21 research outputs found
Genetic diversity, phylogenetic and phylogeographic analyses of Oncideres impluviata (Germar, 1823) (Coleoptera: Cerambycidae) in Rio Grande do Sul state, Brazil
No full textMachado, Dayanna do Nascimento, Costa, Ervandil Corrêa, Perini, Clérison Régis, Valmorbida, Ivair, Souza, Diego de Santana, Pedron, Leandra, Saldanha, Mateus Alves, Froehlich, Ricardo, Schühli, Guilherme, Greff, Henrique Pinton, Oliveira, Jeferson de, Arnemann, Jonas André (2023): Genetic diversity, phylogenetic and phylogeographic analyses of Oncideres impluviata (Germar, 1823) (Coleoptera: Cerambycidae) in Rio Grande do Sul state, Brazil. Revista Brasileira de Entomologia (e20220092) 67: 1-10, DOI: 10.1590/1806-9665-RBENT-2022-009
Soybean aphid (Hemiptera: Aphididae) response to lambda‐cyhalothrin varies with its virulence status to aphid‐resistant soybean
No full textBACKGROUND: 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
Evidence of enhanced reproductive performance and lack-of-fitness costs among soybean aphids, Aphis glycines, with varying levels of pyrethroid resistance
No full textBACKGROUND: Foliar application of insecticides is the main strategy to manage soybean aphid, Aphis glycines (Hemiptera: Aphididae), in the northcentral United States. Subpopulations of A. glycines have multiple nonsynonymous mutations in the voltage-gated sodium channel (vgsc) genes that are associated with pyrethroid resistance. We explored if fitness costs are associated with phenotypes conferred by vgsc mutations using life table analyses. We predicted that there would be significant differences between pyrethroid susceptibility and field-collected, parthenogenetic isofemale clones with differing, nonsynonymous mutations in vgsc genes.
RESULTS: Estimated resistance ratios for the pyrethroid-resistant clones ranged from 3.1 to 37.58 and 5.6 to 53.91 for lambdacyhalothrin and bifenthrin, respectively. Although life table analyses revealed some biological and demographic parameters to be significantly different among the clonal lines, there was no association between levels of pyrethroid resistance and a decline in fitness. By contrast, one of themost resistant clonal lines (SBA-MN1-2017) had a significantly higher finite rate of increase, intrinsic rate of increase and greater overall fitness compared to the susceptible control and other pyrethroid-resistant clonal lines.
CONCLUSIONS: Our life history analysis suggests that there are no negative pleotropic effects associated with the pyrethroid resistance in the clonal A. glycines lines used in this study. We discuss the potential impact of these results on efficacies of insecticide resistance management (IRM) and integrated pest management (IPM) plans directed at delaying the spread of
pyrethroid-resistant A. glycines.This article is published as Valmorbida, Ivair, Brad S. Coates, Erin W. Hodgson, Molly Ryan, and Matthew E. O'Neal. "Evidence of enhanced reproductive performance and lack of fitness costs among soybean aphid, Aphis glycines, with varying levels of pyrethroid resistance." Pest Management Science (2022). doi:10.1002/ps.6820.
This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA
Exploring the Dynamics of Virulent and Avirulent Aphids: A Case for a ‘Within Plant’ Refuge
No full textThe 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
Exploring the mechanisms and consequences of soybean aphid (Hemiptera: Aphididae) resistance to pyrethroids
No full textSoybean 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
Faunistic analysis of pest insects and their natural enemies associated with hairy fleabane in soybean crop1
No full textABSTRACT In addition to competing with crops, weeds can provide shelter for arthropods in cropping fields and adjacent areas. This study aimed to investigate the occurrence and population fluctuation of insect pests and their natural enemies associated with hairy fleabane (Conyza spp.), in soybean farming areas. The predominant species were Schizaphis graminum, Taylorilygus apicalis, Empoasca spp. and Nysius simulans. Species that comprise important pest complexes, including stink bugs and caterpillars, can develop on fleabane plants. Among them, the stink bugs Edessa meditabunda, Dichelops spp., Piezodorus guildinii, Nezara viridula and Euschistus heros, as well as the caterpillars Anticarsia gemmatalis, Spodoptera frugiperda, Spodoptera eridania, Chrysodeixis includens and Helicoverpa spp. have prevailed. The most common natural enemies were Orius spp., Eriopis connexa, Cycloneda sanuiinea and Chrysoperla spp. The population fluctuation analysis indicated that hairy fleabane mainly hosted stink bugs at the beginning of the crop cycle and after soybean maturation. The caterpillars, however, use this weed as an alternative host throughout the crop cycle, continuing after soybean maturation and harvesting. For natural enemies species, the population fluctuation depends on the occurrence of insects that serve as a food source for them. Thus, it is possible to conclude that hairy fleabane is an important alternative host for pest insects and their natural enemies in soybean crops
