The red sunflower seed weevil, Smicronyx fulvus LeConte (Coleoptera: Curculionidae), is the most destructive seed-feeding pest of sunflower in North America. The life history of S. fulvus (e.g., univoltine, overwintering within 6 cm of soil surface) suggests several strategies to limit crop damage, but insecticides remain the primary management tool. To facilitate broader management of S. fulvus, a degreeday model for adult emergence was developed and tested. Emergence of adults under controlled conditions produced a lower developmental threshold of 5 degrees C, approximate to 970 degree-days to first emergence, and approximate to 1160 degreedays to 50% emergence. Soil temperature data showed accumulated degree-days were similar 5 cm below turf and 10 cm beneath bare soil. Observed emergence of weevils in field plots occurred several days earlier than predicted (using 5 cm turf or 10 cm bare soil temperatures) when soil was kept free of vegetation. However, observed emergence was similar to predicted emergence when plots were shaded by spring wheat, which is representative of crops planted after sunflower for much of North America. Though access to soil (rather than ambient) temperature data is needed, this first degree-day model provides a tool to help growers avoid S. fulvus damage using early planting or early-maturing hybrids.

Abstract Introduction Food production is a global challenge and consequently there is considerable interest in manipulating the rhizobiome using microbial inoculants (MI) to support sustainable agriculture. The effectiveness of MI needs to be evaluated under diverse environmental conditions, especially for nitrogen‐fixing legume crops, for which interactions between their associated bacteria and other soil biota may be particularly important. Materials and Methods We investigated how three commercially available types of plant growth‐promoting MI, alone and in combination (B5: five species of Bacillus bacteria, GP: four species of Trichoderma fungi, N2: Paenibacillus polymyxa bacteria) impacted field pea (Fabales: Fabaceae, Pisum sativum L.) in the greenhouse and a 2‐year field experiment. Results In the greenhouse, we found that effects of MI on plant performance varied, with positive effects of MI only apparent when plants were grown in the winter and likely under greater stress, because they lacked nodules. Plants grown in the summer had nodules and 2‐week‐old MI plants had less root biomass and total plant weight than noninoculated controls, but the weight of 4‐week‐old MI plants was similar to or greater than that of the controls. In the field, the root‐to‐shoot biomass ratio was highest in noninoculated controls and positive effects of N2 on shoots and B5 on shoots and pod densities did not translate into differences in pod weight or total plant weight. In most cases, plants inoculated with all three inoculants performed similar to those receiving a single inoculant, whereas root colonization by arbuscular mycorrhizal fungi was higher for B5 plants than plants in the other treatments. Conclusions Overall, B5 was the inoculant most often associated with increased plant biomass. This research underscores the need to consider microbial and environmental context when evaluating MI.

Periodic assessments of reference condition wetlands are needed to determine changes over time; however, they are rarely conducted. The vegetation from past assessments, 1998 to 2004, was compared to 2016 assessments of 12 reference wetlands in the Missouri Coteau sub-ecoregion of the Prairie Pothole Region using nonmetric multidimensional scaling and permutational multivariate analysis of variance. Analyses indicated the vegetation in the 2016 assessments trended away from the abundance of native highly conservative species as found during the 1998 to 2004 assessments. Instead, the 2016 plant communities trended towards lower abundance of the same native conservative species and higher abundance of non-native species. Both the average coefficient of conservatism values and floristic quality index values significantly declined, supporting the interpretation that reference wetlands were moving towards plant communities with lower abundance of highly conservative species. The assumption that reference wetlands in the Prairie Pothole Region will change little over time is challenged by these findings. Vegetation in refence wetlands within the Prairie Pothole Region is no longer resembles past monitoring and is trending towards a distinct vegetation composition. Future management will need to consider the potential of reference wetlands' vegetation composition moving away from a historic baseline and how this may impact future wetland assessment, especially when vegetation is compared to reference conditions.

