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Stink bugs (Hemiptera: Pentatomidae) are an increasing threat to soybean (Fabales: Fabaceae) production in the North Central Region of the United States, which accounts for 80% of the country’s total soybean production. Characterization of the stink bug community is essential for development of management programs for these pests. However, the composition of the stink bug community in the region is not well defined. This study aimed to address this gap with a 2-yr, 9-state survey. Specifically, we characterized the relative abundance, richness, and diversity of taxa in this community, and assessed phenological differences in abundance of herbivorous and predatory stink bugs. Overall, the stink bug community was dominated by Euschistus spp. (Hemiptera: Pentatomidae) and Chinavia hilaris (Say) (Hemiptera: Pentatomidae). Euschistus variolarius (Palisot de Beauvois) (Hemiptera: Pentatomidae), C. hilaris and Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) were more abundant in the northwestern, southeastern and eastern parts, respectively, of the North Central Region of the United States. Economically significant infestations of herbivorous species occurred in fields in southern parts of the region. Species richness differed across states, while diversity was the same across the region. Herbivorous and predatory species were more abundant during later soybean growth stages. Our results represent the first regional characterization of the stink bug community in soybean fields and will be fundamental for the development of state- and region-specific management programs for these pests in the North Central Region of the United States.

Host plant resistance may be an effective option to manage soybean aphid, Aphis glycines (Matsumura) (Hemiptera: Aphididae), an important pest on soybean (Glycine max (L.) Merr.) in the U.S. Movement of soybean aphid may be altered by the presence of resistance (i.e., Rag [Resistance to Aphis glycines]) genes in soybean and changes in movement may affect the spatial pattern of a species. This study aims to assess the effects of Rag1 and pyramided Rag1+Rag2 aphid-resistant varieties on movement of soybean aphid under laboratory conditions and to evaluate potential impacts of this movement on spatial pattern of soybean aphid under field conditions. Results from the greenhouse study showed more movement of soybean aphid on both aphid-resistant varieties than the susceptible variety when aphids were placed on unifoliate leaves and no statistically significant difference in movement between Rag1 and pyramided Rag1+Rag2 varieties. When aphids were placed on new growth, movement was greater on pyramided Rag1+Rag2 than the Rag1 and susceptible variety. However, under field conditions, the spatial patterns of soybean aphid in plots with susceptible, Rag1 or pyramided Rag1+Rag2 varieties were aggregated and did not differ among varieties in vegetative and reproductive growth stages. These results are of relevance because they suggest that aspects of soybean aphid management that may be sensitive to changes in spatial pattern of the pest (e.g., natural enemy efficacy and sampling plans) may not be impacted by implementation of varieties with these resistance genes for host plant resistance.

The brown marmorated stink bug, Halyomorpha halys (Stal) (Hemiptera: Pentatomidae), has spread across North America and is causing serious economic damages. Current management of this pest is based primarily on use of insecticides, which can disrupt integrated pest management programs. Alternatively, biological control is a more benign management tactic. This study provides the first examination of potential impact of parasitoids and predators of pentatomid eggs in Minnesota. Over 2 yr, 10,074 fresh and 9,870 frozen H. halys eggs were deployed in two forest and two soybean habitats in St. Paul, Minnesota from June to August. Our results demonstrate that rates of parasitism and predation were low, accounting for only 0.4 and 3.7%, respectively, across years, habitats, and egg states. In general, the parasitoid Telenomus podisi Ashmead (Hymenoptera: Scelionidae), had higher impacts on H. halys eggs in soybean, and generalist predators were more prevalent in forest habitats. Overall, predation was higher on fresh versus frozen eggs, and parasitism was not consistent across egg states. Although the rates of H. halys mortality due to natural enemies were low, results of our study may be conservative estimates of their true impact. Also, sentinel egg mass surveys should account for undeveloped parasitoids to better quantify H. halys egg mortality by native parasitoids. Alternative management tactics, such as the introduction of Trissolcus japonicus (Ashmead) (Hymenoptera: Scelionidae), could be considered to improve biological control of H. halys. Our findings serve as the foundation for future work on biological control of this pest and other pentatomids.

Stink bugs (Hemiptera: Heteroptera: Pentatomidae) that occur in Minnesota wheat have received little attention. Due to the invasion of Halyomorpha halys (Stal) and the increasing abundance of native stink bugs in the region, a 2-yr statewide survey and 2-yr season-long survey were conducted to characterize the species composition, abundance, and seasonal dynamics of Pentatomidae in wheat. Surveys were performed using sweep-net sampling in wheat fields. Fourteen species of Pentatomidae (thirteen herbivorous and one predatory) were detected across both surveys. The recent invader, H. halys , was not collected in either survey. In the statewide survey, Euschistus variolarius (Palisot de Beauvois) was the most abundant species (63.08 and 75.33% of adults in 2011 and 2012, respectively) and the most prevalent species (collected from 10.53 and 51.54% of fields in 2011 and 2012, respectively). Species of intermediate abundance and prevalence were Euschistus servus euschistoides (Vollenhoven), Euschistus ictericus (L.), and Podisus maculiventris (Say). Across both years of the season-long survey, adults of herbivorous species first appeared in fields in early June followed by the appearance of herbivorous nymphs in early July. The abundance of nymphs peaked in late July to the beginning of August in 2013 and in early July in 2014. Adults were detected in fields throughout the season. The results presented here provide baseline information on the species composition, abundance, and seasonal dynamics of Pentatomidae in Minnesota wheat and will be necessary for documentation of changes to this fauna.

