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Crop wild relatives (CWRs) have high levels of genetic diversity compared to their domesticated descendants. Soybean (Glycine max) has over 20 species of CWRs, most of which are in secondary and tertiary gene pools. Glycine soja, hereafter ‘soja,’ is the only wild relative in the primary gene pool, i.e., species that readily cross with soybean. Soja has many advantageous traits that may be transferrable to soybean, including resistance to insect pests, with particularly strong sources of resistance to the soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae). Soybean aphid has been a major soybean pest in the United States and Canada since 2000 and a longstanding pest in East Asia. This paper reviews the challenges of developing soybean with durable resistance to soybean aphid in light of multiple, virulent biotypes in North America and China. It also examines particular challenges in evaluating soja germplasm for soybean aphid resistance and resultant solutions to those challenges. Soja germplasm is widely available, but from our experience, the logistics associated with reliably procuring high-quality soja seed has posed the main challenge in working with this CWR. This review highlights soja accessions identified with strong resistance to soybean aphid and their genetic bases, and it discusses possible strategies for exploiting aphid-resistant soja accessions to improve soybean pest management.

The soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), remains an important pest of soybean, Glycine max (L.) Merr., in areas of the Midwestern United States and southern Canada. Options for managing soybean aphid are currently limited to insecticides and aphid-resistant varieties. Farmers commonly employ a prophylactic treatment of soybean seed with a neonicotinoid insecticide such as thiamethoxam and often a remedial, late-season application of foliar insecticides such as the pyrethroid, λ-cyhalothrin. Environmental concerns about detrimental side effects of neonicotinoids and the substantiation of pyrethroid resistance in field populations of soybean aphid have strengthened the case for planting aphid-resistant soybean cultivars. We conducted a three-year field study in eastern South Dakota, United States, that evaluated commercially-available active substances and enhanced plant materials for soybean aphid management that included a thiamethoxam seed treatment, spray application of λ-cyhalothrin, and an aphid-resistant soybean cultivar containing a pyramid of the Rag1 and Rag2 aphid-resistance genes. Soybean aphid infestations had sustained, economically injurious levels in 2015, but not the other two years. The three management tactics independently reduced soybean aphid population densities. Thiamethoxam and the resistant cultivar suppressed cumulative aphid-days (CAD) in all three years, whereas the λ-cyhalothrin spray decreased CAD in 2015 and 2017. By far, the resistant cultivar had the greatest impact on soybean aphid populations, reducing CAD by 28- to 150-fold year−1, with mean numbers of aphids much less than 100 soybean aphids plant−1. Thiamethoxam seed treatment reduced CAD by 1.7- to 3.5-fold year−1, and λ-cyhalothrin reduced it from 2.0- to 5.6-fold year−1. Soybean yield was not affected by treatments in 2015. Yield was greater for the susceptible than for the resistant cultivar in 2016, and yield was greater for plots without foliar insecticide in 2017. Implications for the use of these management tactics against soybean aphid are discussed.

The soybean aphid (Aphis glycines) is an important pest of soybean (Glycine max). Wild soybean (Glycine soja; also known as ‘soja’) has many useful traits, including some accessions with aphid resistance that may be incorporated into modern soybean cultivars. The objective of this work was to evaluate 76 selected soja accessions and 14 associated soybean accessions for resistance against two virulent colonies of soybean aphid in environmental-chamber experiments. In free-choice tests, soja accessions PI 407175, PI 407190, PI 407206, PI 407240, PI 507624 and PI 562558 were resistant against the Accrue colony, and PI 407191wf and PI 597458 C were resistant against the Volga16 colony. None of the soybean test accessions except the resistant check, PI 437696, showed resistance against either colony in free-choice tests. In no-choice tests, soja accession PI 507624 showed strong resistance against the Accrue colony; whereas PI 407240 and PI 407190 had intermediate aphid levels; PI 597458 C showed strong resistance to Volga16 aphids, and PI 407191wf had an intermediate level of resistance. Based on results from both sets of tests, soja accessions PI 507624 and PI 597458 C may be strong candidates in breeding programs to develop aphid-resistant soybean cultivars.

The soybean aphid (Aphis glycines Matsumura) is a major pest of soybean (Glycine max (L.) Merr.) in eastern Asia and in North America. Aphid-resistant soybean cultivars have been developed as a non-chemical management tactic, but viability of this tactic may depend on the availability of diverse resistance sources, including wild soybean (Glycine soja Siebold and Zucc.), in order to counter various resistance-breaking soybean aphid biotypes. In this study, 10 wild soybean accessions were identified as resistant in free-choice screening assays against avirulent soybean aphid biotype 1, and eight of the accessions were advanced for follow-up in two, 20-day-long no-choice assays. Two accessions, PI 65549 and PI 135624, did not differ from resistant check PI 549046 in number of aphids per plant after 10 and 20 days of infestation; accessions 99PI101404B, PI 549035 B, and PI 342618 A had more aphids than PI 549046 by day 20, but fewer aphids than known susceptible accessions. In a second no-choice assay, accessions 99PI81762 and PI 101404 A had fewer aphids than other test accessions but more aphids than PI 549046 by day 20. Because of particularly strong resistance in PI 135624 and PI 65549, these two accessions should be genetically characterized and tested for resistance against virulent soybean aphid biotypes.

