https://repositorio.ifgoiano.edu.br/handle/prefix/149 2026-06-10T08:54:02Z https://repositorio.ifgoiano.edu.br/handle/prefix/6624 Título: SENSIBILIDADE DE ISOLADOS DE Fusarium spp. CAUSADORES DA SÍNDROME DA MORTE SÚBITA DA SOJA À MISTURA FLUXAPIROXADE + PIRACLOSTROBINA Autor(es): Lima, Milton Luiz da Paz Primeiro Orientador: Gonçalves, Debora Janine Silva Abstract: Soybean sudden death syndrome, caused by Fusarium species, represents one of the major phytosanitary challenges affecting the crop. This study aimed to characterize Fusarium spp. isolates regarding their sensitivity to the fluxapyroxad + pyraclostrobin mixture by evaluating mycelial growth, area under the mycelial growth progress curve (AUMGPC), mycelial growth rate (MGR), and EC50. A total of 44 isolates collected from Goiás State, Brazil, were analyzed. The results revealed high phenotypic variability, with a predominance of sensitive isolates, along with the presence of moderately sensitive and insensitive subpopulations, indicating an early shift in sensitivity. AUMGPC was the most representative parameter of overall isolate behavior. Although the fungicide mixture still shows good average efficacy, continuous monitoring and the adoption of integrated management strategies are recommended to preserve its effectiveness over time. Editor: Instituto Federal Goiano Tipo: Dissertação 2026-04-01T00:00:00Z https://repositorio.ifgoiano.edu.br/handle/prefix/6615 Título: RESISTÊNCIA MÚLTIPLA DE Amaranthus Spp. A INIBIDORES DE EPSPS E ALS EM POPULAÇÕES COLETADAS EM REGIÕES DO ESTADO DE GOIÁS Autor(es): Silva, Samuel Afonso Sampaio Primeiro Orientador: Cunha, Paulo César Ribeiro Abstract: The increasing occurrence of herbicide-resistant weed populations has become one of the main challenges for agricultural production. In this context, species of the genus Amaranthus stand out due to their high adaptive capacity and the occurrence of biotypes resistant to different mechanisms of action. This study aimed to evaluate the sensitivity of Amaranthus spp. populations to glyphosate (EPSPS inhibitor) and chlorimuron (ALS inhibitor) using dose–response curve methodology. The experiments were conducted under greenhouse conditions, using nine populations collected from agricultural areas in the municipalities of Cristalina and Orizona, Goiás State, Brazil. Increasing herbicide doses were applied, and visual control (%) was assessed at 28 days after application, while relative dry mass (%) was used as a complementary variable. Data were fitted to a four parameter log-logistic model (LL.4), and the doses required to achieve 50% (ED₅₀) and 80% (ED₈₀) control were estimated. For the dry mass variable, growth reduction parameters were interpreted only for populations with satisfactory model fit, while for the others, a descriptive approach based on minimum and maximum observed values was adopted. The results revealed significant differences in sensitivity among the populations. For glyphosate, most populations showed resistance, particularly POP2, POP3, POP4, and POP5, whereas POP7 and POP9 were characterized as susceptible. For chlorimuron, resistance was even more pronounced, especially in POP8, POP1, and POP5, while POP7 showed higher susceptibility. The integrated analysis of ED₅₀, ED₈₀, and resistance factors (RF) confirmed the occurrence of resistant populations. These findings indicate the presence of multiple resistance to EPSPS and ALS inhibitors in Amaranthus spp. populations in Goiás State, Brazil, highlighting the need for integrated weed management strategies to mitigate resistance evolution. Editor: Instituto Federal Goiano Tipo: Dissertação 2026-04-27T00:00:00Z https://repositorio.ifgoiano.edu.br/handle/prefix/6541 Título: EFICÁCIA DO HERBICIDA CLETHODIM NO CONTROLE DO CAPIM-AMARGOSO (Digitaria insularis) Autor(es): Alvim, Jéssica da Fonseca Primeiro Orientador: Cunha, Paulo César Ribeiro da Primeiro Membro da Banca: Cunha, Paulo César Ribeiro da Segundo Membro da Banca: Araújo, Lucas da Silva Terceiro Membro da Banca: Freitas, Marco Antonio Moreira de Abstract: Sourgrass (Digitaria insularis) is one of the weed species with the greatest agronomic impact in Brazil, mainly due to its capacity for perennialization, vigorous regrowth, and accumulation of reserves in rhizomes, characteristics that make chemical control difficult. Among the available herbicides, clethodim, an ACCase inhibitor, is widely used for the management of this species; however, its efficacy may be reduced by environmental, operational, and chemical factors that interfere with herbicide absorption, translocation, and stability. Therefore, the objective of this study was to evaluate the main factors that compromise clethodim performance in the desiccation of mature D. insularis plants during the soybean pre-sowing period. Four experiments were conducted at the Staphyt experimental