The brown marmorated stink bug, Halyomorpha halys (Stal) (Hemiptera: Pentatomidae), poses a new threat to soybean, Glycine max (L.) Merrill (Fabaceae), production in the north central USA. As H. halys continues to spread and increase in abundance in the region, the interaction between H. halys and management tactics deployed for other pests must be determined. Currently, the soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is the most abundant and damaging insect pest of soybean in the region. Aphid-resistant soybean, mainly with the Rag1 gene, is commercially available for management of A. glycines. Here, experiments were performed to evaluate the effects of Rag1 aphid-resistant soybean on the mortality, development, and preference of H. halys. In a no-choice test, mortality of H. halys reared on Rag1 aphid-resistant soybean pods was significantly lower than when reared on aphid-susceptible soybean pods (28 vs. 53%). Development time, adult weight, and proportion females of surviving adults did not differ when reared on Rag1 aphid-resistant or aphid-susceptible soybean pods. In choice tests, H. halys exhibited a preference for Rag1 aphid-resistant over aphid-susceptible soybean pods after 4 h, but not after 24 h. Halyomorpha halys exhibited no preference when tested with vegetative-stage or reproductive-stage soybean plants. The preference by H. halys for Rag1 aphid-resistant soybean pods and the decreased mortality when reared on these pods suggests that the use of Rag1 aphid-resistant soybean may favor this emerging pest in the north central USA.

Use of crop inputs, including prophylactic application of insecticides, has increased in soybean production. A liquid fertilizer-ready formulation of the insecticide bifenthrin was recently labeled for in-furrow use with a starter fertilizer on soybean. An experiment was conducted at six sites (three in Minnesota and three in Ohio) in 2013 and two sites (Minnesota) in 2014 to evaluate effects on soybean of prophylactic in-furrow applications of a liquid fertilizer-ready insecticide (bifenthrin) and a 2-6-16 (N-P-K) liquid starter fertilizer alone and in combination. Across three site-years in Minnesota where insect injury was recorded, the insecticide decreased the percentage of plants with seedcorn maggot injury (P = 0.0291). However, across all site-years, insecticide and fertilizer had no effect (P > 0.05) on plant population, plant height, or grain yield. Prophylactic use of these additional inputs under typical soybean-growing conditions in this region may not provide a return on investment. Accepted for publication 24 March 2016. Published 30 March 2016.

Soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is a non-native and damaging pest of soybean [Glycine max (L.) Merr.] in the north central United States. We screened 78 soybean lines (maturity groups 000 to I) for resistance to soybean aphid and categorized resistance (i.e., antibiosis or antixenosis) in lines that showed putative resistance. Selected lines were also included in field trials at Rosemount and St. Paul, MN, in 2014. We detected antibiosis in PI 639534A, PI 639537, and PI 605765B and antixenosis in PI 507713. PI 605765B and PI 639537 performed better than susceptible varieties in both field trials with natural infestations of soybean aphid. We also documented antixenosis within IA3027, a line previously assumed to be susceptible to soybean aphid, which underscores the importance of including multiple susceptible and resistant controls for comparison in resistance screening studies. These additional sources of resistance may provide soybean breeders more options for incorporating resistance into early-maturing soybean varieties and allow different types of host plant resistance to be pyramided into varieties for growers.

Soybean aphid, Aphis glycines Matsumura, remains the key insect pest of soybean, Glycine max (L.) Merrill, in the north-central United States. Management of this pest has relied primarily on scouting and application of foliar insecticides based on an economic threshold (ET) of 250 aphids per plant. This review explains why this ET remains valid for soybean aphid management, despite changes in crop value and input costs. In particular, we review how soybean aphid impacts soybean yield, the role of biology and economics in recommendations for soybean aphid management, and the short- and long-term consequences of inappropriately timed insecticide applications. Accepted for publication 13 December 2016.

Soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is the most economically important insect pest of soybean in the north central United States. Scouting-based integrated pest management (IPM) programs could become more efficient and more widely adopted by using plant spectral reflectance to estimate soybean aphid injury. Our objective was to determine whether plant spectral reflectance is affected by soybean aphid feeding. Field trials were conducted in 2013 and 2014 using caged plots. Early-, late-, and noninfested treatments were established to create a gradient of soybean aphid pressure. Whole-plant soybean aphid densities were recorded weekly. Measurements of plant spectral reflectance occurred on two sample dates per year. Simple linear regression models were used to test the effect of cumulative aphid-days (CAD) on plant spectral reflectance at 680 nm (RED) and 800 nm (NIR), normalized difference vegetation index (NDVI), and relative chlorophyll content. Data indicated that CAD had no effect on canopy-level RED reflectance, but CAD decreased canopy-level NIR reflectance and NDVI. Canopy- and leaf-level measurements typically indicated similar plant spectral response to increasing CAD. CAD generally had no effect on relative chlorophyll content. The present study provides the first documentation that remote sensing holds potential for detecting changes in plant spectral reflectance induced by soybean aphid. The use of plant spectral reflectance in soybean aphid management may assist future IPM programs to reduce sampling costs and prevent prophylactic insecticide sprays.

The invasion by Halyomorpha halys (Stål) and an increasing abundance of native Pentatomidae pose a threat to soybean, Glycine max (L.) Merrill, production in northern states. A risk assessment framework was used to provide an initial assessment of the risk of Pentatomidae affecting soybean production in northern states. A caged field study was performed over two years to assess the response of soybean to H. halys feeding. Cages placed over R4 soybean were infested with 0, 1, 2, 4, or 8 fourth-instar H. halys nymphs per 0.3 row-m, and the insects were allowed to feed for 15 to 16 days. Feeding by H. halys on soybean affected yield components, maturity, and quality (i.e., seed injury). Season-long monitoring of soybean fields was performed via sweep net sampling to assess the likelihood of herbivorous Pentatomidae occurring on soybean during plant growth stages susceptible to feeding injury. Adults of herbivorous species were collected at low densities in fields in mid- to late July before collection of herbivorous nymphs. Herbivorous nymphs were first collected in the R3 and R4 soybean growth stages and their abundance peaked during the R6 soybean growth stage. This preliminary assessment indicates that if populations of exotic and native herbivorous Pentatomidae continue to increase in abundance, they will pose a threat to northern soybean production.

