring is currently being performed to verify H. halys presence and damage

A survey of native parasitoids ofHalyomorpha halysin Northern Italy and Switzerland

Introduction: The brown marmorated stink bug, Halyomorpha halys,is an Asian polyphagous species that has become an invasive crop pest in North America and Europe. After its first detection in Switzerland in 2004, it was subsequently found in other European countries such as Italy, where, since 2012, it has rapidly spread in the northern regions, becoming a threat to many crops, especially in pear and peach orchards. Results/Conclusion: Overall, most egg parasitism was due to the generalist parasitoid Anastatus sp. (Eupelmidae) and, at a lower level, to various Scelionidae species (e.g. Trissolcus cultratus). In northern Italy, the amount of parasitized eggs ranged from 3.1% in 2014 to 0.9% in 2015 in Emilia Romagna, and from 0.3% on exposed egg-masses to 21.4% on egg-masses collected in a natural habitat in 2015 in Piedmont. Overall parasitism in Switzerland was 4.4% in 2013

Current distribution and voltinism of the brown marmorated stink bug, Halyomorpha halys, in Switzerland and its response to climate change using a high-resolution CLIMEX model

Climate change can alter the habitat suitability of invasive species and promote their establishment. The highly polyphagous brown marmorated stinkbug, Halyomorpha halys Stål (Hemiptera: Pentatomidae), is native to East Asia and invasive in Europe and North America, damaging a wide variety of fruit and vegetable crops. In Switzerland, crop damage and increasing populations have been observed since 2017 and related to increasing temperatures. We studied the climatic suitability, population growth, and the number of generations under present and future climate conditions for H. halys in Switzerland, using a modified version of the bioclimatic model package CLIMEX. To address the high topographic variability in Switzerland, model simulations were based on climate data of high spatial resolution (approx. 2 km), which significantly increased their explanatory power, and identified many more climatically suitable areas in comparison to previous models. The validation of the CLIMEX model using observational records collected in a citizen science initiative between 2004 and 2019 revealed that more than 15 years after its accidental introduction, H. halys has colonised nearly all bioclimatic suitable areas in Switzerland and there is limited potential for range expansion into new areas under present climate conditions. Simulations with climate change scenarios suggest an extensive range expansion into higher altitudes, an increase in generations per year, an earlier start of H. halys activity in spring and a prolonged period for nymphs to complete development in autumn. A permanent shift from one to two generations per year and the associated population growth of H. halys may result in increasing crop damages in Switzerland. These results highlight the need for monitoring th

First discovery of adventive populations of Trissolcus japonicus in Europe

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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