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We present a synthetic review and expert consultation that assesses the actual risks posed by arthropod pests in four major crops, identifies targets for integrated pest management (IPM) in terms of cultivated land needing pest control and gauges the implementation “readiness” of non-chemical alternatives. Our assessment focuses on the world’s primary target pests for neonicotinoid-based management: western corn rootworm (WCR, Diabrotica virgifera virgifera) in maize; wireworms (Agriotes spp.) in maize and winter wheat; bird cherry-oat aphid (Rhopalosiphum padi) in winter wheat; brown planthopper (BPH, Nilaparvata lugens) in rice; cotton aphid (Aphis gossypii) and silver-leaf whitefly (SLW, Bemisia tabaci) in cotton. First, we queried scientific literature databases and consulted experts from different countries in Europe, North America, and Asia about available IPM tools for each crop-pest system. Next, using an online survey, we quantitatively assessed the economic relevance of target pests by compiling country-level records of crop damage, yield impacts, extent of insecticide usage, and “readiness” status of various pest management alternatives (i.e., research, plot-scale validation, grower-uptake). Biological control received considerable scientific attention, while agronomic strategies (e.g., crop rotation), insurance schemes, decision support systems (DSS), and innovative pesticide application modes were listed as key alternatives. Our study identifies opportunities to advance applied research, IPM technology validation, and grower education to halt or drastically reduce our over-reliance on systemic insecticides globally. he authors would like to thank the Stichting Triodos Foundation (The Netherlands) for funding the Task Force on Systemic Pesticides (TFSP) as a totally independent research group, for making this study and the relative open access possible. The Stichting Triodos Foundation received funds from the Umwelt Stiftung Greenpeace (Germany), Pollinis (France) and the M.A.O.C. Gravin van Bylandt Stichting (The Netherlands).

Diversifying cropland plant communities is prerequisite to restoring ecosystem functions in agricultural habitats. Cover crops are one such way to improve biodiversity, and broadcasting calcium carbonate-coated (lime) seeds can be a viable method for plant establishment. In addition to improving seed-to-soil contact, calcium carbonate may also reduce arthropod granivory. Here we examine the effect of this seed-coating technology on arthropod granivory for seven cover crop species under field conditions. Carabidae, Gryllidae, and Staphylinidae were the three most frequently collected granivorous taxa in pitfall samples, and Pterostichus permundus and Gryllus pennsylvanicus represented 60.8% of all individual granivores. Cover crop seed damaged was variable among plant species. Among all plant species, the presence of a seed coating significantly reduced granivory by nearly 40% in the 7-d field exposure. Individually, hairy vetch and sorghum × sudan seeds were especially protected by calcium carbonate. No positive correlations were observed between invertebrate groups and the number of seeds consumed. Alternative methods for assessing the functionality of granivorous arthropod communities should be pursued, as activity-density measured from pitfall traps failed to reveal important cover crop seed consumers. Protection of cover crop seeds from granivory through a calcium carbonate coating may allow producers to adjust seeding rates and save on costs, increasing the rate of adoption for this conservation practice.

To increase the resilience of our food system, we must better understand how ecosystem services such as pest control and pollination provided by a diverse insect community contribute to crop yield. We examined how landscape heterogeneity relates to insect and pollinator diversity, and how insect and pollinator diversity relates to yield of Brassica carinata, a new biofuel crop within common farming practices. Over two years, we planted 35 × 1 acre sites in a roughly 1000‐km2 area near Brookings, South Dakota, in the Prairie Coteau. We randomly assigned each site to a combination of three common farming practices: tilling (yes/no), added honey bee hives (yes/no), and treatment with systemic neonicotinoids (yes/no). Insect and pollinator diversity and the heterogeneity of the surrounding landscape at multiple spatial scales were calculated. We observed a significant positive relationship between insect (and pollinator) diversity and yield when fields were untreated, without hives, nor seed treatments. All farming practices within this study increase yield. However, farming practices alter the relationship between yield and insect (and pollinator) diversity. The addition of seed treatment or tillage negates the relationship between insect (and pollinator) diversity with yield. There was no relationship between seed treatment, diversity, and yield for all insects, and the application of seed treatment resulted in lower pollinator diversity. Increased landscape heterogeneity was correlated with more insect diversity at the 1000‐m scale and pollinator diversity at the 3000‐m scale. Our results show that increasing large‐scale landscape heterogeneity increases insect diversity, which serves as a substitute for common farming practices such as application of pesticides, tilling, or bee hives. Increased landscape heterogeneity could increase farmers' net profitability by replacing input costs associated with tillage and seed treatments.

Agroecosystems represent a large geographical footprint in most terrestrial landscapes, and management decisions within these systems affect their function in species conservation. We evaluated the effects that rangeland management systems (based on stocking density, rotation frequency, and the number of avermectin applications) have on conserving the dung arthropod community in the Northern Great Plains of North America. Comprehensive bioinventories of arthropods were collected from 16 rangelands using core samples of dung pats. Ivermectin was quantified in pats from each ranch using enzyme-linked immunosorbant assay (ELISA). Arthropods in dung were abundant (116,244 specimens) and diverse in eastern South Dakota (172 morphospecies). Rangelands managed with more regenerative practices (frequent rotation at high stocking densities and lack of ivermectin applications) had greater species richness, diversity, predator species abundance, and dung beetle abundance than more conventionally managed rangelands. Ivermectin quantity in cattle pats was negatively correlated with dung beetle abundance and diversity. This work shows that herd management (specifically high-intensity, frequent rotational grazing and eliminating prophylactic ivermectin use) that aims to mimic intensive grazing of large migrating herds of ruminants can foster dung arthropod community structure, a key trait correlated with nutrient cycling, pest suppression, and productivity of cattle-grazed rangelands.

