Sites In Wisconsin Research Articles

Differential survival of alfalfa varieties interseeded into corn silage

AbstractInterseeding alfalfa (Medicago sativa L.) into silage corn (Zea mays L.) can improve forage yield, farm profitability, and soil conservation, but unreliable alfalfa establishment hampers on‐farm adoption. This study evaluated seedling survival and growth of 36 alfalfa varieties differing in reported plant traits when interseeded at two Wisconsin sites in 2015 and at single sites in Wisconsin, Michigan, and Pennsylvania in 2016. Subplots of alfalfa varieties were sprayed with prohexadione‐calcium (PHD) at 0 or 0.42 kg acid equivalent (a.e.) ha–1 to assess changes in seedling survival mediated by this growth retardant. After corn harvest in 2015, average stand density of varieties in Wisconsin ranged from 15 to 94 plants m–2 without PHD and from 52 to 199 plants m–2 with PHD. Stand density largely determined subsequent first‐cut alfalfa dry matter yield, which ranged from 1.1 to 6.3 Mg ha–1. After corn harvest in 2016, stand density of varieties averaged across PHD treatments ranged from 113 to 248 plants m–2 in Michigan and Pennsylvania, compared with only 0.5 to 26 plants m–2 in Wisconsin; PHD treatment improved stand density only in Wisconsin but could not ensure adequate establishment under wet conditions that favored vigorous corn growth and foliar disease on alfalfa. Overall, establishment was poorly related to measured or reported alfalfa traits, but ‘55H94’ and hybrids were consistently among the best performing cultivars. Further work is needed to understand seedling survival mechanisms and to develop improved germplasm and production practices to ensure reliable establishment of interseeded alfalfa.

Enoxaparin is associated with lower rates of mortality than unfractionated Heparin in hospitalized COVID-19 patients.

BackgroundCoagulopathies are a major class among COVID-19 associated complications. Although anticoagulants such as unfractionated Heparin and Enoxaparin are both being used for therapeutic mitigation of COVID associated coagulopathy (CAC), differences in their clinical outcomes remain to be investigated.MethodsWe analyzed records of 1,113 patients in the Mayo Clinic Electronic Health Record (EHR) database who were admitted to the hospital for COVID-19 between April 4, 2020 and August 31, 2020, including 19 different Mayo Clinic sites in Arizona, Florida, Minnesota, and Wisconsin. Among this patient population, we compared cohorts of patients who received different types of anticoagulants, including 441 patients who received unfractionated Heparin and 166 patients who received Enoxaparin. Clinical outcomes at 28 days were compared, and propensity score matching was used to control for potential confounding variables including: demographics, comorbidities, ICU status, chronic kidney disease stage, and oxygenation status. Patients with a history of acute kidney injury and patients who received multiple types of anticoagulants were excluded from the study.FindingsWe find that COVID-19 patients administered unfractionated Heparin but not Enoxaparin have higher rates of 28-day mortality (risk ratio: 4.3; 95% Confidence Interval [C.I.].: [1.8, 10.2]; p-value: 8.5e−4, Benjamini Hochberg [BH] adjusted p-value: 2.1e−3), after controlling for potential confounding factors.InterpretationThis study emphasizes the need for mechanistically investigating differential modulation of the COVID-associated coagulation cascades by Enoxaparin versus unfractionated Heparin.FundingThis work was supported by Nference, inc.

Occupancy and Detectability of Northern Long‐eared Bats in the Lake States Region

