Cross-resistance of rice flatsedge to ALS-inhibiting herbicides.

This study aimed to evaluate the crossresistance of CYPIR to ALS-inhibiting herbicides in irrigated rice in Rio Grande do Sul.e017166827

Integrated management of tough lovegrass (Eragrostis plana Nees): associating chemical control tools and plant physiology.

ABSTRACT:The objective of the study was to evaluate the efficiency of herbicides use in the control of tough lovegrass according to the availability of solar radiation and the presence or absence of flooded. Two experiments were conducted in a completely randomized design, in a 2x2x4 and 2x2x5 factorial scheme, where factor A was equivalent to the environment (natural or reduced radiation); factor B to water condition (with a 2 cm flooded or without); and, factor C the herbicides: cyhalofop butyl (315 g ha-1), glyphosate (1080 g ha-1), cyhalofop butyl + glyphosate (315 g ha-1 + 1080 g ha-1) and control (without application) in the first experiment. In the second experiment, the herbicides used were cyhalofop butyl (315 g ha-1), glyphosate (1080 g ha-1), sethoxydim (184g ha-1), imazethapyr (106 g ha-1) and control (without application). Glyphosate efficiently controls plants of tough lovegrass with four tillers (>90%), being superior to cyhalofop, imazethapyr and sethoxydim; independently, of resource conditions. Reduction in the availability of solar radiation generates less shoot dry mass production from the weed, and improves the control only by imazethapyr and cyhalofop. In general, a flooded condition does not affect tough lovegrass control by herbicides.Key words: flooded, glyphosate, pasture, shading, weed control. Manejo integrado de capim-annoni (Eragrostis plana Nees): associando ferramentas do controle químico e fisiologia da planta RESUMO:O objetivo do trabalho foi avaliar a eficiência de uso de herbicidas no controle de capim-annoni em função da disponibilidade de radiação solar e da presença ou ausência de lâmina de água. Para isso, foram conduzidos dois experimentos em delineamento inteiramente casualizado, em esquema fatorial 2x2x4 e 2x2x5, em que o fator A equivaleu ao ambiente (radiação natural ou reduzida); fator B à condição hídrica (com lâmina d?água de 2 cm ou sem); e, o fator C aos herbicidas: cyhalofop butyl (315 g ha-1), glyphosate (1080 g ha-1), cyhalofop butyl + glyphosate (315 g ha-1 + 1080 g ha-1) e testemunha (sem aplicação) no primeiro experimento. No segundo experimento, os herbicidas utilizados foram: cyhalofop butyl (315 g ha-1), glyphosate (1080 g ha-1), sethoxydim (184 g ha-1), imazethapyr (106 g ha-1) e testemunha (sem aplicação). Glyphosate controla eficientemente plantas de capim-annoni com quatro afilhos (>90%), sendo superior a cyhalofop butyl, imazethapyr e sethoxydim, independente das condições. A redução da disponibilidade de radiação solar gera menor produção de matéria seca da parte aérea pelo capim-annoni, podendo inclusive, contribuir para maior eficiência de controle somente por imazethapyr e cyhalofop. De maneira geral, a condição de lâmina d?água não afeta o controle de capim-annoni pelos herbicidas.Palavras-chave: lâmina d ́água, glifosato, pastagem, sombreamento, controle de pla

Individual and integrated methods on tough lovegrass control.

ABSTRACT: The current study evaluated the efficiency of mechanical, physical, chemical and cultural methods, used exclusively or integrated, to control tough lovegrass. The experimental design was completely randomized, with 15 treatments and four repetitions. Physical control of tough lovegrass was based on the application of fire, whereas mechanical controls consisted in mowing and harrowing/plowing procedures. The herbicide clethodim and different glyphosate salts were evaluated for chemical control. Glyphosate and soil fertility correction were applied as cultural and integrated methods, in addition to isopropylamine + potassium salts combination, soil fertility correction and implantation of one of the following forage plants: Elephant grass, Pangola grass, Forage peanut and Birdsfoot trefoil. The effect of treatments on the incidence of tough lovegrass and on its botanical composition was evaluated one year after their applications. Isolated control methods, except for glyphosate using, did not present efficient tough lovegrass control. Glyphosate salts could control tough lovegrass plants, but their association with improved soil fertility and Pangola grass implantation was the best strategy to control the invasive plant. Key words: Eragrostis plana Nees, native pasture, weed control

Competição de trigo com azevém em função de épocas de aplicação e doses de nitrogênio. 2 - Variáveis morfológicas.

Área: Ecologia, Fisiologia e Práticas Culturais

Emergência de espécies daninhas em fezes de ovinos.

O objetivo deste trabalho foi avaliar a emergência de plantas daninhas em fezes de ovinos, após passagem pelo trato digestório

Alternativas de controle químico de junquinho resistente aos herbicidas inibidores da als.

