Teses e Dissertações
URI permanente desta comunidadehttps://locus.ufv.br/handle/123456789/1
Teses e dissertações defendidas no contexto dos programas de pós graduação da Instituição.
Navegar
62 resultados
Resultados da Pesquisa
Item Potential of integrating mating disruption with resistance management and stable isotope to track dispersion of lepidopteran pests(Universidade Federal de Viçosa, 2024-02-19) Santos, Camila Oliveira; Pereira, Eliseu José Guedes; http://lattes.cnpq.br/5853930490709215Recent advances in organic synthesis have enabled the production of more cost-effective insect pheromone formulations for mating disruption over extensive agricultural areas. Mating disruption can interrupt the chemical communication system between males and females, safeguarding crops in treated regions. The technique can suppress Spodoptera frugiperda populations, a polyphagous lepidopteran pest causing significant global economic losses. However, validating mating disruption remains an ongoing effort. Results revealed a high percentage of mating disruption in four out of the five locations tested and a reduction in plant damage in three locations due to the pheromone application. While the crop yield was not significantly impacted, a significant decrease in ear damage was observed in treated areas. These findings highlight the potential of synthetic pheromones to disrupt mating and mitigate plant damage in maize fields infested by this pest. Escalating issues of evolution of resistance to conventional control methods in S. frugiperda increases the need for alternative approaches. Mating disruption, which affects the success of pest mating, is a potential tool to benefit resistance management. In that matter, we aimed to monitor the susceptibility of S. frugiperda populations to insecticides and Bt traits while exploring the feasibility of mating disruption as a resistance management tool. Neurotoxic insecticides demonstrated continued efficacy against the larvae despite concerns regarding potential resistance development within the benzoylurea insecticide group. Two populations exhibited incomplete resistance to the dual-gene Bt maize, which impacted various life-history population traits. We discussed the potential benefits and challenges of implementing mating disruption within insect resistance management strategies. Additionally, understanding the insect movement patterns between host plants is essential to effectively implementing these biorational pest management tools. Nitrogen-15 (15N) is a stable isotope and offers a promising tool for tracking insect dispersal among agricultural fields. Applying 15N-enriched fertilizers to specific crop areas allows plants to be labeled with a distinct isotopic signature, which can be transferred between host plants and their herbivores. The 15N levels in plant tissues were significantly higher in treatments sprayed with the isotope than in the control. The moths originating from isotope-treated plants absorbed the labeled nitrogen isotope into their tissues, although a non-significant difference was found among insects from treated and control plants. Our findings highlight the potential of integrating mating disruption with resistance management and 15N isotope tracing as feasible tools for improving our capacity to manage agricultural pests effectively. Further field trial replications should help refine and integrate these techniques into sustainable pest management programs, ensuring effective and resilient crop protection strategies. Keywords: pheromone, Spodoptera frugiperda, behavioral manipulation, insecticides and Bt crops, tracing tool, nitrogen.Item Varronia curassavica Jacq. (Boraginaceae) as an agroecological tool for coffee pest management(Universidade Federal de Viçosa, 2022-08-04) Andrade, Fernanda Pereira; Venzon, Madelaine; http://lattes.cnpq.br/4646342097390133Coffee (Coffea sp.) is a crop of great relevance in agriculture. However, its productivity can be severely affected by the attack of pests, such as Leucoptera coffeella and Hypothenemus hampei. The coffee leaf miner, L. coffeella, is a key coffee pest in the Neotropics. The larvae feed on the parenchyma of coffee leaves decreasing the photosynthesis capacity and leading to significant losses in yield. The coffee berry borer, H. hampei, is the most damaging insect pest of coffee worldwide. This pest lives inside the coffee berry consuming the seeds thus reducing the quantity and quality of the coffee grains. The most common method of control to both pests is the use of synthetic pesticides, which have