station in Formosa, Goiás, Brazil, evaluating: (i) application timing; (ii) the effect of spray solution storage time of clethodim, applied alone or in mixture with auxinic herbicides; (iii) the interaction between clethodim and auxinic herbicides combined with the effect of mechanical mowing performed after application; and (iv) the comparative performance of commercial formulations subjected to mowing at different intervals after application. Weed control was visually assessed at 7, 14, 21, 28, and 35 days after application, and data were analyzed using linear mixed models in R software. Application timing significantly influenced clethodim performance. Applications performed at 4:00 p.m. resulted in greater control efficiency, whereas applications at 4:00 a.m. resulted in lower efficacy, highlighting the negative effect of environmental conditions such as lower temperatures, dew presence, and variations in relative humidity. Spray solution storage for up to 72 hours showed variable effects among products, but clethodim and halauxifen-methyl demonstrated greater stability, whereas triclopyr-butotyl and 2,4-D showed a gradual reduction in control. The association of clethodim with auxinic herbicides resulted in antagonism, particularly when followed by immediate mowing, which reduced herbicide absorption due to rapid removal of foliar tissue. Intervals of 2 to 4 hours between application and mowing mitigated this effect, allowing greater translocation and improved control. Among the formulations evaluated, 2,4-D and triclopyr-butotyl showed lower performance, whereas halauxifen-methyl stood out for its higher efficiency when mixed with clethodim. Among the commercial clethodim formulations, Grasidim and Cletodim CCAB 240 EC® showed superior performance when associated with delayed mowing. It is concluded that clethodim efficacy is influenced by application timing, being reduced when applied under less favorable environmental conditions, by antagonistic interactions with auxinic herbicides, by prolonged spray solution storage when associated with certain auxins, and by differences in performance among the evaluated formulations. Optimizing these factors is essential to maximize control of perennial sourgrass during pre-sowing desiccation. Editor: Instituto Federal Goiano Tipo: Dissertação 2023-03-20T00:00:00Z https://repositorio.ifgoiano.edu.br/handle/prefix/6506 Título: EFICÁCIA DE ATRAZINA EM COMPARAÇÃO COM TERBUTILAZINA NO CONTROLE DE PLANTAS DANINHAS NA CULTURA DO MILHO (Zea mays L.) Autor(es): Paslauski, Gilberto Primeiro Orientador: Freitas, Marco Antonio Moreira de Primeiro Membro da Banca: Freitas, Marco Antonio Moreira de Segundo Membro da Banca: Santos, Leonardo de Castro Terceiro Membro da Banca: Zuchi, Jacson Abstract: This study evaluated, under field conditions, the comparative efficacy of the herbicides atrazine and terbuthylazine in weed management in maize (Zea mays L.), as well as the performance of mesotrione applied alone or in mixture with atrazine, considering pre- and post-emergence placements. The guiding research question was: which products and doses ensure efficient control between 7 and 28 days after application (DAA), with agronomic safety and environmental coherence? The experiment was conducted in a randomised complete block design with 14 treatments (untreated control; five doses of atrazine; six doses of terbuthylazine; mesotrione alone; mesotrione + atrazine), with visual control assessments (0–100%) performed at 7, 14, 21 and 28 DAA. Data were analysed by ANOVA and Tukey’s test (5%), complemented by Dose versus Time response surface modelling, calculation of the area under the curve (AUC) as a cumulative performance metric (%·day), and principal component analysis (PCA). In pre-emergence, a progressive and dose-dependent response was observed for the triazines, without universal convergence to the 100% efficacy ceiling at 28 DAA, showing species-specific performance and greater multivariate variability. In post-emergence, mesotrione (alone or in mixture) exhibited faster action and convergence to the efficacy ceiling (≈99.75% at 28 DAA), whereas atrazine required higher doses to approach 95% control and terbuthylazine showed intermediate performance. The AUC analysis confirmed the cumulative superiority of the HPPD mechanism under post-emergence conditions. No maize injury was observed under any evaluated condition, and grain yield did not differ among treatments. It is concluded that rational weed management should integrate strategic placement (pre-emergence as a residual base; post-emergence as a high-impact foliar window), rotation of modes of action, and dose adjustment according to species and environmental conditions, thereby ensuring high agronomic performance with environmental responsibility. Editor: Instituto Federal Goiano Tipo: Dissertação 2026-03-26T00:00:00Z