ABSTRACTThe northern long‐eared bat (Myotis septentrionalis) is one of the bat species most affected by white‐nose syndrome. Population declines attributed to white‐nose syndrome contributed to the species’ listing as federally threatened under the 1973 Endangered Species Act. Although one of the most abundant Myotine bats in eastern North America prior to white‐nose syndrome, little is known about northern long‐eared bats in the upper Midwest, USA. We assessed the habitat associations of the northern long‐eared bats on a regional scale using occupancy models that accounted for uncertainty in nightly detection to provide needed information on the distribution as white‐nose syndrome has recently arrived in this area. We monitored bat activity using zero‐crossing frequency‐division bat detectors for 10–15 nights at 20 detector sites at each of 3 sampling areas in Michigan, USA, and 6 sampling areas in Wisconsin, USA, stratified by mesic and xeric habitat types. We constructed northern long‐eared bat nightly detection histories for our occupancy analysis using maximum likelihood estimates from 2 commercially‐available automated identification programs: Kaleidoscope and Echoclass. We sampled for a total of 2,174 detector‐nights. Both Kaleidoscope and Echoclass identified northern long‐eared bat passes on 110 detector‐nights, whereas on 1,968 detector‐nights neither program identified a northern long‐eared bat call. Only one program or the other identified northern long‐eared bat calls on 206 detector‐nights, indicating an overall agreement rate of 35% on nights when calls were detected. We analyzed these data using an occupancy analysis accounting for the potential for false positives to assess the relationship between northern long‐eared bat presence and habitat characteristics. Our analyses indicated that the probability of a false positive at a site was low (0.015; 95% CI 0.009–0.021), and detection probability, but not occupancy, declined from 2015 to 2016 for sites in Wisconsin sampled in both years. Occupancy was positively associated with distance into the forest interior (distance from nearest road). © 2020 The Wildlife Society.

Landscape composition and configuration have scale-dependent effects on agricultural pest suppression

Increasing landscape heterogeneity (composition and configuration) can enhance natural enemy populations and support pest suppression in agricultural landscapes. Using a network-based data mining approach, we examined independent gradients of landscape composition and configuration at six spatial scales that were associated with pest suppression services measured at 32 sites in Michigan and Wisconsin, USA. We compared the relative effects of landscape composition and configuration across scales with those of local crop type (corn or grassland). We found that multiple gradients of configurational heterogeneity were independent of composition and strongly associated with pest suppression, with different configuration metrics being predictive of pest suppression depending on the spatial scales and regions considered. Landscapes that were more configurationally heterogeneous at smaller spatial scales consistently supported higher pest suppression. In Michigan, pest suppression increased in landscapes with high edge contrast between annual crops and surrounding habitats and high edge density of grassland within 250−500 m radii. In Wisconsin, pest suppression increased with large core area of grassland and high field density within a 250 m radius. The main compositional effect we found was a positive relationship between grassland cover and pest suppression occurring at larger spatial scales (1000−1500 m) and occurring in Wisconsin but not in Michigan. Our findings demonstrate that effects of landscape composition and configuration on pest suppression differ across spatial scales and vary regionally. The network-based data mining techniques used here could be useful for disentangling intercorrelated landscape metrics in a variety of other contexts in landscape ecology.

Summer Outbreak of Severe RSV-B Disease, Minnesota, 2017 Associated with Emergence of a Genetically Distinct Viral Lineage.

Respiratory syncytial virus (RSV) typically causes winter outbreaks in temperate climates. During summer 2017, the Minnesota Department of Health received a report of increased cases of severe RSV-B infection. We compared characteristics of summer 2017 cases with those of 2014-2018 summers. To understand the genetic relatedness among viruses, we performed high-throughput sequencing of RSV from patients with a spectrum of illness from sites in Minnesota and Wisconsin. From May to September 2017, 58 RSV cases (43 RSV-B) were reported compared to 20-29 cases (3-7 RSV-B) during these months in other years. Median age and frequency of comorbidities were similar, but 55% (24/43) were admitted to the ICU in 2017 compared to 12% in preceding 3 years (odds ratio, 4.84, P < .01). Sequencing was performed on 137 specimens from March 2016 to March 2018. Outbreak cases formed a unique clade sharing a single conserved nonsynonymous change in the SH gene. We observed increased cases during the following winter season, when the new lineage was the predominant strain. We identified an outbreak of severe RSV-B disease associated with a new genetic lineage among urban Minnesota children during a time of expected low RSV circulation.

