Transgenic corn and cotton that produce Cry and Vip3Aa toxins derived from Bacillus thuringiensis (Bt) are widely planted in the United States to control lepidopteran pests. The sustainability of these Bt crops is threatened because the corn earworm/bollworm, Helicoverpa zea (Boddie), is evolving a resistance to these toxins. Using Bt sweet corn as a sentinel plant to monitor the evolution of resistance, collaborators established 146 trials in twenty-five states and five Canadian provinces during 2020–2022. The study evaluated overall changes in the phenotypic frequency of resistance (the ratio of larval densities in Bt ears relative to densities in non-Bt ears) in H. zea populations and the range of resistance allele frequencies for Cry1Ab and Vip3Aa. The results revealed a widespread resistance to Cry1Ab, Cry2Ab2, and Cry1A.105 Cry toxins, with higher numbers of larvae surviving in Bt ears than in non-Bt ears at many trial locations. Depending on assumptions about the inheritance of resistance, allele frequencies for Cry1Ab ranged from 0.465 (dominant resistance) to 0.995 (recessive resistance). Although Vip3Aa provided high control efficacy against H. zea, the results show a notable increase in ear damage and a number of surviving older larvae, particularly at southern locations. Assuming recessive resistance, the estimated resistance allele frequencies for Vip3Aa ranged from 0.115 in the Gulf states to 0.032 at more northern locations. These findings indicate that better resistance management practices are urgently needed to sustain efficacy the of corn and cotton that produce Vip3Aa.

Overwintering success is an important determinant of arthropod populations that must be considered as climate change continues to influence the spatiotemporal population dynamics of agricultural pests. Using a long-term monitoring database and biologically relevant overwintering zones, we modeled the annual and seasonal population dynamics of a common pest, Helicoverpa zea (Boddie), based on three overwintering suitability zones throughout North America using four decades of soil temperatures: the southern range (able to persist through winter), transitional zone (uncertain overwintering survivorship), and northern limits (unable to survive winter). Our model indicates H. zea population dynamics are hierarchically structured with continental-level effects that are partitioned into three geographic zones. Seasonal populations were initially detected in the southern range, where they experienced multiple large population peaks. All three zones experienced a final peak between late July (southern range) and mid-August to mid-September (transitional zone and northern limits). The southern range expanded by 3% since 1981 and is projected to increase by twofold by 2099 but the areas of other zones are expected to decrease in the future. These changes suggest larger populations may persist at higher latitudes in the future due to reduced low-temperature lethal events during winter. Because H. zea is a highly migratory pest, predicting when populations accumulate in one region can inform synchronous or lagged population development in other regions. We show the value of combining long-term datasets, remotely sensed data, and laboratory findings to inform forecasting of insect pests.

The soybean gall midge (Resseliella maxima Gagné) was recently identified as a new species causing injury to soybean in the Midwestern United States. Although this insect was only recently identified, it has likely been present in soybean fields for at least the last 8 yr based on anecdotal reports. The soybean gall midge has historically been observed late in the season on soybean plants that were believed to have been previously compromised by a plant pathogen or mechanical damage with little to no concern for economic losses. In late June 2018, dead and dying plants were found to be associated with the soybean gall midge across four midwestern states. The distribution of plant injury in the field, larval feeding within the stem, and timing of infestation indicate that it is likely an important pest of soybean. Yield losses in soybean gall midge infested fields can be up to 100% for the first 30 meters from the field edge, with losses of 17–31% further into the field. The rapid development of the soybean gall midge as an important pest of soybean has left large gaps in the knowledge necessary to develop an integrated pest management program.

Abstract Cover crops (CC) support populations of pest and beneficial arthropods. The status of these arthropods in the subsequent cash crop depends on several factors such as CC species, management, biomass production, and weather conditions. A systematic review was performed to identify how CC management influences pest and beneficial arthropods and to identify knowledge gaps for the future research efforts. Eight studies included in this review indicated that CC increase beneficial arthropods or some beneficial arthropods compared with the CC managed fields. A minority of the studies indicated an increase in pest presence when using CC. Cover crop species, termination time and methods, and CC management had variable responses on arthropod activity-density. The variable responses, differences on study designs, and complexity of CC management influence arthropod activity in a CC-corn [Zea mays L. (Poaceae)]/soybean [Glycine max L. (Fabaceae)] system, limiting our ability to draw a broad and effective conclusion about the CC management impact on arthropods. Local research studies are needed to identify the impact of CC biomass quality and quantity, CC biomass thresholds for pest and beneficial arthropods, and cash crop yield impact of CC management-arthropod-related studies. Studies using the standard farming practices of each U.S. region and using standard measurements are needed to guide farmers that use cover crops. This systematic review aims to provide a better understanding of how the complexity of management in cover crop-corn/soybean management affects arthropod activity-density and to identify potential gaps in research and address future research needs.