The soybean aphid (SA), Aphis glycines Matsumura, is a major pest of soybean in the north-central United States and south-central Canada. It is controlled primarily with insecticides, but the development of aphid-resistant soybean cultivars may provide an alternative management tactic. The viability of this management tactic depends on a diverse set of resistance sources in order to counter various resistance-breaking biotypes of SA, and the identification of new sources of resistance necessitates additional testing of soybean germplasm. The current study used no-choice tests to identify SA resistance in seven early maturing (maturity group I) soybean plant introductions (PIs) that had been advanced from free-choice screening trials. The tests showed PI 437353 and PI 612759 C had an intermediate level of resistance against avirulent SA, whereas PI 437282, PI 437658, PI 437733, PI 548417, and PI 548530 exhibited no significant resistance. Additional research is needed to determine if the source of resistance in PI 437353 and PI 612759 C is due to novel resistant genes, which would help diversify resistance to SA in soybean. Screening and follow-up tests of additional soybean germplasm is warranted in order to ensure the development of durable, SA-resistant cultivars.

Soybean aphid (Aphis glycines Matsumura) is a pest of soybean [Glycine max (L.) Merr] in the Midwestern U.S. and southern Canada. Host plant resistance provides an alternative to insecticides for soybean aphid management. Soybean with Rag1 + Rag2 aphid resistance is available commercially but does not protect against soybean aphid biotype 4 colonization. To find sources of resistance to soybean aphid biotype 4, we turned to soybean’s progenitor Glycine soja (Sieb. and Zucc.). Twenty soja plant introductions (PIs) with previously identified resistance to avirulent soybean aphid biotype 1 were assessed in free-choice tests against biotype 4, followed by a no-choice test for promising PIs. Experiments were repeated using three soybean aphid biotype 4 colonies, collected from separate site-years (Lomira, WI 2013; Volga, SD 2015, 2016). Free-choice tests identified six, three, and eight soja PIs with putative resistance to Lomira13, Volga15, and Volga16 aphid colonies, respectively. No-choice tests identified six, two, and six soja PIs that continued to suppress Lomira13, Volga15, and Volga16 aphids, respectively. PI 65549 and PI 101404A were resistant to each of the three colonies of soybean aphid biotype 4 and may contribute to durable resistance against soybean aphid.

New geographical records of zoological species are often discovered through processing undetermined specimens. Here, new records of five native species of lady beetles (Coleoptera: Coccinellidae) are reported for the central United States based on processing previously undetermined material from entomological collections: Cephaloscymnus laevis Gordon, Hyperaspidius insignis Casey, Hyperaspis punctata LeConte, Hippodamia apicalis Casey, and Anatis lecontei Casey. The new record for C. laevis represents a considerable range extension northward, whereas records for the other four species denote relatively minor geographic range extensions. These findings support the notion that systematic processing of undetermined collection material will yield new insights into the geographic ranges of various zoological species and improve understanding of biodiversity.

Soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), infestations of soybean, Glycine max (L.) Merr. (Fabales: Fabaceae), and the associated yield loss have led to a large dependence on insecticidal management in soybean throughout the Midwestern United States. However, several populations of pyrethroid-resistant soybean aphids have recently been found in Iowa, Minnesota, North Dakota and South Dakota, which highlights the importance of alternative management approaches. One such alternative method is host-plant resistance, which uses naturally occurring plant defenses in crop cultivars to reduce the potential for yield loss from a pest population. Current soybean aphid-resistant cultivars do not protect against all soybean aphids due to the presence of virulent biotypes. In particular, soybean aphid biotype 4 is virulent to Rag1 and Rag2 resistance genes both individually and in combination. However, we hypothesized that resistance to biotype 4 may exist in previously identified, but uncharacterized resistant soybean plant introductions (PIs). To test this, we evaluated 51 previously identified but uncharacterized soybean aphid-resistant PIs for their resistance to colonies of soybean aphid biotype 4 collected in separate site-years (Lomira, WI 2013; Volga, SD 2015, 2016). Free-choice tests identified 14 PIs with putative resistance to ‘Lomira13’, two to ‘Volga15’, and eight to ‘Volga16’ soybean aphid colonies. Follow-up, no-choice tests corroborated two to three resistant PIs per colony, and PI 437696, which was resistant to each of the three colonies and could aid in breeding efforts and an integrated approach to soybean aphid management.

The use of neonicotinoid insecticides in the United States has grown by about a factor of four since the mid-2000s. Seed treatments account for a significant fraction of overall insecticide application to crops, and a large proportion of major U.S. crops are now planted using seed treated with neonicotinoids. Neonicotinoid insecticidal seed treatments are primarily intended to protect crops against sporadic or minor early-season pests. A better understanding of factors that influence the risk of economic infestations and extent of crop damage by sporadic pests is needed to target neonicotinoid insecticidal seed treatments use based on expected pest pressure. In a series of papers, we review the distribution, ecology, and historical management of seed and seedling pests targeted by neonicotinoid seed treatments in U.S. corn (Zea mays), soybean (Glycine max), wheat (Triticum aestivum), and cotton (Gossypium hirsutum L.). This information is key to region-specific management practices that reduce the risks and increase the benefits of neonicotinoid seed treatments.