Investigating maternity roost selection by northern long-eared bats at three sites in Wisconsin

Investigating maternity roost selection by northern long-eared bats at three sites in Wisconsin

Pathogen Prevalence in Fractured versus Granular Aquifers and the Role of Forward Flow Stagnation Zones on Pore-Scale Delivery to Surfaces.

Lesser pathogen prevalence is well recognized in granular versus fractured aquifers; however, the impact of residence time (inactivation/death) versus removal (pore-scale delivery to surfaces) on pathogen prevalence remains unaddressed. The objective of this study was to examine the specific role of pore-scale delivery to surfaces (removal) as an explanation of contrasting pathogen prevalence in granular versus fractured media from Wisconsin. Inactivation/death was obviated by the use of nonbiological colloids in column transport experiments conducted in representative media from the two Wisconsin sites. Trends in retention as a function of colloid size were examined using nano- to microsized (0.1-4.2 μm) carboxylate-modified polystyrene latex microspheres that represented virus- to protozoa-sized pathogens. Several orders of magnitude greater removal of all colloid sizes were observed in granular relative to those in fractured media, whereas the size corresponding to minimum retention contrasted between the two media. Particle trajectory simulations in collectors (flow fields with surfaces) representing granular versus fractured media captured the observed contrasting retention and trends with colloid size. These results demonstrate that flow impingement on surfaces at forward flow stagnation zones drives contrasting pore-scale delivery to surfaces in granular versus fractured media and potentially the observed contrasting pathogen prevalence in granular versus fractured aquifers.

Cooking and Community

Abstract For many years, archaeological research regarding the Oneota tradition has focused on broad similarities and trends among groups spread over a wide geographical area. While this research is important for understanding the tradition, examinations of synchronic variability between Oneota groups have been underdeveloped. Exploring this variability may help archaeologists better understand how different groups adapted to various social and environmental circumstances and the processes that led to the emergence of different historical social groups in the upper Midwest and eastern prairies. In order to begin exploring this variability in core practices, a pilot study was completed comparing cooking and foodways practices found during an analysis of vessel function on stylistically Oneota pots recovered at the Tremaine site (47Lc95) in Wisconsin and the Morton Village site (11F2) in Illinois. Preliminary results show that food practices between these two groups varied, possibly as a response to different social circumstances.

\u201cPisando Fuerte\u201d: an evidence-based falls prevention program for Hispanic/Latinos older adults: results of an implementation trial

BackgroundWe previously developed Pisando Fuerte (PF), a linguistically and culturally appropriate version of “Stepping On”, an evidence-based fall prevention program building on self-efficacy and adult learning principles. The purpose of this study is to describe the implementation of PF at two community organizations in Wisconsin.MethodsPF consisted of 2 h sessions delivered in Spanish over the course of 8 weeks by two trained leaders, at two community sites in Wisconsin. Participants identified strategies for falls prevention and practiced progressive balance and strength exercises. The RE-AIM framework guided the mixed-methods evaluation. Falls Behavioral Risk Scale (FaB) (Outcomes), and uptake of protective behaviors (Individual Maintenance) were evaluated 6 months after completion. Fidelity of delivery (Implementation) was evaluated by an independent assessor for three sessions at each site using a-priori criteria based on key elements of Stepping On.ResultsTwenty-four Hispanic/Latino individuals, whose primary language is Spanish, were enrolled in two workshops. The mean age was 70.5 years; 71% were female, and five reported a fall in the year prior. Outcomes: There was a non-statically significant decrease in the number of falls per person [RR: 0.33 (95%CI: 0.096–1.13)] at 6 months. There was a statistically significant improvement of the mean Falls Behavioral Risk Scale (FaB) (baseline = 2.69 vs. 6-months post-intervention = 3.16, p < 0.001). Adoption: Barriers to adoption included leader training in English, time to identify Spanish-speaking guest experts, and time to prepare for each session. Implementation: Satisfactory fidelity of delivery was achieved in 69% of the elements; fidelity lapses were more common in the use of adult learning strategies and programmatic aspects. Eighty eight percent of participants completed the program, and 95% of them adequately demonstrated the exercises. Maintenance: At 6 months, 57.9% of participants continued doing exercises, 94% adopted safer walking strategies, and 67% executed at least one home safety recommendation. These results are similar to those seen in the original Stepping On program.ConclusionsOur study shows good fidelity of delivery with implementation of “Pisando Fuerte”. Pre-post data demonstrate a significant reduction in falls behavioral risk among Hispanic/Latino participants, similar to results with “Stepping On”.Trial registrationClinicalTrials.gov, NCT03895021. Registered March 29, 2019.

