Characterization of pyrethroid resistance in the western corn rootworm Diabrotica \u3ci\u3evirgifera virgifera\u3c/i\u3e LeConte

The western corn rootworm (WCR), Diabrotica virgifera virgifera Le Conte (Coleoptera: Chrysomelidae), is a major pest of maize (Zea mays L.) in the United States and has continuously challenged our ability to develop sustainable pest management solutions. Resistance to chemical insecticides, crop rotation, and most recently transgenic plants that express toxins derived from Bacillus thuringiensis Berliner (Bt) have been well documented among WCR populations. Furthermore, US regulatory insecticide prohibitions and the lack of new active ingredients have reduced the options for WCR control. Pyrethroid insecticides are one of the few remaining chemical options. Therefore, the recent confirmation of WCR field-evolved resistance to pyrethroids in the US western Corn Belt is a major concern. The present research aimed to characterize WCR pyrethroid resistance. The initial objective was to evaluate the field performance of formulated pyrethroids on pyrethroid-resistant WCR populations. An aerial application simulation method was developed to evaluate the performance of foliar adulticides whereas soil insecticides targeting WCR larvae were tested in field plots with representative WCR populations. Laboratory bioassays estimated the susceptibility of tested WCR populations against the active ingredients of formulated insecticides. Results indicated that relatively low levels of WCR pyrethroid resistance are enough to significantly impact the performance of pyrethroid products commonly used for either adult or larval control. A second objective was to artificially select a pyrethroid-resistant WCR population to be used along with field populations for pyrethroid resistance characterization. A population was selected in the laboratory with a diagnostic bifenthrin concentration for several generations reaching levels of pyrethroid resistance observed in field-collected WCR populations. A pilot heritability investigation suggested that a major portion of WCR bifenthrin resistance phenotypic variance may be due to genetic variation, and that a substantial increase in resistance could be expected afterexposure. Finally, the third objective was to identify WCR pyrethroid resistance mechanisms. Biochemical assays and High-Throughput RNA Sequencing results revealed that insecticide-related metabolism in pyrethroid-resistant WCR populations was significantly enhanced compared to pyrethroid-susceptible populations. The relevance of results is discussed within the context of WCR pyrethroid resistance monitoring and management. Advisor: Lance J. Meink

Ter fé é dançar na beira do abismo

The visual essay of this proposition is composed of ten photographs digitally manipulated in an embroidery software. The images present a dance between mother and daughter and their construction process unites two substantial practices in my artistic work: performative photographs with my mother and embroidery research, which now incorporates digital elements. The text discusses aspects that constitute the essay as well as some theoretical and conceptual bases that cross my artistic research. Starting from the articulation between the concepts of Escrevivência, Self-writing and Autopoiesis, I bet on the narration of the self as an erotic act and I understand eroticism as a position before the world, which concerns the aesthetic, ethical and political dimension of life in society.El ensayo visual de esta propuesta consta de diez fotografías manipuladas digitalmente en un software de bordado. Las imágenes presentan una danza entre madre e hija y su proceso de construcción une dos prácticas sustanciales en mi trabajo artístico: las fotografías performativas con mi madre y la investigación del bordado, que ahora incorpora elementos digitales. El texto aborda aspectos que constituyen el ensayo, así como algunas bases teóricas y conceptuales que atraviesan mi investigación artística. Partiendo de la articulación entre los conceptos de Escrevivência, Escritura del Yo y Autopoiesis, apuesto por la narración del yo como acto erótico y entiendo el erotismo como una posición ante el mundo, que se refiere a la dimensión estética, ética y política de vida en sociedad.Este ensaio visual é composto por dez fotografias manipuladas digitalmente em um software de bordado. As imagens que apresentam dois corpos dançando unem duas práticas substanciais na minha pesquisa artística: fotografias performativas com a minha mãe e experimentações com bordado, que agora incorpora elementos digitais. O texto discorre sobre aspectos formais que constituem o ensaio, bem como sobre algumas bases teóricas e conceituais que atravessam o meu processo criativo. Partindo da articulação entre os conceitos de Escrevivência, Escrita de Si e Autopoiesis e entendendo o erotismo como um posicionamento político diante do mundo, que diz respeito a dimensão estética e ética da vida em sociedade, aposto na narração de si enquanto ato erótico de reafirmação da vid