The red imported fire ant, Solenopsis invicta, is one of the most prolific invasive species to the Southeastern U.S. These invaders preferentially colonize highly disturbed land and grassland habitat. Management of livestock in pasture systems can have a profound impact on the level of disturbance in grassland habitats, and we hypothesized that pasture management would have a significant effect on S. invicta abundance in the Southeastern U.S., and arthropod diversity would negatively correlate with this invasive species. We studied the effects that pasture management systems (based on stocking density, rotation frequency, and insecticide application rates) have on fire ant mound abundance and arthropod diversity for the soil, foliar, and dung communities. S. invicta mounds were quantified and mound areas were documented along transect lines in six pastures. Soil and foliar arthropod communities were collected along the same transect lines, and dung communities sampled from pats within the pasture system. Pastures managed under adaptive multi-paddock (AMP) practices had 3.35× more S. invicta mounds and 4.64× more mound area than their conventionally managed counterparts. However, arthropod diversity did not correlate with S. invicta abundance for any of the three arthropod communities sampled. This study shows pasture management can have a significant impact on S. invicta mound abundance, but arthropod communities in AMP managed pastures did not suffer decreased diversity from increased abundance of S. invicta. Additionally, this study demonstrates that this invasive species does not necessarily contribute to diversity decline, at least under AMP pasture systems.

Declining pollinator populations worldwide are attributed to multiple stressors, including the loss of quality forage. Habitat management in agricultural areas often targets honey bees (Apis mellifera L.) specifically, with the assumption that native bees will benefit from an ‘umbrella species’ strategy. We tested this theory using a conservation physiology approach to compare the effects of landscape composition and floral dietary composition on the physiological status of honey bees and Melissodes desponsa in eastern South Dakota, USA. The total glycogen, lipid and protein concentrations were quantified from field collected bees. Next-generation sequencing of the trnL chloroplast gene from bee guts was used to evaluate dietary composition. The effects of landscape and dietary composition on macronutrient concentrations were compared between bee species. As the mean land-use patch area increased, honey bee glycogen levels increased, though M. desponsa experienced a decrease in glycogen. Protein levels decreased in honey bees as the largest patch index, a measure of single patch dominance, increased versus M. desponsa. Lipids in both species were unaffected by the measured landscape variables. Dietary analysis revealed that honey bees foraged preferentially on weedy non-native plant species, while M. desponsa sought out native and rarer species, in addition to utilizing non-native plants. Both species foraged on Asteraceae, Oleaceae and Fabaceae, specifically Melilotus sp. and Medicago sp. Dietary composition was not predictive of the macronutrients measured for either species. Together, these data highlight the management importance of including patch area in conservation recommendations, as bee species may have divergent physiological responses to landscape characteristics. While solitary bees may forage on weedy introduced plants in agricultural areas, robust strategies should also reincorporate native plant species, though they may not be preferred by honey bees, to maximize overall health and diversity of pollinator communities.

Sugar feeding by biological control agents, such as parasitoid wasps, may enhance their ability to control crop pests, although its importance is likely to vary greatly through space and time. Here we quantified temporal variation in the potential importance of sugar resources associated with honeydew secreted by the pea aphid (Acyrthosiphon pisum (Harris) (Hemiptera: Aphididae)) in determining levels of parasitism of the alfalfa weevil (Hypera postica (Gyllenhal) (Coleoptera: Curculionidae)) by its dominant parasitoid, Bathyplectes curculionis (Thomson) (Hymenoptera: Ichneumonidae) across irrigated alfalfa fields in Montana, United States over 5 yr. A positive association between parasitism of H. postica and A. pisum densities at the across-site scale was observed in 2 of 5 yr, with parasitism increasing twofold to fourfold over gradients in A. pisum density. The relationship was strongest in the 2 yr of lowest parasitoid relative to host densities, when increases in per capita effects of individual parasitoids would be expected to be particularly important. Acyrthosiphon pisum densities were at their lowest in these same years, suggesting that they may generally be sufficiently abundant that parasitoids are not limited by sugars in most years. This conclusion is supported by results of anthrone tests which revealed a high level of sugar-fed parasitoids (>50%) in a year of high aphid abundance. More studies, such as this one, that explore the frequency with which increasing sugar resource availability actually enhances parasitism levels in the field will be critical to gauge the broader potential of sugar resource addition (e.g., through flowering strips, banker plants or sugar sprays) to bolster biological control.

Neonicotinoid seed-treatments are used frequently in sunflower production to prevent early-season herbivory, and have been implicated in declines in non-target species. Over three site-years, both insecticide treated (Cruiser ® , rate: 0.25 mg a.i. (thiamethoxam)/seed) and untreated sunflower ( Helianthus annuus [Family: Asteraceae]) fields were planted in Eastern and Central South Dakota. Foliar and subterranean predatory arthropod communities and pollinator populations were compared among the two treatments. A greenhouse study was performed to collect and quantify toxins in extra-floral nectar from treated and untreated sunflowers. A laboratory assay was performed to examine the effect of an artificial nectar diet laced with thiamethoxam or clothianidin on survival, fecundity and mobility of Coleomegilla maculata (De Geer [Coleoptera: Coccinellidae]). Seed-treated fields had significantly fewer above-ground natural enemies and pollinators than untreated fields, while subterranean predators were unaffected. Beetle flip-over times increased as concentration of thiamethoxam in diet increased, but clothianidin showed no effect. Neither toxin affected number of eggs oviposited by beetles, or size of developing oocytes. However, there was a negative correlation between increasing thiamethoxam concentration and number of developing eggs. Extra-floral nectar (EFN) collected from treated greenhouse-grown plants contained thiamethoxam (range: 1.23 ± 0.09 ppb to 4.83 ± 0.63 ppb), but no clothianidin. Toxin-laden EFN was identified as a potential route of exposure between beneficial arthropods and seed-applied neonicotinoids. Risks of neonicotinoid seed treatment use are discussed in the light of additional exposure pathways being confirmed.