The use of insecticides at planting has been a common crop management practice in cotton for several decades. Historically, U.S. cotton growers relied on in-furrow applications of insecticides, such as aldicarb, to control early-season insect pests. In-furrow applications have largely been replaced with insecticide-treated seed. Since 2012, more than 60% of the U.S. cotton crop is planted with seed treated with insecticide, primarily the neonicotinoids imidacloprid or thiamethoxam. Several insects or insect groups are included on the labels of these neonicotinoids for use as seed treatments. An increased understanding of the risks associated with economically injurious populations of insect pests is needed to optimize use of early-season insecticides and reduce over-reliance on them in cotton, especially when initial decisions for insect control before planting have subsequent influence on future pest abundance. Existing literature pertaining to these early-season cotton insect pests was examined to identify factors favoring their distribution and abundance and the importance of insect control tactics used at planting. The relative importance of some of these pests is dependent on the cotton-growing region and impacted by local production practices. Thrips (predominantly Frankliniella spp.) (Thysanoptera: Thripidae) are the most prevalent early-season insect group in cotton across the United States and the primary target of initial insect control. Other targeted insects include the black cutworm, Agrotis ipsilon (Hufnagel) (Lepidoptera: Noctuidae), aphids (predominantly Aphis gossypii Glover) (Hemiptera: Aphididae), plant bugs (Hemiptera: Miridae), and wireworms (Coleoptera: Elateridae).

Soybean faces potential economic damage from a wide variety of early-season invertebrate pests. The objective of this article was to determine the extent and intensity of nine early-season soybean insect pests targeted for control by insecticidal seed treatments in the United States and to identify various management options for them: bean leaf beetle (Cerotoma trifurcate Förster, Coleoptera: Chrysomelidae); grape colaspis, Colaspis brunnea (F.) (Coleoptera: Chrysomelidae); leafhoppers (Hemiptera: Ciccadellidae); seedcorn maggot, Delia platura (Meigen) (Diptera: Anthomyiidae); soybean aphid (Aphis glycines Matsumura, Hemiptera: Aphididae); threecornered alfalfa hopper, Spsistilus festinus (Say) (Hemiptera: Membracidae); thrips (Thysanoptera: Thripidae); white grubs (Coleoptera: Scarabaeidae); and wireworms (Coleoptera: Elateridae). Seedcorn maggot, white grubs, and wireworms have been limited to a relatively small proportion of soybean fields with readily defined factors regarding their risk. However, questions about the pest status of the other six pests were identified. Bean leaf beetle, which vectors Bean pod mottle virus to soybean, has been present across major soybean-production regions, but frequency and proportion of soybean fields that economically impacted is not adequately documented. The impact of threecornered alfalfa hopper and thrips on soybean productivity varied within regions, but specific reasons for the variation were unclear. Early-season management of grape colaspis and leafhoppers has been infrequent, but factors that promoted economic injury and the need for management in specific fields were undetermined. Although early-season management of soybean aphid has not proven feasible for individual fields, questions remain regarding its management in fields near overwintering stands and the possibility for areawide suppression.

A preventative insecticide treatment is a tactic compatible with an integrated pest management (IPM) strategy for a particular pest only when a rescue treatment is not a realistic option, and if there is a reasonable expectation of economic damage by that pest. Most corn, Zea mays L., planted in the United States is protected from several sporadic early-season insect pests by neonicotinoid seed treatments, usually without the knowledge of the threat posed in a given field. We undertook an extensive literature review of these sporadic pests to clarify the prevalence of economic infestations in different regions of the United States, and the agronomic, biotic, and abiotic factors that affect the likelihood of attack. The summaries of the prevalence and risk factors presented here should help farmers and consultants better assess the value of preventative protection of seedling corn under local conditions, and provide others with a better understanding of the complexities farmers face in assessing risks posed by potential pests. The profiles suggest that, in general, pressure from most sporadic pests on seedling corn is rare or local, seldom high enough to decrease yield. However, this is not true in all regions for all sporadic pests. An important issue exposed by the profiles is that the value of preventative insecticide protection of seedling corn depends on understanding the likely combined pressure from multiple species. While such risk may often still be negligible, there is a great need for robust methodology to assess the risk posed by multiple pests. This represents a significant challenge for future research.

The Hessian fly, Mayetiola destructor (Say) (Diptera: Cecidomyiidae); cereal aphids (Hemiptera: Aphididae); and wireworms (Coleoptera: Elateridae) are three common and important insect pests of seedling wheat, Triticum aestivum L., in the United States. Though less common as pests, false wireworms (Coleoptera: Tenebrionidae) may also be problematic in situations that favor wireworms. In addition, cereal aphids vector viruses that cause barley yellow dwarf, a serious and widespread wheat disease. Scientific journal publications, review articles, and management guidebooks on wheat insect pests were consulted to determine the extent and intensity that these pests impose on wheat production in the United States. Widespread outbreaks occur infrequently, but local outbreaks happen nearly every year for the three major pests and cause several millions of dollars in crop losses annually. Hessian fly perennially threatens wheat in the southeastern United States, and wireworms are persistent pests in northwestern wheat-production systems. Otherwise, the particular location and severity of outbreaks vary yearly and are largely unpredictable. However, particular agronomic practices can greatly reduce risk of infestation such as elimination of volunteer wheat and weedy hosts and planting wheat during periods of reduced pest abundance. In addition, resistant cultivars can limit Hessian fly and Russian wheat aphid (Diuraphis noxia [Kurdjumov]) damage in some areas, but virulent biotypes of each pest complicate their management. Although several preemptive tactics reliably suppress infestations and barley yellow dwarf severity, they are not compatible in all agricultural systems. Consequently, insecticides are necessary in certain areas and within particular production systems to manage major early-season insect pests of wheat.

