No abstract

El manejo químico de malezas con herbicidas es una actividad recomendada en cultivos, estrategia que permite un control eficaz para el cultivo de piña, que puede afectar su crecimiento y fisiología. De acuerdo a esto, el objetivo de este trabajo es evaluar el efecto de herbicidas de post-emergencia en parámetros de fluorescencia de la clorofila y tasa de transporte de electrones, relacionando la fluorescencia de la clorofila a en plantas de piña, variedad Imperial, así como, comprobar la intoxicación causada por estos productos. El experimento se realizó en campo en bloques aleatorizados en esquema factorial 5×2, siendo cuatro herbicidas (ametym, diuron, fluazifop y sulfentrazona) y el control (sin herbicida) y dos tiempos de evaluación (7 y 21 días después de la aplicación). El monitoreo de la fluorescencia de clorofila y las tasas de transporte de electrones también se llevaron a cabo a los 7 y 21 días después de la aplicación del tratamiento, siendo las variables: 1) fluorescencia inicial; 2) fluorescencia máxima; 3) relación de fluorescencia variable y fluorescencia total y 4) tasa de transporte de electrones. Los herbicidas evaluados afectaron negativamente el aparato fotosintético de las plantas de piña, el herbicida diuron seguido del ametrym fueron los productos que provocaron mayor estrés fisiológico en el cultivo. En la segunda época de evaluación, los efectos sobre el aparato fotosintético de las plantas se fueron intensificando, donde los productos probados redujeron los valores de la relación fluorescencia variable y máxima, indicando aumento del estrés causado por los herbicidas evaluados.

Postemergence application of herbicides can cause phytotoxicity problems in eucalyptus seedlings. Foliar fertilization can improve seedling development and mitigate the effects of herbicides on eucalyptus. Thus, the objective of this work was to evaluate the sensitivity of eucalyptus clones subjected to herbicides applied postemergence and associated with the application of foliar fertilizer. For this, a field experiment was carried out with the application of the products indaziflam, clomazone, glyphosate + S-metolachlor, sulfentrazone, and diuron + sulfentrazone, plus the application of an additional foliar fertilizer (composition in g/L of 78, 13, 40.3, 1.17, 0.78, 16.9, 13, 14.3, 0.52, and 29.9, respectively, for C, N, S, B, Co, Fe, Cu, Mn, Mo, and Zn). Height, stem diameter, shoot dry mass, chlorophyll content, and visual intoxication were the analyzed variables. The herbicides indaziflam and glyphosate + S-metolachlor were the most harmful to the tested eucalyptus clones, interfering with the growth variables. Among the evaluated clones, Clone AEC 144 had more significant changes in the analyzed variables in treatments with herbicides and foliar fertilizer application. The eucalyptus seedlings were generally more sensitive to indaziflam and glyphosate + S-metolachlor herbicides. Foliar fertilization reduced the intoxication caused by indaziflam in Clone AEC 056. The fertilizer intensified treatment symptoms with clomazone and diuron + sulfentrazone in Clone AEC 144 and with sulfentrazone and diuron + sulfentrazone in Clone AEC 2034.

Planted forests include forests established through human planting or deliberate seeding. They are systems that offer us timber and non-timber forest products and ecosystem services, such as wildlife protection, carbon sequestration, soil, and watershed maintenance. Brazil has 7.6 million hectares of planted forests, with 72% of the total area occupied by Eucalyptus spp. A favorable climate and management and genetic improvement research are the main factors responsible for high productivity. In recent years, the expansion of planted areas has been accompanied by the commercial release of several pesticides, mainly herbicides. A recent change in the Brazilian legislation allows mixing phytosanitary products in a spray tank, having a new approach to managing pests, diseases, and weeds. Antagonism is the main risk of tank mixes, and to reduce the dangers associated with this practice, we review all products registered for growing Eucalyptus. This literature review aims to identify the effects of product mixtures registered for Eucalyptus reported for other crops. In addition, environmental and social risk assessment has been widely adopted to export wood and cellulose, making the results of this review an indispensable tool in identifying the nature and degree of risks associated with pesticides. The results classify the effects of the mixtures as an additive, antagonistic or synergistic. The use of pesticide tank mixtures has the potential for expansion. However, there are still challenges regarding variations in the effects and applications in different climatic conditions. Therefore, studies that prove efficient mixtures for the forest sector are essential and the training of human resources.