The alfalfa weevil (Hypera postica (Gyllenhal); Coleoptera: Curculionidae), is a destructive pest of alfalfa (Medicago sativa Linnaeus; Fabaceae) worldwide. The biological control parasitoid, Microctonus aethiopoides Loan (Hymenoptera: Braconidae), was successfully introduced, and considered highly effective, in the eastern and mid-western United States of America. Redistribution efforts carried out throughout the 1980s reported initial establishment in the northern Great Plains, however follow-up studies to assess long-term persistence and efficacy are lacking. We resurveyed the counties in which M. aethiopoides had been initially recovered following redistribution in Montana (Flathead and Petroleum counties), Wyoming (Platte County), and South Dakota (Brookings County), to gauge whether this species has become permanently established and, if so, assess levels of parasitism in the field. We collected adult weevils from five fields in each county, and reared them in the laboratory to assess parasitism. Despite rearing more than 1000 weevils, no parasitoids were recovered from any of the locations sampled in our study, suggesting a widespread failure of M. aethiopoides to persist in the region. Thus, M. aethiopoides does not currently appear to be an important biological control agent of alfalfa weevil in the northern Great Plains. More intensive surveys will be required to assess the extent of the distributional limits of this species throughout the region.

The early detection of insects during grain storage and processing remains a major issue for the cereal industry, especially when immature stages are hidden inside the grain kernels. For this reason, we developed a qPCR method to detect and quantify one of the main pests of stored products in rice: the coleopteran internal feeder Rhyzopertha dominica. For that purpose, a specific primer set was designed to amplify artificial infestations of this pest in rice. Then, using a regression model, a standard curve was generated that correlated individuals to adult equivalent DNA quantity (inverse of the Ct value). Results revealed that the designed primer set was specific for R. dominica when tested against the other 4 common internal feeders in grain. The technique showed to be accurated (DNA was detected in more than 73% of the samples) and sensitive to insect presence (i.e. from 0.02 adults, 0.1 3rd instar to pupae or 13 egg to 2nd instar detectable per kg of rice). Moreover, the detection of R. dominica was strongly associated with a given infestation size: DNA quantity increased along with the size of the population. The use of the described qPCR protocol in grain and milling factories may enhace the critical detection and quantification of R. dominica populations in raw materials and processed food.

Methyl salicylate (MeSA) is a commonly emitted herbivore-induced plant volatile (HIPV) known to attract insect predators in agricultural crops. However, thorough studies on whether MeSA can increase their ecological functioning or their attraction under field conditions are still lacking. Here, we conducted laboratory, greenhouse, and field studies to address the hypothesis that two agriculturally important predatory insects (the ladybeetle Hippodamia convergens Guerin-Meneville and the lacewing Chrysoperla rufilabris Burmeister) respond physiologically and behaviorally to MeSA, which may lead to increased predation and oviposition. In laboratory studies using electro-antennography, we found that male and female H. convergens and C. rufilabris antennae can detect MeSA; however, for both species, female antennae responded more strongly. In greenhouse studies using cages and wind tunnels, H. convergens females were attracted to, and arrested by, MeSA; this attraction increased egg predation. Attraction of C. rufilabris females to MeSA also increased oviposition. In field studies, mark-release-recapture experiments were performed to investigate H. convergens and C. rufilabris attraction to MeSA over various distances in cranberry fields. More H. convergens and C. rufilabris were caught on yellow sticky cards placed close (0–30 m) to the predator release site than at farther distances, regardless of whether the cards were baited with MeSA or not. In conclusion, H. convergens and C. rufilabris adults detected, and were attracted to, MeSA under laboratory and greenhouse conditions, resulting in higher predation and oviposition, but this attraction was not observed under field conditions. These results demonstrate that predator responses to HIPVs can be complex in real agricultural settings.

In the current “tiered” paradigm for evaluating risks of insecticidal products, one of the first decisions that must be made is the selection of indicator species to be used in toxicity assays. However, as yet, no formal system has been developed to determine whether proposed indicator species are relevant to the ecology of the crop system where the product will be released. Here, we propose a protocol that provides information on the ecology and trophic linkages of organisms within agro-ecosystems, and demonstrate its implementation within maize agro-ecosystems, which have been a major focus of recent insecticidal developments. We use molecular gut-content assays and network analysis to identify species that are likely to be exposed to plant-incorporated products, and that likely have important functional roles in interaction webs in the maize ecosystem. The vast majority of arthropod abundance was found in the soil (97% of specimens per m2 were found in the soil column). Only nine of the 382 morphotaxa met all three of the ecological criteria (high abundance, corn consumption, degree of connectedness within the network) for inclusion as indicator species, only one of which, Orius insidiosus (Say) (Hemiptera: Anthocoridae), has routinely been considered in risk assessment. Ecological data collected in studies such as this one can be used to ensure that insecticide risk assessments are ecologically relevant. We advocate the use of large-scale field bio-inventories, combined with molecular gut-content assays and ecological network analysis as regular components of the preparation and design phases of all future risk-assessment programs.

