http://repositorio.ufc.br/handle/riufc/56 2026-06-11T18:23:12Z 2026-06-11T18:23:12Z Araújo, Jackson de Lima http://repositorio.ufc.br/handle/riufc/85671 2026-06-09T12:41:44Z 2025-01-01T00:00:00Z

Título: Eficácia de inseticidas contra Aleurodicus cocois Curtis, 1846 (Hemiptera: Sternorrhyncha: Aleyrodidae) e seletividade a Amblyseius largoensis Muma, 1955 (Mesostigmata: Phytoseiidae) Autor(es): Araújo, Jackson de Lima Abstract: Cashew cultivation, an important sector of Brazilian agriculture, faces phytosanitary challenges that compromise productivity and fruit quality, largely due to the limited availability of registered pesticides and the lack of crop-specific management strategies. Therefore, the development and evaluation of effective alternatives for pest control are essential. Among the main threats is the cashew whitefly, Aleurodicus cocois Curtis, 1846 (Hemiptera: Sternorrhyncha: Aleyrodidae), a sap-sucking insect that colonizes the aerial parts of plants, reduces the photosynthetic area, causes loss of branch vigor and premature leaf drop, ultimately decreasing yield. Among the natural enemies associated with cashew, the predatory mite Amblyseius largoensis Muma, 1955 (Mesostigmata: Phytoseiidae) plays a relevant role in regulating pest populations, contributing to integrated pest management. This study evaluated the efficacy of six neurotoxic insecticides (Abamectin, Acephate, Flupiradifurone, Imidacloprid, Acetamiprid, and Tiametoxam) against A. cocois, considering exposure time, susceptibility by instar, and the determination of lethal concentrations (LC50 and LC90) for the insecticides that showed higher mortality in the initial evaluations. Subsequently, the selectivity of LC90 to the predator A. largoensis was assessed through analyses of survival, prey consumption, oviposition, egg viability, and food conversion efficiency under topical and residual exposure. Bioassays with A. cocois revealed differences among treatments, in which Acephate, Flupiradifurone, and Tiametoxam caused mortality above 80%, whereas Imidacloprid, Acetamiprid, and Abamectin resulted in mortality equal to or lower than 63.5% within the first 24 hours. After 48 hours, all treatments showed increased lethality, and after 72 hours, mortality reached total or near-total levels. Susceptibility was high and uniform across most instars, except for the fourth instar treated with Abamectin, which showed lower mortality and greater variability in response. Concentration-response curves indicated high toxicity of Tiametoxam, Acephate, and Flupiradifurone. Regarding LC90 selectivity to A. largoensis, Acephate was highly toxic under both exposure routes, compromising predator persistence in the agroecosystem. Tiametoxam, although not causing high mortality, altered biological parameters, reducing oviposition, prey consumption, and egg viability. In contrast, Flupiradifurone showed high selectivity, not affecting survival, reproduction, or food conversion efficiency, with reduced egg viability only under residual exposure. These findings indicate compatibility of Flupiradifurone and partial compatibility of Tiametoxam with A. largoensis, demonstrating their potential for use in integrated pest management programs in cashew cultivation. Tipo: Tese

2025-01-01T00:00:00Z Nunes, Liliane Ribeiro http://repositorio.ufc.br/handle/riufc/85333 2026-03-13T21:36:52Z 2024-01-01T00:00:00Z

Título: Práticas agronômicas aplicadas a cultura do hibisco: estratégias de manejo em função do potencial produtivo Autor(es): Nunes, Liliane Ribeiro Abstract: Hibiscus sabdariffa cultivation presents advantages ranging from production to consumption, however, in view of scarce research, the phytotechnical aspects of the crop are still poorly understood, which often makes greater investments in its production unfeasible. Considering the influence of good agronomic practices on optimizing crop productivity, this study aimed to: 1- Establish the ideal spacing for hibiscus cultivation based on growth and productivity results; 2- Determine whether the different doses of biofertilizer used and the practice of apical pruning affect the biometric and physiological aspects of the plant H. sabdariffa, as well as verify whether these factors may directly influence crop productivity. The treatments of six distinct spacings were applied for the evaluation of variables and determination of productivity. The spacing was chosen according to general evaluations of the results and adapted to the crop. Thus, five different doses of foliar fertilization were applied in the second test, and the practice of topping was carried out in half of the experiment to evaluate new results and determine best practices. The studies revealed that hibiscus undergoes changes when different spacings are applied in its cultivation. In view of the significant height results when the plant was grown at wider spacings. In addition, wider spacings also contributed to a gradual increase in the number of structures at stage 1 (closed green flower bud structure), stage 2 (closed reddish flower bud structure), number of flowers and fruits. As well as calyx and capsule structures, which were also positively influenced under these same conditions. For productivity, expressive numbers were observed at reduced spacings, though not significant. The continuation of the study showed that the number of branches was significantly affected by fertilization levels, without the topping technique. Significant responses were observed for stage 1, dry mass of calyces and capsules. The 0,5 g/L fertilizer dose was the most responsive when associated with the topping technique. For productivity, no significant differences were observed. Tipo: Tese