Autorretrato Infamiliar | Non-familiar self-portrait

Este ensaio é parte de um projeto fotográfico em desenvolvimento onde registro o corpo da minha mae junto ao meu dentro do espaço doméstico, tematizando uma relação conflituosa. ORCIDhttps://orcid.org/0000-0002-7526-337

Western corn rootworm pyrethroid resistance confirmed by aerial application simulations of commercial insecticides

The western corn rootworm (Diabrotica virgifera virgifera LeConte) (WCR) is a major insect pest of corn (Zea mays L.) in the United States (US) and is highly adaptable to multiple management tactics. A low level of WCR field-evolved resistance to pyrethroid insecticides has been confirmed in the US western Corn Belt by laboratory dose-response bioassays. Further investigation has identified detoxification enzymes as a potential part of the WCR resistance mechanism, which could affect the performance of insecticides that are structurally related to pyrethroids, such as organophosphates. Thus, the responses of pyrethroid-resistant and -susceptible WCR populations to the commonly used pyrethroid bifenthrin and organophosphate dimethoate were compared in active ingredient bioassays. Results revealed a relatively low level of WCR resistance to both active ingredients. Therefore, a simulated aerial application bioassay technique was developed to evaluate how the estimated resistance levels would affect performance of registered rates of formulated products. The simulated aerial application technique confirmed pyrethroid resistance to formulated rates of bifenthrin whereas formulated dimethoate provided optimal control. Results suggest that the relationship between levels of resistance observed in dose-response bioassays and actual efficacy of formulated product needs to be further explored to understand the practical implications of resistance

Bifenthrin Baseline Susceptibility and Evaluation of Simulated Aerial Applications in \u3ci\u3eStriacosta albicosta\u3c/i\u3e (Lepidoptera: Noctuidae)

Striacosta albicosta (Smith) is a maize pest that has recently expanded its geographical range into the eastern United States and southeastern Canada. Aerial application of pyrethroids, such as bifenthrin, has been a major practice adopted to manage this pest. Reports of field failure of pyrethroids have increased since 2013. Striacosta albicosta populations were collected in 2016 and 2017 from maize fields in Nebraska, Kansas, and Canada and screened with bifenthrin active ingredient in larval contact dose-response bioassays. Resistance ratios estimated were generally low in 2016 (1.04- to 1.32-fold) with the highest LC50 in North Platte, NE (66.10 ng/cm2) and lowest in Scottsbluff, NE (50.10 ng/cm2). In 2017, O’Neill, NE showed the highest LC50 (100.66 ng/cm2) and Delhi, Canada exhibited the lowest (6.33 ng/cm2), resulting in a resistance ratio variation of 6.02- to 15.90-fold. Implications of bifenthrin resistance levels were further investigated by aerial application simulations. Experiments were conducted with a spray chamber where representative S. albicosta populations were exposed to labeled rates of a commercial bifenthrin formulation. Experiments resulted in 100% mortality for all populations, instars, insecticide rates, and carrier volumes, suggesting that levels of resistance estimated for bifenthrin active ingredient did not seem to impact the efficacy of the correspondent commercial product under controlled conditions. Results obtained from this research indicate that control failures reported in Nebraska could be associated with factors other than insecticide resistance, such as issues with the application technique, environmental conditions during and/or after application, or the insect’s natural behavior. Data generated will assist future S. albicosta resistance management programs

Enhanced metabolism and selection of pyrethroid-resistant western corn rootworms (Diabrotica virgifera virgifera LeConte)