We investigated the roles of diet and landscape diversity on the health of two bee species. Both shared many of the same food resources. However, physiological responses to landscape changes were significantly different. Conservation strategies should focus on the size of pollinator plantings and flower diversity to improve bee health., Declining pollinator populations worldwide are attributed to multiple stressors, including the loss of quality forage. Habitat management in agricultural areas often targets honey bees (Apis mellifera L.) specifically, with the assumption that native bees will benefit from an ‘umbrella species’ strategy. We tested this theory using a conservation physiology approach to compare the effects of landscape composition and floral dietary composition on the physiological status of honey bees and Melissodes desponsa in eastern South Dakota, USA. The total glycogen, lipid and protein concentrations were quantified from field collected bees. Next-generation sequencing of the trnL chloroplast gene from bee guts was used to evaluate dietary composition. The effects of landscape and dietary composition on macronutrient concentrations were compared between bee species. As the mean land-use patch area increased, honey bee glycogen levels increased, though M. desponsa experienced a decrease in glycogen. Protein levels decreased in honey bees as the largest patch index, a measure of single patch dominance, increased versus M. desponsa. Lipids in both species were unaffected by the measured landscape variables. Dietary analysis revealed that honey bees foraged preferentially on weedy non-native plant species, while M. desponsa sought out native and rarer species, in addition to utilizing non-native plants. Both species foraged on Asteraceae, Oleaceae and Fabaceae, specifically Melilotus sp. and Medicago sp. Dietary composition was not predictive of the macronutrients measured for either species. Together, these data highlight the management importance of including patch area in conservation recommendations, as bee species may have divergent physiological responses to landscape characteristics. While solitary bees may forage on weedy introduced plants in agricultural areas, robust strategies should also reincorporate native plant species, though they may not be preferred by honey bees, to maximize overall health and diversity of pollinator communities.

Over the past decade, abnormalities have been documented in white-tailed deer (Odocoileus virginianus) in west-central Montana. Hypotheses proposed to explain these anomalies included contact with endocrine disrupting pesticides, such as imidacloprid. We evaluated the effects of imidacloprid experimentally at the South Dakota State University Wildlife and Fisheries Captive Facility where adult white-tailed deer females and their fawns were administered aqueous imidacloprid (an untreated control, 1,500 ng/L, 3,000 ng/L, and 15,000 ng/L). Water consumption, thyroid hormone function, behavioral responses, and skull and jawbone measurements were compared among treatments. Additionally, liver, spleen, genital, and brain imidacloprid concentrations were determined by an enzyme-linked immunosorbent assay (ELISA). Results indicated that 1) control deer consumed more water than treatment groups, 2) imidacloprid was present in the organs of our control group, indicating environmental contamination, 3) as imidacloprid increased in the spleen, fawn survival, thyroxine levels, jawbone lengths, body weight, and organ weights decreased, 4) adult female imidacloprid levels in the genitals were negatively correlated with genital organ weight and, 5) behavioral observations indicated that imidacloprid levels in spleens were negatively correlated with activity levels in adult females and fawns. Results demonstrate that imidacloprid has direct effects on white-tailed deer when administered at field–relevant doses.

Land use, habitat, and forage quality have emerged as critical factors influencing the health, productivity, and survival of honey bee colonies. However, characterization of the mechanistic relationship between differential land-use conditions and ultimate outcomes for honey bee colonies has been elusive. We assessed the physiological health of individual worker honey bees in colonies stationed across a gradient of agricultural land use to ask whether indicators of nutritional physiology including glycogen, total sugar, lipids, and protein were associated with land-use conditions over the growing season and colony population size the subsequent spring during almond pollination. Across the observed land-use gradient, we found that September lipid levels related to growing-season land use, with honey bees from apiaries surrounded by more favorable land covers such as grassland, pasture, conservation land, and fallow fields having greater lipid reserves. Further, we observed a significant relationship between total protein during September and population size of colonies during almond pollination the following February. We demonstrate and discuss the utility of quantifying nutritional biomarkers to infer land-use quality and predict colony population size.

Nearly 2.5 billion smallholders cultivate the world’s arable land, strategically positioned to tackle multiple Anthropocene challenges. When consciously adopting ecologically-based pest management practices, they can improve resource use efficiency, slow biodiversity loss, curtail environmental pollution and safeguard human health. Yet, the effective implementation of knowledge-intensive management practices requires underlying ecological concepts to be well-understood. Here, drawing upon published social science research spanning 1910–2016, we illuminate deficiencies in the world’s farmers’ ecological literacy and in their valuation of insect-mediated ecosystem services. Though tribal people and indigenous folk possess sophisticated knowledge of insects that occur within farm settings, contemporary farmers on average know a mere 1.9–2.3 pestiferous herbivores and 0.5–0.9 pest-killing organisms (out of a respective 8 and 3 taxa) in a particular crop or cropping system. Ecosystem services such as biological pest control are annually worth hundreds of dollars ha−1 but remain unknown to nearly 70% of farmers globally. Also, agricultural systems with deficient ecological literacy tend to foster a greater dependency upon chemically-synthesized pesticides. If this ‘cognitive handicap’ can be remediated, farmers could become agro-biodiversity stewards and champions in redressing multiple aspects of global environmental change.