a low effectiveness due to the selection of resistant populations. Additionally, the excessive use of these products could have a severe impact in the environment and non-target individuals. An alternative for the management of these pests could be the use of specific plants and their secondary metabolites, such as the essential oils. Varronia curassavica is a medicinal species that produces an essential oil with a range of biological activities besides attracting natural enemies, such as the Chrysopidae. The specie Chrysoperla externa is an important biological control agent of a variety of pests, including L. coffeella and H. hampei. In this study, I investigate whether V. curassavica can be used in the management of L. coffeella and H. hampei and benefit their natural enemy C. externa. I performed a greenhouse experiment to evaluate if the association of V. curassavica plants with coffee plants would affect the oviposition of L. coffeella and its predator C. externa (Chapter I). The association of the V. curassavica plants with coffee plants didn’t affect L. coffeella oviposition, however, it increased the C. externa oviposition. I also investigate the effects of the V. curassavica essential oil in the oviposition and the development of eggs and mines of L. coffeella (Chapter II). The V. curassavica essential oil inhibited the oviposition of L. coffeella but did not affect the development of its eggs and mines. I evaluated the lethal and sublethal effects of V. curassavica essential oil on H. hampei, assessing the mortality rates, the mobility of H. hampei, and the repellence of the essential oil to this pest (Chapter III). The essential oil of V. curassavica is toxic to H. hampei and affects its mobility, but it wasn’t repellent to the pest in the concentration tested. This study demonstrates that V. curassavica plant and its essential oil could be a safer alternative in the management of the key coffee pests. Keywords: Coffea sp. Leucoptera coffeella. Hypothenemus hampei. Chrysoperla externa.Item Interaction of tomato plants infected by the nematode Meloidogyne javanica on aboveground herbivore Tetranychus urticae and on behaviour of its predator Phytoseiulus macropilis(Universidade Federal de Viçosa, 2021-10-15) Morales Murillo, Jose Jahir; Pallini Filho, Angelo; http://lattes.cnpq.br/5321738006837614Tritrophic interactions play an important role in the dynamics of arthropods with their hosts. By inducing defenses, plants respond to herbivore attacks, may affect your development. The general objective of this research was to investigate the effect of the nematode Meloidogyne javanica on the performance of the herbivore Tetranychus urticae in tomato plants and, subsequently, whether the nematode infestation affectedthe behavior of its predator Phytoseiulus macropilis. In the first experiment with the herbivore, tomato plants were infested with 2,000 eggs of the nematode M. javanica for a period of 40 days. The immature development, oviposition and preference for choosing plants with or without the nematode were evaluated. A second experiment was carried out with different levels of nematode eggs’ infestation (1,000 and 6,000) atdifferent exposure times (15, 30, and 45 days after infestation). In this experiment, onlyimmature development and survival were evaluated. The spider mite in the first experiment did not show significant differences on immature development and survival,oviposition and preference. For the second experiment, the development of the herbivore T. urticae was affected, with high mortality compared to the control at 30 and45 days after nematode infestation. For the predatory mite, preference experiments evaluated plants attacked simultaneously by the herbivore mite and the nematode or only by the herbivore mite. The predatory mite showed no preference for plants inoculated with the nematode, however, more eggs were found in these plants. The results of this study indicated that with high initial infestation and over time of exposureto the pathogen, the quality of the plant is affected and, consequently, the performanceof aboveground herbivores. The attraction of more predators to plants with nematode infestation increased after 24 hours, which may have varied the number of females that oviposited in this treatment. Thus, it is important to understand the effect on plants when they are attacked by spatially separated organisms above and below ground. In the same way, knowing the importance of direct and indirect interactions in ecological communities it is possible to develop new management