Most natural mortality of the red sunflower seed weevil, Smicronyx fulvus LeConte (Coleoptera: Curculionidae), occurs while larvae overwinter in the soil. To test the hypothesis that S. fulvus mortality is related to low temperatures, experiments were used to (i) evaluate the temperature at which larvae freeze (= supercooling point [SCP]), (ii) assess possible vertical movement between entry into the soil in fall and adult emergence in summer, and (iii) determine if realistic soil temperatures could explain patterns of overwintering mortality. Mean SCP for groups of S. fulvus larvae differed between years and months, but only ranged from -20.93 to -22.68 °C. Most overwintering larvae were found within 6 cm of the soil surface, but larvae appeared to move 1-2 cm deeper between pairs of successive sample dates (September to January, January to April). Significant larval mortality that occurred between January and April 2021 was tentatively attributed to a period in February where daily minimum soil temperatures ranged from -8 to -12 °C. When overwintering under control conditions (constant 4 °C) was interrupted with week-long exposure to -4, -8, or -12 °C in a cold bath, significant S. fulvus mortality was seen for temperatures at or below -8 °C. Combined results suggest that mortality of overwintering S. fulvus is likely caused by continuous exposure to low temperatures that may not be cold enough to freeze larvae. Additionally, the shallow overwintering by S. fulvus supports the idea that routine farm management, including tillage and herbicide incorporation, may help limit populations of this sunflower pest.

We surveyed the insect fauna associated with Urophora cardui L. (Diptera: Tephritidae) galls on Canada thistle, Cirsium arvense L. (Asterales, Asteraceae), in parts of the northern Great Plains, U.S., by field-collecting galls and rearing or dissecting out the insects. We also examined the relationships between gall biomass and insect density and biomass. Urophora cardui were widespread, and the gall biomass was positively correlated with fly density and fly biomass. We recovered Isohydnocera tabida (LeConte) (Coleoptera: Cleridae) from galls in two counties, which represents a new host record and provides vital information on the little-known immatures of this predatory species. Pteromalus elevatus (Walker) (Hymenoptera: Pteromalidae) was the dominant parasitoid that emerged from the U. cardui galls. Individual galls typically only had one insect species, and occasionally both U. cardui and P. elevatus were present, but it was rare for other insects to be present in galls housing I. tabida. This study adds to the taxonomic literature of gall-inhabiting insect species and provides new information on the predators of U. cardui, specifically a little-known clerid beetle species.

Examining how insects are represented in artwork can provide insight into people’s perceptions and attitudes towards arthropods, as well as document human–insect interactions and how they change through time. Fireflies are well-known bioluminescent beetles (Coleoptera: Lampyridae) of great cultural significance, especially in Japan. A selection of online museum collections, art databases, and dealer websites were used to find artwork featuring fireflies, with an emphasis on Japanese ukiyo-e wood block prints from the Edo, Meiji, and Taishō time periods (1600–1926). Quotes from early twentieth century texts were used to provide additional historical context. Over 90 different artists created artwork featuring fireflies, including several renowned masters. Artists depicted adult fireflies in a variety of ways (e.g., relatively accurately, more generalized, symbolic or abstract, yellowish dots) in the absence and presence of people. Most images were set outdoors during the evening near water, and primarily featured women and children, groups of women, and large parties catching fireflies or observing caged fireflies. ‘Beauties’, geisha, courtesans, kabuki actors, and insect vendors were also common subjects. Various types of collecting tools and a diversity of cages were featured, as well as insect vendors. The artwork highlights the complex connections between fireflies and humans. Insect-related art can contribute to education and conservation efforts, particularly for dynamic insects such as fireflies that are facing global population declines.

Aphids are important pests of pecans in Georgia. Although previous studies conducted seasonal monitoring of pecan aphids, these studies were done at a single experimental site. In addition, only a few seasonal monitoring studies have tracked pecan aphid mummies parasitized by the aphid parasitoid, Aphelinus perpallidus Gahan. The objective of this study was to assess the seasonal phenology of yellow pecan aphid (Monelliopsis pecanis Bissell), blackmargined aphid [Monellia caryella (Fitch)], black pecan aphid [Melanocallis caryaefoliae (Davis)], aphid mummies, and adult A. perpallidus in four Georgia commercial orchards, with varying aphid management regimes, in 2019 and 2020. Comparison of overall aphid and parasitoid numbers between sites revealed few consistent annual patterns in both years. Aphid seasonal trends were consistent among sites and followed the patterns seen in previous studies, with the yellow aphid complex peaking in May, June, September, and October and black pecan aphids peaking in late September and October. Despite varying levels of insecticide application between sites, aphid phenology followed a similar seasonal pattern and remained low, throughout both growing seasons. This may indicate that growers can apply low frequencies of insecticides and still achieve pecan aphid control. Parasitism numbers were highest in the low insecticide frequency site compared with the other three sites. Mummies varied in their correlation with yellow aphid complex and black pecan aphid numbers. Parasitoid numbers typically followed the cycle of their host throughout the season.