Neonicotinoid seed treatments are extensively used to systemically protect corn from invertebrate herbivory. Interseeding cover crops can promote beneficial insect communities and their ecosystem services such as predation on pests, and this practice is gaining interest from farmers. In this study, cereal rye (Secale cereale) and hairy vetch (Vicia villosa) were planted between rows of early vegetative corn that had been seed-treated with thiamethoxam. Thiamethoxam and its insecticidal metabolite, clothianidin were quantified in cover crop leaves throughout the growing season. Thiamethoxam was present in cereal rye at concentrations ranging from 0 to 0.33 ± 0.09 ng/g of leaf tissue and was detected on six out of seven collection dates. Cereal rye leaves contained clothianidin at concentrations from 1.05 ± 0.22 to 2.61 ± 0.24 ng/g and was present on all sampling dates. Both thiamethoxam and clothianidin were detected in hairy vetch on all sampling dates at rates ranging from 0.10 ± 0.05 to 0.51 ± 0.11 ng/g and 0.56 ± 0.15 to 9.73 ± 5.04 ng/g of leaf tissue, respectively. Clothianidin was measured at a higher concentration than its precursor, thiamethoxam, in both plant species on every sampling date. Neonicotinoids entering interseeded cover crops from adjacent treated plants is a newly discovered route of exposure and potential hazard for non-target beneficial invertebrates. Future research efforts should examine the effects of systemic insecticides on biological communities in agroecosystems whose goal is to diversify plant communities using methods such as cover cropping.

Species that are involved in multitrophic interactions are affected by the trophic levels that are above and below them in both indirect and direct ways. In this experiment, interactions among ants (Formica montana Wheeler; Hymenoptera: Formicidae), aphids (Myzus persicae [Sulzer]; Hemiptera: Aphididae), lepidopteran eggs (Pieris rapae [L.]; Lepidoptera: Pieridae), and lady beetles (Coleomegilla maculata DeGeer; Coleoptera: Coccinellidae) were examined on canola (Brassica napus L.; Brassicales: Brassicaceae) to determine whether aphids mediate interactions between ants and eggs and if aphid-tending ants will protect these species from predation by the lady beetles. The first trial examined how ant attendance affected aphid and egg survival over 72 h when these herbivores were present on their own or in combination. The second trial examined these same interactions when a lady beetle was included in the system. Ants consumed significantly more aphids when this prey was offered alone than when egg...

Pollinating insects are in decline throughout the world, driven by a combination of factors including the loss of forage resources. The maize (Zea mays L.)– and soybean [Glycine max (L.) Merr.]–dominated agriculture of the Central and Midwestern United States produces a landscape relatively devoid of nectar and pollen resources. Introducing specialty oilseeds into current crop rotations could provide abundant floral resources for pollinating insects as well as a high-value crop for growers. We investigated the nectar sugar resources and insect visitation throughout flower anthesis of nine specialty oilseed crops in west-central Minnesota and eastern South Dakota during the 2013 and 2014 growing seasons. Total sugar produced over anthesis (TS) was highest for echium (Echium plantagineum L.) at 472 kg ha⁻¹. Canola (Brassica napus L.), crambe (Crambe abyssinica Hochst.), echium, borage (Borago officinalis L.), and cuphea (Cuphea viscosissima Jacq. × Cuphea lanceolata W. T. Aiton) produced enough sugar in one hectare to supply the annual sugar needs of a least one managed honey bee (Apis mellifera L.) colony. Pollinators visited flowers of all crops, with as many as 90 insects min⁻¹ observed. Our study is unique as we measured nectar sugar production, flower density, and insect visitation throughout anthesis for multiple specialty oilseed crops, providing a seasonwide perspective of the flux of nectar resources for pollinators. Adding specialty oilseed crops into current crop rotations could aid in reversing pollinator decline by providing forage resources that are lacking in the current agricultural landscape.

Aphids have important effects on the abundance and occurrence of tending ants, predators, and pests in agronomic systems, and DNA-based gut content analysis can aid in establishing predator–prey interactions. The purpose of this study was to determine how the presence of aphids, ants, and pest individuals interact within canola (syn. oilseed rape) fields. Using seasonal data from canola fields, the relationships among ants, aphids and pest individuals were determined, along with the use of PCR techniques in order to amplify aphid DNA and confirm food web links on predators who consume aphids. We determined that aphid presence positively influences the number of ants and predators in a community, and diminishing aphid populations over the growing season were associated with declines in both ants and predators. These reduced populations of predators and aphids may have provided the opportunity for a key pest, Pieris rapae to build populations as the season ensued. This research suggests that complex interactions among herbivores and shared predators contribute to pest outbreaks.

Biological control, a globally-important ecosystem service, can provide long-term and broad-scale suppression of invasive pests, weeds and pathogens in natural, urban and agricultural environments. Following (few) historic cases that led to sizeable environmental up-sets, the discipline of arthropod biological control has—over the past decades—evolved and matured. Now, by deliberately taking into account the ecological risks associated with the planned introduction of insect natural enemies, immense environmental and societal benefits can be gained. In this study, we document and analyze a successful case of biological control against the cassava mealybug,Phenacoccus manihoti(Hemiptera: Pseudococcidae) which invaded Southeast Asia in 2008, where it caused substantial crop losses and triggered two- to three-fold surges in agricultural commodity prices. In 2009, the host-specific parasitoidAnagyrus lopezi(Hymenoptera: Encyrtidae) was released in Thailand and subsequently introduced into neighboring Asian countries. Drawing upon continental-scale insect surveys, multi-year population studies and (field-level) experimental assays, we show howA. lopeziattained intermediate to high parasitism rates across diverse agro-ecological contexts. Driving mealybug populations below non-damaging levels over a broad geographical area,A. lopeziallowed yield recoveries up to 10.0 t/ha and provided biological control services worth several hundred dollars per ha (at local farm-gate prices) in Asia’s four-million ha cassava crop. Our work provides lessons to invasion science and crop protection worldwide. Furthermore, it accentuates the importance of scientifically-guided biological control for insect pest management, and highlights its potentially large socio-economic benefits to agricultural sustainability in the face of a debilitating invasive pest. In times of unrelenting insect invasions, surging pesticide use and accelerating biodiversity loss across the globe, this study demonstrates how biological control—as a pure public good endeavor—constitutes a powerful, cost-effective and environmentally-responsible solution for invasive species mitigation.

