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- DissertaçãoAcesso aberto (Open Access)Capacidade de tamponamento de fósforo em solos do Estado do Paraná(Universidade Estadual do Norte do Paraná, 2026) Inoue, Marcos Yassuhiro; Kölln, Oriel Tiago; https://orcid.org/0000-0002-8507-9808; http://lattes.cnpq.br/8041626078120100; Kölln, Oriel Tiago; https://orcid.org/0000-0002-8507-9808; http://lattes.cnpq.br/8041626078120100; Tiecher, Tales; https://orcid.org/0000-0001-5612-2849; http://lattes.cnpq.br/7665378790484936; Silva, Francisco Carlos Mainardes da; https://orcid.org/0009-0004-8008-620X; http://lattes.cnpq.br/9683269855531828; Müller, Marcelo Marques Lopes; https://orcid.org/0000-0002-5466-2398; http://lattes.cnpq.br/3504404305495448; Rodrigues, Diego Resende; https://orcid.org/0000-0002-9495-8943; http://lattes.cnpq.br/9381400899886153Phosphorus (P) partial saturation of sorption sites through corrective phosphate fertilization represents a key strategy for improving nutrient use efficiency in tropical and subtropical soils. The State of Paraná does not yet have a formalized and explicit method for recommending corrective fertilization. In this context, the objective of this study was to quantify the phosphorus buffering capacity (PBC) of soils from Paraná, adopting it as a baseline parameter for the recommendation of corrective P rates, as well as to develop predictive models based on clay content and/or remaining phosphorus (Prem). The experiment was conducted at the Soil Laboratory of the State University of Northern Paraná (UENP/CLM). Twenty-six soil samples were collected across the State of Paraná at a depth of 0–20 cm. When necessary, pH correction was performed through incubation with hydrated lime, targeting a pH of 5.5 in CaCl₂. The samples were characterized and incubated for 20 days with 12 different P rates, determined based on the maximum phosphorus adsorption capacity (MPAC), in three replicates. Triple superphosphate was used as the phosphorus source. At the end of the incubation period, soil P contents were determined by Mehlich-1 extraction and quantified using the colorimetric method. Mathematical models were fitted using segmented regression. Phosphorus buffering capacity (PBC) was then determined as the inverse of the slope coefficients of the fitted linear segments. The amounts required to increase soil P concentration by 1 mg dm⁻³ ranged from 2.557 to 58.824 kg P ha⁻¹. Exploratory data analysis enabled the grouping of estimated PBC values into classes according to clay content, organized into a practical interpretation and recommendation table. Mean values ranged from 3.94 kg P ha⁻¹ in soils with less than 250 g kg⁻¹ of clay to 25.89 kg P ha⁻¹ in soils with more than 400 g kg⁻¹ of clay. Considering soils with initial P availability classified as "very low," the required doses to reach sufficiency levels ranged approximately from 135 to 450 kg P₂O₅ ha⁻¹, depending on clay content, indicating that current recommendations may underestimate P requirements in highly clayey soils. Additionally, predictive models were developed using clay content and Prem as single predictors, as well as a multiple regression model incorporating both variables. The inclusion of Prem improved the explanatory power of the model. PBC increased significantly with increasing clay content. The PBC estimation table proved consistent for practical recommendation purposes, although the predictive models showed greater sensitivity in soils with clay contents between 400 and 550 g kg⁻¹. For the State of Paraná, where no formally established method for corrective phosphate fertilization currently exists, phosphorus buffering capacity (PBC) shows potential as a technical tool to support the definition of corrective P application rates.
- DissertaçãoAcesso aberto (Open Access)Mudança de pH em caldas à base de glyphosate no controle de plantas daninhas(Universidade Estadual do Norte do Paraná, 2026) Ferreira, Emilene Aparecida dos Santos; Rodrigues, Diego Resende; https://orcid.org/0000-0002-9495-8943; http://lattes.cnpq.br/9381400899886153; Rodrigues, Diego Resende; https://orcid.org/0000-0002-9495-8943; http://lattes.cnpq.br/9381400899886153; Ferreira, Silvio Douglas; https://orcid.org/0000-0002-8989-4498; http://lattes.cnpq.br/0270087159948589; Gandolfo, Marco Antonio; https://orcid.org/0000-0003-2314-3752; http://lattes.cnpq.br/5560552732033631; Precipito, Lais Maria Bonadio; http://lattes.cnpq.br/5942464936055299Herbicide use has become essential in agricultural management, with glyphosate standing out as one of the most widely used active ingredients for the effective control of several weed species. Its mode of action is based on the inhibition of essential amino acid synthesis, thereby preventing plant growth. A key factor determining the efficacy of this herbicide is the pH of the spray solution. The level of acidity or alkalinity may affect both the stability of the active ingredient and its absorption by plants. Specifically, under acidic pH conditions, glyphosate molecules tend to remain in their non-dissociated form, which facilitates cuticular penetration. Therefore, the objective of this study was to evaluate the influence of pH variation on the efficacy of different commercial glyphosate formulations. For this purpose, seven formulations were tested at three pH levels: the original pH of each product, pH 3.0, and pH 9.0. Analyses of the physicochemical properties of the solutions were performed to better understand the behavior of the formulations under different conditions. Applications were carried out on Raphanus raphanistrum (wild radish), followed by visual assessments of control percentage. The Crucial® spray solution at pH 3.0 showed the best performance, achieving approximately 95% control at 28 days after application, demonstrating that herbicide efficacy depends on the interaction between formulation type, salt constituent, and spray solution pH.