Flowering oilseed crops have the potential to diversify agroecosystems currently dominated by corn and soybeans and improve the provision of ecosystem services such as pest control. Nectar and pollen feeding may increase natural enemy fitness and searching behaviour, increasing their survival and prey consumption rates. The soybean aphid (Aphis glycines Matsumura; Hemiptera: Aphididae) is a particularly widespread and costly agricultural pest. In this study, we evaluate the effects of two flowering oilseed crops, cuphea and calendula, on the survival of the insidious flower bug (Orius insidiosus Say; Hemiptera: Anthocoridae) and its consumption levels of A. glycines placed on soybean plants. We also evaluated the survival of O. insidiosus when placed on glandular and non-glandular cuphea varieties. The amount of A. glycines that remained unconsumed by O. insidiosus did not differ among treatments. Because mortality levels of O. insidiosus were higher on glandular compared to non-glandular cuphea p...

Recent detections of adults of three previously common, native species of lady beetles [Coccinella novemnotata Herbst, Coccinella transversoguttata richardsoni Brown, and Adalia bipunctata (L.); Coleoptera: Coccinellidae] during surveys at several sites in western South Dakota and western Nebraska provided impetus for additional sampling of lady beetles in that region. The current study systematically sampled for lady beetles among three dominant habitats in the region in 2010 and 2011. Four techniques (sucrose-baited and nonbaited yellow sticky traps, sweepnetting, visual searches) sampled 4,036 adult and 830 larval coccinellids comprising 10 species. Coccinella septempunctata L., Hippodamia convergens Guerin-Meneville, Hippodamia parenthesis (Say), and Brachiacantha albifrons (Say) were the most common species. C. novemnotata ranked fifth in abundance, with 94 sampled in small grains, 20 in alfalfa, and 5 in grassland pasture; 58 larval C. novemnotata were sampled primarily in small-grain field...

Ex situ rearing of Coccinella novemnotata Herbst (Coleoptera: Coccinellidae), a Nearctic native that has declined precipitously, may be important for experimentation and conservation. Rearing success may depend on optimizing an aphid prey diet. The objective was to compare development, survivorship and adult size of C. novemnotata reared on diets of various aphid (Hemiptera: Aphididae) species. Diets of Acyrthosiphon pisum (Harris) and A. pisum + Rhopalosiphum padi L. were most suitable for rearing C. novemnotata. Single species diets of other aphids had low suitability for C. novemnotata. Combining A. pisum with one of the other aphid species improved diet suitability compared to diets of other species alone. Knowledge of C. novemnotata development and survival on various aphid species may not only aid in ex situ rearing, but could also be used to identify habitats where C. novemnotata may be extant or those with suitable prey for reestablishment or augmentation of C. novemnotata.

Soybean aphid (SA; Aphis glycines Matsumura) is a major pest of soybean (Glycine max (L.) Merr.) in North America, particularly the north- ern United States. Identification of SA resis - tance in early-maturing soybeans will facilitate development of aphid-resistant cultivars for this region. In this study, 330 soybean germplasm accessions from Maturity Group (MG) I, along with 11 resistant or susceptible checks, were evaluated against SA in greenhouse by caged (no-choice) and noncaged tests. Germplasm accessions that showed resistance in these tests were then tested in the field under natural infestations supplemented by artificial inocu - lation. In the greenhouse tests, accessions PI 189946, PI 153214, and PI 437075 exhibited low SA levels (

Soybean aphid (Aphis glycines Matsumura) (Hemiptera: Aphididae) is a major pest of soybean in northern production regions of North America, and insecticides have been the primary management approach while alternative methods are developed. Knowledge of arthropod natural enemies and their impact on soybean aphid is critical for developing biological control as a management tool. Soybean is a major field crop in South Dakota, but information about its natural enemies and their impact on soybean aphid is lacking. Thus, this study was conducted in field plots in eastern South Dakota during July and August of 2004 and 2005 to characterize foliar-dwelling, arthropod natural enemies of soybean aphid, and it used exclusion techniques to determine impact of natural enemies and ants (Hymenoptera: Formicidae) on soybean aphid densities. In open field plots, weekly soybean aphid densities reached a plateau of several hundred aphids per plant in 2004, and peaked at roughly 400 aphids per plant in 2005. Despite these densities, a relatively high frequency of aphid-infested plants lacked arthropod natural enemies. Lady beetles (Coleoptera: Coccinellidae) were most abundant, peaking at 90 and 52% of all natural enemies sampled in respective years, and Harmonia axyridis Pallas was the most abundant lady beetle. Green lacewings (Neuroptera: Chrysopidae) were abundant in 2005, due mainly to large numbers of their eggs. Abundances of arachnids and coccinellid larvae correlated with soybean aphid densities each year, and chrysopid egg abundance was correlated with aphid density in 2005. Three-week cage treatments of artificially infested soybean plants in 2004 showed that noncaged plants had fewer soybean aphids than caged plants, but abundance of soybean aphid did not differ among open cages and ones that provided partial or total exclusion of natural enemies. In 2005, plants within open cages had fewer soybean aphids than those within cages that excluded natural enemies, and aphid density on open-cage plants did not differ from that on noncaged plants and those accessible by small predators. In a separate 3-yr experiment, exclusion of ants from soybean plants did not lead to differences in soybean aphid density compared with ant-accessible plants. Overall, these results suggest that the soybean aphid natural enemy guild is unsaturated and could be enhanced to improve biological control of soybean aphid in South Dakota.

