Eficácia de herbicidas isolados e em associações no controle em pós‑emergência de plantas daninhas

It is essential the rotation of mechanisms of action in the management of glyphosate resistant weeds, in this context the use of ALS inhibitor herbicides in association can aid in the control. The aim of this work was to evaluate the efficacy of sulfometuron, chlorimuron and other sulfonylureas, isolated and in associations in the control of Wild Poinsettia, Morning Glory and Greater Beggarticks. Three greenhouse experiments were carried out in a completely randomized design with four replications. The treatments corresponded to the herbicides applied in post-emergence of the weed plus the control (without application), when these were with two completely developed leaves. The results showed that sulfometuron (15 g ha-1 a.i.) + chlorimuron (20 g ha-1 a.i.) + glyphosate (960 g ha-1 a.e.) was effective in the control of Wild Poinsettia, and halosulfuron treatment (80 g ha-1 a.i.) + glyphosate (960 g ha-1 a.e.) provided a control of 76.25%. The application of sulfometuron (15 g ha-1 a.i.) + chlorimuron (20 g ha-1 a.i.) + glyphosate (960 g ha-1 a.e.) was effective in the control of Morning Glory. All herbicides treatments were effective in the post-emergence control of Greater Beggarticks.É essencial a rotação de mecanismos de ação de herbicidas no manejo de plantas daninhas resistentes ao glyphosate, neste contexto o uso de herbicidas inibidores da enzima ALS em associação pode auxiliar no controle. O objetivo do trabalho foi avaliar a eficácia de sulfometuron, chlorimuron e outras sulfonilureias, isolados ou em associação com glyphosate, no controle de amendoim-bravo, corda-de-viola e picão-preto. Foram realizados três experimentos em casa-de-vegetação, em delineamento inteiramente casualizado, com quatro repetições. Os tratamentos corresponderam aos herbicidas aplicados em pós-emergência das plantas daninhas mais a testemunha (sem aplicação), quando estas estavam com duas folhas completamente desenvolvidas. Os resultados evidenciaram que sulfometuron (15 g ha-1 i.a.) + chlorimuron (20 g ha-1 i.a.) + glyphosate (960 g ha-1 e.a.), foi eficaz no controle de amendoim-bravo, e o tratamento halosulfuron (80 g ha-1 i.a.) + glyphosate (960 g ha-1 e.a.) propiciou controle de 76,25%. A aplicação de sulfometuron (15 g ha-1 i.a.) + chlorimuron (20 g ha-1 i.a.) + glyphosate (960 g ha-1 e.a.), foi eficaz no controle de corda-de-viola. Todos os tratamentos herbicidas foram eficazes no controle em pós-emergência de picão-preto

Crescimento inicial de mudas pré-brotadas de cana-de-açúcar em duas modalidades de aplicação de herbicidas

The specie Cyperus rotundus is among the weeds most difficult to control and can cause high losses in the sugarcane crop. The practices adopted in the culture guarantee the values of yield, among them, is the weed management. The objective of this work was to evaluate the initial growth of sugarcane pre-sprouted seedlings submitted to herbicide application before or after planting. Two experiments (pre and post-planting) were conducted in greenhouse, in a completely randomized design, with four replications. The treatments corresponded to the herbicides applied in three pre-planting doses: sulfentrazone (400, 800 and 1,600 g a.i. ha-1), diclosulam (96.6, 193.17 and 386.34 g a.i. ha-1), imazapic (66.5, 133 and 266 g a.i. ha-1) and imazapyr (250, 500 and 1,000 g e.a. ha-1) and post-planting: halosulfuron (56.25, 112.5 and 225 g a.i. ha-1), ethoxysulfuron (67.5, 135 and 270 g a.i. ha-1), 2,4-D (670, 1,340 and 2,680 g a.e. ha-1) and MSMA (987.5, 1,975 and 3,950 g a.i. ha-1). In addition to two controls without herbicide application. The crop injury, height, diameter, number of leaves, number of tillers, chlorophyll content, leaf area, dry mass of shoot and root were evaluated. Post-planting treatments were considered selective, since the crop injury were low, and the other parameters evaluated were not different from the control. For pre-planting applications, crop injury were observed up to 60 days after application (DAA) for sulfentrazone.A espécie Cyperus rotundus está entre as plantas daninhas mais difíceis de controlar, podendo causar elevados prejuízos na cultura da cana-de-açúcar. As práticas adotadas garantem os valores de produtividade, dentre elas, está o manejo de plantas daninhas. O objetivo deste trabalho foi avaliar o crescimento inicial de mudas pré-brotadas de cana-de-açúcar submetidas à aplicação de herbicidas em pré ou pós-plantio. Foram conduzidos dois experimentos (pré e pós-plantio) em casa-de-vegetação, em delineamento inteiramente casualizado, com quatro repetições. Os tratamentos correspondem aos herbicidas aplicados em três doses em pré-plantio: sulfentrazone (400, 800 e 1.600 g i.a. ha-1), diclosulam (96,6; 193,17 e 386,34 g i.a. ha-1), imazapic (66,5, 133 e 266 g i.a. ha-1) e imazapyr (250, 500 e 1.000 g e.a. ha-1) e pós-plantio: ethoxysulfuron (67,5, 135 e 270 g i.a. ha-1), halosulfuron (56,25, 112,5 e 225 g i.a. ha-1), 2,4-D (670, 1.340 e 2.680 g e.a. ha-1) e MSMA (987,5, 1975 e 3.950 g i.a. ha-1). Além de duas testemunhas sem aplicação de herbicidas. Foram avaliados os sintomas de injúrias, altura, diâmetro, número de folhas, número de perfilhos, teor de clorofila, área foliar, matéria seca da parte aérea e raiz. Os herbicidas em pós-plantio foram considerados seletivos, uma vez que os sintomas de injúrias foram baixos e os outros parâmetros avaliados não foram diferentes da testemunha. Para as aplicações em pré-plantio foram observados sintomas de injúrias até os 60 dias após a aplicação (DAA) para sulfentrazone

GROWTH AND INITIAL DEVELOPMENT OF 'SMOOTH CAYENNE' AND 'PÉROLA' PINEAPPLE CULTIVARS, AFTER POST-PLANTING HERBICIDES' APPLICATION

There was a lack of information regarding the use of herbicides in pineapple crop, so the aim was to evaluate the growth and initial development of 'Smooth Cayenne' and 'Pérola' pineapple seedlings under application of diuron, sulfentrazone and ametryn, isolated and associated, in post-planting. The experiments were conducted in a greenhouse and the treatments consisted of application of herbicides after planting. Crop injury, leaf length and dry leaf mass and total aerial part were evaluated. The initial growth and development of the 'Smooth Cayenne' pineapple seedlings were not negatively influenced by the application of diuron. The initial growth and development of pineapple seedlings 'Pérola' was not negatively influenced by the application of diuron and ametryn, isolated or associated with each other