I began my doctoral program at North Carolina State University (NCSU), Raleigh, in August 1977, after completing an M.S. in entomology from University of Arizona, Tucson, where I worked on the pink bollworm, Pectinophora gossypiella (Saunders), in cotton. I applied to graduate school at NCSU because of the entomology department’s strong reputation for IPM research and extension with an ecological grounding, and faculty such as R. L. Rabb, J. R. Bradley, Jr., R. E. Stinner, and others. Also, after growing up in the San Francisco Bay Area, receiving a B. A. in zoology from University of California, Santa Barbara, and then an M.S. degree in Tucson, I wanted to see something completely different. So, I moved east and quickly transitioned from working in irrigated cotton in the Arizona desert to drained swampland (Lilly 1981) in eastern North Carolina. Around the late 1970s, a pestiferous beetle was causing economic...

Water deficit is the major factor limiting plant growth and crop productivity worldwide. This study was aimed to establish the physiological and genetic basis for improving productivity of cotton under arid land agriculture. Cotton cultivars, Gossypium hirsutum (GH), G. barbadense (GB) and interspecific hybrids (ISHs; G. hirsutum x G. barbadense), were examined under field and greenhouse conditions. In the field, water use efficiency (WUE = total dry matter produced / water used) was always higher in GH cultivars than in GB, while in the greenhouse the opposite ranking was observed. In both environments, however, the ISHs exhibited WUE values either similar to or larger than the largest WUE among the two species. These results suggest that the respective species have evolved different environmental adaptations with respect to WUE, and that combining genes from the two species offer the potential to improve WUE. In the second phase of this study, F2 and F3 (GH x GB) generations were used for genetic mapping of the crop’s productivity and related physiological traits. Productivity of cotton grown under well-watered versus water-limited conditions was shown to be partially accounted for by different quantitative trait loci (QTLs), indicating that adaptation to both conditions can be combined into the same genotype. Genetic mapping clearly implicated reduced leaf osmotic potential as a major component of improved cotton productivity under arid conditions and indicated that selection for WUE alone cannot be expected to improve productivity. The finding that the GH allele is favorable at some loci and the GB allele at other loci indicates that recombination of favorable alleles from each of these species may form novel genotypes that are better-adapted to arid conditions than either of the parental species. Near-isogenic lines being made for the QTLs discovered herein will offer a powerful new tool for the identification of the underlying gene(s) and physiological

The wheat stem maggot (Meromyza americana Fitch) (WSM) is a minor pest of wheat, rye, and other grasses. In 2017, growers in Nebraska reported dead center whorls and excessive tillering in early-season cornfields that followed wheat or rye terminated after planting corn. A survey was conducted to evaluate the risk factors for this insect in cover crop to corn transition systems. In each field, management practices and the percentage of injured plants were recorded. Symptomatic corn plants were collected from each field and dissected to determine larval and plant characteristics. In a few cases, small patches of a field were planted to a cover crop to manage soil erosion, and injured plants were only found where the cover crop was present. From these observations, the hypothesis is that terminating a cover crop after planting corn allowed the WSM larva to move from the dying cover crop to corn to complete its development. Cornfields infested with WSM had a frequency of injured corn plants from 0 to 60% with yield losses estimated at 30 bushels/acre. This paper provides the first detailed documentation of WSM injury in corn and addresses important management practices that may have influenced this uncommon situation.