The soybean aphid, Aphis glycines Matsumura, is frequently a serious pest of soybean in the U.S. and Canada, and an occasional pest of soybean throughout its native range in Asia. Large infestations of this aphid cause economic loss to soybean by reductions in seed yield and oil concentration. Host-plant resistance is a potential alternative to insecticides for managing soybean aphid, and various sources may be evaluated, including adapted cultivars, landraces, and wild ancestors of the crop. To date, few studies have evaluated wild soybean for resistance to soybean aphid. In this study, initial screening assays indicated 20 wild soybean lines with resistance to soybean aphid, and three of the 20 lines had notable resistance in subsequent choice and no-choice assays. Significantly fewer soybean aphids settled on lines PI 468397 A and PI 479749 than on susceptible lines in choice assays, and aphid populations were low and moderately low on these two respective lines in no-choice assays. Populations of soybean aphid on a third line, PI 549046, were equal to or less than those on a resistant check over 3 wks in a no-choice assay. Based on results of the respective choice and no-choice assays, resistance to soybean aphid was manifested as both antixenosis and antibiosis in PI 468397 A and PI 479749, and as antibiosis in PI 549046. This is apparently the first report of resistance to soybean aphid in these three lines, and they provide soybean breeders and pest management practitioners new sources for developing aphid-resistant soybean lines.

Aphids in the genus Uroleucon Mordvilko (Hemiptera: Aphididae) are native herbivores that feed on goldenrod (Solidago spp.) and other Asteraceae in North America. The aphids are potential prey for a wide variety of natural enemies, including native and non-native species of lady beetles (Coleoptera: Coccinellidae). Non-native lady beetles were introduced to aid control of pest aphids in cropland, but some (e.g. Coccinella septempunctata L. and Harmonia axyridis [Pallas]) are known to prey upon Uroleucon aphids in natural and semi-natural settings, raising concerns about their nontarget effects on native aphids. The objective of this study was to estimate non-target risk to Uroleucon aphids from non-native lady beetles. Risk was estimated by evaluating consumption of Uroleucon aphids by lady beetles in no-choice laboratory tests, and by determining incidence of non-native lady beetles within naturally occurring patches of goldenrod and giant sumpweed (Cyclachaena xanthifolia (Nutt.) Fresen.) used ...

The soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is an invasive insect pest of soybean [Glycine max (L.) Merr. (Fabaceae)] in North America, and it has led to extensive insecticide use in northern soybean-growing regions there. Host plant resistance is one potential alternative strategy for managing soybean aphid. Several Rag genes that show antibiosis and antixenosis to soybean aphid have been recently identified in soybean, and field-testing and commercial release of resistant soybean lines have followed. In this article, we review results of field tests with soybean lines containing Rag genes in North America, then present results from a coordinated regional test across several field sites in the north-central USA, and finally discuss prospects for use of Rag genes to manage soybean aphids. Field tests conducted independently at multiple sites showed that soybean aphid populations peaked in late summer on lines with Rag1 or Rag2 and reached economically injurious levels on susceptible lines, whereas lines with a pyramid of Rag1 + Rag2 held soybean aphid populations below economic levels. In the regional test, aphid populations were generally suppressed by lines containing one of the Rag genes. Aphids reached putative economic levels on Rag1 lines for some site years, but yield loss was moderated, indicating that Rag1 may confer tolerance to soybean aphid in addition to antibiosis and antixenosis. Moreover, no yield penalty has been found for lines with Rag1, Rag2, or pyramids. Results suggest that use of aphid-resistant soybean lines with Rag genes may be viable for managing soybean aphids. However, virulent biotypes of soybean aphid were identified before release of aphid-resistant soybean, and thus a strategy for optimal deployment of aphid-resistant soybean is needed to ensure sustainability of this technology.

