Ingresso e assistência estudantil na UFSM: Potencial e necessidade de divulgação no interior do Rio Grande do Sul

Trabalho apresentado no 31º SEURS - Seminário de Extensão Universitária da Região Sul, realizado em Florianópolis, SC, no período de 04 a 07 de agosto de 2013 - Universidade Federal de Santa Catarina.Sabe-se que, atualmente, apenas uma minoria da população brasileira frequenta os bancos acadêmicos, tendo-se relatado diversos fatores que colaboram para a existência desse quadro. Um deles refere-se à falta de informação dos estudantes do ensino médio a respeito da existência de uma universidade pública, cuja gratuidade não se restringe somente às mensalidades, mas também à moradia e à alimentação dos acadêmicos com dificuldades financeiras. Assim, muitas vezes, essas pessoas interrompem os estudos, por não terem conhecimento dos benefícios oferecidos pela universidade pública. A Universidade Federal de Santa Maria tem por objetivos promover o ensino, pesquisa e extensão, colaborando com o poder público na solução de problemas nacionais e objetivando o desenvolvimento do país. A partir de 1998, foi constatada, pelos graduandos do curso de Agronomia, bolsistas do Programa de Educação Tutorial SESu/MEC (PET-Agronomia), a necessidade de um projeto que viesse a suprir o desconhecimento dos estudantes de algumas instituições públicas de ensino médio do Rio Grande do Sul em relação às universidades federais. Nesse sentido, foi proposto, dentro do planejamento de atividades do grupo, a realização do projeto “UFSM Vai à Escola”, que consiste na apresentação da UFSM aos estudantes do ensino médio no Estado do Rio Grande do Sul

Exploring the mechanisms and consequences of soybean aphid (Hemiptera: Aphididae) resistance to pyrethroids

Soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), was first detected in the United States in 2000 and has been actively managed by farmers with foliar insecticide applications. Bifenthrin and lambda-cyhalothrin are insecticides commonly used to control soybean aphid outbreaks. However, control failures were observed and laboratory bioassays confirmed that soybean aphid has evolved resistance to pyrethroids. This research investigated the susceptibility of virulent and avirulent aphids to lambda-cyhalothrin and the mechanisms and fitness costs related with pyrethroid-resistant soybean aphids. Leaf dip bioassays were performed to assess the susceptibility of laboratory and field-collected populations to insecticides. Also, molecular markers were developed to assess the frequency of resistant alleles before and after a foliar insecticide application. Toxicity bioassays revealed that virulent aphids had a higher LC50 compared with virulent aphids, and exposure to the LC25 of lambda-cyhalothrin can trigger hormesis in soybean aphids. These bioassays also confirmed that field-collected aphids have evolved resistance to pyrethroids and sequencing of the voltage-gated sodium channel (vgsc) genes identified non-synonymous mutations associated with resistant aphids. Additionally, molecular markers revealed a high frequency of aphids carrying at least one mutation in the vgsc, and foliar insecticide application significantly increased resistant allele frequency among survivors. Experiments using isofemale lines with varying levels of pyrethroid resistance did not find evidence of fitness cost. Field-evolved soybean aphid resistance to pyrethroids is concerning and will require the development and implementation of integrated pest management (IPM) and insect resistance management (IRM) plans to mitigate the spread of resistant aphids and delay resistance evolution to other management strategies

Exploring the mechanisms and consequences of soybean aphid (Hemiptera: Aphididae) resistance to pyrethroids

Soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), was first detected in the United States in 2000 and has been actively managed by farmers with foliar insecticide applications. Bifenthrin and lambda-cyhalothrin are insecticides commonly used to control soybean aphid outbreaks. However, control failures were observed and laboratory bioassays confirmed that soybean aphid has evolved resistance to pyrethroids. This research investigated the susceptibility of virulent and avirulent aphids to lambda-cyhalothrin and the mechanisms and fitness costs related with pyrethroid-resistant soybean aphids. Leaf dip bioassays were performed to assess the susceptibility of laboratory and field-collected populations to insecticides. Also, molecular markers were developed to assess the frequency of resistant alleles before and after a foliar insecticide application. Toxicity bioassays revealed that virulent aphids had a higher LC50 compared with virulent aphids, and exposure to the LC25 of lambda-cyhalothrin can trigger hormesis in soybean aphids. These bioassays also confirmed that field-collected aphids have evolved resistance to pyrethroids and sequencing of the voltage-gated sodium channel (vgsc) genes identified non-synonymous mutations associated with resistant aphids. Additionally, molecular markers revealed a high frequency of aphids carrying at least one mutation in the vgsc, and foliar insecticide application significantly increased resistant allele frequency among survivors. Experiments using isofemale lines with varying levels of pyrethroid resistance did not find evidence of fitness cost. Field-evolved soybean aphid resistance to pyrethroids is concerning and will require the development and implementation of integrated pest management (IPM) and insect resistance management (IRM) plans to mitigate the spread of resistant aphids and delay resistance evolution to other management strategies