One maternal lineage leads the expansion of Thaumastocoris peregrinus (Hemiptera: Thaumastocoridae) in the New and Old Worlds
No full textThe bronze bug, Thaumastocoris peregrinus, an Australian native insect, has become a nearly worldwide invasive pest in the last 16 years and has been causing significant damage to eucalypts (Myrtaceae), including Eucalyptus spp. and Corymbia spp. Its rapid expansion leads to new questions about pathways and routes that T. peregrinus used to invade other continents and countries. We used mtDNA to characterize specimens of T. peregrinus collected from 10 countries where this species has become established, including six recently invaded countries: Chile, Israel, Mexico, Paraguay, Portugal, and the United States of America. We then combined our mtDNA data with previous data available from South Africa, Australia, and Europe to construct a world mtDNA network of haplotypes. Haplotype A was the most common present in all specimens of sites sampled in the New World, Europe, and Israel, however from Australia second more frequently. Haplotype D was the most common one from native populations in Australia. Haplotype A differs from the two major haplotypes found in South Africa (D and G), confirming that at least two independent invasions occurred, one from Australia to South Africa, and the other one from Australia to South America (A). In conclusion, Haplotype A has an invasion success over many countries in the World. Additionally, analyzing data from our work and previous reports, it is possible to suggest some invasive routes of T. peregrinus to predict such events and support preventive control measures
A docência administrada: problematizando a questão
No full textResumo: O texto que se apresenta é fruto das pesquisas realizadas por ocasião do curso de doutoramento e visa à compreensão da inserção de Sistemas Apostilados de Ensino em escolas públicas municipais. Com base em pesquisa empírica e teórica discorre-se sobre o conceito de Docência Administrada, proposto pelo autor, para ilustrar as consequências desta prática sobre a autonomia docente. Tendo como referencial os estudos provenientes de teóricos da Escola de Frankfurt, em especial Herbert Marcuse, propõe uma reflexão crítica sobre a utilização de apostilas, por meio de um estudo de caso, realizado em dois municípios do noroeste paulista, que propiciou dados para as análises realizadas.
Palavras-chave: Sistema apostilado de ensino; Indústria cultural; Autonomia; Docência administrada.
The Administered Teaching: discussing the question
Abstract: The present text is a result of the researches done for occasion of the doctorate course and tries to understand the insertion of the Education Systems in municipal public schools. Basing on an empirical and theoretical research it tells about the concept of the Administered Teaching, proposed by the author, with final aim to demonstrate the consequences of this practice on teacher\u27s autonomy. The studies of the theorists from the Frankfurt School, especially Hebert Marcuse, are a reference for this text, enabling the critical reflection about the use of the Education systems, through a case study, carried out in two cities from the northwest of São Paulo State, that provided data for the analyses made.
Keywords: Education systems; Cultural industry; Autonomy; Administered systems.
La Docencia Administrada: discutindo la cuestión
Resumen: El Texto que presentase es resultado de las investigaciones desarrolladas por el motivo del curso de doctorado, y todavia tiene la comprensión de la inserción de los sistemas con apostillas de la enseñanza de las escuelas públicas municipales. Con base en investigación empírica y teórica discurre sobre el concepto de docencia administrada, propuesto pr el autor, para la muestra de las consecuencias de esta práctica sobre la autonomia docente. Teniendo como referencial los estudios provenientes de teóricos de la escuela de Frankfurt, en especial Herbert Marcuse, propone una reflexión crítica sobre la utilización de apostillas por medio de un estudio específico, realizado en dos municípios del noroeste paulista, que propició datos para la análisis desarrolladas.
Palabras clave: Sistema con Apostillas de la Enseñanza; Indústria Cultural; Autonomia; Docencia Administrada.
Data de registro: 10/06/2014
Data de aceite: 06/05/201
First report of the occurrence of Ophiocordyceps melolonthae (Ascomycota: Hypocreales: Ophiocordycipitaceae) in larvae of Diloboderus abderus Sturm (Coleoptera: Melolonthidae) in Brazil
No full textRegistro de Chinavia erythrocnemis (Berg, 1878) (Hemiptera: Pentatomidae) em lírio branco no Rio Grande do Sul, Brasil
No full textEste 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
