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Bioestimulantes e voláteis de plantas como ferramentas para o manejo de dalbulus maidis (DeLong & Wolcott) (hemiptera: cicadellidae) em milho
(2025-12-17) CANDIDO, Tatiane Cristina Barbosa
The growing agricultural demand has intensified the use of phytosanitary products, whose excessive and improper application has caused significant impacts on ecosystems. In this context, it becomes essential to develop more sustainable production systems, especially in crops such as maize (Zea mays L.), which is heavily affected by the corn leafhopper, Dalbulus maidis (DeLong & Wolcott, 1923) (Hemiptera: Cicadellidae), one of the main pests of this crop. Given this scenario, the present dissertation aimed to investigate the application and effectiveness of different bioinputs as management strategies for D. maidis. In this study, we evaluated the effects of silicon (Si) and humic substances (HS), applied individually or in combination, on plant growth, colonization, and establishment of D. maidis through behavioral and biological analyses, as well as the assessment of plant defense mechanisms under controlled conditions. The biostimulants did not influence shoot growth, although HS alone promoted root development—an effect that was suppressed when combined with Si. Treatments with Si and Si+HS reduced host plant acceptance for oviposition, without negatively affecting the insect’s biological parameters. Notably, the Si+HS treatment accelerated the development of the first nymphal instar of the leafhopper on maize plants. Although Si treatment slightly enhanced maize resistance to the pest, this effect was not associated with increased levels of total phenolic compounds. Si, whether applied alone or in combination with HS, exhibited a protective effect against pest-induced oxidative stress by reducing the activities of superoxide dismutase (SOD) and catalase (CAT). We also evaluated the effects of the volatile organic compounds (VOCs) myrcene, linalool, methyl salicylate (MeSA), and methyl jasmonate (MeJA) on oviposition preference of D. maidis. In choice bioassays, myrcene at 20 ng μL⁻¹ significantly reduced oviposition, while MeSA at 2 ng μL⁻¹, myrcene at 200 ng μL⁻¹, and linalool at 200 ng μL⁻¹ increased the number of eggs laid. MeJA, however, did not influence oviposition behavior at any of the tested concentrations. These results demonstrate dose-dependent behavioral responses of the pest to specific VOCs, with myrcene acting as a repellent at moderate doses, while MeSA, high-dose myrcene, and linalool acted as attractants to D. maidis. Altogether, the findings highlight the potential of biostimulants and VOCs as promising tools for the integrated management of the corn leafhopper, offering sustainable alternatives capable of modulating the oviposition behavior of D. maidis. Key words: Silicon; Humic Substances; semiochemicals; corn leafhopper; plant defenses; olfactory responses.
O papel da gestão escolar na construção de indicadores de uma escolha acolhedora
(Universidade Federal de Lavras, 2026-02-12) LUCIANO, Moisés Pascoal; CABRAL, Giovanna Rodrigues; COSTA e SILVA, Bethânia Bittencourt; SOUSA, Lenise Teixeira de
In a social context marked by accelerated transformations in forms of coexistence and by the weakening of interpersonal bonds, school welcoming emerges as a structuring dimension of the educational experience. More than a punctual action, welcoming constitutes an ethical and relational principle capable of promoting meaningful learning, fostering students’ well-being, and sustaining formative processes guided by humanization and equity. Within this perspective, this research understands the indicators of a welcoming school not as quantitative metrics or classificatory instruments, but as references constructed from democratic management practices, capable of guiding institutional pathways toward consolidating a culture of listening, belonging, and responsibility for the other. Investigating the role of school management in constructing such indicators proves fundamental for strengthening the institutional climate, enhancing school relationships, and reaffirming the public school’s commitment to the integral formation of individuals. In this direction, this dissertation sought to understand how students from the public school system of the State of Minas Gerais perceive the role of school management in building welcoming indicators, considering student perception as a legitimate source of evaluation capable of guiding decision-making processes. Effective school management is essential to re-signify the educational environment as a welcoming space, positively impacting all subjects involved. Its relevance is supported by the Brazilian Federal Constitution, the National Education Guidelines and Framework Law (LDB), and the National Education Plan (PNE), which establish democratic management as a vital element for the democratization of education. The specific objectives included: a literature review aimed at identifying studies, concepts, and practices related to welcoming, democratic management, and ethical approaches to educational relationships, grounded in frameworks that conceive education as a dialogical encounter and a space of mutual responsibility; and the analysis of students’ perceptions regarding welcoming, considering institutional routines, communication, participation, conflict