303 research outputs found

    Susceptibility of northern corn rootworm (\u3ci\u3eDiabrotica barberi\u3c/i\u3e) populations to Cry3Bb1 and Gpp34/Tpp35Ab1 proteins in seedling and diet overlay toxicity assays

    Get PDF
    The northern corn rootworm, Diabrotica barberi Smith & Lawrence (Coleoptera: Chrysomelidae) is a major pest of maize in the United States Corn Belt. Recently, resistance to Bacillus thuringiensis (Bt) maize was reported in North Dakota and increased use of Bt maize hybrids could facilitate resistance evolution in other maizeproducing states. In this study, susceptibility to Bt proteins was evaluated in wild D. barberi populations from 8 fields collected in 5 different states (Minnesota, Missouri, Nebraska, Iowa, and North Dakota). Field populations were compared to a susceptible D. barberi colony in seedling and diet toxicity assays conducted with 3 concentrations of Cry3Bb1 (0.4, 4.0, and 40.0 ÎĽg/cm2) and Gpp34/Tpp35Ab1 (previously called Cry34/35Ab1; 1.4, 14.0, and 140.0 ÎĽg/cm2). The 2019 population from Meeker Co., Minnesota (MN-2019), exhibited the lowest mortality to Cry3Bb1 and also had nominally lowest mortality to Gpp34/Tpp35Ab1 at the highest concentrations tested in diet toxicity assays. Percent second instar was also highest for larvae of the Minnesota population surviving Cry3Bb1. In seedling assays, MN and IA-2018 populations exhibited the highest proportion survival and dry weight to both proteins expressed in corn. No significant differences in mortality, percent second instar, and dry weight were observed at the highest concentration for both proteins among the populations collected in in 2020. Most D. barberi populations were still highly susceptible to Cry3Bb1 and Gpp34/Tpp35Ab1 proteins based on diet and seedling assays, but resistance appears to be developing in some D. barberi populations. Now that methods are available, resistance monitoring may also be needed for D. barberi in some regions

    The Decline of Remarriage: Evidence From German Village Populations in the Eighteenth and Nineteenth Centuries

    Full text link
    Family reconstitution data for fourteen German village populations permit the examination of remarriage during the eighteenth and nineteenth cen turies. The results provide compelling evidence for a secular decline in the tenden cy to remarry. Pronounced age and sex differentials in the likelihood of remar riage were evident: widows were far less likely to remarry than widowers, and the probability of remarriage declined rapidly with age, particularly for women. The probability of remarriage was also inversely associated with the number and age of children. There were, however, no clear differences in either the probability of remarriage or its tendency to decline over time among major occupational groups. The decline in remarriage probabilities was caused in part by declines in adult mortality, which gradually raised the ages of surviving spouses to levels at which remarriage has historically been rather unlikely. However, age-specific marriage probabilities also declined, affecting both men and women and all oc cupational groups, suggesting the presence of a social change of wide scope. Some comments on possible factors contributing to the decline of remarriage are presented. The need for a comprehensive explanation of remarriage trends and differentials remains an important challenge for family historians.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68212/2/10.1177_036319908501000103.pd

    The BNO-LNGS joint measurement of the solar neutrino capture rate in 71Ga

    Full text link
    We describe a cooperative measurement of the capture rate of solar neutrinos by the reaction 71Ga(\nu_e,e^-)71Ge. Extractions were made from a portion of the gallium target in the Russian-American Gallium Experiment SAGE and the extraction samples were transported to the Gran Sasso laboratory for synthesis and counting at the Gallium Neutrino Observatory GNO. Six extractions of this type were made and the resultant solar neutrino capture rate was 64 ^{+24}_{-22} SNU, which agrees well with the overall result of the gallium experiments. The major purpose of this experiment was to make it possible for SAGE to continue their regular schedule of monthly solar neutrino extractions without interruption while a separate experiment was underway to measure the response of 71Ga to neutrinos from an 37Ar source. As side benefits, this experiment proved the feasibility of long-distance sample transport in ultralow background radiochemical experiments and familiarized each group with the methods and techniques of the other.Comment: 7 pages, no figures; minor additions in version

    Measurement of the Solar Neutrino Capture Rate by the Russian-American Gallium Solar Neutrino Experiment During One Half of the 22-Year Cycle of Solar Activity

    Full text link
    We present the results of measurements of the solar neutrino capture rate in gallium metal by the Russian-American Gallium Experiment SAGE during slightly more than half of a 22-year cycle of solar activity. Combined analysis of the data of 92 runs during the 12-year period January 1990 through December 2001 gives a capture rate of solar neutrinos with energy more than 233 keV of 70.8 +5.3/-5.2 (stat.) +3.7/-3.2 (syst.) SNU. This represents only slightly more than half of the predicted standard solar model rate of 128 SNU. We give the results of new runs beginning in April 1998 and the results of combined analysis of all runs since 1990 during yearly, monthly, and bimonthly periods. Using a simple analysis of the SAGE results combined with those from all other solar neutrino experiments, we estimate the electron neutrino pp flux that reaches the Earth to be (4.6 +/- 1.1) E10/(cm^2-s). Assuming that neutrinos oscillate to active flavors the pp neutrino flux emitted in the solar fusion reaction is approximately (7.7 +/- 1.8) E10/(cm^2-s), in agreement with the standard solar model calculation of (5.95 +/- 0.06) E10/(cm^2-s).Comment: English translation of article submitted to Russian journal Zh. Eksp. Teor. Fiz. (JETP); 12 pages, 5 figures. V2: Added winter-summer difference and 2 reference