Local abundance of Ixodes scapularis in forests: Effects of environmental moisture, vegetation characteristics, and host abundance

Ixodes scapularis is the primary vector of Lyme disease spirochetes in eastern and central North America, and local densities of this tick can affect human disease risk. We sampled larvae and nymphs from sites in Massachusetts and Wisconsin, USA, using flag/drag devices and by collecting ticks from hosts, and measured environmental variables to evaluate the environmental factors that affect local distribution and abundance of I. scapularis. Our sites were all forested areas with known I. scapularis populations. Environmental variables included those associated with weather (e.g., temperature and relative humidity), vegetation characteristics (at canopy, shrub, and ground levels), and host abundance (small and medium-sized mammals and reptiles). The numbers of larvae on animals at a given site and season showed a logarithmic relationship to the numbers in flag/drag samples, suggesting limitation in the numbers on host animals. The numbers of nymphs on animals showed no relationship to the numbers in flag/drag samples. These results suggest that only a small proportion of larvae and nymphs found hosts because in neither stage did the numbers of host-seeking ticks decline with increased numbers on hosts. Canopy cover was predictive of larval and nymphal numbers in flag/drag samples, but not of numbers on hosts. Numbers of small and medium-sized mammal hosts the previous year were generally not predictive of the current year’s tick numbers, except that mouse abundance predicted log numbers of nymphs on all hosts the following year. Some measures of larval abundance were predictive of nymphal numbers the following year. The mean number of larvae per mouse was well predicted by measures of overall larval abundance (based on flag/drag samples and samples from all hosts), and some environmental factors contributed significantly to the model. In contrast, the mean numbers of nymphs per mouse were not well predicted by environmental variables, only by overall nymphal abundance on hosts. Therefore, larvae respond differently than nymphs to environmental factors. Furthermore, flag/drag samples provide different information about nymphal numbers than do samples from hosts. Flag/drag samples can provide information about human risk of acquiring nymph-borne pathogens because they provide information on the densities of ticks that might encounter humans, but to understand the epizootiology of tick-borne agents both flag/drag and host infestation data are needed.

Effect of a Professional Coaching Intervention on the Well-being and Distress of Physicians

Burnout symptoms among physicians are common and have potentially serious ramifications for physicians and their patients. Randomized studies testing interventions to address burnout have been uncommon. To explore the effect of individualized coaching on the well-being of physicians. A pilot randomized clinical trial involving 88 practicing physicians in the departments of medicine, family medicine, and pediatrics who volunteered for coaching was conducted between October 9, 2017, and March 27, 2018, at Mayo Clinic sites in Arizona, Florida, Minnesota, and Wisconsin. Statistical analysis was conducted from August 24, 2018, to March 25, 2019. A total of 6 coaching sessions facilitated by a professional coach. Burnout, quality of life, resilience, job satisfaction, engagement, and meaning at work using established metrics. Analysis was performed on an intent-to-treat basis. Among the 88 physicians in the study (48 women and 40 men), after 6 months of professional coaching, emotional exhaustion decreased by a mean (SD) of 5.2 (8.7) points in the intervention group compared with an increase of 1.5 (7.7) points in the control group by the end of the study (P < .001). Absolute rates of high emotional exhaustion at 5 months decreased by 19.5% in the intervention group and increased by 9.8% in the control group (-29.3% [95% CI, -34.0% to -24.6%]) (P < .001). Absolute rates of overall burnout at 5 months also decreased by 17.1% in the intervention group and increased by 4.9% in the control group (-22.0% [95% CI, -25.2% to -18.7%]) (P < .001). Quality of life improved by a mean (SD) of 1.2 (2.5) points in the intervention group compared with 0.1 (1.7) points in the control group (1.1 points [95% CI, 0.04-2.1 points]) (P = .005), and resilience scores improved by a mean (SD) of 1.3 (5.2) points in the intervention group compared with 0.6 (4.0) points in the control group (0.7 points [95% CI, 0.0-3.0 points]) (P = .04). No statistically significant differences in depersonalization, job satisfaction, engagement, or meaning in work were observed. Professional coaching may be an effective way to reduce emotional exhaustion and overall burnout as well as improve quality of life and resilience for some physicians. ClinicalTrials.gov identifier: NCT03207581.