- DissertaçãoAcesso aberto (Open Access)Atividade larvicida e caracterização fitoquímica do extrato hidroetanólico de Ruta graveolens L. contra Aedes aegypti(Universidade Estadual do Norte do Paraná, 2026) Costa, Poliana Caruline Rosa da; Peixoto, Erika Cosendey de Mello; https://orcid.org/0000-0002-9608-4282; http://lattes.cnpq.br/0963818563395019; Rodrigues, Diego Resende; https://orcid.org/0000-0002-9495-8943; http://lattes.cnpq.br/9381400899886153; Rodrigues, Diego Resende; https://orcid.org/0000-0002-9495-8943; http://lattes.cnpq.br/9381400899886153; Bovolenta, Yves Rafael; https://orcid.org/0000-0001-9684-1848; http://lattes.cnpq.br/4601902582773437; Silva, José Renato da; https://orcid.org/0000-0002-8289-7768; http://lattes.cnpq.br/8034221689854743The increase in diseases transmitted by mosquito vectors and the resistance associated with the continuous use of synthetic insecticides highlight the need for effective and environmentally safe alternatives. Therefore, this study aimed to evaluate the larvicidal activity of the hydroethanolic extract of Ruta graveolens L. against Aedes aegypti larvae, as well as to chemically characterize the extract. The extract was obtained by maceration in a 70% hydroethanolic solution, followed by concentration and lyophilization. A. aegypti eggs were collected using ovitraps in the municipality of Bandeirantes, Paraná, Brazil, and the larvae were reared to the L3 and L4 stages. Larvicidal bioassays were performed in quadruplicate, with 40 larvae per treatment, using concentrations of 0.25, 0.5, and 1 mg/mL, along with positive and negative controls. After 48 hours of exposure, mortality rates of 65% were observed at concentrations of 0.25 and 0.5 mg/mL, whereas the concentration of 1 mg/mL resulted in 100% mortality, a result equivalent to the commercial larvicide used as positive control. Phytochemical analysis revealed high levels of total phenolics (58.76 ± 1.70 mg GAE/g) and total flavonoids (41.55 ± 1.30 mg QE/g). LC-MS/MS analysis confirmed the presence of rutin in the extract, while quercetin was not detected. These results demonstrate the strong larvicidal potential of the hydroethanolic extract of R. graveolens, particularly at the concentration of 1 mg/mL, indicating its viability as an alternative for A. aegypti control and supporting further studies to determine lethal doses and assess toxicological safety.