Biological control constitutes one of the world’s prime ecosystems services, and can provide long-term and broad-scale suppression of invasive pests, weeds and pathogens in both natural and agricultural environments. Following (very few) widely-documented historic cases that led to sizeable environmental up-sets, the discipline of insect biological control has -over the past three decades- gone through much-needed reform. Now, by deliberately taking into account the ecological risks associated with insect biological control, immense environmental and societal benefits can be gained. In this study, we document and analyze a rare, successful case of biological control against the invasive mealybug, Phenacoccus manihoti (Hemiptera: Pseudococcidae) which invaded Southeast Asia in 2008, where it caused substantial crop losses and triggered 2- to 3-fold surges in agricultural commodity prices. In 2009, the host-specific parasitoid Anagyrus lopezi (Hymenoptera: Encyrtidae) was released in Thailand and subsequently introduced into neighboring Asian countries. Drawing upon continental-scale insect surveys, multi-year population studies and (field-level) experimental assays, we show how A. lopezi attained intermediate to high parasitism rates across diverse agro-ecological contexts. Driving mealybug populations below non-damaging levels at a continental scale, A. lopezi allowed yield recoveries up to 10.0 t/ha and provided biological control services worth several hundred dollars per ha (at local farm-gate prices) in Asia’s 4-million ha cassava crop. Our work provides lessons to invasion science and crop protection worldwide, heralds a new era for insect biological control, and highlights its potentially large socio-economic benefits to agricultural sustainability in the face of a debilitating invasive pest. In times of unrelenting insect invasions, surging pesticide use and accelerating (invertebrate) biodiversity loss across the globe, this study unequivocally demonstrates how biological control – as a pure public good – constitutes a powerful, cost-effective and environmentally-responsible solution for invasive species mitigation.

Driven by factors such as an increased reliance on genetically modified crops, government policies, and market forces, the crop mix in South Dakota and elsewhere in the United States has become less diverse and moved toward the production of corn and soybeans as the most predominant cash crops over the past two decades. Coinciding with a reduced complexity of crop rotation practices, the prevalence of mono-cropping has increased and crop chemical usage has changed as well. Overall, the reduced reliance on traditional crop rotation practices for mitigating pests corresponds with an increase in crop acres treated with insecticides, expressed as a proportion of total cropland acres, and referred to in the literature as the extensive usage of insecticides. In this paper, we identify how changing cropping patterns in South Dakota have affected the extensive usage of insecticides, an aspect often overlooked by producers and policy makers. Results indicate that increased corn production has contributed to an increase in the share of cropland acres treated with insecticides at the county level in eastern South Dakota.

Cereal aphid complexes are responsible for reducing spring wheat production worldwide. Generalist predators may contribute to reducing cereal aphid numbers and preventing significant damage to crops. A two-year survey identifying the arthropod community on wheat vegetation, at the soil surface and within the soil of wheat fields was conducted to better guide conservation efforts. The arthropod complex in wheat was diverse with 103 taxa identified. The soil-dwelling arthropod community had the greatest abundance and diversity when compared with the foliar-dwelling community. Sentinel Rhopalosiphum padi L. (bird cherry-oat aphid, BCOA) were placed on wheat plants and predator gut-content analysis employed to identify specific species actively consuming cereal aphids. Twenty five percent of collected predators tested positive for R. padi DNA in their guts. The diverse and abundant predatory arthropod community reduced cereal aphid numbers, which remained at low densities throughout the duration of the study.

As pollinator decline continues, the need to provide high value forage for insects increases. Finding agricultural crops to diversify the landscape and provide forage is one way to improve pollinator health. Three winter industrial oilseed crops (pennycress, winter camelina, and winter canola) were grown in Morris, Minnesota, and Brookings, South Dakota, during the winters of 2012–2013 and 2013–2014. Each of the three crops has pollinator-friendly flowers and value as winter cover crops and cash seed crops. The crops were evaluated for pollinator use, nectar production, green cover, and yield. Pennycress, camelina, and canola flowers had high insect activity with maximum visitation rates of 67 ± 11.5, 22 ± 3.1, and 61 ± 6.8 insects min−1. Cumulative nectar produced by pennycress, camelina, and canola was 13, 100, and 82 kg of sugar ha−1 during the 2014 anthesis period, providing an important food resource to pollinators during early spring when there is little else on the agricultural landscape that is blooming. Green cover in early spring ranged from 0 to 60% amongst the three crops, with camelina providing >25% green cover across all four site-years. Maximum seed yields were 1.1 ± 0.04, 1.4 ± 0.05, and 1.2 ± 0.19 Mg ha−1 for pennycress, camelina, and canola, respectively, which are economically viable harvests. Of the three crops, winter camelina provided the highest combined agroecosystem value through pollinator resources, green cover, and seed yields.

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...