The invasive soybean aphid, Aphis glycines Matsumura, is an important pest in North American soybean production. Predators can play an important role in suppressing A. glycines. However, current A. glycines management practices rely primarily on broad-spectrum insecticides, which can adversely affect natural enemy populations. An alternative is the use of selective insecticides that control the targeted pest species, while having a reduced impact on natural enemies. In greenhouse and laboratory assays, we tested the effects of lambda-cyhalothrin, two rates of flonicamid, which is currently not registered for use in soybean, and a formulated mixture of pyrthrins and azadirachtin on A. glycines and its natural enemies, Chrysoperla rufilabris (Burmeister), Orius insidiosus (Say) and Hippodamia convergens (Guerin-Meneville). All insecticides significantly reduced A. glycines populations. Lambda-cyhalothrin was highly toxic to the natural enemies tested. Flonicamid showed the lowest toxicity to natural enemies...

Diapause and cold tolerance can profoundly affect the distribution and activity of temperate insects. Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), an alien invasive species from Asia, enters a winter dormancy in response to environmental cues. We investigated the nature of this dormancy and its effects on H. halys cold tolerance, as measured by supercooling points, lower lethal temperatures, and overwintering field mortality. Dormancy was induced by rearing individuals in the laboratory or under field conditions. We confirmed H. halys dormancy to be a state of diapause and not quiescence, and the life stage sensitive to diapause-inducing cues is between the second and fifth instar. In the laboratory, supercooling points of diapausing adults reached significantly lower temperatures than nondiapausing adults, but only when given enough time after imaginal ecdysis. Supercooling points of diapausing adults in overwintering microhabitats also decreased over time. Diapause increased adult survival after acute cold exposure in the laboratory and prolonged cold exposure in the field. Following diapause induction in the laboratory, changes to temperature and photoperiod had no significant effect on lower lethal temperatures and changes to photoperiod had no effect on supercooling points. Additionally, induction of diapause in the laboratory did not result in significantly different cold tolerance than natural field induction of diapause. This work demonstrates that H. halys diapause confers greater cold tolerance than a nondiapausing state and likely improves the probability of successful overwintering in some temperate climates. Hence, knowledge of diapause status could be used to refine forecasts of H. halys overwintering field mortality.

Since the first observation of soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), in North America in 2000, it has become the most economically damaging insect of soybean in the Upper Midwest of the United States. For the last 17 yr, soybean aphid management has relied almost entirely on the use of foliar-applied broad-spectrum insecticides. However, in 2015 in Minnesota, failures of foliar-applied pyrethroid insecticides were reported and pyrethroid resistance was confirmed with laboratory bioassays using lambda-cyhalothrin and bifenthrin. In 2016 and 2017, further reports of failures of pyrethroid insecticides and/or laboratory confirmation of resistance occurred in Iowa, North Dakota, South Dakota, and Manitoba. In response to the challenge posed by insecticide-resistant soybean aphids, we recommend several management strategies for minimizing further development of resistance and subsequent pest-induced crop losses: 1) scout and use the economic threshold to determine when to apply insecticides, 2) apply the insecticides properly, 3) assess efficacy 3–5 d after application, and 4) alternate to a different insecticide group if another application is required. In the long term, soybean aphid management must move beyond insecticide-based management to true integrated pest management by incorporating multiple tactics.

Cover crops offer environmental and agricultural benefits, but adoption remains low. Soybean growers have indicated that the adoption of rye as a winter cover crop would increase, if it was shown to offer suppression of a key soybean pest, the soybean aphid Aphis glycines. We performed an on-farm evaluation of two cropping systems utilized in organic production and reduced-herbicide input production. One system includes a rye cover crop, whereas the other does not. At six and five location-years in Minnesota, A. glycines and predator populations, respectively, were measured and compared between the systems with and without rye. The system with the rye cover crop significantly suppressed A. glycines populations on soybean at five of six location-years. Predators appeared to respond more to prey abundance than to plant diversity. An exposure analysis examining biological control potential revealed no differences between soybean with and without rye at any location-year. Insect control can be added to the multiple benefits of rye winter cover crops.

Stink bugs (Hemiptera: Pentatomidae) have historically not been pests of soybean in Minnesota. In response to the invasion of Halyomorpha halys (Stål) and reports of increasing abundance of species native to North America, a state-wide survey of soybean was conducted over 3 yr in Minnesota to determine species composition, abundance, and seasonal dynamics of Pentatomidae associated with soybean. Fourteen species of Pentatomidae (12 herbivorous and two predatory) were collected from soybean. H. halys was not detected in this survey. Among the herbivorous species found, adults of Euschistus variolarius (Palisot de Beauvois) had the greatest relative abundance (60.51%) and frequency of detection (18.44%), followed by Euschistus servus euschistoides (Say) (19.37 and 3.04%, respectively) and Chinavia hilaris (Say) (5.50 and 1.69%, respectively). Abundance of herbivorous nymphs and adults exceeded an economic threshold (20 nymphs and adults per 100 sweeps) in 0.82% of fields in 2012 but not in 2011 or 2013. The frequency of detection of herbivorous species and ratio of nymphs to adults increased with increasing reproductive growth stage of soybean. In two of three years, herbivorous adults were more abundant in the edge compared with interior of fields. Two predatory Pentatomidae, Podisus maculiventris (Say) and Podisus placidus Uhler, comprised 5.95 and 1.62% of the pentatomid adults. Though the species composition of Pentatomidae in Minnesota soybean differs from that in eastern and southern states, the spatial (i.e., greater abundance near field edge) and seasonal dynamics (i.e., increasing abundance and reproduction with increasing reproductive maturity of soybean) in soybean appear similar.