    Parasitism of Adult Pentatomidae by Tachinidae in Soybean in the North Central Region of the United StatesPheylan

    Get PDF
    Stink bugs (Hemiptera: Pentatomidae) are agricultural pests of increasing significance in the North Central Region of the United States, posing a threat to major crops such as soybean. Biological control can reduce the need for insecticides to manage these pests, but the parasitism of stink bugs byTachinidae (Diptera) is poorly characterized in this region. The objective of this study was to evaluate the rate of parasitism of stink bugs by tachinids over 2 yr from nine states across the North Central Region. Parasitism was assessed by quantifying tachinid eggs on the integument of stink bug adults. Parasitism rates (i.e., percent of adult stink bugs with tachinid eggs) were compared across stink bug species, states, stink bug sex, and years.The mean percent parasitism of stink bugs by tachinids was about 6% across the region and did not differ among stink bug species. Mean percent parasitism was significantly higher in Missouri than in northern and western states. In addition, male stink bugs had significantly higher mean percent parasitism than females. Stink bug species commonly found in soybean in the region showed some parasitism and are therefore potentially vulnerable to oviposition by these parasitoids.This is the first study to characterize the level of parasitism of stink bugs by tachinids across the North Central Region

    Measurement of the solar neutrino capture rate with gallium metal

    Get PDF
    The solar neutrino capture rate measured by the Russian-American Gallium Experiment (SAGE) on metallic gallium during the period January 1990 through December 1997 is 67.2 (+7.2-7.0) (+3.5-3.0) SNU, where the uncertainties are statistical and systematic, respectively. This represents only about half of the predicted Standard Solar Model rate of 129 SNU. All the experimental procedures, including extraction of germanium from gallium, counting of 71Ge, and data analysis are discussed in detail.Comment: 34 pages including 14 figures, Revtex, slightly shortene

    Pollinators and Other Insect Visitations on Native and Ornamental Perennials in Two Landscapes

    Get PDF
    Many pollinator insects, especially honey bees [Apis mellifera Linnaeus (Apidae)] and wild bees, are experiencing population decline because of forage and habitat losses. Planting perennial flowering taxa is one method of increasing pollinator habitat. The objectives of this study were to evaluate the potential of 27 native species and ornamental perennial cultivars to determine their ability to attract insect pollinators in a rural and an urban landscape in North Dakota, assess the potential of these perennials to attract other beneficial insects and insect pests, and identify the bee species visiting these perennials. Five to eight native species and/or ornamental cultivars each from four genera, Monarda L. (bee balm), Hylotelephium H. Ohba (stonecrop), Baptisia Vent. (wild indigo), and Symphyotrichum Nees (aster), were tested. Weekly observations of individual plants during flowering and their pollinator visitations from 2018 to 2020 indicated that insect pollinators were present for the earliest flowering perennials in June and until the latest flowering perennials during the second week of October or the first freeze. A total of 16,194 insect pollinators were observed, and 87.8% of these pollinator visitations were Hymenoptera and Diptera. Significant landscapes Ă— perennial flowering taxa interactions were detected for all insect groups, except for syrphid flies, for which both main effects were significantly different. Overall, honey bees and beetles preferred to visit Hylotelephium and Symphyotrichum. The wild bees, lepidopterans, and syrphids preferred Hylotelephium, Symphyotrichum, and Monarda. Tachinids preferred Symphyotrichum. Blow flies preferred Hylotelephium. More beneficial insect visitations (i.e., 96.0%) and fewer insect pest visitations (i.e., 30.4%) were counted on the rural landscape. A total of 3311 bee individuals were identified as species from the following families: Apidae, Andrenidae, Colletidae, Megachilidae, and Halictidae. Thirty-one and 21 bee species were unique to the rural and urban landscapes, respectively. The two most common wild bees were Ceratina calcarata Robertson on the cultivar S. oblongifolium (Nutt.) G.L. Nessom October Skies and Lasioglossum imitatum (Smith) on some Monarda and Hylotelephium. These findings suggest that pollinator visitations are influenced by the landscape and varied among the perennial flowering taxa in some cases. However, all evaluated perennial flower taxa would be suitable for attracting and supporting pollinators in rural or urban landscape settings in the northern Great Plains

    Presence-Absence Sampling Plans for Stink Bugs (Hemiptera: Pentatomidae) in the Midwest Region of the United States

    Get PDF
    Stink bugs represent an increasing risk to soybean production in the Midwest region of the United States. The current sampling protocol for stink bugs in this region is tailored for population density estimation and thus is more relevant to research purposes. A practical decision-making framework with more efficient sampling effort for management of herbivorous stink bugs is needed. Therefore, a binomial sequential sampling plan was developed for herbivorous stink bugs in the Midwest region. A total of 146 soybean fields were sampled across 11 states using sweep nets in 2016, 2017, and 2018. The binomial sequential sampling plans were developed using combinations of five tally thresholds at two proportion infested action thresholds to identify those that provided the best sampling outcomes. Final assessment of the operating characteristic curves for each plan indicated that a tally threshold of 3 stink bugs per 25 sweeps, and proportion infested action thresholds of 0.75 and 0.95 corresponding to the action thresholds of 5 and 10 stink bugs per 25 sweeps, provided the optimal balance between highest probability of correct decisions (≥ 99%) and lowest probability of incorrect decisions (≤ 1%). In addition, the average sample size for both plans (18 and 12 sets of 25 sweeps, respectively) was lower than that for the other proposed plans. The binomial sequential sampling plan can reduce the number of sample units required to achieve a management decision, which is important because it can potentially reduce risk/cost of management for stink bugs in soybean in this region
    • …
    corecore