Evolved gas analysis (EGA) mass-spectrometry (MS) is used to characterize the solid state pyrolysis decomposition pathways of air- and moisture-sensitive organometallic compounds. In this study, the single-source GaAs compounds (Et2AsGaEt2)(3) (1), (t-Bu2AsGaEt2)(2) (2), and [t-Bu(H)AsGaEt2](2) (3) were heated in capillary tubes under inert condition and the volatile products were analyzed by MS. In addition, the relative ratios of evolved gases were characterized using gas chromatography (GC), while the solid state pyrolysis products were analyzed by EDS, 1H NMR and XRD. Pyrolysis of GaAs single-source materials in the solid state reveals chemical information on the stability of the GaAs bond, an observation masked in gas-phase analysis of single-source materials during chemical vapor deposition. Information on GaAs bond stability may be elucidated due to the volatility of the by-products formed during Ga-As precursor pyrolysis. Loss of GaAs bond integrity in materials with alkyl substitution on Ga and As leads to formation of mobile and volatile alkyl diarsine species, as was observed for the pyrolysis of 1. An in-situ method to monitor solid-state pyrolysis by mass spectrometry identified the loss of a tetraalkyl-diarsine as the critical factor that drives formation of sub-stoichiometric GaAs products from single-source precursors. Replacing a single alkyl group on the As atom with a H (precursor 3) leads to the loss of an alkane instead of tetraalkyl-diarsine formation. Solid-state pyrolysis precursor 3 results in the formation of polycrystalline GaAs in up to 58% yield with a 52:48 Ga:As stoichiometry.

Maize, Zea mays L., is an economically important crop grown throughout the world. Corn rootworm, Diabrotica spp. (Coleoptera: Chrysomelidae), larvae constitute a significant economic threat to maize production in the United States, where yield losses and management costs associated with corn rootworm species exceed $1 billion annually. Furthermore, the introduction of the western corn rootworm, D. virgifera virgifera LeConte, into maize‐producing regions of Europe has made managing corn rootworm larval injury an international concern. Larvae injure maize plants by feeding on root tissue and are the primary target of management activities. Products commonly used to protect root systems from injury include chemical insecticides (seed or soil applied) and genetically modified maize hybrids expressing toxins derived from Bacillus thuringiensis Berliner (Bt). The confirmation of field‐evolved resistance to various Bt toxins in populations of the western corn rootworm presents a significant management challenge. We performed a meta‐analysis to provide a broad understanding of the relative efficacy of the primary products currently being used to manage corn rootworm larval injury, including insecticidal seed treatments, soil insecticides and Bt hybrids (with and without the addition of soil insecticide). Our analysis is unique in the breadth of locations and years included – we analysed 135 individual trials conducted from 2003 through 2014 at multiple sites in both Illinois and Nebraska. Panel data were produced by pairing the mean node‐injury rating for each treatment of a given trial with the mean node‐injury rating for untreated maize. Linear regression models were developed to estimate the relationship between the potential for corn rootworm larval injury and product performance. For a given level of injury potential, the parameters estimated reveal differences in the degree of root protection offered by the various product categories analysed. Implications for developing long‐term, integrated, and sustainable practices for managing this important pest of maize are discussed.

Western bean cutworm, Striacosta albicosta (Smith) (Lepidoptera: Noctuidae), is a native, univoltine pest of corn and dry beans in North America. The current degree-day model for predicting a specified percentage of yearly moth flight involves heat unit accumulation above 10 degrees C after 1 May. However, because the moth's observed range has expanded into the northern and eastern United States, there is concern that suitable temperatures before May could allow for significant S. albicosta development. Daily blacklight moth catch and temperature data from four Nebraska locations were used to construct degree-day models using simple or sine-wave methods, starting dates between 1 January and 1 May, and lower (-5 to 15 degrees C) and upper (20 to 43.3 degrees C) developmental thresholds. Predicted dates of flight from these models were compared with observed flight dates using independent datasets to assess model performance. Model performance was assessed with the concordance correlation coefficient to concurrently evaluate precision and accuracy. The best model for predicting timing of S. albicosta flight used simple degree-day calculations beginning on 1 March, a 3.3 degrees C (38 degrees F) lower threshold, and a 23.9 degrees C (75 degrees F) upper threshold. The revised cumulative flight model indicated field scouting to estimate moth egg density at the time of 25% flight should begin when 1,432 degree-days (2,577 degree-days degrees F) have accumulated. These results underscore the importance of assessing multiple parameters in phenological models and utilizing appropriate assessment methods, which in this case may allow for improved timing of field scouting for S. albicosta.

Western corn rootworm is an important corn pest in the U.S. Some farmers noted unexpected corn rootworm injury of transgenic hybrids as early as 2008; however, the full extent of product performance is still not fully understood. We conducted telephone focus groups with farmers in 2013 to gain their perspective of current and future issues for corn rootworm. Respondents were surprised how quickly corn rootworm injury escalated in their fields and were disappointed with incorrect diagnoses from consultants and seed companies. Most participating farmers saw university Extension as an unbiased source of information.