Oviposition decisions by herbivorous insects hinge on multiple factors, with some of the most important being enemy-free space and competition for resources. It is important to understand whether and how herbivores and predators can influence the maternal egg-laying preference when they are alone and in combination with host plants. Here, we evaluate whether the presence of aphids (a competitor) or a lady beetle larvae (a predator) influence host plant selection by an ovipositing butterfly. Canola (Brassica napus L.) was the highest quality of three putative Brassicaceae host plants for aphids Myzus persicae (Sulzer) (Hemiptera: Aphididae), while the butterfly Pieris rapae (L.) (Lepidoptera: Pieridae) showed similar survival on all. Canola was used to determine that the presence of a competitor herbivore (aphids) had no effect on butterfly oviposition behavior. However, predators significantly influenced the number of eggs laid on the plants, especially on those plants that had both aphids and a lady beetle larva present in combination. We expect that adult female P. rapae did not lay their eggs on the treatment that involved both herbivorous competition and predation risk, due to the combined risk factors along with the volatile chemicals and aphid alarm pheromones emitted on those plants that contained both the aphids and lady beetle larva.

Understanding the factors that constrain or promote symbiotic microbial communities gives a clearer picture of the niches that can be occupied by a host organism. Many insects harbor symbiotic microbes that can alter various aspects of insect behavior and biology including digestion, sex determination, and pathogen defense. Habitat diversity has a major influence on insect and microbial diversity within an environment. In the current study, we assessed how habitat biodiversity affects the bacterial species richness within the gastrointestinal tract of insects. We measured species abundance of plants and insects present in three replicated habitats (prairie, pasture, and maize fields) that inherently represent a continuum of biological diversities. Gut bacterial symbiont diversity of the crickets Gryllus pennsylvanicus Burmeister and Allonemobius sp. (Orthoptera: Gryllidae) were described using terminal restriction fragment length polymorphism analysis of rRNA genes. The resulting data show that gut bacterial diversity of both cricket species is positively correlated with biodiversity according to habitat type. This demonstrates that microbial diversity within insect gastrointestinal tracts, and possibly their functions within these insects, is tied to the biodiversity within the habitats where insects live. These results have important implications as to how reductions in habitat biodiversity may affect the ecological functions and services that the remaining species can perform.

The long coevolutionary history between sunflowers (Helianthus annuus, Asterales: Asteraceae) and arthropods in the northern Great Plains has resulted in a commonly grown oilseed crop that harbors a large diversity of insects. A bioinventory of foliar and subterranean arthropods was performed in 22 sunflower fields over a period of three site years in central and eastern South Dakota. Overall, 467 morphospecies were collected. From foliage, 15 arthropod orders were observed. Those containing the greatest species diversity were Hymenoptera, Coleoptera, Hemiptera, Diptera and Araneae with 80; 53; 53; 40 and 30 morphospecies each, respectively. Subterranean arthropods from 19 orders were collected. The five orders containing the highest number of morphospecies were Coleoptera, Hymenoptera, Hemiptera, Araneae and Diptera containing 77; 17; 14; 11 and nine morphospecies respectively. Although bioinventories can be expensive and time consuming, information gathered from them has many uses, including ef...

BACKGROUND The aphid Nasonovia ribisnigri (Mosley) (Hemiptera: Aphididae) and the thrips Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) are common pests in Mediterranean lettuce crops, where Orius spp. are common generalist predators. Predation by Orius spp. was studied in a lettuce plot by conventional polymerase chain reaction (PCR) and real-time PCR analyses using specific primers of both main pests. Also, high-throughput sequencing was used to have a wider approach of the diet of these predators in natural field conditions. RESULTS Molecular analyses indicated a higher predation on N. ribisnigri in spring and on F. occidentalis in summer. Predation on alternative prey, like Collembola, was also found in both seasons. Real-time PCR was more sensitive than conventional PCR in showing the target trophic links, whereas high-throughput sequencing revealed predation on other natural enemies – intraguild predation (IGP), showing other trophic interactions of Orius majusculus within the studied ecosystem. CONCLUSIONS This study gives important information about the trophic relationships present in Mediterranean lettuce crops in different periods of the year. The detected predation by Orius spp. on alternative prey, as well as on other natural enemies, should be further investigated to clarify whether it adds or detracts to the biological control of N. ribisnigri and F. occidentalis. © 2015 Society of Chemical Industry

We assess how herbivore density and insecticide dose affects the tri-trophic interactions among thiamethoxam-treated wheat (Triticum sp.), Rhophalosiphum padi and the predatory Coleomegilla maculata DeGeer. In the first experiment 2nd and 4th instar C. maculata were fed aphids reared for 24 h on wheat plants treated with sub-lethal thiamethoxam soil drenches to assess the effect of insecticidal dose on the predator. In the second experiment a constant, sub-lethal thiamethoxam soil drench was used on wheat plants, but the plants were infested with different densities of aphids. Aphids from each density treatment were then fed to C. maculata 2nd instars. Insecticide levels within wheat and aphid tissues were quantified using a competitive ELISA. In experiment one, 4th instars of C. maculata displayed no negative effects after consuming aphids from treated plants. However, 2nd instars of C. maculata ate more treated aphids than untreated aphids and larval development times varied between the untreated larvae and those receiving the low dose of the insecticide. In experiment two, the 2nd instar C. maculata displayed slower walking speeds after consuming aphids from low aphid density plants. Thiamethoxam within wheat tissue was found at higher levels with increasing dose. This insecticide was also found at higher levels in wheat plants with the lowest aphid density. Clothianidin, a toxic metabolite of thiamethoxam, was found in aphids that had fed on thiamethoxam-treated wheat, but no differences between treatments were observed. The neonicotinoid treatment altered the quality of R. padi as prey for 2nd instar C. maculata, but this depended on the aphid infestation level on the plants. In addition to revealing a potential deleterious effect of thiamethoxam systemic insecticides in wheat, our assays provide insight into the design and interpretation of toxicity assays involving systemic neonicotinoids and herbivores.