techniques andstrategies for crop protection. Keywords: Tritrophic interactions. Root system. Aboveground herbivory. Induced response.Item Conservation biological control of coffee leaf miner: role of green lacewings and parasitoids(Universidade Federal de Viçosa, 2021-10-29) Martins, Elem Fialho; Venzon, Madelaine; http://lattes.cnpq.br/3805068995988626Coffee leaf miner, Leucoptera coffeella, is a key coffee pest in the Neotropics. The larvae feed on the parenchyma between surfaces of coffee leaves causing decrease of the photosynthesis rate leading to significant losses in yield and in the longevity of coffee plant. Several natural enemies are involved in coffee leaf mine biological control, such as wasps, ants, parasitoids and green lacewings. However, normally their populations are not enough to decrease or to maintain the coffee leaf mine populations below threshold levels in coffee monocultures, due to their dependence on resources, such as pollen and nectar, which are scarce in conventional systems. The association of plant species to coffee crops might represent an effective strategy through the provision of alternative food and refuge for natural enemies. I investigate here whether the diversification of Coffea arabica crops with Inga edulis “erva-baleeira”, Varronia curassavica “inga”, Senna macranthera “fedegoso” and non-crop plants favors the biological control of coffee leaf miner by its predators and parasitoids. These plants can provide resources such as nectar and pollen constantly, shelter and oviposition and mating sites for natural enemies with either extrafloral nectaries (I. edulis and S. macranthera) and/or inflorescences (V. curassavica). Firstly, we performed laboratory experiments to evaluate whether the immature stages of the green lacewing Ceraeochrysa cubana are able to prey on the immature stages of coffee leaf miner (Chapter I). Larvae of C. cubana successfully prey on eggs and pupae of coffee leaf miner, being the first report about green lacewing predation on the pest eggs. We also investigate whether V. curassavica provides selective resources to C. cubana without benefiting coffee leaf miner adults (Chapter II). Larvae of C. cubana survived longer in the presence of V. curassavica inflorescences, and decrease the population growth rate of the pest. In the field, we evaluated the visitors of the inserted plants and whether the strategic diversification with I. edulis, S. macranthera and V. curassavica added to non-crop areas under management of no pesticide use influence the abundance and richness of predatory green lacewings and wasps, increase the parasitism and control coffee leaf miner compared to conventional coffee systems (Chapter III). I found that ants are the most abundant visiting insects of I. edulis, S. macranthera and V. curassavica. In addition, I found that although there was no significant difference in the abundance of green lacewings and wasps between systems, parasitism rate was higher in the diversified. Despite that, there was no difference in the pest infestation comparing to conventional coffee systems in 2019 and 2021, but in 2020 it was higher in the diversified. However, CLM populations did not reach threshold in any system. Our study demonstrates through laboratory and field experiments that it is possible to improve the biological control of coffee leaf miner with safe strategies to environment and humans, in addition to maintaining biodiversity in coffee agroecosystems. Keywords: Leucoptera cofeella. Conservation biological control. Ceraeochrysa cubana, Varronia curassavicaItem Compendium of neotropical termite genera: morphology and ecology database, ontology and applicability(Universidade Federal de Viçosa, 2022-08-31) Guimarães, Marco Paulo Macedo; Souza, Og Francisco Fonseca de; http://lattes.cnpq.br/0288968992537309Biological databases are fundamental tools for modern research, offering a wide range of relevant data. Over the past two decades, the explosion of interconnected data has spurred the development and adoption of database technologies. Here we propose the first termite morphology and ecology database model, coupled with a standard ontology, and apply the database in a specific study. With the database, it was possible to extract information about the internal and external morphology and ecology of the 108 genera that occur in the Neotropical region. We also created an ontology model based on the internal and external morphology of termites to support the integration between databases. Furthermore, we show that it is possible to apply the