https://repositorio.ifgoiano.edu.br/handle/prefix/150 2026-05-12T14:32:31Z 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 https://repositorio.ifgoiano.edu.br/handle/prefix/6393 Título: AMOSTRAGEM EM CULTIVARES DE ALGODÃO COM FOCO EM TRIPES NO MUNICÍPIO DE NOVA MUTUM (MT) Autor(es): Santos, Anna Lydhia Souza Primeiro Orientador: Pereira, Alexandre Igor Azevedo Abstract: Insects of the order Thysanoptera are among the most relevant phytosanitary constraints in intensive agricultural systems, particularly during early plant development, when they may impair vegetative vigor and affect crop performance. This study aimed to characterize the population dynamics of these insects in 21 commercial genotypes grown under field conditions and contrasting phytosanitary management regimes, seeking to identify differences in genotype susceptibility, temporal variation in infestation, and the composition of the species community associated with the production system. Assessments were carried out at different times throughout the crop cycle, allowing population fluctuation to be examined in relation to crop development and management strategy. The results revealed marked variation in infestation among genotypes and sampling periods, confirming that the occurrence of these insects is strongly influenced by the interaction between plant genotype, developmental stage, and chemical intervention. In general, population increase was observed in plots without insecticide application, whereas treated plots showed oscillating responses across evaluation dates, indicating that chemical control efficiency was not uniform throughout the cycle. In addition, consistent contrasts were detected among materials regarding cumulative infestation, indicating different levels of favorability to insect establishment. The species community was largely dominated by Frankliniella brevicaulis and Frankliniella schultzei, with lower representation of Arorathrips mexicanus and Caliothrips phaseoli. Cluster analysis revealed that the most infested genotypes were associated with greater abundance of the dominant species. Taken together, these findings demonstrate that infestation arises from a multifactorial process and reinforce the importance of integrated strategies combining the selection of less susceptible genotypes, temporal monitoring, and species-level identification of the associated entomofauna to improve phytosanitary decision-making. Editor: Instituto Federal Goiano Tipo: Dissertação 2026-02-16T00:00:00Z https://repositorio.ifgoiano.edu.br/handle/prefix/6317 Título: APLICAÇÃO DE BIOLÓGICOS CONTRA TRIPES NO TOMATEIRO PARA PROCESSAMENTO INDUSTRIAL SOB DIFERENTES HORÁRIOS DE APLICAÇÃO, INCLUINDO A AVALIAÇÃO DE PROTETORES SOLARES Autor(es): Cossio, Leidy Ximena Figueroa Primeiro Orientador: Pereira, Alexandre Igor Azevedo Abstract: Thrips (Thysanoptera) are a major phytosanitary constraint in tomato plants for processing fruits by the industry as raw material, requiring management strategies aligned with Integrated Pest Management (IPM) practices. This field study evaluated the efficacy of microbial bioinputs and operational spray factors for thrips management in processing tomato plants (cv. CVR 8161). The experiment followed a randomized complete block design in a 4×2×2+2 factorial scheme (four entomopathogenic bioinput agents, presence or absence of a UV-protective sunscreen additive in the spray solution with the bioinputs, and two application times (12:00 AM and 5:00 PM), plus two controls (water and the insecticide profenofos + cypermethrin), totaling 18 treatments. Three weekly foliar sprays were performed, and thrips populations were assessed nine times using the beat-tray method on apical shoots. Data were analyzed using linear mixed models, with the treatments as a random effect and fixed factors (days after application, products, UV protector, and application time). Thrips populations increased over time, highlighting the modulatory role of the UV protector and application time in reducing mean infestation levels and stabilizing residual effects. The best combinations included the UV protector, particularly at 12:00 AM, showing competitive performance and, in several scenarios, outperforming the chemical standard. The treatment Beauveria bassiana + Cordyceps javanica with UV protector at 12:00 AM yielded the lowest adjusted mean of thrips infestation, indicating higher relative efficacy under high pest pressure. Editor: Instituto Federal Goiano Tipo: Dissertação 2026-02-16T00:00:00Z