The soybean aphid, Aphis glycines Matsumura, is an economically important soybean pest. Many studies have demonstrated that predatory insects are important in suppressing A. glycines population growth. However, to improve the utilization of predators in A. glycines management, sampling plans need to be developed and validated for predators. Aphid predators were sampled in soybean fields near Rosemount, Minnesota, from 2006-2007 and 2013-2015 with sample sizes of 20-80 plants. Sampling plans were developed for Orius insidiosus (Say), Harmonia axyridis (Pallas), and all aphidophagous Coccinellidae species combined. Taylor's power law parameters from the regression of log variance versus log mean suggested aggregated spatial patterns for immature and adult stages combined for O. insidiosus, H. axyridis, and Coccinellidae in soybean fields. Using the parameters from Taylor's power law and Green's method, sequential fixed-precision sampling plans were developed to estimate the density for each predator taxon at desired precision levels of 0.10 and 0.25. To achieve a desired precision of 0.10 and 0.25, the average sample number (ASN) ranged from 398-713 and 64-108 soybean plants, respectively, for all species. Resulting ASNs were relatively large and assumed impractical for most purposes; therefore, the desired precision levels were adjusted to determine the level of precision associated with a more practical ASN. Final analysis indicated an ASN of 38 soybean plants provided precision of 0.32-0.40 for the predators. Development of sampling plans should provide guidance for improved estimation of predator densities for A. glycines pest management programs and for research purposes.

International audience; The harlequin ladybird, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), is native to Asia but has been intentionally introduced to many countries as a biological control agent of pest insects. In numerous countries, however, it has been introduced unintentionally. The dramatic spread of H. axyridis within many countries has been met with considerable trepidation. It is a generalist top predator, able to thrive in many habitats and across wide climatic conditions. It poses a threat to biodiversity, particularly aphidophagous insects, through competition and predation, and in many countries adverse effects have been reported on other species, particularly coccinellids. However, the patterns are not consistent around the world and seem to be affected by many factors including landscape and climate. Research on H. axyridis has provided detailed insights into invasion biology from broad patterns and processes to approaches in surveillance and monitoring. An impressive number of studies on this alien species have provided mechanistic evidence alongside models explaining large-scale patterns and processes. The involvement of citizens in monitoring this species in a number of countries around the world is inspiring and has provided data on scales that would be otherwise unachievable. Harmonia axyridis has successfully been used as a model invasive alien species and has been the inspiration for global collaborations at various scales. There is considerable scope to expand the research and associated collaborations, particularly to increase the breadth of parallel studies conducted in the native and invaded regions. Indeed a qualitative comparison of biological traits across the native and invaded range suggests that there are differences which ultimately could influence the population dynamics of this invader. Here we provide an overview of the invasion history and ecology of H. axyridis globally with consideration of future research perspectives. We reflect broadly on the contributions of such research to our understanding of invasion biology while also informing policy and people.

We evaluated the hypothesis that the use of an autumn-seeded winter rye, Secale cereale L., cover crop in soybean, Glycine max (L.) Men., could lead to decreased insect pest pressure. We compared insect pest and natural enemy populations in an organic soybean production system with soybeans planted into an autumn-seeded rye cover crop (i.e., soybeans planted in spring into a rye cover crop that had been planted the previous autumn). Small-plot experiments were conducted at two locations in southwestern Minnesota to compare insect populations on soybean planted into fallow ground versus soybean planted into rye that was managed by mowing using three different techniques. Densities of potato leafhopper, Empoasca fabae (Harris), were significantly lower on soybean in all of the rye treatments compared with soybean without rye at both locations. Densities of soybean aphid, Aphis glycines Matsumura, were significantly lower on all of the treatments incorporating rye than the soybean-only treatment at ...

Fur einen kompakten Wuchs lasst sich bei vielen Kulturen auf einen Einsatz von wuchsregulierenden Masnahmen nicht verzichten. Auch verschiedene Topfkrauterarten neigen zu einem unerwunschten Streckungswachstum. Die Verwendung von chemischen Wachstumsregulatoren ist jedoch in der Produktion von Topfkrautern generell verboten. Fur einen kompakten Wuchs wird an der Staatlichen Lehr- und Versuchsanstalt fur Gartenbau (LVG) Heidelberg alternativ das Verfahren einer mechanischen Reizbehandlung seit mehreren Jahren bei verschiedenen Topfkrauter- und Zierpflanzenkulturen erfolgreich eingesetzt. Dabei wurde die starkste Reduktion des Langenwachstums erzielt, wenn die Pflanzen in den fruhen Morgenstunden mit zeitlich unterbrochenen Beruhrungsreizen behandelt wurden. In 2009 und 2010 pruften die Versuchsansteller die Wirkung von Beruhrungsreizen (wissenschaftlich: Thigmomorphogenese) auf ein groseres Sortiment an okologisch produzierten Topfkrautern. Grune und rote Basilikumsorten, Petersilie, Koriander, Zitronenmelisse und Kerbel sowie vier verschiedene Minzesorten wurden eine Woche nach Kulturbeginn mit Hilfe eines Streichelwagens kontinuierlich 108-mal pro Tag mechanisch gestreichelt. Alle mechanisch gereizten Krauterarten und -sorten zeigten im Vergleich zu den unbehandelten Pflanzen ein tendenziell oder signifikant geringeres Streckungswachstum (Abb. 6) und einen somit stabileren Pflanzenaufbau. Art- und sortenabhangig konnte auf diese Weise die Qualitat der Topfkrauter sichtbar verbessert werden.

Soybean aphid [ Matsumura (Hemiptera: Aphididae)] is the most damaging insect pest of soybean [ (L.) Merr.] in the Upper Midwest of the United States and is primarily controlled by insecticides. Soybean aphid resistance (i.e., genes) has been documented in some soybean accessions but more sources of resistance are needed. Incorporation of the resistance into marketed varieties has also been slow. Genome-wide association mapping can aid in identifying resistant accessions by correlating phenotypic data with single nucleotide polymorphisms (SNPs) across a genome. Aphid population measures from 2366 soybean accessions were collected from published studies screening cultivated soybean () and wild soybean ( Siebold & Zucc.) with aphids exhibiting Biotype 1, 2, or 3 characteristics. Genotypic data were obtained from the SoySNP50K high-density genotyping array previously used to genotype the USDA Soybean Germplasm Collection. Significant associations between SNPs and soybean aphid counts were found on 18 of the 20 soybean chromosomes. Significant SNPs were found on chromosomes 7, 8, 13, and 16 with known genes. SNPs were also significant on chromosomes 1, 2, 4 to 6, 9 to 12, 14, and 17 to 20 where genes have not yet been mapped, suggesting that many genes remain to be discovered. These SNPs can be used to determine accessions that are likely to have novel aphid resistance traits of value for breeding programs.