database to extract information that can be used in a specific study. Keywords: Isoptera. Catalogue. Graph. Entomology.Item Toxicological assessments of lethal and sublethal effects caused by exposure to agrochemicals in stingless bees (APIDAE, Meliponini)(Universidade Federal de Viçosa, 2022-07-18) Botina Jojoa, Lorena Lisbetd; Martins, Gustavo Ferreira; http://lattes.cnpq.br/1172197581383868Brazil has a wide diversity of species of stingless bees of the tribe Meliponini, with 244 described species. In the last decade, after a reported decline in bees’ colonies, stingless bees have been used as a study model in toxicological assessments in the tropical regions. These assessments consider mainly the risks associated with exposure to agrochemicals, which can affect the health of these essential pollinators and consequently compromise their ecosystem services. The present study aimed (a) to review the literature considering the toxicological assessments of agrochemicals in stingless bees in Brazil, (b) to provide a big picture considering the scenario and the trends of research on bees and their interaction with agrochemicals in the last 76 years, including species, methods of exposure and tested agrochemicals, (c) to provide adapted protocols for carrying out toxicological assessments in stingless bees; and (d) to assess the lethal and sublethal effects of larval exposure on the stingless bee Partamona helleri to different agrochemicals. Data from the literature review and meta-analysis (implementing artificial intelligence) underwent identification, screening, eligibility and inclusion phases, and toxicological assessments with agrochemicals were analyzed according to exposure via and development stage. The number of studies considering the exposure of stingless bees to agrochemicals, particularly insecticides, has increased over the last decade. However, these studies cover only 2.9% of the stingless bee species in Brazil. Toxicological assessments of agrochemicals on pollinators mainly comprise the order Hymenoptera (Apidae), on emphasis Apis mellifera. The group of insecticides, especially neonicotinoids, were the most studied in bees and the main route of exposure used was acute and under laboratory conditions. The protocols described here were successfully validated, exhibiting a high survival rate between 80 – 100% of the control treatment via chronic exposure in larvae and via acute exposure in adults, respectively, which is necessary to satisfy regulatory authorities. The survival rate of larvae orally treated with three agrochemicals was affected, according to dose and type of compound, and the recommended field doses of copper sulfate (CuSO4), and spinosad were highly toxic, unlike glyphosate. Locomotion was altered in adults derived from treated larvae, and the gut microbiota composition did not change by agrochemical. It can conclude that the systematic reviews, the description of the methods of toxicological assessments and exposure to agrochemicals assessing the possible lethal and sublethal effects on stingless bees described here can improve the knowledge regarding the role that agrochemicals play in the decline of stingless bees, as well as point out the gaps that need to be filled. In this way, the data obtained provide a comprehensive overview of the risks that these pollinators may be suffering because of human activities. Keywords: Behavior. Gut microbiota. Risk assessment. Systematic review. Wild bees.Item Ação da isca à base de isocicloseram em colônias de Atta sexdens (L.)(Universidade Federal de Viçosa, 2022-07-29) Cruz, Luana de Souza; Guedes, Raul Narciso Carvalho; http://lattes.cnpq.br/1003845020976232As formigas-cortadeiras são pragas de difícil controle, pois são insetos sociais e possuem táticas de defesas e sistema de seleção dos vegetais que cortam. O uso de inseticidas, na atualidade, é a melhor alternativa no controle às formigas, apesar dos danos que potencialmente causam ao ambiente. Têm-se buscado o avanço de novos formicidas com objetivo de controlar esses insetos, reduzindo assim as perdas causadas por sua atividade forrageira, além de minimizar seus efeitos potencialmente adversos ao ambiente. O plinazolin, tem se mostrado uma alternativa potencial no controle de formigas-cortadeiras, demonstrando alta eficiência em estudos de campo, porém pouco se sabe sobre como este composto atua nas colônias de formigas-cortadeiras. Assim, o objetivo principal desse trabalho é elucidar como a isca à base de plinazolin atua em colônias de formigas- cortadeiras Atta sexdens e seus possíveis