Although most pests of soybeans, Gycine max (L.), in the Northern Great Plains are managed using pesticides, farm management practices that encourage biodiversity offer promising long-term, sustainable solutions for controlling insect and weed pests profitably. The recent invasion of the Northern Great Plains by the soybean aphid (Aphis glycines Matsumura; Hemiptera: Aphididae) has had potentially important implications for insect communities in soybeans of this region, although recent descriptions of this regional community are scarce. We describe how three pest management systems that vary in the intensity with which they rely on herbicides and insecticides (chemically intensive, reduced chemical, and spring cover crop treatments) affect insect pest populations, arthropod predator communities, weed assemblages, and soybean yield and profitability. Soybean aphids exceeded economic thresholds in all three years, and insecticides successfully suppressed these outbreaks in the two chemical treatments; aphids exceeded the economic injury level in the cover crop treatment in two of three study years. Bean leaf beetle (Cerotoma trifurcata Forster; Coleoptera: Chrysomelidae) populations were sub-economic in all treatments; insecticides targeting soybean aphid also reduced bean leaf beetles in the first year of study when beetle populations were at their highest. Foliar-dwelling predator populations were substantially higher in the cover crop treatment than in the chemical treatments in all years of study; population declines in the latter treatments were strongly associated with insecticide applications targeting soybean aphids. Foliar predator populations did not rebound within the growing season after insecticides were applied. Soil predator populations were largely unaffected by treatment (except in 2006, when they were more abundant in the cover crop treatment than in the chemical treatments). Weed communities varied among treatments and study years, with few consistent trends except that the chemically intensive treatment had lower weed densities than the other treatments. Although input costs of the cover crop and reduced chemical treatments were lower than the chemically intensive treatment, the chemically intensive treatment was the most profitable of the three. Nevertheless, we contend that the cover crops can be managed more efficiently in order to increase the profitability and competitiveness of this treatment while gaining the long-term benefits gleaned from conserving biodiversity in our agroecosystems. Published by Elsevier Ltd.

Coccinella novemnotata L., the ninespotted lady beetle, and Coccinella transversoguttata richardsoni Brown, the transverse lady beetle, are predatory species whose abundance has declined significantly over the last few decades in North America. An ex situ system for continuously rearing these two beetles is described here to aid conservation efforts and facilitate studies aimed at determining factors in their decline and possible recovery. All rearing of lady beetles was conducted in the laboratory at or near room temperatures and 16:8 L:D photoperiod. The two coccinellid species were each reared separately, and different life stages were handled independently. Eggs were collected every 1 to 2 d and placed in holding containers, and individual clutches were transferred to cages with prey when their eggs began to hatch. Neonate larvae were fed live bird cherry-oat aphids (Rhopalosiphum padi (L.)) for 3 to 4 d, and second instars were trans- ferred to different cages and fed live pea aphids (Acyrthosiphon pisum (Harris)). Third and fourth instars were also fed pea aphids, but reared individually in small cups to preclude cannibalism. Upon pupation, individuals were collectively trans- ferred to fresh cups and placed in a different container for the duration of pupation. Newly emerged adults were collected within containers about 2 d after eclosion. Adults were housed in cages stocked with live pea aphids, supplemental food, and rumpled paper towels as oviposition substrate. Over 80% of egg clutches were deposited by beetles on rumpled paper towels versus other surfaces within cages, and incidence of cannibalism of egg clutches was greatly reduced on rumpled paper towels. Techniques for successful rearing of these two coccinellids and future research regarding adaptations to fur- ther optimize their rearing methods are discussed.

Coccinella novemnotata, the nine-spotted lady beetle, was historically one of the most common lady beetles across the US and southern Canada. In the 1980s it became extremely rare and has remained rare. In 2008 adult C. novemnotata were collected from field populations in Oregon and South Dakota and initial observations suggested that these individuals seemed smaller than the mean size of the species historically. These observations led to a series of experiments to determine if there had been significant decrease in size and if any decrease found was due to a genetic change or to environmental factors. In the first of these studies we quantified the size of C. novemnotata collected in the field and the size of Coccinella septempunctata, a congeneric introduced species that was collected in the same habitats and has been implicated as a cause for C. novemnotata decline. The size of these field-collected individuals of both species was compared with the size of historical specimens and individuals reared in the laboratory. Field-collected C. novemnotata adults were significantly (20%) smaller than specimens bred in captivity and specimens from collections. To determine if prey limitation alone could yield the range of sizes observed we reared larvae across a range of prey availability. There was a significant effect of prey availability and adult sizes across treatments bracketed the range we found in the field. Low fed larvae are significantly smaller than high fed larvae. While these results do not definitively point to any single explanation for the decline of this species they are consistent with expectations for competition between C. novemnotata and C. septempunctata.

The soybean aphid, Aphis glycines Matsumura, has become a serious pest of soybean [Glycine max (L.) Merr.] in North America, and host-plant resistance is one potential management tool. In the current study, various F2-derived soybean selections with the Rag1 gene for resistance to soybean aphid were evaluated among F2-derived soybean selections without Rag1 and among contemporary soybean lines in a two-year field test. Overall, aphid levels per plant were over tenfold greater in 2006 than in 2005, but lines generally performed similarly relative to one another between years with regard to aphid-infestation levels. In both years, the Rag1 selections ILL4, ILL27, ILL35, ILL37, ILL64RR, ILL76RR, and ILL77RR had the lowest mean number of soybean aphids per plant. In 2005, three putative Rag1 selections—ILL26, ILL67RR, and ILL87—had intermediate aphid infestation levels greater than those of other Rag1 selections, and in 2006 ILL26 and ILL67RR also had intermediate aphid levels that did not differ from all oth...