2024-01-01T00:00:00Z Araújo, Karolina Rafrana da Silva de http://repositorio.ufc.br/handle/riufc/84308 2026-01-16T18:49:34Z 2025-01-01T00:00:00Z

Título: Impactos na fisiologia das plantas, bioecologia e resistência de pentatomideos à inseticidas e seletividade a Telenomus podisi (Ashmead, 1893) (Hymenoptera: Scelionidae) Autor(es): Araújo, Karolina Rafrana da Silva de Abstract: Euschistus heros (Fabricius, 1794) is an economically important insect pest in soybean Glycine max L. and Diceraeus melacanthus (Dallas, 1851) (Hemiptera: Pentatomidae) for corn Zea mays L., with little incidence in soybean crops. Therefore, it is necessary to evaluate the adaptation in the biology and behavior of these species in these crops to estimate the damage and enable control alternatives, avoiding negative interference with natural enemies. Given this, the objectives were: To study the biology of D. melacanthus in soybean, corn, and artificial diet; to evaluate the efficiency of insecticides on E. heros; to determine the effects of the products on Telenomus podisi (Ashmead, 1893) (Hymenoptera: Scelionidae); and to evaluate photosynthetic parameters in soybean (R4) under attack by D. melacanthus. The experiments were conducted under controlled conditions at the Applied Entomology Laboratory (LEA-UFGD) - Dourados-MS. Biological parameters of D. melacanthus were determined on soybean, corn (V3-V4), and artificial diet, evaluating survival, longevity, and fecundity. The efficiency of five insecticidal molecules used on soybean and corn was also evaluated: Thiamethoxam + Lambda- Cyhalothrin; Bifenthrin + Carbosulfan; Acephate + Bifenthrin; Acetamiprid + Bifenthrin; and Etiprole, in dose-response and survival curve assays on E. heros, as well as the effect of these molecules on parasitism and emergence of T. podisi in pre-parasitism assays. Furthermore, the effect of D. melacanthus attack on different soybean cultivars at the reproductive stage (R4) was evaluated, focusing on photosynthesis, transpiration rate, stomatal conductance, Soil Plant Analysis Development (SPAD) index, and chlorophyll content. Survival analysis of the female green-bellied beetles showed significant differences between treatments, with the artificial diet and the Bt soybean and conventional corn treatments resulting in the highest probability of survival over time. Regarding insecticidal molecules, Acephate + Bifenthrin caused the greatest negative effect on T. podisi, while Etiprole had the least effect. As a result, it was observed that D. melacanthus attack on soybeans significantly reduced the photosynthetic rate, SPAD index, and chlorophyll content, and increased the transpiration rate and stomatal conductance. Tipo: Tese

2025-01-01T00:00:00Z Nazareno, Lailla Sabrina Queiroz http://repositorio.ufc.br/handle/riufc/83546 2025-11-26T17:32:59Z 2023-01-01T00:00:00Z

Título: Selênio na micropropagação de cultivares de batata-doce Autor(es): Nazareno, Lailla Sabrina Queiroz Abstract: Sweet potato (Ipomoea batatas L.) is a crop of major socioeconomic importance, commonly propagated vegetatively. Micropropagation enables the production of disease-free plantlets and the application of nutritional enhancement protocols, such as selenium (Se) biofortification, an essential mineral for human health. Selenium deficiency is associated with immunodeficiency, hypothyroidism, reduced fertility, cardiovascular disorders and some types of cancer. Biofortification strategies have shown positive results in crops such as rice, wheat and beans, but knowledge gaps remain regarding their effects on sweet potato during in vitro culture. This study aimed to evaluate biometric traits, photosynthetic pigments, DNA content, survival rate and Se accumulation in sweet potato cultivars micropropagated under diferente Se sources and concentrations. Three independent experiments were conducted in a completely randomized design using the cultivars Campina, Italiana-branca and Brazlândia- branca supplemented with sodium selenite or sodium selenate (0, 5, 10, 15, 20 and 25 μmol L−1). In Chapter 1, cv. Campina showed greater shoot length, number of green leaves and fresh biomass at 5 μmol L−1 of selenite, whereas leaf senescence increased at 25 μmol L−1. Selenium accumulation increased proportionally with concentration, and moderate doses preserved epidermal integrity. In Chapter 2, cv. Campina exhibited the best biometric responses between 0–5 μmol L−1, while Italiana-branca responded positively up to 10 μmol L−1. Campina accumulated higher Se levels in shoots and roots, indicating greater absorption and distribution capacity. In Chapter 3, cv. Brazlândia-branca showed enhanced growth and photosynthetic pigment content between 10–15 μmol L−1 of selenate, whereas selenite promoted Se accumulation mainly in roots. Nuclear DNA quantification by flow cytometry confirmed that none of the Se sources or concentrations compromised genomic stability, and ex vitro survival was high. Selenium supplementation during micropropagation proved effective in improving early plantlet performance and promoting controlled Se accumulation, varying according to cultivar, source and concentration. Low to moderate Se doses (5–10 μmol L−1) favored growth, and the differential accumulation patterns highlight the potential of sweet potato for future biofortification strategies. Tipo: Tese

2023-01-01T00:00:00Z