Characterizing scales of hydrogeological heterogeneity in ice-marginal sediments in Wisconsin, USA

Creating a geological framework for hydrogeological investigations in ice-marginal settings is challenging, as the dynamic nature of ice margins results in heterogeneous sediments and complex geometries that are difficult to characterize geologically and hydraulically. In this study, a multi-scale and multi-tool approach was used to develop a robust and hydraulically calibrated conceptual model of a site in Wisconsin (USA), which constrains the subsurface geologic and hydraulic heterogeneity onsite and can be utilized offsite and in similar settings. Facies analysis, including detailed logging of sediment cores integrated with geophysical surveys, was used to reconstruct the glacial history of the site and to identify key sedimentation styles. Depth-discrete multilevel monitoring wells were used to measure hydraulic head and to explore the relationship between hydraulic conditions and stratigraphy. Results indicate that hydraulic and geological heterogeneity do not necessarily coincide, as hydraulic head profiles of the heterogeneous sediments showed little head change with depth. The minimal observed hydraulic heterogeneity in this complex geologic system is likely due to relatively small and spatially limited differences in hydraulic conductivities, limited water-table relief, and minimal natural or induced transience to enhance local head differentials. Hydraulic data were also used to provide new insights on the style and scale of geologic heterogeneity known to influence permeability within ice-marginal sediments; this is especially relevant at the study site where fine-scale bedding (millimeters to tens of centimeters scale) and lateral continuity of units (meters to hundreds of meters scale) influence water recharge and dense nonaqueous phase liquids migration and distribution.

Reducing Water‐Soluble Phosphorus in Soil through Flue Gas Desulfurization Gypsum Application: Year of Application Effects at Multiple Sites in Wisconsin

Phosphorus runoff from agricultural land to surface water bodies, such as the Great Lakes, is an important environmental concern. Soil amendments, such as gypsum, may alter the chemistry of the soil solution to reduce the amount of water-soluble P (WSP) available for loss to runoff, and as such, the NRCS now recommends gypsum application as a Conservation Practice Standard (Code 333) for improving water quality. Interest in gypsum use has also increased as availability has increased from production of flue gas desulfurization (FGD) gypsum at many coal-burning power plants throughout the United States. This study tested three rates of unincorporated, surface-broadcast FGD gypsum application at 23 field sites in Wisconsin. The optimal rate for reducing WSP concentration and the relationship between selected soil properties and the beneficial effect of FGD gypsum application were evaluated. The FGD gypsum reduced WSP ( < 0.0001), with a significant effect compared with the control at the lowest tested rate of 1120 kg ha at 5 of the 23 sites. Few other sites saw a significant benefit. Correlation indicated that sites showing a beneficial reduction of WSP from FGD gypsum application were those with greater soil test P ( = 0.0002) and lower cation exchange capacity ( = 0.0087) values.