mediation, and the promotion of emotional well-being. As an educational product derived from the research, the e-book Embracing Lives – Stories and Strategies for School Welcoming was developed, composed of pedagogical narratives representing different student realities and focused on strategies that promote inclusion, belonging, and the valuing of diversity within the school environment. The methodology was grounded in humanistic and ethical perspectives that sustain the centrality of relationships in education, articulating dialogue, autonomy, otherness, and care as structuring principles of educational practices. Martin Buber’s philosophy of the “I–Thou” relationship and Paulo Freire’s pedagogy of autonomy constitute essential references for understanding welcoming as a dialogical and humanizing practice in the school context. To these contributions is added Emmanuel Lévinas’ philosophy of alterity and ethics of responsibility, centered on unconditional responsibility for the other and on the recognition of irreducible singularity. Taken together, these perspectives reinforce that educational relationships are not limited to the transmission of content but constitute ethical encounters in which each subject is called to recognize, welcome, and respond to the presence of the other. Thus, public schools must assume the commitment to promote quality education that is equitable and sensitive to differences, creating conditions for each student to be valued in their singularity and prepared for the full exercise of citizenship and work, in accordance with principles of social justice and ethical responsibility. Keywords: school welcoming; educational indicators; school management; democratic management of education; alterity; autonomy; ethics.
Trabalho institucional de constituição de mercados: perspectivas de agentes influentes no estado de Minas Gerais sobre o segmento de cerveja artesanal.
(Universidade Federal de Lavras, 2025-10-30) Cougo, Juliano Silva; Brito, Mozar José de; Tonelli, Dany Flavio; Pinheiro, Daniel Calbino; Baeta, Odemir Vieira Baeta; Morais, Cesar Augusto Tureta De; Cezar, Layon Carlos
Beer is an ancient beverage that has traversed human history, establishing rituals, beliefs, symbolisms, crafts, organizations, and markets. In Brazil, records indicate its production since the mid-seventeenth century, although its market consolidation occurred from the 1830s onward. Initially, this market exhibited heterogeneous configurations, with a predominance of small producers adopting distinct production techniques and commercial strategies. With the advent of new production technologies from the twentieth century onward, the beer market was reconfigured through the expansion of large-capital firms. These companies acquired smaller breweries, expanded their operational reach, and standardized processes and products, leading to the domination of the sector by large conglomerates. However, by the late 1990s, agents interested in producing, consuming, and commercializing beer through recipes, production processes, and business models that challenged the hegemony of the established market began to emerge in the country. This movement resulted in the formation of the so-called “craft” segment, constituting a fraction of the sector characterized by its own activities, practices, and discourses. Within this context, this study sought to investigate the institutional work involved in the market constitution of the craft beer segment, focusing on the actions of influential agents in the state of Minas Gerais. The qualitative research takes this state as its locus of analysis due to its significant role in structuring the segment, despite the fact that little has been documented regarding the relevance of Minas Gerais in this field. Epistemologically constructionist, the research is grounded in Institutional Theory and, more specifically, in the Institutional Work perspective, with the aim of describing the processes of institutional creation, maintenance, and disruption that have formed and/or sustained the segment. Additionally, the study is anchored in the assumptions of the Sociology of Markets, also from an institutional perspective. Data were collected through nonparticipant observation in productive organizations and events, documentary research, and semistructured interviews with 51 agents located in or influential within the beer network of the state. Thematic Content Analysis was employed as the methodological tool. The results describe the historical-institutional construction of the segment in Minas Gerais. Subsequently, the main institutional works directed toward the constitution and continuity of the segment are presented, characterizing the practices and discourses embedded in the cognitive-cultural, normative, and regulatory dimensions of the institutions operating in the market. Finally, the effects of these activities are reported, such as new institutional works aimed at expanding the craft beer field in Brazil. The main contributions of the research lie in documenting the brewing history of Minas Gerais based on its institutions, presenting market constitution practices that can be replicated in other sectors, and offering an innovative analytical approach by applying Institutional Work theory to market constitution, thereby providing support for new analytical possibilities. Keywords: craft beer; institutional work; market formation.