efeitos relevantes nas diferentes castas, desde efeitos letais a subletais. Além disso, avaliar a sobrevivência das operárias com dieta semi-sólida, contendo o ingrediente ativo. Além disso, avaliou-se consumo foliar, massa de lixo produzida, volume do jardim de fungo, sobrevivência das colônias e interações entre as castas. Os efeitos dessa isca foram comparados aos efeitos da isca comercial contendo sulfluramida e uma isca artesanal utilizada como controle. O plinazolin causou supressão das colônias ocasionando rápida mortalidade das operárias, comprometendo a vida da colônia. Além dos efeitos letais às formigas e colônias, o plinazolin foi disperso de forma igualitária entre as castas causando redução no consumo foliar e na massa lixo produzida pelas colônias em decorrência da rápida mortalidade das operárias. Do mesmo modo, a dieta semi-sólida com plinazolin afetou a mortalidade de todas as castas mostrando que o ingrediente ativo foi disperso de forma igualitária, ao contrário apresentou a sulfluramida que evidenciou mortalidade de jardineiras nos primeiros dias após exposição das iscas. Por outro lado, os resultados mostraram que o plinazolin desencadeou maior número de interação entre as operárias forrageadoras tratadas e não tratadas em relação a colônias não expostos a este composto. Assim, concluiu-se que a isca de plinazolin desencadeia supressão rápida das colônias ao afetar drasticamente todas as castas comprometendo todas as atividades do ninho, apesar de não comprometer o carregamento. Além disso, plinazolin também mostra efeito retardado em operárias forrageadoras não comprometendo o carregamento das iscas, mas subsequentemente interferindo em suas interações comportamentais e causando mortalidade destas. Tais efeitos comprometem a sobrevivência da rainha e da colônia. Palavras-chave: Atrativos. Controle químico. Toxicologia.Item Systematic literature review and meta-analysis of phytochemicals as insecticides: trends and knowledge gaps(Universidade Federal de Viçosa, 2022-06-27) Collares, Lara Jardim; Guedes, Raul Narciso Carvalho; http://lattes.cnpq.br/2378283802353808To understand the context, the biases, and knowledge gaps of research with insecticides of botanical origin, this literature review was carried out assessing 76 years of research and covering 4,780 scientific articles for qualitative and quantitative analyses, including three meta-analyses. The study pointed out that the main botanical insecticides belong to the following major chemical groups: terpenoids, terpenes and carbonyl, which were all mainly tested in Coleoptera, Lepidoptera and Diptera insects. The survey also shows that despite the exponential growth of publications over the years, there are some biases and gaps that require attention. The evident focus on mortality estimates neglects the assessment of sublethal effects. In addition, most studies use only one group of species as experimental models (stored grain pests), which limits the applicability and representativeness of the results and information generated. As a result, the most common mode of exposure is by fumigation and contact. Thus, there is a predominance of estimates of lethal concentrations rather than lethal doses in these studies. Therefore, based on the evidence gathered, we recognize the need of studies with a broader range of insect species and the need to identify and characterize the molecules responsible for the insecticidal effect. This will allow us to circumvent current biases and recognize the main patterns of the relationship between the origin and structure of phytochemicals and their physiological and behavioral effects on insects. Keywords: Botanic molecules. Insect. Review.Item Find where they are: predicting suitable areas for the invasive species Erthesina fullo (Hemiptera: Pentatomidae)(Universidade Federal de Viçosa, 2023-02-18) Santos, Renata Cordeiro dos; Picanço, Marcelo Coutinho; http://lattes.cnpq.br/0803880010323134Erthesina fullo (Thunberg) (Hemiptera: Pentatomidae) is an invasive pest from Asia that was recently detected in Europe (2017) and South America (2021). This pest has a high risk of establishment in introduced areas due to polyphagia and adaptation to various temperatures. Yet, there are no data about potentially suitable areas for species occurrence outside its native range despite the recent invasion events. In this study, we presented a model for the potential distribution of E. fullo based on the CLIMEX algorithm. We created the model using global species occurrence (1424 points), three climate scenarios (current, 