Exploring the mechanisms and consequences of soybean aphid (Hemiptera: Aphididae) resistance to pyrethroids

Soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), was first detected in the United States in 2000 and has been actively managed by farmers with foliar insecticide applications. Bifenthrin and lambda-cyhalothrin are insecticides commonly used to control soybean aphid outbreaks. However, control failures were observed and laboratory bioassays confirmed that soybean aphid has evolved resistance to pyrethroids. This research investigated the susceptibility of virulent and avirulent aphids to lambda-cyhalothrin and the mechanisms and fitness costs related with pyrethroid-resistant soybean aphids. Leaf dip bioassays were performed to assess the susceptibility of laboratory and field-collected populations to insecticides. Also, molecular markers were developed to assess the frequency of resistant alleles before and after a foliar insecticide application. Toxicity bioassays revealed that virulent aphids had a higher LC50 compared with virulent aphids, and exposure to the LC25 of lambda-cyhalothrin can trigger hormesis in soybean aphids. These bioassays also confirmed that field-collected aphids have evolved resistance to pyrethroids and sequencing of the voltage-gated sodium channel (vgsc) genes identified non-synonymous mutations associated with resistant aphids. Additionally, molecular markers revealed a high frequency of aphids carrying at least one mutation in the vgsc, and foliar insecticide application significantly increased resistant allele frequency among survivors. Experiments using isofemale lines with varying levels of pyrethroid resistance did not find evidence of fitness cost. Field-evolved soybean aphid resistance to pyrethroids is concerning and will require the development and implementation of integrated pest management (IPM) and insect resistance management (IRM) plans to mitigate the spread of resistant aphids and delay resistance evolution to other management strategies

Exploring the mechanisms and consequences of soybean aphid (Hemiptera: Aphididae) resistance to pyrethroids

Soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), was first detected in the United States in 2000 and has been actively managed by farmers with foliar insecticide applications. Bifenthrin and lambda-cyhalothrin are insecticides commonly used to control soybean aphid outbreaks. However, control failures were observed and laboratory bioassays confirmed that soybean aphid has evolved resistance to pyrethroids. This research investigated the susceptibility of virulent and avirulent aphids to lambda-cyhalothrin and the mechanisms and fitness costs related with pyrethroid-resistant soybean aphids. Leaf dip bioassays were performed to assess the susceptibility of laboratory and field-collected populations to insecticides. Also, molecular markers were developed to assess the frequency of resistant alleles before and after a foliar insecticide application. Toxicity bioassays revealed that virulent aphids had a higher LC50 compared with virulent aphids, and exposure to the LC25 of lambda-cyhalothrin can trigger hormesis in soybean aphids. These bioassays also confirmed that field-collected aphids have evolved resistance to pyrethroids and sequencing of the voltage-gated sodium channel (vgsc) genes identified non-synonymous mutations associated with resistant aphids. Additionally, molecular markers revealed a high frequency of aphids carrying at least one mutation in the vgsc, and foliar insecticide application significantly increased resistant allele frequency among survivors. Experiments using isofemale lines with varying levels of pyrethroid resistance did not find evidence of fitness cost. Field-evolved soybean aphid resistance to pyrethroids is concerning and will require the development and implementation of integrated pest management (IPM) and insect resistance management (IRM) plans to mitigate the spread of resistant aphids and delay resistance evolution to other management strategies

Exploring the Dynamics of Virulent and Avirulent Aphids: A Case for a ‘Within Plant’ Refuge