The soybean aphid, Aphis glycines, is a pest of soybean in Asia, and it has become a major pest of this crop in North America with large outbreaks that cause significant yield loss. Host-plant resistance is one management tactic being developed against soybean aphid in North America, and resistance may be manifested as antixenosis, antibiosis, or tolerance. In this study, choice tests were conducted to identify antixenosis to soybean aphids in several soybean lines. The soybean lines 'Dowling,' PI 230977, 'Jackson,' 'Cobb' and 'Palmetto' had strong antixenosis to soybean aphid, and lines PI 71506, G93-9223, 'Braxton,' 'Cook,' 'IAC-1,' 'Ripley,' and 'Tie feng 8' were moderately antixenotic. The intermediate level of antixenosis in PI 71506 contrasts with previous results, and suggests biotypic differences in the responses of soybean aphid to this line. Shoot length, shoot width, and seedling dry mass were also measured to test for any association between aphid host choice and plant size. Plant-size parameters varied by soybean line in all tests. However, the relation between aphid host choice and plant-size parameters was generally weak and not consistent across tests, suggesting that other undetermined plant characteristics were important in host selection. The identification of antixenosis in several soybean lines provides soybean breeders and pest management practitioners with additional options for managing soybean aphid through host-plant resistance. Antixenosis may be important on its own, and it may prove be complimentary to the antibiosis mode of resistance by reducing selection on resistance-breaking biotypes of soybean aphid, thereby prolonging the usefulness of plant resistance as a non-chemical means of managing soybean aphid.

Hesler, Louis S., Losey, John E., Allee, Leslie L., Smyth, Rebecca Rice (2014): New Records of Coccinellidae (Coleoptera) from Wyoming, USA. The Coleopterists Bulletin 68 (1): 127-130, DOI: 10.1649/0010-065X-68.1.128, URL: http://dx.doi.org/10.1649/0010-065x-68.1.128

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.

Resistance to the soybean aphid (Aphis glycines Matsumura) was characterized in segregating populations from crosses of soybean [Glycine max (L.) Merr.] accession PI 71506 to susceptible cultivars, and compared to Rag1 resistance from the cultivar ‘Dowling.’ Two susceptible adapted cultivars were crossed with PI 71506 or Dowling. In no-choice greenhouse assays, resistance corresponded to a single dominant gene model for both the PI 71506-derived and Dowling-derived populations. Segregation of aphid resistance in SD1111RR × PI 71506 F2:3 populations in aphid field-cage trials also fit a single-gene model, as did segregation of aphid resistance in the F2:5 generation. However, other genetic effects may also contribute to aphid resistance from PI 71506. Comparison with Rag1 resistance from Dowling indicated that PI 71506 resistance was weaker than that associated with Rag1, but antixenosis resistance from PI 71506 was effective against an Ohio aphid biotype that has overcome Rag1 resistance.

Coccinella septempunctata L. is a widespread Palearctic species that has been introduced several times into North America within the last century. It is generally considered monomorphic with seven elytral maculae in North America. In this paper, we document variation in elytral macular patterns of C. septempunctata based on examination of 674 (567 North American and 107 Palearctic) specimens of C. septempunctata and 382 digital submissions of North American C. septempunctata. Two beetles lacked apical maculae, and 18 beetles had paired humeral markings. Humeral markings were consistent in position and typically had less-dense black pigmentation than maculae. Sixteen of the 18 beetles with paired humeral markings were from 11 states in the United States, one was from Alberta, Canada, and one was from Italy. Some specimens had asymmetrical elytral markings that included pock marks, irregular fuscous markings, or both. Nineteen specimens of C. septempunctata (19 North American, 1 Palearctic) and 16 ...

The soybean aphid, Aphis glycines Matsumura, is a serious pest of soybean [Glycine max (L.) Merr.] in the USA and Canada, and a sporadic pest of soybean in Asia. Infestations by soybean aphid cause economic loss to soybean through reductions in seed yield and oil concentration. Aphid-resistant soybean lines are needed to supplant insecticides for managing soybean aphid, and resistant lines may be developed from both domesticated and wild soybean lines. Free-choice assays of 42 lines of wild soybean (Glycine soja Siebold and Zucc.) in this study identified line 99PI522233 as resistant to soybean-aphid biotype 1. That line was advanced for follow-up assays with wild soybean lines PI 469399 B, PI 507825, PI 507840 and PI 507843, which had previously been screened as aphid resistant. Line 99PI522233 had significantly fewer soybean aphids than other lines except the resistant check in the second and third weeks of a no-choice assay, but the four other putatively resistant lines did not show resistance in the no-choice assay. Thus, line PI99522233 may be advanced for genetic characterization of its resistance, and it should be tested for resistance against virulent soybean aphid biotypes.

Adalia bipunctata (L.), Coccinella transversoguttata richardsoni Brown, and C. novemnotata Herbst (Coleoptera: Coccinellidae) were previously common throughout much of North America, but their numbers have declined drastically over the last few decades. This paper reports on recent findings of these species at nine sites in western South Dakota and western Nebraska in 2008. Nine A. bipunctata, 11 C. transversoguttata richardsoni, and 12 C. novemnotata were among 930 coccinellids sampled overall. An additional C. transversoguttata richardsoni was among coccinellids captured on a sticky trap in a wheat field during survey for cereal leaf beetle, Oulema melanopus (L.), in Butte, County, South Dakota in 2000. In several instances, adult C. transversoguttata richardsoni and C. novemnotata were observed on plants with other coccinellids, especially Hippodamia convergens Guerin-Meneville, a native species, and Coccinella septempunctata L., a non-native species. Coccinella septempunctata was observed fee...