Ingibjörg Jónsdóttir (1), Þorvaldur Þórðarson (1), Ármann Höskuldsson (1), Ashley Davis (2), David Schneider (3), Robert Wright (4), Laszlo Kestay (5), Christopher Hamilton (6), Andrew Harris (7), Diego Coppola (8), Magnús Tumi Guðmundsson (1), Tobias Durig (1), Gro Pedersen (1), Vincent Drouin (1), Friðrik Höskuldsson (9), Hreggviður Símonarson (9), Gunnar Örn Arnarson (9), Magnús Örn Einarsson (9), Morten Riishuus (1), and the Volcanology and Natural Hazard Group, University of Iceland Team

Western bean cutworm, Striacosta albicosta (Smith) (Lepidoptera: Noctuidae), is a native pest of dry beans (Phaseolus vulgaris L.) and corn (Zea mays L.). Historically, the western bean cutworm was distributed in the western United States, but since 1999 eastward expansion has been observed. In corn, economic impact is caused by larval ear feeding. Information on western bean cutworm biology, ecology, and economic impact is relatively limited, and the development of economic injury levels (EILs) and economic thresholds (ETs) is required for more effective management. Studies during 2008-2011, across three ecoregions of Nebraska, sought to characterize western bean cutworm survival and development of EILs and ETs. Calculations of EILs and ETs incorporated the dynamics of corn price, management cost, and pest survival. The results from the current study demonstrated low larval survival of this species (1.51-12.82%). The mean yield loss from one western bean cutworm larva per plant was 945.52 kg/ha (15.08 bu/acre), based on 74,100 plants per ha. Economic thresholds are expressed as a percentage of plants with at least one egg mass. This study is the first study that explicitly incorporates variable management costs and crop values into western bean cutworm EIL calculations, and larval survival into ET calculations.

Edamame soybeans are a speciality food item for fresh and processed markets and they are harvested at a physiologically immature (R6) stage. Bean leaf beetle, Cerotoma trifurcata, is a sporadic pest of soybean in Nebraska, however, its pest status and abundance has increased in the recent years due to an increase in soybean acreage. This was a field experiment aimed at determining the population growth rate of bean leaf beetle on two edamame soybean cultivars, 'Butterbeans' and 'Envy,' at two planting dates during 2004 and 2005 in Nebraska. The population growth of beetles was significantly higher on 'Butterbeans' than on 'Envy' for both the first and second planting periods in both 2004 and 2005 seasons. The beetle infestation differences were noticed on plants at the late reproductive growth stages, R5 and R6. Additionally, the beetle infestation on 'Butterbeans' growth stages in 2004 and 2005 was significantly different for the first and second planting dates. On average, the beetles were higher on plants at the late reproductive stages than the other stages for first and second planting periods. Similarly, ' Envy' growth stages showed significant difference in beetle infestation during the first and second planting dates. Significantly high beetle infestations were observed at the vegetative growth stages. The study revealed that population growth of bean leaf beetles on edamame soybeans is affected by the planting date, season and cultivar choice.

A greenhouse experiment was conducted to evaluate the interactive effects of different Fusarium oxysporum f. sp. vasinfectum isolates at increasing inoculum densities with Meloidogyne incognita on partially resistant (Stoneville (ST) 4554B2RF) and susceptible (FiberMAX (FM) 9058F) cotton cultivars. Disease incidence and area under the disease progress curve (AUDPC) were significantly higher for FM 9058F compared to ST 4554B2F for all the Fov isolates, densities and M. incognita combinations. Differences in pathogenicity were observed among the Fov isolates tested, suggesting that variability in aggressiveness may exist in populations of the fungus, though all isolates were within the same Race grouping (Race 1). A total of four isolates showed significantly higher AUDPC in the absence of M. incognita at higher inoculum densities of Fov; while two isolates had significantly higher AUDPC in the presence of M. incognita at low inoculum densities. Plant growth differed between cultivars where FM 9058F plants were shorter, and had decreased root, shoot, and total plant weights compared to ST 4554B2RF. Plants inoculated with M. incognita had root galls and were stunted with reduced shoot weight and total plant weight. Management of Fusarium wilt can be substantially improved by using partially resistant cultivars or reducing the inoculum density of root-knot nematode.