Landscape diversification with flowering plants can benefit pollinators and natural enemies, although insect pests can also use floral resources for nutrition and chemoprotection. Corn rootworms (Coleoptera: Chrysomelidae, Diabrotica spp.) are major pests of corn (Zea mays L.), and while subterranean larvae primarily feed on corn roots, adult rootworms commonly consume floral resources from other plant species. We quantified the species, density, and sex of adult corn Diabroticite rootworm beetles on wild and cultivated sunflower, corn, and squash, quantified pollen within the bodies of adult northern corn rootworms [NCR, D. barberi (Smith & Lawrence)], and investigated how consumption of sunflower and corn pollen by NCR adults impacted predation of their eggs by two soil-dwelling mites with different feeding specialization. NCR were the most common Diabroticite species on sunflower inflorescences and western corn rootworm (WCR, D. v. virgifera LeConte) were more abundant in corn and squash blossoms. Pollen feeding by NCR adults did not impact egg predation by omnivorous Tyrophagus putrescentiae (Schrank) (Acari: Sarcoptiformes, Acaridae), but predatory Stratiolaelaps scimitus (Womersley) (Acari: Mesostigmata, Laelapidae) ate eggs less frequently and took longer to feed on eggs from NCR females that had fed on sunflower pollen. This research suggests pollen feeding by adult NCR can impact predation of their eggs. While increasing plant diversity can benefit natural enemies and pest control within agroecosystems, it is important to consider how floral resources alter dietary preferences of biocontrol agents.

Insecticidal neonicotinoid seed treatments are a common agricultural insect pest management strategy; however, effects on nontarget pests and omnivorous arthropods are understudied. We used a series of experiments to evaluate impacts of the neonicotinoid seed treatment thiamethoxam on densities of herbivorous twospotted spider mites (Tetranychus urticae Koch [Acari: Tetranychidae]) and feeding behavior of western flower thrips (Frankliniella occidentalis Pergande [Thysanoptera: Thripidae]), an omnivore that feeds on spider mite eggs but is also a significant plant pest. Spider mite densities were higher on neonicotinoid-treated soybeans, but only when mites were not spatially confined. We then examined how availability of thiamethoxam-treated food items (i.e., eggs from spider mites reared on treated soybeans, soybean leaf discs, or a combination of the two), and previous exposure to thiamethoxam-treated soybean impacted thrips feeding. Regardless of the presence of leaf tissue, thrips consumed fewer spider mite eggs laid by females reared on treated soybeans, suggesting spider mite eggs can serve as poisoned prey. Overall, thrips consumed less treated soybean leaf tissue, and thrips on treated leaf discs had a lower percentage of herbivorous feeding events and consumed more nontreated spider mite eggs, indicating a dietary shift from herbivory to predation. The neonicotinoid status of spider mite eggs and prior exposure of thrips also caused shifts in the number and size of leaf scars, likely as a result of altered foraging behavior and/or movement. Shifts between herbivory and predation have implications for thrips damage, virus transmission, and pest management, especially in systems with mixtures of nontreated and neonicotinoid-treated plants.

The soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae) is a serious pest of the soybean plant, Glycine max, a major world-wide agricultural crop. We assembled a de novo genome sequence of Ap. glycines Biotype 1, from a culture established shortly after this species invaded North America. 20.4% of the Ap. glycines proteome is duplicated. These in-paralogs are enriched with Gene Ontology (GO) categories mostly related to apoptosis, a possible adaptation to plant chemistry and other environmental stressors. Approximately one-third of these genes show parallel duplication in other aphids. But Ap. gossypii, its closest related species, has the lowest number of these duplicated genes. An Illumina GoldenGate assay of 2380 SNPs was used to determine the world-wide population structure of Ap. Glycines. China and South Korean aphids are the closest to those in North America. China is the likely origin of other Asian aphid populations. The most distantly related aphids to those in North America are from Australia. The diversity of Ap. glycines in North America has decreased over time since its arrival. The genetic diversity of Ap. glycines North American population sampled shortly after its first detection in 2001 up to 2012 does not appear to correlate with geography. However, aphids collected on soybean Rag experimental varieties in Minnesota (MN), Iowa (IA), and Wisconsin (WI), closer to high density Rhamnus cathartica stands, appear to have higher capacity to colonize resistant soybean plants than aphids sampled in Ohio (OH), North Dakota (ND), and South Dakota (SD). Samples from the former states have SNP alleles with high FST values and frequencies, that overlap with genes involved in iron metabolism, a crucial metabolic pathway that may be affected by the Rag-associated soybean plant response. The Ap. glycines Biotype 1 genome will provide needed information for future analyses of mechanisms of aphid virulence and pesticide resistance as well as facilitate comparative analyses between aphids with differing natural history and host plant range.

Beneficial root microbes may mitigate negative effects of crop pests by enhancing plant tolerance or resistance. We used a greenhouse experiment to investigate impacts of commercially available microbial root inoculants on growth and biomass allocation of wheat (Triticum aestivum L. [Cyperales: Poaceae]) and on survival and growth of the gall-inducing wheat pest Hessian fly, Mayetiola destructor (Say). A factorial design was used, with two near-isogenic wheat lines (one susceptible to Hessian fly, the other resistant), two levels of insect infestation (present, absent), and four inoculants containing: 1) Azospirillum brasilense Tarrand et al. (Rhodospirillales: Azospirillaceae), a plant growth-promoting bacterium, 2) Rhizophagus intraradices (N.C. Schenck & G.S. Sm.) (Glomerales: Glomeraceae), an arbuscular mycorrhizal fungus, 3) A. brasilense + R. intraradices, and 4) control, no inoculant. Larval feeding stunted susceptible wheat shoots and roots. Plants had heavier roots and allocated a greater proportion of biomass to roots when plants received the inoculant with R. intraradices, regardless of wheat genotype or insect infestation. Plants receiving the inoculant containing A. brasilense (alone or with R. intraradices) had comparable numbers of tillers between infested and noninsect-infested plants and, if plants were susceptible, a greater proportion of aboveground biomass was allocated to tillers. However, inoculants did not impact density or performance of Hessian fly immatures or metrics associated with adult fitness. Larvae survived and grew normally on susceptible plants and mortality was 100% on resistant plants irrespective of inoculants. This initial study suggests that by influencing plant biomass allocation, microbial inoculants may offset negative impacts of Hessian flies, with inoculant identity impacting whether tolerance is related to root or tiller growth.

Agricultural intensification and landscape simplification have reduced flowering plant abundance and diversity worldwide, with subsequent negative effects on pollinators. To mitigate these effects, research and conservation have focused on incorporating flowering plants into agricultural landscapes through on-farm natural areas or flowering crops. However, while cover crops provide numerous agroecosystem services, they have received little attention for their role in providing floral resources for pollinators. In this study, we examined the value of cover crops for providing supplemental summer floral resources for both managed and wild bees in the Northern Great Plains of the United States, where a large proportion of honey bee colonies spend the summer. Specifically, using an experimental randomized plot design, we compared floral resources and bee visitation rates across 1, 2, 3, and 6-species cover crop mixes as well a 6-species annual native wildflower mix. We found that cover crop treatments including buckwheat provided the highest summer-long floral cover, higher than the annual native wildflower mix in which only two of six species bloomed, and that total bee visitation rates increased with higher floral cover. However, different bees were attracted to different treatments; honey bees and bumble bees were most attracted to mixes containing phacelia, while large-bodied solitary bees were more attracted to mixes including cultivated sunflower and to the wildflower mix, illustrating that the optimal plantings for attracting social or managed bees may differ from those attracting solitary wild bees. Additionally, while similar numbers of bee species visited the three main plants in our treatments (buckwheat, phacelia, and cultivated sunflower) more rare species visited cultivated sunflower while more common bees visited buckwheat and phacelia. Our results highlight the value of annual cover crops for providing pollinator resources in agricultural landscapes, particularly on rotated land where perennial flower plantings are less feasible, but illustrate trade-offs between attracting a large number of common generalist or managed bees versus attracting fewer individuals but species of potential conservation concern.