2030, and 2080), and biological information available. We then estimated the ecoclimate index and weekly growth index to determine the suitability of regions in a general scenario over time. Under the current climate scenario, our model demonstrates that suitable areas for E. fullo comprised America, Africa, Europe, and Oceania. These areas are inside tropical and subtropical climates. However, the suitability was reduced in those climates (-28%) under future climate scenarios, increasing in temperate regions. In addition, the weekly growth index of E. fullo was positively correlated with the photoperiod. Our study can guide future efforts to avoid potential invasion and establishment of E. fullo outside its current range. Keywords: Invasion. Distribution modeling. Yellow-spotted stink bug. Biosecurity. CLIMEX. Climate change.Item Bioeconomia para manejo racional de Spodoptera frugiperda em milho: relação injúria-produtividade e níveis de dano econômico em diversos cenários(Universidade Federal de Viçosa, 2023-05-12) Souza, Thadeu Carlos de; Pereira, Eliseu José Guedes; http://lattes.cnpq.br/5861213318935614A lagarta do cartucho do milho, Spodoptera frugiperda (Lepidoptera: Noctuidae) é considerada muito destrutiva em cultivos de milho, porém se desconhece a relação numérica da intensidade da sua injúria foliar com a produtividade de milho em condições representativas dos cultivos comerciais. Neste trabalho, determinamos curvas de dano e níveis de dano econômico (NDE) para S. frugiperda como desfolhadora em cultivos de milho grão e milho silagem. O trabalho foi conduzido nas safras de 2020/21 (1a safra, outubro–fevereiro) e 2021/22 (2a safra, março–julho), em quatro municípios de Minas Gerais, Brasil. Nos cultivos de milho, rotularam-se plantas com diferentes intensidades de injúria foliar pela lagarta do cartucho baseando-se na escala Davis. No ponto adequado para colheita, contabilizou-se a produção de cada planta rotulada, em silagem ou grãos. Com esses valores, estimou-se a porcentagem de produtividade da planta em relação à das plantas sem injúria foliar da lagarta do cartucho. Na análise de regressão para cada safra e finalidade da produção, equações do modelo logístico de três parâmetros se ajustaram adequadamente aos dados de produtividade em função da intensidade de injúria foliar. A máxima perda de produtividade foi 20-30% na maior intensidade de injúria (valor 9 na escala Davis, plantas com o cartucho destruído). As plantas tiveram nula redução na produtividade quando submetidas a baixas intensidades da desfolha pela lagarta do cartucho (valores 1–5 na escala Davis, i.e., até várias lesões com mais de 2,5 cm de comprimento nas folhas do cartucho). Esse padrão de tolerância à desfolha ocorreu nas plantas das duas épocas de cultivo. Na 1a safra, a curva de dano de grãos foi mais inclinada (7,3%) do que a de silagem (4,5%), mas na 2a safra declividade das curvas para grãos e silagem com semelhante (6,5 vs. 6,9%). O custo de controle do inseto em milho grão foi em média 4,3 e 2,0% do valor da produção em médio e alto grau de investimento, respectivamente. Para silagem, o custo de controle foi de 3,6 e 1,7% para na 1a safra. Na 2a safra, esse custo representou 3,6 e 1,7% (grão) e 1,4 e 1,0% (silagem) para médio e alto investimento, respectivamente. O menor valor de NDE em intensidade de injúria na escala Davis para milho grão na 1a safra foi de 8,0 e 7,1 para médio e alto grau de investimento. Para milho silagem esses valores foram de 5,9 e 5,4. Na 2a safra, para milho grão com alto ou médio investimentos, os valores de NDE foram de 6,1 e 5,5 e, para silagem, de 5,8 e 5,5, respectivamente. Esses menores valores foram obtidos no cenário de duas aplicações manuais por hectare. Valores fixo de NC podem ser tomados como 75% desses valores de NDE. Esta pesquisa é pioneira em fornecer informações realísticas sobre NDE para milho grão e silagem e elas podem ser utilizadas por produtores de milho e outros agentes em diversas regiões no mundo. Coletivamente, os resultados mostram que a situação de menor nível dano econômico da lagarta do cartucho em milho ocorre quando 100% das plantas apresentam injúria de nota 4 na escala Davis (i.e., NDE = 4). O atual valor de NC recomendado (20% de plantas com injúria foliar Davis nota 3) é, no mínimo, cinco vezes menor que o valor de NDE aqui obtido, sendo assim bastante conservativo como nível de ação para controle de S. frugiperda em cultivos de milho. Palavras-chave: Lagarta do cartucho. Zea mays. Tolerância. Injúria. Escala Davis. Tomada de decisão de controle de pragas.