- DissertaçãoAcesso aberto (Open Access)Suplementação hídrica de vitaminas do complexo B, vitamina C, potássio e zinco: impactos no desempenho e na qualidade da água de alevinos de Oreochromis niloticus(Universidade Estadual do Norte do Paraná, 2026) Carezia, Júlia Navarro Fini; Silva, Marcos Augusto Alves da; https://orcid.org/0000-0002-5570-8677; http://lattes.cnpq.br/4973981237909142; Silva, Marcos Augusto Alves da; https://orcid.org/0000-0002-5570-8677; http://lattes.cnpq.br/4973981237909142; Porto, Petrônio Pinheiro; https://orcid.org/0000-0002-2999-7612; http://lattes.cnpq.br/1751366795715746; Souza, João Ricardo Malheiros de; https://orcid.org/0000-0002-3211-8148; http://lattes.cnpq.br/3868528104536319; Salvador, Rogério; http://lattes.cnpq.br/8305553541747517; Souza, Felipe Pinheiro de; https://orcid.org/0000-0003-3436-4147; http://lattes.cnpq.br/1642955376796651Brazilian agribusiness plays a fundamental role in the country’s economy, including aquaculture, which has shown significant growth, especially in the production of tilapia (Oreochromis niloticus). This species stands out due to its high adaptability and rapid production cycle, with the state of Paraná accounting for approximately 36% of national production. Among the main factors influencing productivity are water quality management and the improvement of zootechnical indices. In this context, the present study aimed to evaluate the use of a formulated product based on vitamins and minerals, applied directly to the culture water, on the productive performance of fingerlings, with the goal of improving weight gain and growth without compromising water quality. The experiment was conducted in a completely randomized design, with three treatments (control, product application once a week, and twice a week), three replicates, and 57 experimental units per treatment. Nine aquaria with a capacity of 113 L were used, each containing 19 fish. Throughout the experimental period, water quality parameters (dissolved oxygen, temperature, pH, ammonia, nitrite, and hardness) were monitored and remained within appropriate ranges, with no differences observed among treatments. Regarding zootechnical performance, a substantial increase in biomass was observed in all treatments. The initial mean weight ranged from 7.80 to 7.89 g, while final values were 33.57 g, 36.28 g, and 35.77 g for the control, weekly application, and twice-weekly application treatments, respectively. The mean weight gain was 26.29 ± 12.27 g, 28.95 ± 15.18 g, and 28.48 ± 12.37 g, with no statistically significant differences (p > 0.05), although supplemented treatments showed a trend toward higher gain. Length growth was also continuous, with initial values ranging from 7.32 to 7.53 cm and final values from 11.69 to 12.24 cm, resulting in mean increases of 4.60 ± 1.65 cm, 4.89 ± 1.91 cm, and 4.74 ± 1.57 cm, respectively, also without significant differences. Despite the absence of statistically significant effects, the results indicate a trend toward improvement in zootechnical indices with supplementation. However, longer experimental periods and possible adjustments to the experimental design are necessary to confirm its effects on productive performance.
- DissertaçãoAcesso aberto (Open Access)Parâmetros biológicos de Spodoptera cosmioides (Walker, 1858) (Lepidoptera: Noctuidae) e potencial de nematoides entomopatogênicos para manejo na soja(Universidade Estadual do Norte do Paraná, 2026) Tominaga, Bruna Kanno; Alves , Viviane Sandra; https://orcid.org/0000-0003-2381-8115; http://lattes.cnpq.br/3794580975938452; Alves, Viviane Sandra; https://orcid.org/0000-0003-2381-8115; http://lattes.cnpq.br/3794580975938452; Silva, Marco Aurélio Tramontin da; https://orcid.org/0000-0002-1019-1926; http://lattes.cnpq.br/8341476195396585; Rodrigues, Diego Resende; orcid.org/0000-0002-9495-8943; http://lattes.cnpq.br/9381400899886153Spodoptera cosmioides (Walker, 1858) (Lepidoptera: Noctuidae) is a pest of great economic importance that affects several crops, making the adoption of control measures essential once it is detected in the field. Knowledge of its life cycle, colony optimization, and the identification of efficient natural enemies are fundamental steps for the development of management programs. Thus, this study aimed to investigate the biology of S. cosmioides under different diets and to improve evaluations of the use of entomopathogenic nematodes (EPNs) in its management under laboratory and greenhouse conditions. Experiments were conducted to evaluate the biology of S. cosmioides fed on an artificial diet and soybean leaves. In addition, the survival of S. cosmioides after EPN inoculation in pupae, the foliar consumption of larvae over time after EPN inoculation, and the survival of EPNs applied to the aerial parts of soybean plants under greenhouse conditions were assessed. Differences in the life cycle duration of S. cosmioides were observed depending on the diet, both in early instars and in the pupal and adult stages. The artificial diet resulted in a shorter life cycle and higher female fecundity. In the nematode assays, EPN inoculation reduced foliar consumption of S. cosmioides by more than 65% after 24 hours. After foliar application on soybean plants in greenhouse conditions, both isolates showed 100% infectivity, causing mortality in Galleria mellonella. However, there was a rapid decline in efficacy over time, with reduced mortality after 12 hours and no effect after 36 hours, indicating loss of viability of infective juveniles (IJs). In the soil, however, survival was higher, with an average infectivity of 54.7% and stability of the UEL08 isolate over 72 hours. The effectiveness against pupae was low (0–4%), with no differences among treatments. It is concluded that the Greene diet is a viable alternative for maintaining S. cosmioides colonies, and that EPNs have potential for use in its control, as they significantly reduced foliar consumption of infected larvae. On the other hand, foliar application without adjuvants is not viable, since a rapid loss of IJ viability and infectivity was observed, indicating the need for further studies to develop strategies to enhance IJ survival over longer periods.