The establishment of the multicolored Asian lady beetle, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), in North America has resulted in negative impacts on fruit production. We investigated the overwintering survival of H. axyridis after feeding on four diets: injured wine grape berries, 25% sucrose solution, water, and a control containing no food or water. After being exposed to these diets for 6 days, live individuals were transferred to clean plastic Petri dishes, and held at 5 ± 1 °C in growth chambers throughout the winter. Survival was recorded every month. Adult lady beetles collected during the overwintering flight in mid-October had higher survival rates than beetles collected from soybean fields in mid-August. These results suggest that an adaptation period prior to diapause increases the chances of lady beetle survival over the winter. In addition, injured wine grape berries, sugar, and water decreased beetle mortality during the overwintering months. Our results also showed that under similar conditions, females have higher survival during the winter than males. The importance of sugar and water on winter survival may drive H. axyridis adults to vineyards for feeding on wine grapes. Finally, we tested if adults of H. axyridis and the European paper wasp, Polistes dominulus Christ (Hymenoptera: Vespidae), were able to break the grape skin. Harmonia axyridis adults and paper wasps were not able to cause the primary injury to berries of Frontenac grapes under laboratory conditions. These results suggest that control of paper wasps in vineyards may not affect H. axyridis aggregations, and that H. axyridis feeding on wine grapes depends on previous injury to grape berries.

In summer 2007, the Asian parasitoid Binodoxys communis (Hymenoptera: Braconidae) was released in North America for control of the exotic soybean aphid, Aphis glycines (Hemiptera: Aphididae). Despite its comparatively narrow host range, releases of B. communis may still constitute a risk to native aphid species. To estimate the risk of exposure of non-target aphids to B. communis, we merged assessments of temporal co-occurrence with projections of spatial overlap between B. communis and three native aphid species, and in-field measurements of the incidence of ecological filters that may protect these aphids from parasitism. Temporal co-occurrence was assessed between A. glycines and native aphids (Aphis asclepiadis, Aphis oestlundi, and Aphis monardae) at four different locations in Minnesota, USA. The degree of temporal overlap depended greatly on location and aphid species, ranging between 0 and 100%. All of the native aphids were tended by multiple species of ants, with overall ant-attendance ranging from 26.1 to 89.6%. During temporal overlap with A. glycines, 53 ± 11% of A. monardae colonies were partly found in flower heads of their host plant, with flowers acting as a physical refuge for this aphid. The extent of geographic overlap between B. communis and native aphids based upon Climex modeling was 17–28% for A. monardae, 13–22% for A. oestlundi, 46–55% for A. asclepiadis and 12–24% for the A. asclepiadis species complex. The estimated overall probability of potential exposure of B. communis on native aphids was relatively low (P = 0.115) for A. oestlundi and high (P = 0.550) for A. asclepiades. Physical and ant-mediated refuges considerably lowered probability of population-level impact on A. monardae, and could lead to substantial reduction of exposure for the other native aphids. These findings are used to make broader statements regarding the ecological safety of current B. communis releases and their potential impact on native aphid species in North America.

The multicolored Asian lady beetle, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) is a generalist predator of aphids and other soft-bodied insects and has been utilized in biological control programs around the world. Over the last two decades, this species has spread throughout much of the continental USA and southern Canada. Despite the benefits it offers as a biological control agent, H. axyridis is perhaps most well known for its adverse impacts. In this paper we provide a review of the North American experience with H. axyridis, focusing on these adverse impacts, which can be classified into three general categories: impacts on non-target arthropods, impacts on fruit production and impacts as a household invader. The impacts of H. axyridis on non-target arthropods and, to lesser extent, the impacts as a household invader possibly could have been anticipated, due to its generalist feeding preferences and overwintering behavior in Asia. However, it is unlikely that the impacts on fruit production could have been anticipated. Therefore, even in retrospect, it is difficult to predict the potential impacts that an introduced natural enemy might have in its adventive range.

A promising natural enemy for release against the Asian soybean aphid, Aphis glycines Matsumura, in North America is the aphidiine braconid wasp Binodoxys communis (Gahan). The aphid Aphis monardae Oestlund, a native of North America’s tall-grass prairies, is a non-target species that may be at risk from releases of B. communis . This paper describes ecological facets of A. monardae populations in their native habitat that could protect them from attack by this exotic biological control agent. In prairie habitats, A. monardae populations aggregate in flower heads of their host plant, Monarda fistulosa L. On this host plant, aphids are also commonly tended by four ant species, and ant-tended colonies are larger than un-attended colonies. Laboratory studies showed that parasitism rates of A. monardae by B. communis are significantly higher on vegetative M. fistulosa than on M. fistulosa flower heads. In addition, attendance of A. monardae by the ant Lasius neoniger Emery significantly decreased parasitism by B. communis . Ants attacked and killed host-seeking adult parasitoids, and preyed upon B. communis mummies. No evidence was found that B. communis reared from A. monardae are less susceptible to attack by ants than parasitoids reared from A. glycines . M. fistulosa flower heads and attendance by L. neoniger may act as refuges for A. monardae against B. communis . Our work describes spatial refuges as ecological filters that separate non-target organisms from exotic natural enemies. Implications for classical biological control of A. glycines are discussed.