Core Ideas Soybean leaf temperature, seed quality, and yield not impacted by road dust treatments. Chlorophyll content showed some difference in treatments, no decipherable trends. Periodic applications of road dust, even at high rates, showed little impact on soybeans. Road dust is a common by‐product of transportation and it is important to understand its impact on crop production. The objective of this study was to determine if dust applied to the foliage of soybean plants [ Glycine max (L.) Merr.] impact its physiological characteristics (i.e., chlorophyll content and leaf temperature), yield, and seed quality (i.e., seed protein, oil composition, and amino acids). In 2015 and 2016 soybeans were planted using a randomized block design with eight replicates. Dust was applied weekly to soybean treatment areas at designated rates of 0, 15.8, 78.8, 158 g m −2 , in 2015, and 0, 15.8, 78.8, 158, 2 × 158, and 315 g m −2 in 2016. The 2 × 158 g m −2 treatment was 158 g m −2 applied twice per week. Plant measurements included leaf temperature, chlorophyll content, yield, and seed quality. No significant differences for leaf temperature, yield, yield components, and seed composition were found in either year ( P > 0.05). Therefore, results of the study indicated that weekly and bi‐weekly applications of dust, even at high rates, had little if any impact on soybean production and seed quality likely due to inert nature of the dust or soybean resilience to dust coverage.

Wild and managed bees are needed to move sunflower (Heliantbus annuus L.) pollen, both to create hybrid seed and to encourage high, consistent yields when those hybrids are subsequently grown. Among floral traits that influence bee preference, floret size may be critical, as the depth of the corolla affects the accessibility of nectar. Sampling and observation of inbred maintainer (HA) lines were used to assess variation in floret size, and to measure any effects of floret size on pollinator visitation. Among 100 inbreds sampled, there was significant variation among the lines, with floret lengths of 6.8-9.9 mm. Floret length, measured before anthesis, was closely related to corolla depth during anthesis and was consistent between 2 years (environments). Pollinator observations on 30 inbred lines showed floret size explained a majority (52%) of the variation in wild bee preference, with a reduction in floret length of 2 mm more than doubling pollinator activity. Though honey bee, Apis mellifera L., colonies were located approximate to 60 m from the plots, near-zero honey bee activity in the sunflowers precluded an assessment of how strongly this managed pollinator is affected by floret length. Production of inbreds and hybrids with smaller florets could enhance sunflower pollination, but genetic markers for floret size are needed to facilitate selection, and an understanding of potential trade-offs also is required. Information on variation and heritability of other traits, such as pollen and nectar rewards, could help explain residual variation in wild bee visitation to sunflowers.

Transgenic glyphosate-resistant (GR) soybean (Glycine max L. Merr.) is cultivated throughout the United States. Soybean growth is influenced by the presence of weeds, although managing non-crop vegetation can potentially impact soil arthropods, which are being increasingly recognized for their impacts on soil health, plant growth, and above-ground trophic interactions. We investigated how weed management (weedy controls, hand-weeded, glyphosate herbicide) and soil insecticide (chlorpyrifos) application affected densities of soil arthropods, soil nutrient availability, soybean growth and yield, and densities of an above-ground herbivore on sandy and clayey soils for two consecutive growing seasons. The soil insecticide treatment was intended to lower densities of subterranean arthropods to gain insight into how their presence influenced other factors, although their densities were primarily reduced the first year of the study. Surprisingly, weed management and soil insecticide use had virtually no interactive effects on any response. Weed presence had a positive effect on soil K at the sandy site and on nodule density per unit root. Negative effects of weed management on plant growth and aphids were related to the presence of weeds rather than herbicide use. Reduced soybean aphid density (at the clayey site) and soil P availability (at the sandy site) were associated with insecticide treated plots. Conversely, several measures of plant productivity, including number of nodules per unit root, and root and shoot biomass increased in + insecticide plots compared to other treatments, although effect strength depended on year and location. Collembola were the dominant soil microarthropod, and their densities in 2012 were negatively associated with nodule numbers in 2013. One explanatory hypothesis is that increased plant growth in plots treated with insecticide was caused by altered soil arthropod-microorganism interactions, possibly affecting arbuscular mycorrhizae function. This work highlights the importance of management decisions that affect soil arthropods in annual legume production systems.