hat is a resilient, healthy soil? A resilient soil is capable of recovering from or adapt-ing to stress, and the health of the living/biological component of the soil is cru-cial for soil resiliency. Soil health is tightly coupled with the concept of soil quality (table 1), and the terms are frequently used interchangeably. The living component of soil or soil biota represents a small fraction (

Drosophila suzukii Matsumura (Diptera: Drosophilidae) is an invasive, highly polyphagous pest of soft-skinned fruits throughout much of the world. A better understanding of the ecology of adult flies, including their nutritional resources, is needed to advance ecologically based management approaches. In this study, we evaluate the capability of polymerase chain reaction-based gut content analysis to detect a known food resource from DNA extracted from laboratory-reared flies. Using strawberry as a focal host and available DNA primers, we validated that DNA from this host could be detected for up to 7 d post-consumption. With the development of specific primers for additional hosts, we expect that this technique will enable researchers to better understand how D. suzukii adults use, and move between, nutritional resources.

Pesticides are a necessary component of the monoculture-based food production system. The chemical management of pests can affect non-target organisms, including honey bees. Risk assessment is a way to evaluate the cost–benefit of pesticide use to honey bees and involves understanding the exposure routes and hazards posed by each particular pesticide. The effects of insecticides on bees are intuitively recognized, but other types of pesticides can affect honey bees too. Even “inactive” ingredients in a pesticide formulation can pose a risk to bees. Bees encounter pesticides as they forage in the environment through direct exposure to pesticide applications, and through contaminated resources such as pollen, nectar, water, comb, and propolis. Pesticides can affect bees in myriad ways. The toxicity of pesticides is highly context-specific, challenging risk assessments. Mortality is the most commonly measured effect of pesticides on bees but sublethal effects range from developmental problems, reduced reproductive fitness, diminished overwintering capacity, and numerous behavioral issues that may not kill the bee outright, but may kill the hives. The pervasiveness of pesticides in the environment means that bees cannot avoid exposure to numerous chemicals. Selecting for bees that are adapted to agrichemical-intensive landscapes may be a short-term solution, but the dynamic evolution of chemical use may prohibit long-term tolerances. Beekeepers and farmers need to work together to create and promote reduced chemical intensive food production systems. This is the only long-term answer for the survival of honey bees and biodiversity in general.

BACKGROUND Hoverflies (Diptera: Syrphidae) are generalist predators of a great variety of pests. Nasonovia ribisnigri (Hemiptera: Aphididae) and Frankliniella occidentalis (Thysanoptera: Thripidae) are two common pests in Mediterranean lettuce crops, where they occur alongside alternative prey (e.g. Collembola). A semi-field experiment was conducted in an experimental lettuce plot where hoverfly predation on N. ribisnigri, F. occidentalis and Collembola was studied by conventional PCR and qPCR using specific primers, as well as by next-generation sequencing (NGS) in order to reveal other potential trophic interactions. RESULTS Trophic linkages between hoverflies and N. ribisnigri were the strongest both in spring and summer. F. occidentalis and Collembolans were also detected in both seasons, but with less frequency. qPCR detected a higher frequency of consumption than conventional PCR when both tests were run at optimal conditions. NGS analyses showed intraguild predation on other hoverfly species, as well as on anthocorids, spiders and even aphid parasitoids. CONCLUSIONS Conventional PCR and qPCR provided important insights into Mediterranean hoverfly species predation on target pest and non-pest prey. NGS gave a complementary approach revealing a broader diet of these predators within the studied ecosystem. © 2014 Society of Chemical Industry

Many herbivorous arthropods use defensive chemistry to discourage predators from attacking. This chemistry relies on the ability of predators to rapidly learn to recognize and avoid offensive stimuli. Western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), employs multifaceted chemical defences in its haemolymph, which may contribute significantly to its success as a major economic pest. Here, we test the hypothesis that agrobiont predators can rapidly learn to recognize and avoid WCR larvae, and will thereby reduce their contribution to WCR suppression. In controlled feeding assays, the effectiveness of WCR haemolymph defences varied across three predator taxa (crickets, centipedes, and ants). Centipedes (Chilopoda: Lithobiidae) were minimally affected by WCR defences, but crickets [Gryllus pennsylvanicus Burmeister (Orthoptera: Gryllidae)] spent less time feeding on WCR than on an undefended control prey, house fly maggots. However, we uncovered no evidence indicating that experienced crickets rapidly learn to avoid WCR larvae, indicating that haemolymph defences offer few, if any, survival benefits for WCR. Colonies of ants [Lasius neoniger Emery (Hymenoptera: Formicidae)] switched from low worker participation in initial attacks on WCR to higher worker participation in subsequent attacks, indicating an attempt to overcome, rather than avoid, WCR haemolymph defences. These results suggest that a diverse assemblage of natural enemies will show a diverse array of behavioural responses to toxic pest prey, and highlight the importance of behavioural diversity in driving the function of natural enemy assemblages.

Understanding infield predator dispersal is crucial for designing predator conservation programmes. A study aimed at evaluating methods of collecting insects in protein-marking studies and monitoring predator movement was conducted. Results indicate that collection by sweep net does not result in false positives and predator groups displayed distinct dispersal patterns.