The multicolored Asian lady beetle, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), has become a popular study organism due to its promise as a biological control agent and its potential adverse, non-target impacts. Behavioral and ecological research on H. axyridis, including examinations of its impacts, could benefit from non-destructive or non-disruptive sexing techniques for this coccinellid. External morphological characters were evaluated for H. axyridis (succinea color form) sex determination in laboratory and field studies. The shape of the distal margin of the fifth visible abdominal sternite accurately predicted H. axyridis sex for all beetles examined. Males consistently had a concave distal margin, while females had a convex distal margin. In addition, pigmentation of the labrum and prosternum were both significantly associated with H. axyridis sex; males had light pigmentation and females had dark pigmentation. Labrum and prosternum pigmentation increased from light to dark with decreasing rearing temperature and increasing time after adult eclosion for females. Male pigmentation was only affected by a decrease in rearing temperature. Validation through in-field collections indicated that these predictors were accurate. However, labrum pigmentation is a more desirable character to use to determine sex, because it is more accurate and easily accessible. Therefore, we recommend using labrum pigmentation for in-field sex determination of H. axyridis. Implications of this diagnostic technique for applied and basic research on this natural enemy are discussed.

The use of selective insecticides may improve conservation of natural enemies and therefore contribute to the success of integrated pest management (IPM) programs. In this study, the toxicity of two commonly used selective insecticides, indoxacarb and spinosad, to the multicolored Asian lady beetle, Harmonia axyridis (Pallas), was evaluated. Third instars and adults of H. axyridis were exposed to indoxacarb at 50 and 100% of the field rate (FR), to spinosad at 100% FR and to water (untreated check) under laboratory conditions via three routes of exposure. Treatments were applied directly on insects (i.e., topical application), on Petri dishes (i.e., residues), or on soybean aphids, Aphis glycines Matsumara (i.e., treated prey). Mortality of exposed individuals in each life stage was recorded 2 and 7 days after treatment. Logistic regression indicated that indoxacarb at 100% FR, followed by indoxacarb at 50% FR, was more insecticidal than spinosad to third instars. Mortality was higher when H. axyridis were exposed to both insecticides via residues followed by treated prey. Indoxacarb at 100 or 50% FR was insecticidal to adults. Adults were tolerant to spinosad via all routes of exposure. The present results suggest that indoxacarb may decrease H. axyridis field populations by causing mortality to larvae and adults via all routes of exposure. Implications of the toxicity of indoxacarb to H. axyridis within an IPM context and possible reasons for the differences in susceptibility of H. axyridis for each route of exposure are discussed.

Soybean aphid, Aphis glycines Matsumura, can be an economically important pest in soybean, Glycine max (L.) Merrill. In 2002 and 2003, we evaluated the use of nonattractive pan traps to estimate soybean aphid densities in commercial soybean fields. A regression analysis indicated a strong relationship between log-transformed pan trap counts and whole-plant counts (r2 = 0.70). To measure soybean aphid dispersion as characterized by each sampling method, Taylor's power law a and b values were calculated. The mean-to-variance ratios for pan trapping (a = 0.85, b = 1.63, r2 = 0.96) were comparable to whole-plant counts (a = 1.67, b = 1.99, r2 = 0.93). The precision and cost (i.e., time) of each sampling method was evaluated using relative net precision. Both sampling methods were generally precise throughout the season (

The efficacy of two systemic, insecticidal seed treatments, imidacloprid (Gaucho®) and thiamethoxam (Cruiser®), were evaluated for control of the bean leaf beetle, Cerotoma trifurcata (Forster), on early-growth-stage snap beans, Phaseolus vulgaris L., over multiple planting dates (2002–2003) in southern Minnesota, US. A new foliar damage rating scale was developed for quantifying the efficacy of control tactics for protecting snap beans from C. trifurcata feeding. Both insecticide seed treatments provided a high level of C. trifurcata control, as measured by significant differences in foliar damage ratings, compared to the untreated plots, for all planting dates tested. Foliar damage ratings for thiamethoxam and imidacloprid were generally superior to the chlorpyrifos (Lorsban®) seed treatment when C. trifurcata pressure was high. In addition, for early planting dates, some seed treatments were as effective as foliar applications of bifenthrin (Capture®) for protecting yield. Based on economic risk analysis for eight planting dates, over 2 years, thiamethoxam appeared to be the most consistent seed treatment for C. trifurcata control. This conclusion is based on thiamethoxam providing significant improvements in damage ratings compared to chlorpyrifos, the highest economic returns per hectare, and economic variability levels (as measured by SD of adjusted gross returns) that were similar to those of imidacloprid and chlorpyrifos. The overall performance of thiamethoxam and imidacloprid for snap beans is discussed within the context of improving C. trifurcata management programs for growers in the Midwestern US.

Use of selective insecticides, such as spinosad and indoxacarb, that are more toxic to lepidopteran pests than to Harmonia axyridis (Pallas), could facilitate conservation of this predator in sweet corn integrated pest management (IPM). We examined the effects of spinosad and indoxacarb on survival, development, and reproduction of H. axyridis by spraying first instars and adult females. Treatments for the first instar assay were spinosad at 10, 25, and 50% of the field rate (FR), indoxacarb at 10% FR, and water (untreated check). We recorded survival of each life stage, developmental time to adults, and adult weight. Treatments for the adult female assay were spinosad at 50 and 100% FR, indoxacarb at 50% FR, and water (control). Each day, we recorded female survival and reproductive capacity. Indoxacarb decreased survival of first instars and adults, extended the developmental time for first instars to become adults, and reduced the fecundity of H. axyridis females. Spinosad decreased survival of first instars, extended the time for first instars to become adults, decreased weight gain, and reduced the fertility of H. axyridis females. Our results suggest that spinosad and indoxacarb may reduce H. axyridis population growth by affecting its survival, development, and reproduction. We also conclude that indoxacarb, when applied at 10% FR, has more lethal and sublethal effects on H. axyridis than spinosad applied at 10, 25 or 50% FR. The importance of sublethal effects of insecticides, as well as acute toxicity, in toxicological studies with natural enemies is discussed within the context of biological control and IPM.