Modest immigration can rescue a reintroduced carnivore population

ABSTRACTReintroductions are frequently conducted to restore carnivore populations, though many fail despite following best management practices. Although demographic approaches are increasingly used to assess reintroduced populations, immigration is often overlooked in reintroduction planning and assessment. American martens (Martes americana) were reintroduced to 2 sites in Wisconsin, the Nicolet and Chequamegon national forests, which have anecdotally experienced differential population recovery. Via non‐invasive sampling and a mark‐recapture framework, we explored the possible mechanisms behind the divergent trajectories of the Nicolet National Forest (Nicolet) population, which appears to be recovering, and the Chequamegon National Forest (Chequamegon) population, which appears to be declining toward extinction. We tested for site‐level differences in survival, estimated population size, and calculated immigration rates based on simulations of the original reintroductions to the Nicolet. We then projected each population forward, both with and without our estimated immigration rate. We calculated a current population size of 66 female martens in the Nicolet, and estimated that the reintroduced population would have reached this size if supplemented by 1 female immigrant per year. We simulated future populations with the estimate of 1 female immigrant per year; this sustained level of immigration to the Nicolet reduced the probability of extinction to &lt;1% over the next 100 years. When we applied the same rate of immigration to the starting population of 22 female martens in the Chequamegon, extinction probabilities were reduced by approximately 30%. Despite similarities between the 2 reintroduction sites, we propose that the differential population recovery was primarily due to modest rates of immigration to the Nicolet and the relative isolation of the Chequamegon population. Martens in the Chequamegon have been projected to go extinct in the foreseeable future, yet increasing connectivity with the Nicolet or Upper Peninsula of Michigan could improve persistence. Our results illustrate the effect of modest immigration on reintroduction success and the importance of planning for connectivity across reintroduction sites. © 2019 The Wildlife Society.

Adjuvants for Prohexadione‐Calcium Applied to Alfalfa Interseeded into Corn

Core Ideas Optimal adjuvant selection for ensuring effectiveness of prohexadione‐Ca applied to interseeded alfalfa is unknown. All adjuvants tested provided equivalent effectiveness for prohexadione‐Ca applied to interseeded alfalfa. Supplemental ammonium sulfate did not further enhance the effectiveness of prohexadione‐Ca. Application of the growth retardant prohexadione‐calcium (calcium 3‐oxido‐5‐oxo‐4‐propionylcyclohex‐3‐enecarboxylate; PHD) on interseeded alfalfa (Medicago sativa L.) improves its establishment under silage corn (Zea mays L.). This study evaluated the relative effectiveness of crop oil concentrate (COC), high surfactant oil concentrate (HSOC), methylated seed oil (MSO), and nonionic surfactant (NIS) as adjuvants for commercially formulated PHD (Apogee) when applied with and without supplemental ammonium sulfate (AMS). Acidified solutions of PHD (0.25 kg a.i. ha−1) plus adjuvants were sprayed on 23 to 27 cm tall glyphosate‐resistant alfalfa seedlings that were interseeded immediately after corn planting at two sites in Wisconsin. All PHD–adjuvant–AMS combinations were equally effective, reducing alfalfa height by an average of 16% within 4 wk after treatment and increasing alfalfa stand counts after corn harvest by 30% compared with the non‐PHD treated control. The results suggested a variety of adjuvants may be used when applying PHD to interseeded alfalfa.

Methods for Estimating Axle Factors and Axle Classes from Vehicle Length Data

This study developed methods to estimate axle factors and vehicle class from length-based data streams. A set of eight methods was proposed and evaluated in different testing schemes intended to observe performance on homogeneous and heterogeneous data. The initial analysis used length-based data from 61 sites in Wisconsin. The research team compared performance of the methods estimating axle factors and vehicle class proportions. Performance was comparable and consistent between homogeneous and heterogeneous subsets of data. The research team selected two methods for a final round of analysis based on their accuracy and robustness to heterogeneity. For the final round of analysis, the research team assembled a multistate dataset using data from Wisconsin and from 14 other states represented in a dataset from the Long Term Pavement Performance program. The final round of analysis compared performance under different seasons, facility type, and road character (urban vs. rural). Performance of the two identified methods was deemed appropriate and they are recommended for implementation.