Road dust impacts almost all terrestrial areas of the planet and may impact vegetation and nearby ecosystems. Therefore, research methods are needed for applying road dust in a controlled manner on targeted areas (e.g. plants). Three dust application methods, sifter, sieve, and sprayer, were investigated for their uniformity in applying dust in a 0.75 m × 0.75 m area. Within the treatment area 196, 37-ml cups were placed in a uniform fashion to collect dust applied at 15.8, 78.8, and 158 g. At the 15.8 and 78.8 g rates, the coefficient of uniformity for each method was >98% indicating a uniform amount of dust applied. At the 158 g rate, the sifter and sieve had coefficient of uniformities >95%, while the sprayer had a significantly lower (p < 0.05) coefficient of uniformity (46%). Although the sifter and sieve were simpler to use and the least expensive options, the sprayer may be more useful when applying dust to larger areas when the exact amount of dust entering and exiting the systems does not need to be controlled. This research is useful to anyone looking to apply road dust or similar sized particulates under controlled field or laboratory conditions.

The broad feeding habits of generalist predators can lead to uncertainty about their impacts on particular pests. Due to prey switching, consumption of one pest species by generalist predators might decrease as densities of attractive alternative prey increase. To test this, we used molecular tools to examine presence/absence of two-spotted spider mites (Tetranychus urticae) in the guts of predatory Nabis and Geocoris bugs, in potato (Solarium tuberosum) crops grown using either organic or conventional farming methods. Previous work suggested that organic potato fields house relatively high densities of alternative prey, which might disrupt predators' consumption of spider mites. While densities of spider mites and of the attractive alternative prey green peach aphids (Myzus persicae) did not consistently differ between farming systems, their densities varied widely between years and among fields within each year. The likelihood of detecting spider mite predation was not correlated with spider mite densities, such that we often recorded mite consumption in fields where these pests were rare. Spider mite consumption also was not significantly altered when we detected predation of green peach aphids. However, we found consistently higher numbers of both predator taxa in organic fields than in conventional fields. Altogether, we found that generalist predators continue to consume spider mites against a background of changing numbers of mites and aphids. This suggests that diverse alternative prey availability may not weaken the impact of robust populations of natural enemies found on organic farms.

Integrated pest management (IPM) tactics may effectively control focal pests, but it is also important to test the compatibility of different tactics, and consider non-target organisms. We investigated the effects of a neonicotinoid seed treatment and Rag resistance genes used for soybean aphid (Aphis glycines Matsumura) control on reproduction of a non-target herbivore (twospotted spider mite, Tetranychus urticae Koch) in short-term greenhouse experiments. We also examined interactions between spider mites and a specialist phytoseiid mite [Ambylseius fallacis (Garman)] and assessed the effects of a co-occurring opportunistic omnivore [Frankliniella occidentalis (Pergande)] by including thrips density as a covariate. There were no interactive or main effects of the presence of Rag genes on the densities of any of the arthropods. Overall, effects of the seed treatment on spider mite densities varied, with no difference when mites were confined in clip cages, and higher populations on seed-treated plants when on whole plants. Predatory mites had a consistent negative impact on spider mites, and densities of A. fallacis immatures were similar between seed treated and non-seed treated plants. However, the relationship between spider mite and thrips densities was different between these two plant types, but only in the clip cage experiment lacking predatory mites. This research highlights the importance of considering how IPM tactics might affect non-target organisms.