Estudo da viabilidade de complexação de piperidinas densamente funcionalizadas e xanteno com ciclodextrina
(Universidade Federal de Lavras, 2026-02-09) Pires, Adriene Simões; Pinto, Luciana de Matos Alves; Thomasi, Sérgio Scherrer; Ribeiro, Lígia Nunes de Morais; Bellete, Bárbara Sayuri
The multicomponent synthesis process is a highly efficient methodology for constructing molecules with varied structures and diverse biological applications. It also adheres to the principles of green chemistry, as it reduces waste generation since the reaction is performed in a single step. The greatest chemical inspiration for the design of bioactive molecules comes from nature; piperidine and xanthene scaffolds are chemical structures inspired by plant secondary metabolites. These chemical structures exhibit a wide spectrum of biological activities, including anticancer, antiviral, antifungal, antidiabetic, and insecticidal properties, among others. In a distinct field, cyclodextrins stand out. These are cyclic oligosaccharides formed by glucose monomers linked by α-1,4 glycosidic bonds. The formation of inclusion complexes occurs through the encapsulation of apolar molecules (like hydrophobic bioactive) within the structural apolar cavity, establishing weak intermolecular interactions as London forces. The polar and hydrophilic CD exterior allows the interaction of molcules with the aqueous medium. This enables the solubilization of previously insoluble bioactives, such as functionalized piperidines and xanthenes. Furthermore, complexation offers chemical protection to the bioactive against external factors like pH and temperature, ensuring the structural integrity of the compound. The objective of this work was to study the feasibility of forming inclusion complexes between β-cyclodextrin and two different organic molecules classes: piperidines and xanthenes. Combining these strategies, it was observed that the complex formation with xanthenes was satisfactory, promoting the integrity of the molecule with an established ideal stoichiometry of 1:1 effectively. However, satisfactory results were not observed for the piperidines. Two hypotheses were raised: either the molecule's low intrinsic solubility interferes with the chemical equilibrium between the complexed and free forms, hindering the visualization of the solubilization effects provided by the cyclodextrin, or the β-cyclodextrin's small cavity may not properly accommodate the molecule, opening ways for new explorations. Thus, the formation of inclusion complexes is seen as a viable approach for the future application of these organic molecules, enabling the development of more efficient therapeutic systems with improved pharmaceutical performance and broader applicability of these structures. Keywords: inclusion complexes; densely functionalized piperidines; xanthenes; multicomponent synthesis; bioactives; cyclodextrin.
Diagnóstico do potencial fisiológico de sementes de canola por descritores e aprendizado de máquina
(Universidade Federal de Lavras, 2026-02-16) Silva, Daniel Lima da; Pires, Raquel Maria de Oliveira; Nery, Marcela Carlota; Pires, Raquel Maria de Oliveira; Oliveira, Gustavo Roberto Fonseca de; Pereira, Márcio Dias
The physiological quality of seeds is essential for the initial establishment of crops, especially in expanding species such as canola (Brassica napus L.). The species is strategic for the global energy transition, as a raw material for biofuel production, in addition to industrial and food uses. Traditional tests to evaluate seed quality, although well established, have limitations related to their destructive nature, subjectivity, and the time required to obtain results. In this context, multispectral image analysis is an alternative, as it enables rapid and non-destructive evaluations. Therefore, the objective of this study was to investigate the efficiency of multispectral image analysis, associated with machine learning algorithms, in assessing the physiological quality of canola seeds. Six batches of seeds from two cultivars (Nuola and Diamond) were analyzed, characterized by traditional physiological tests. Multispectral images were captured using VideometerLab 4 equipment at 19 wavelengths of reflectance and autofluorescence. The main spectral descriptors were selected using the Gini decrease index. Supervised classification models were adjusted using Random Forest, Neural Networks, and PLS-DA. The results showed that spectral descriptors, especially reflectance at 780 nm and autofluorescence in the 470/500 nm combination, were efficient in discriminating vigor levels, showing an inversely proportional correlation with physiological tests. Therefore, multispectral image analysis associated with machine learning algorithms proved to be efficient for diagnosing the physiological potential of canola seeds, with high potential for application in automated quality control systems. Keywords: Brassica napus L. var. oleifera Moench; vigor; autofluorescence; machine learning.