An invasive, exotic coccinellid, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), was recently identified as a potential hazard to immature monarch butterflies, Danaus plexippus L. (Lepidoptera: Nymphalidae). To further evaluate the risk of H. axyridis impacting D. plexippus, we evaluated the influence of an alternate prey, Aphis nerii Boyer de Fonscolombe (Homoptera: Aphididae), on the predation rate of H. axyridis on D. plexippus larvae. When first-instar D. plexippus were placed in petri dish arenas with third-instar H. axyridis and varying densities of A. nerii, D. plexippus survival after 24 h increased significantly from 0% with 0 A. nerii present to 73% with 30 A. nerii present. In predation studies conducted in field cages, survival of D. plexippus larvae decreased with increasing densities of H. axyridis larvae and tended to increase with increasing A. nerii densities. These studies indicate that H. axyridis will feed on D. plexippus larvae in the presence of A. nerii, but that the presence of A. nerii lessens the severity of predation on D. plexippus.

A classical biological control agent, Harmonia axyridis (Pallas), is having both beneficial and detrimental impacts in North America. The objective of this study was to evaluate the cold hardiness of H. axyridis in North America. Supercooling points and survival at subzero temperatures of field-collected and insectary-reared H. axyridis were examined. The mean (±SE) supercooling points for eggs and pupae (i.e., nonfeeding stages) were −27.0 ± 0.18°C and −21.3 ± 0.52°C, respectively. The mean supercooling points for larvae and adults (i.e., feeding stages) were −14.17 ± 0.33 and −11.9 ± 0.53°C, respectively. Sex and color morph (i.e., red: f. succinea versus black: f. spectabilis) had no effect on the supercooling point of H. axyridis adults. Mean supercooling points of H. axyridis adults from Minnesota and Georgia were significantly lower during winter months than summer months. The mortality of H. axyridis increased significantly after individuals were exposed to temperatures below the mean supe...

The potential for a classical biological control agent, Harmonia axyridis (Pallas), to have non-target effects on populations of the monarch butterfly, Danaus plexippus (L.), was examined using no-choice predation studies under laboratory and caged field conditions. Three separate laboratory functional response experiments were conducted with adult and larval H. axyridis preying on immature D. plexippus . Nonlinear functional responses for third instar H. axyridis preying on D. plexippus eggs and first instars reached plateaus at about 25 and 15 prey consumed per day, respectively. A linear response resulted for adult H. axyridis preying on D. plexippus eggs. Potted Asclepias syriaca L. placed into large field-cages were infested with first instar D. plexippus and third instar H. axyridis . Survival of first instar D. plexippus was significantly lower in cages with H. axyridis larvae than in cages without H. axyridis larvae. The present experiments identify H. axyridis as a potential stressor to populations of D. plexippus. Further research is needed to assess the likelihood of D. plexippus exposure to H. axyridis in the field and to quantify the likelihood of H. axyridis having an adverse effect on D. plexippus in the presence of other prey, particularly aphids. These data could be used to develop an ecological risk assessment.

In response to concerns of increasing significance of stink bugs (Hemiptera: Heteroptera: Pentatomidae) in northern states, a survey was conducted over 2 yr in Minnesota to characterize the Pentatomidae associated with field corn, Zea mays L. Halyomorpha halys (Stal), an exotic species, was not detected in this survey, despite continued detection of this species as an invader of human-made structures in Minnesota. Five species of Pentatomidae (four herbivorous; one predatory) were collected from corn. Across years, Euschistus variolarius (Palisot de Beauvois) and Euschistus servus euschistoides (Vollenhoven) had the greatest relative abundances and frequencies of detection. In 2012, the abundance of herbivorous species exceeded 25 nymphs and adults per 100 plants (i.e., an economic threshold) in 0.48% of fields. However, the abundance of herbivorous species did not reach economic levels in any fields sampled in 2013. The frequency of detection of herbivorous species and ratio of nymphs to adults was highest during reproductive growth stages of corn. The predator species, Podisus maculiventris (Say), was detected in 0 to 0.32% of fields. These results provide baseline information on the species composition and abundance of Pentatomidae in Minnesota field corn, which will be necessary for documentation of changes to this fauna as a result of the invasion of H. halys and to determine if some native species continue to increase in abundance in field crops.

Times Cited: 0 0; International audience; Inferences about introduction histories of invasive species remain challenging because of the stochastic demographic processes involved. Approximate Bayesian computation (ABC) can help to overcome these problems, but such method requires a prior understanding of population structure over the study area, necessitating the use of alternative methods and an intense sampling design. In this study, we made inferences about the worldwide invasion history of the ladybird Harmonia axyridis by various population genetics statistical methods, using a large set of sampling sites distributed over most of the species' native and invaded areas. We evaluated the complementarity of the statistical methods and the consequences of using different sets of site samples for ABC inferences. We found that the H.axyridis invasion has involved two bridgehead invasive populations in North America, which have served as the source populations for at least six independent introductions into other continents. We also identified several situations of genetic admixture between differentiated sources. Our results highlight the importance of coupling ABC methods with more traditional statistical approaches. We found that the choice of site samples could affect the conclusions of ABC analyses comparing possible scenarios. Approaches involving independent ABC analyses on several sample sets constitute a sensible solution, complementary to standard quality controls based on the analysis of pseudo-observed data sets, to minimize erroneous conclusions. This study provides biologists without expertise in this area with detailed methodological and conceptual guidelines for making inferences about invasion routes when dealing with a large number of sampling sites and complex population genetic structures.

As a result of the introduction of Sirex noctilio F. into North America, there has been increased interest in the poorly-described native Siricidae communities. To date, few studies have surveyed specifically for Siricidae, and many reports of native siricid populations are byproducts of sampling efforts targeting Coleoptera. We report results from a survey targeted specifically at native and exotic Siricidae in Minnesota. We used Lindgren funnel traps from 2006 to 2008 baited with α/β-pinene (Sirex lure), ethanol (EtOH), EtOH + α-pinene, or Ips 3-part lures. We captured 704 native Siricidae comprising seven species, of which none were exotic. To our knowledge, this is one of the largest field collections of Siricidae from a single discrete set of localities in existence. Adult Siricidae began flying in June and continued into October each year. The α/β-pinene lure was most effective, but the EtOH + α-pinene lure was also moderately effective. We compare our data with those from several states and provinces in the Great Lakes Region of North America. Our data provide insight into the community composition of native Siricidae in Minnesota, while concurrently providing evidence that S. noctilio populations have not yet reached this far into the continental United States.