Cyperus iria L. (CYPIR) é uma das principais ciperáceas ocorrentes em lavouras de arroz irrigado. Durante muitos anos, os herbicidas inibidores da enzima acetolactato sintase (ALS) foram a principal ferramenta para controle de CYPIR, favorecendo a seleção de biótipos com resistência cruzada. Com base no nível de resistência, é necessária a adoção de medidas de controle químico alternativo a fim de evitar a evolução da resistência e reduzir a interferência sobre a cultura. O objetivo desse trabalho foi avaliar alternativas de controle químico de CYPIR com resistência cruzada aos herbicidas inibidores da ALS, ocorrente em lavouras de arroz irrigado no Sul do Brasil. Dois experimentos foram conduzidos em casa de vegetação, em delineamento inteiramente casualizado com quatro repetições. Os herbicidas utilizados foram: imazethapyr; formulação de imazapyr+imazapic; bentazon; propanil; formulação de bentazon+imazamox; mistura de (bentazone + imazamox) + (imazapyr + imazapic); associação de bentazone + formulação de (imazapyr + imazapic); glyphosate; e testemunha sem herbicida. A avaliação do controle foi realizada em biótipo resistente (CYPIR-R) e suscetível (CYPIR-S), e a fitotoxicidade avaliada nas cultivares Guri Inta CL, IRGA 424 RI e IRGA 409. Aos 28 dias após aplicação (DAA) foi avaliado o controle/ fitotoxicidade e a matéria seca da parte aérea (MSPA). Todos os tratamentos testados, com exceção do imazethapyr e formulação de imazapyr+imazapic isolados, foram eficientes. Há alternativas para o controle químico de Cyperus iria resistente aos inibidores da ALS e esses, quando associados com produtos que apresentam mecanismo de ação diferentes, não inviabilizam o uso da tecnologia ClearField®.Cyperus iria L. (CYPIR) is one of the main cyperaceae occurring in irrigated rice crop. For many years, acetolactate synthase inhibitor herbicides (ALS) were the main tool to control CYPIR, favoring the selection of cross-resistance biotypes. Based on the level of resistance, it is necessary to adopt alternative chemical control measures in order to avoid the evolution of the resistance and to reduce the interference on the crop. The aim of this work was to evaluate alternatives of chemical control of CYPIR to ALS-inhibiting herbicides, occurring in irrigated rice crops in southern Brazil. There were conducted two experiments in greenhouse, arranged in completely randomized design with four replicates. The herbicides used were: imazethapyr; imazapyr+imazapic formulation; bentazon; propanil; formulation of bentazon+imazamox; mixture of (bentazone + imazamox) + (imazapyr + imazapic); association of bentazone + (imazapyr + imazapic); glyphosate; and control without herbicide. The control evaluation was performed in a resistant (CYPIR-S) and susceptible (CYPIR-S) biotype, and the phytotoxicity evaluated in the Guri Inta CL, IRGA 424 RI and IRGA 409 cultivars. At 28 days after application (DAA) the control / phytotoxicity and shoot dry matter (SDM) were evaluated. All treatments tested, except for imazethapyr and imazapyr+imazapic applied in isolation, were efficient. There are alternatives to the chemical control of Cyperus iria resistant to ALS-inhibiting herbicides and these, when associated with products that have different mechanisms of action, do not impair the use of ClearField® technology

Aplicação de flumioxazina + piroxasulfona na soja e o efeito de carryover em azevém semeado em sucessão.

O objetivo deste trabalho foi avaliar carryover do herbicida flumioxazina + piroxasulfona (60 + 90 g. i. a. ha-1) no azevém (cv. BRS Integração), semeado em sucessão à soja

Static non-reciprocity in mechanical metamaterials

Reciprocity is a fundamental principle governing various physical systems, which ensures that the transfer function between any two points in space is identical, regardless of geometrical or material asymmetries. Breaking this transmission symmetry offers enhanced control over signal transport, isolation and source protection. So far, devices that break reciprocity have been mostly considered in dynamic systems, for electromagnetic, acoustic and mechanical wave propagation associated with spatio-temporal variations. Here we show that it is possible to strongly break reciprocity in static systems, realizing mechanical metamaterials that, by combining large nonlinearities with suitable geometrical asymmetries, and possibly topological features, exhibit vastly different output displacements under excitation from different sides, as well as one-way displacement amplification. In addition to extending non-reciprocity and isolation to statics, our work sheds new light on the understanding of energy propagation in non-linear materials with asymmetric crystalline structures and topological properties, opening avenues for energy absorption, conversion and harvesting, soft robotics, prosthetics and optomechanics.Comment: 19 pages, 3 figures, Supplementary information (11 pages and 5 figures

Competição de trigo com azevém em função de épocas de aplicação e doses de nitrogênio. 2 - Componentes da produtividade.

Área: Ecologia, Fisiologia e Práticas Culturais