The Nineteenth Biennial Meeting of the International Plant Resistance to Insects (IPRI) Workshop was held 28–31 March 2010 in Charleston, SC. This workshop was attended by 71 participants from six countries. There were 17 symposium papers (three symposia), 22 submitted papers, 9 student competition papers, and 21 posters presented. The abstracts of 52 of the 69 presentations and posters are presented herein.

The direct effects of three soybean parentages, each represented by an Aphis glycines-resistant and susceptible isoline, on the fitness and performance of two key predators (Orius insidiosus and Harmonia axyridis) were evaluated in the laboratory. Predators were reared from hatch through adulthood in Petri dishes with cut trifoliolate leaves of the designated soybean variety, using eggs of Ephestia kuehniella as surrogate prey to eliminate prey-mediated effects of the host plant. Preimaginal survival and development, sex ratio, adult longevity, fecundity, and size were compared among treatments and a no-plant control. An additional experiment compared life-history parameters of predators caged with soybean versus Ipomoea hederacea (ivyleaf morning glory). Aphid resistance reduced the adult longevity of H. axyridis, but O. insidiosus was unaffected by resistance traits. However, adult O. insidiosus lived longer on soybeans with Group C base genetics than the other soybean varieties. Other parameters were not affected by soybean base genetics or resistance, but both predators generally performed worse on soybean than on I. hederacea or no-plant controls. The results suggest that soybean varietal selection, particularly with respect to A. glycines-resistance, may directly affect biological control agents. Also, implications of the generally poor suitability of soybean for natural enemies are discussed within the context of current crop production practices.

An updated list of 79 species of Coccinellidae for South Dakota is presented. The list represents a net increase in the state coccinellid fauna from a previously published list of 66 species and subspecific taxa, and it also includes nomenclatural updates. Thirteen species have been added to the list as new state records: Didion punctatum (Melsheimer), Didion nanum (LeConte), Scymnus paracanus linearis Gordon, Scymnus fraternus LeConte, Hyperaspis inflexa Casey, Hyperaspis lugubris (Randall), Hyperaspis troglodytes Mulsant, Hyperaspis brunnescens Dobzhansky, Hyperaspis quadrivittata LeConte, Brachiacantha decempustulata (Melsheimer), Brumoides septentrionis septentrionis (Weise), Hippodamia expurgata Casey, and Hippodamia sinuata crotchi Casey. Two specimens of Coccinella septempunctata L., collected in 1978 represent a new state record of this species from South Dakota. Eight other species were added after reviewing previously published species records and faunal distribution maps. Several entri...

In the last two decades, three previously common coccinellids (Adalia bipunctata (L.), Coccinella transversoguttata richardsoni Brown, and Coccinella novemnotata Herbst) have declined in abundance in South Dakota, while two invasive species (Coccinella septempunctata (L.) and Harmonia axyridis (Pallas)) have become established there. The objectives of this study were to survey coccinellids in various habitats in South Dakota to better characterize the current coccinellid fauna, determine the extent of exploitation by invasive coccinellids, and possibly identify refuge habitats of previously common coccinellid species. Overall, 2827 coccinellids, comprising 23 species, were collected on yellow sticky traps in field and woody habitats and during timed visual searches in field crops. Adalia bipunctata was found during additional sampling in Butte County in western South Dakota. However, it was not present in samples from eastern and central parts of the state, which is consistent with previous findi...

The soybean aphid, Aphis glycines Matsumura, is a pest of soybean [Glycine max L. (Merrill)] in Asia, and its recent establishment in North America has led to large, recurring outbreaks that have challenged pest management practitioners to seek environmentally responsible means for its control. Growth-chamber experiments identified resistance to A. glycines in soybean lines ‘Perrin’; ‘Tracy-M,’ its glabrous near-isoline ‘D88-5328,’ and its densely pubescent near-isoline ‘D88-5272’; ‘D75-10169,’ its glabrous near-isoline ‘D90-9216,’ and a densely pubescent near-isoline ‘D90-9220.’ Tracy-M and D75-10169 were antixenotic to A. glycines in host-selection tests. In no-choice nymphiposition tests, the number of nymphs deposited by A. glycines on D75-10169, Perrin, and Tracy-M did not differ from that on other lines after 24- and 48-h test periods. Under conditions in which A. glycines were free to distribute on plants over a 48-h period, aphids were found primarily on stems and trifoliolate leaves of Perrin, Tracy-M, D75-10169 and a resistant control, ‘Dowling,’ whereas the majority of aphids infesting susceptible lines ‘91B91’ and ‘Davis’ were distributed on unifoliolate leaves. Irrespective of shoot structure, low numbers of A. glycines were found on Dowling compared to other lines. The mean number of days to reproductive maturity for A. glycines did not differ among lines. Aphis glycines produced fewer nymphs during the first 7 d of reproduction on Perrin, Tracy-M, D75-10169 and Dowling compared to Davis, and fewer A. glycines progeny were produced on D75-10169 and Dowling than on 91B91. Results show that Dowling continues to be a strong source of resistance to A. glycines. Perrin, Tracy-M, and D75-10169 have been used as sources of resistance to other insects, and discovery of resistance to A. glycines in these three lines may increase their utility in soybean breeding programs.