Western corn rootworm (WCR) pyrethroid resistance has been previously reported in the United States (US) western Corn Belt, and cross-resistance and synergism studies suggested that both target site insensitivity and enhanced metabolism may be conferring WCR resistance to pyrethroids. The present study aimed to investigate the potential mechanisms of WCR pyrethroid resistance and to estimate the heritability of the resistance trait. Biochemical assays using model substrates and spectrophotometry revealed 2–4-fold higher activity of P450s and esterases in pyrethroid-resistant WCR populations, whereas the biological activity of glutathione S-trans- ferase was similar between populations tested. No mutation in the voltage-gated sodium channel was detected in pyrethroid-resistant WCR individuals by sequencing PCR products containing the para-homologous L1014, T929, and M918 amino acid positions that are commonly associated with target site mutations in other pyre- throid-resistant insects. A pilot estimation of pyrethroid resistance heritability obtained during laboratory se- lection of a WCR population suggested a major genetic component of the resistance trait and predicted a 10-fold increase in WCR bifenthrin resistance within ~7 generations of insecticide lethal exposure. Results support earlier indirect evidence that enhanced metabolism may be contributing to WCR resistance to pyrethroids and illustrates the potential of WCR pyrethroid resistance evolution

Western corn rootworm pyrethroid resistance confirmed by aerial application simulations of commercial insecticides

The western corn rootworm (Diabrotica virgifera virgifera LeConte) (WCR) is a major insect pest of corn (Zea mays L.) in the United States (US) and is highly adaptable to multiple management tactics. A low level of WCR field-evolved resistance to pyrethroid insecticides has been confirmed in the US western Corn Belt by laboratory dose-response bioassays. Further investigation has identified detoxification enzymes as a potential part of the WCR resistance mechanism, which could affect the performance of insecticides that are structurally related to pyrethroids, such as organophosphates. Thus, the responses of pyrethroid-resistant and -susceptible WCR populations to the commonly used pyrethroid bifenthrin and organophosphate dimethoate were compared in active ingredient bioassays. Results revealed a relatively low level of WCR resistance to both active ingredients. Therefore, a simulated aerial application bioassay technique was developed to evaluate how the estimated resistance levels would affect performance of registered rates of formulated products. The simulated aerial application technique confirmed pyrethroid resistance to formulated rates of bifenthrin whereas formulated dimethoate provided optimal control. Results suggest that the relationship between levels of resistance observed in dose-response bioassays and actual efficacy of formulated product needs to be further explored to understand the practical implications of resistance

Evaluation of identification and susceptibility for Candida spp. isolated directly from positive blood culture bottles

Determination of the susceptibility profile of isolates of Candida from blood culture bottles is extremely important for correctly guiding patient pharmacotherapy. ,e aim of this study was to compare the results of analysis of Candida isolated directly from blood culture bottles by the VITEK MS MALDI-TOF identification system and the fluconazole disk diffusion assay with those of standard identification methods. Testing directly from the bottle allowed results 24 to 48 hours quicker than the standard method. ,ere was a categorical agreement of 51.64% (47 of 91 samples) between the results of analysis directly from the bottle and analysis by the standard method. Regarding species identification, there was 96.15% agreement for Candida parapsilosis (25 of 26 samples). Categorical agreement between the rapid and standard disk diffusion methods was 95%, and the agreement between the rapid disk diffusion method and the broth microdilution method was 97%. Only minor errors in the rapid method were observed: 3 (5%) in the standard disk diffusion method and 2 (3%) in the broth microdilution method. Our study concluded that the rapid disk diffusion method for fluconazole is a fast, easy, reproducible, and consistent method. Its timely implementation for testing antifungal agents in the clinical microbiology laboratory can help reduce profile release times, thus helping to determine the most appropriate antifungal treatment

Bifenthrin Baseline Susceptibility and Evaluation of Simulated Aerial Applications in \u3ci\u3eStriacosta albicosta\u3c/i\u3e (Lepidoptera: Noctuidae)