The soybean aphid, Aphis glycines (Hemiptera: Aphididae), is an invasive pest that can cause severe yield loss to soybeans in the North Central United States. A tactic to counter this pest is the use of aphid-resistant soybean varieties. However, the frequency of virulent biotypes that can survive on resistant varieties is expected to increase as more farmers use these varieties. Soybean aphids can alter soybean physiology primarily by two mechanisms, feeding facilitation, and the obviation of resistance, favoring subsequent colonization by additional conspecifics. We developed a nonlocal, differential equation population model to explore the dynamics of these biological mechanisms on soybean plants coinfested with virulent and avirulent aphids. We then use demographic parameters from laboratory experiments to perform numerical simulations via the model. We used this model to determine that initial conditions are an important factor in the season-long cooccurrence of both biotypes. The initial population of both biotypes above the resistance threshold or avirulent aphid close to resistance threshold and high virulent aphid population results in coexistence of the aphids throughout the season. These simulations successfully mimicked aphid dynamics observed in the field- and laboratory-based microcosms. The model showed an increase in colonization of virulent aphids increases the likelihood that aphid resistance is suppressed, subsequently increasing the survival of avirulent aphids. This interaction produced an indirect, positive interaction between the biotypes. These results suggest the potential for a ‘within plant’ refuge that could contribute to the sustainable use of aphid-resistant soybeans.This article is published as Banerjee, Aniket, Ivair Valmorbida, Matthew E. O’Neal, and Rana Parshad. "Exploring the Dynamics of Virulent and Avirulent Aphids: A Case for a ‘Within Plant’Refuge." Journal of economic entomology 115, no. 1 (2022): 279-288. doi: 10.1093/jee/toab218. Posted with permission. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited

Soybean aphid (Hemiptera: Aphididae) response to lambda‐cyhalothrin varies with its virulence status to aphid‐resistant soybean

BACKGROUND: Soybean aphid, Aphis glycines, is an invasive insect in North America, considered one of the most important pests of soybean. Their management relies heavily on foliar insecticides, but there is growing effort to expand these tools to include aphid-resistant varieties. We explored if the LC50 and LC25 of lambda-cyhalothrin varied between virulent (Resistance to Aphis glycines (Rag) soybeans) and avirulent (susceptible to Rag-genes soybeans) populations of soybean aphid with a leaf-dip bioassay. We also investigated the response to the LC25 of lambda-cyhalothrin on adults (F0) and their progeny (F1) for both avirulent and virulent soybean aphid. RESULTS: The LC50 of the virulent aphid population was significantly higher compared with the LC50 of the avirulent population. The LC25 significantly reduced fecundity of the F0 generation of avirulent soybean aphid, but no significant effect was observed for virulent aphids. In addition, the LC25 significantly shortened the adult pre-oviposition period (APOP) and lengthened total pre-oviposition period (TPOP) of avirulent aphids, while the mean generation time (T) was significantly increased. For the virulent aphid, sublethal exposure significantly lengthened development time of first and third instars, TPOP, and adult longevity. In addition, all demographic parameters of virulent soybean aphid were significantly affected when they were exposed to the LC25 of lambda-cyhalothrin. CONCLUSION: Our results demonstrate lambda-cyhalothrin is less toxic to virulent aphids and exposure to the LC25 can trigger hormesis which may have implications for the long-term management of this pest with this insecticide as well as with aphid-resistant varieties of soybean.This is the peer reviewed version of the following article: Valmorbida, Ivair, Dionei S. Muraro, Erin W. Hodgson, and Matthew E. O'Neal. "Soybean aphid (Hemiptera: Aphididae) response to lambda‐cyhalothrin varies with its virulence status to aphid‐resistant soybean." Pest management science (2019), which has been published in final form at doi: 10.1002/ps.5661. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.</p

Registro de Chinavia erythrocnemis (Berg, 1878) (Hemiptera: Pentatomidae) em lírio branco no Rio Grande do Sul, Brasil

Este é o primeiro registro da ocorrência de Chinavia erythrocnemis sobre a planta ornamental Lilium longiflorum, comumente denominada de lírio branco, no Rio Grande do Sul, Brasil

Registro de Chinavia erythrocnemis (Berg, 1878) (Hemiptera: Pentatomidae) em lírio branco no Rio Grande do Sul, Brasil

Este é o primeiro registro da ocorrência de Chinavia erythrocnemis sobre a planta ornamental Lilium longiflorum, comumente denominada de lírio branco, no Rio Grande do Sul, Brasil