Incidence and taxonomic richness of mosquitoes in the diets of little brown and big brown bats

Bats have been portrayed as important consumers of mosquitoes, but evidence supporting this claim is surprisingly scant. We collected the fecal material of 2 common North American bats at 22 sites in Wisconsin, United States and screened samples for mosquitoes using a recently improved molecular method for detecting arthropod DNA. Overall, we detected 17 discrete operational taxonomic units assigned to the mosquito family (Diptera: Culicidae), 15 of which were assigned at the species level. We detected mosquitoes in 71.9% of samples and at all sampling sites for little brown bats (Myotis lucifugus). By comparison, we detected mosquitoes in 33.3% of samples and one-half of the sampling sites for big brown bats (Eptesicus fuscus). Our results suggest that the incidence and taxonomic richness of mosquito prey consumed by bats is considerably higher than has been previously shown. In light of globally declining bat populations, we propose that future studies reassess the importance of trophic interactions between bats and mosquitoes.

Evaluating grass–legume forage mixtures across different environments

This article summarizes results from a field experiment was across six study sites in Maryland, Pennsylvania, Utah, Virginia, Wisconsin, and Wyoming. The main objective of this study was to evaluate alfalfa and tall fescue mixtures across a wide range of environments to assess mixture productivity, weed suppression, and fertilizer nitrogen replacement value (FNRV) of alfalfa. Earn 1 CEU in Crop Management by reading this article and taking the quiz at www.certifiedcropadviser.org/education/classroom/classes/551.

Plant Resistance to Colorado Potato Beetle (Coleoptera: Chrysomelidae) in Diploid F2 Families Derived From Crosses Between Cultivated and Wild Potato.

Colorado potato beetle, Leptinotarsa decemlineata Say (Coleoptera: Chrysomelidae), is a serious global pest of potato, Solanum tuberosum L. Management of L. decemlineata has relied heavily on insecticides, but repeated evolution of insecticide resistance has motivated the exploration and development of alternative strategies, such as plant resistance. The recent development of two diploid potato families derived from crosses between cultivated and wild potato species (S. chacoense and S. berthaultii) has provided a unique opportunity to reexamine plant traits for resistance breeding. In this 2-yr study, we surveyed select F2 clones for the induction of L. decemlineata mortality and a reduction in defoliation in no-choice feeding assays when challenged with adults and larvae from three sites in Wisconsin. We tested for an association with glandular trichome density and foliar levels of the glycoalkaloids chaconine and solanine. Several potato clones demonstrated resistance in specific feeding assays, but none excelled consistently across experiments. Mortality and defoliation generally differed significantly among L. decemlineata populations, which could be indicative of heritable variation in beetle responses to plant defenses or variation in the physiological status of the beetle populations tested. Contrary to expectations, higher trichome density increased mortality or decreased defoliation in only a few cases, and levels of mortality and defoliation were unrelated to foliar glycoalkaloid content, warranting further investigation of the defense mechanisms of resistant clones. In addition to identifying several potential L. decemlineata resistance sources, this study underscores the need to include multiple insect populations in surveys of plant resistance to this diverse pest.

A Comparison of Resistance to Imidacloprid in Colorado Potato Beetle (Leptinotarsa decemlineata Say) Populations Collected in the Northwest and Midwest U.S.

The Colorado potato beetle, Leptinotarsa decemlineata Say, is a serious pest of potato, Solanum tuberosum L., worldwide. Leptinotarsa decemlineata has a history of repeated adaptation to insecticides, and exhibits a geographic pattern of decreasing insecticide resistance from east to west in the USA. Imidacloprid is one of the most widely used insecticide in western states. In this study, we measured imidacloprid resistance among larval and adult L. decemlineata from ten locations in the Columbia Basin (southeastern Washington and northeastern Oregon) using topical LD50 bioassays, and compared them to estimates from ten locations in Minnesota and Wisconsin. Larval and adult imidacloprid LD50’s and mean percent mortality were generally lowest in Washington and Oregon, but some sites exhibited reductions in mortality comparable to those observed at some Wisconsin sites. Adult LD50’s suggest L. decemlineata in the Columbia Basin may be evolving in response to selection by neonicotinoid insecticides, but larval data suggest high susceptibility to imidacloprid remains in most populations. Future work should expand resistance monitoring efforts to include more regions in the West and other insecticide modes of action.