Striacosta albicosta (Smith) is a maize pest that has recently expanded its geographical range into the eastern United States and southeastern Canada. Aerial application of pyrethroids, such as bifenthrin, has been a major practice adopted to manage this pest. Reports of field failure of pyrethroids have increased since 2013. Striacosta albicosta populations were collected in 2016 and 2017 from maize fields in Nebraska, Kansas, and Canada and screened with bifenthrin active ingredient in larval contact dose-response bioassays. Resistance ratios estimated were generally low in 2016 (1.04- to 1.32-fold) with the highest LC50 in North Platte, NE (66.10 ng/cm2) and lowest in Scottsbluff, NE (50.10 ng/cm2). In 2017, O’Neill, NE showed the highest LC50 (100.66 ng/cm2) and Delhi, Canada exhibited the lowest (6.33 ng/cm2), resulting in a resistance ratio variation of 6.02- to 15.90-fold. Implications of bifenthrin resistance levels were further investigated by aerial application simulations. Experiments were conducted with a spray chamber where representative S. albicosta populations were exposed to labeled rates of a commercial bifenthrin formulation. Experiments resulted in 100% mortality for all populations, instars, insecticide rates, and carrier volumes, suggesting that levels of resistance estimated for bifenthrin active ingredient did not seem to impact the efficacy of the correspondent commercial product under controlled conditions. Results obtained from this research indicate that control failures reported in Nebraska could be associated with factors other than insecticide resistance, such as issues with the application technique, environmental conditions during and/or after application, or the insect’s natural behavior. Data generated will assist future S. albicosta resistance management programs

UNIVERSITY STUDENTS IN THE CONTEXT OF COVID-19: PROFILE, BEHAVIORS AND ACADEMIC ACTIVITIES

Objetivo: descrever o perfil sociodemográfico, as atividades acadêmicas e os comportamentos de estudantes universitários no contexto da pandemia de COVID-19. Método: estudo transversal, descritivo, quantitativo, que teve os dados coletados entre agosto e setembro de 2020, via formulário Google forms, no Rio Grande de Sul, Brasil. Os dados foram analisados utilizando a estatística descritiva. Resultados: de 536 estudantes da disciplina optativa de Saúde mental em emergências humanitárias, ofertada pela Universidade Federal de Pelotas, no semestre alternativo, em 2020, 464 participaram. Desses, 53,45% estavam em isolamento e distanciamento social, 40,73% tiveram piora da situação financeira, 66,59% buscaram apoio familiar e 85,96% acompanharam atividades a distância. Conclusão: o distanciamento e o isolamento social foram fundamentais para o controle da infecção pela COVID-19, porém apresentaram fatores negativos, como piora da situação financeira, e positivo, a adaptação às novas abordagens para a continuidade das aulas remotas.Objective: to describe the sociodemographic profile, academic activities, and behaviors of college students in the context of the COVID-19 pandemic. Method: cross-sectional, descriptive, quantitative study, which had data collected between August and September 2020, via Google forms, in Rio Grande de Sul, Brazil. Data were analyzed using descriptive statistics. Results: of 536 students in the optional discipline of Mental Health in Humanitarian Emergencies, offered by the Federal University of Pelotas, in the alternate semester in 2020, 464 participated. Of these, 53.45% were in isolation and social withdrawal, 40.73% had worsening financial situation, 66.59% sought family support, and 85.96% followed distance activities. Conclusion: the distancing and social isolation were fundamental for the control of the infection by COVID-19, but presented negative factors, such as worsening of the financial situation, and positive, the adaptation to the new approaches for the continuity of the remote classes.Objetivo: describir el perfil sociodemográfico, las actividades académicas y los comportamientos de los estudiantes universitarios en el contexto de la pandemia de COVID-19. Método: estudio transversal, descriptivo, cuantitativo, que tuvo datos recogidos entre agosto y septiembre de 2020, a través de formularios de Google, en Rio Grande de Sul, Brasil. Los datos se analizaron mediante estadísticas descriptivas. Resultados: de 536 estudiantes de la disciplina optativa de Salud mental en emergencias humanitarias, ofertada por la Universidad Federal de Pelotas, en el semestre alternativo, en 2020, participaron 464. De ellos, el 53,45% se encontraba en situación de aislamiento y distanciamiento social, el 40,73% presentaba un empeoramiento de la situación económica, el 66,59% buscaba apoyo familiar y el 85,96% realizaba actividades a distancia. Conclusión: el distanciamiento y el aislamiento social fueron fundamentalespara el control de la infección por COVID-19, pero presentaron factores negativos, como el empeoramiento de la situación financiera, y positivos, la adaptación a los nuevos enfoques para la continuidad de las clases a distancia