This study aimed to evaluate insecticides for management of adults of the grape colaspis in Minnesota soybean. The study was conducted at the University of Minnesota Research, Outreach and Education Park near Rosemount, Minnesota. On 24 Jun 2015, soybean seeds (variety: P19T01R) were sown 3.81 cm deep at a seeding rate of 508,970 seeds/ha. The spacing between rows was 17 cm. Plots were arranged in a randomized complete block design with five replications of three treatments (Table 1). Plots were 3.05 m wide by 9.14 m long …

This experiment was part of an effort to evaluate materials for management of SBA in Minnesota. The experiment was conducted at the University of Minnesota Outreach, Research and Education Park near Rosemount, MN. On 27 May 2014, soybean seed (variety: S17-B3) was sown 1.5 inches (3.81 cm) deep at a seeding rate of 165,678 seeds per acre (409,399 seeds per ha). Spacing between rows was 30 inches (76.2 cm). Plots were arranged in a randomized complete block design with 12 treatments and four replications. Each plot consisted of four rows 30 ft (9.14 m) long. Plots within blocks were separated by 5 ft (1.52 m) of fallow ground …

This experiment was part of an effort to evaluate materials for management of SBA in Minnesota. The experiment was conducted at the University of Minnesota Outreach, Research and Education Park near Rosemount, MN. On 1 May 2015, soybean seed (variety: Legend Seed LS20R20N) was sown 3.81 cm deep at a seeding rate of 296,400 seeds/ha. Spacing between rows was 0.76 m. Plots were arranged in a randomized complete block design with three treatments and four replications. Each plot was four rows by 9.14 m long. Plots within replications were separated by 1.52 m of fallow ground and replications were separated by 3.05 m of fallow ground. …

To improve the utilization of the multicolored Asian lady beetle, Harmonia axyridis (Pallas), as a natural enemy in integrated pest management (IPM) programs for sweet corn, Zea mays L., fixed-precision enumerative sequential sampling plans for this coccinellid were developed and validated. Data were collected from sweet corn plots during 2000 to 2004, with means ranging from 0.02 to 11.83 H. axyridis (larvae and adults combined) per plant. Taylor’s power law parameters from the regression of log variance versus log mean suggested an aggregated distribution for larvae and the combined count of larvae and adults in sweet corn. For IPM purposes, a plan was developed for H. axyridis larvae and adults to provide a desired precision level of 0.25 (SEM/mean), resulting in an average sample number of 65 whole plants. However, for the purposes of ecological or applied research (with desired precision = 0.10), an average sample number of 205 plants was necessary.

Use of insecticides with low toxicity to natural enemies is an important component of conservation biological control. In this study, we evaluated the toxicity of insecticides used in sweet corn, Zea mays L., and soybean, Glycine max (L.) Merr., to the multicolored Asian lady beetle, Harmonia axyridis (Pallas), under laboratory and field conditions. Field experiments conducted in sweet corn in 2003 and 2004 and in soybean in 2003, showed that H. axyridis was the most abundant predator. In sweet corn, densities of H. axyridis larvae in plots treated with spinosad or indoxacarb were generally higher than in plots treated with chlorpyrifos, carbaryl, bifenthrin, and A-cyhalothrin. In soybean, densities of H. axyridis larvae in plots treated with chlorpyrifos were higher than in plots treated with lambda-cyhalothrin. Laboratory experiments were conducted to evaluate the acute toxicity of insecticides to eggs, first and third instars, pupae, and adults. Spinosad, followed by indoxacarb, were the least toxic insecticides for all life stages of H. axyridis. Conventional insecticides showed high toxicity to H. axyridis when applied at field rates under laboratory conditions. Overall, first instars were most susceptible to the insecticides tested, followed by third instars and adults, eggs, and pupae. Our results suggest that spinosad, and to a lesser extent indoxacarb, offer reduced toxicity to H. axyridis and would be beneficial for conservation biological control in agricultural systems where H. axyridis is abundant.

The objective of this study was to assess the potential pest status of Harmonia axyridis (Pallas) on autumn-ripening fruit. In autumn, H. axyridis has been observed feeding on pumpkins, apples, grapes, and raspberries in Minnesota. To determine whether H. axyridis can inflict primary feeding damage to fruit (i.e., breaking the skin of the fruit), we conducted laboratory feeding experiments with undamaged pumpkins, apples, grapes, and raspberries. The only fruit that H. axyridis was able to damage directly was raspberry. Laboratory choice tests were conducted to determine whether H. axyridis exhibits a preference between damaged and undamaged fruit, between cultivars of fruit, and between sugar water and water alone. For all fruits tested, H. axyridis showed a preference for damaged fruits over undamaged fruits. H. axyridis also exhibited a strong preference for sugar water over water alone. However, few differences were exhibited in preference between cultivars of fruit. In autumn, it seems that H. axyridis is an opportunist, taking advantage of previously damaged fruit, caused by other agents.

The objective of these studies was to assess the degree to which bean leaf beetle, Cerotoma trifurcata (Forster), will feed on cucurbits. In 2003, we documented an infestation of C. trifurcata in a commercial pumpkin field near Rosemount, MN, USA. To evaluate C. trifurcata feeding on cucurbits, we conducted laboratory no-choice and choice test feeding studies. In the laboratory, C. trifurcata fed most heavily on cotyledon-stage cucumber plants, followed by pumpkin and squash. With soybean plants present, C. trifurcata still fed on cucumber plants. However, C. trifurcata appeared to prefer soybeans until the quality of the soybean plants was diminished through feeding damage. This is the first known report of C. trifurcata feeding on cucurbits. The pest potential of C. trifurcata in cucurbit cropping systems should be further evaluated.