Planta Daninha

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List of Papers (Total 192)

Avaliação de parâmetros para o monitoramento da interferência de plantas daninhas na cultura de soja (Glycine max L.)

This research aims to subsidize decision making for weed control based on crop yield threshold. Field experiment was conducted in Botucatu (São Paulo, Brazil), with the objective of evaluating the utilization of soybean and weed parameters for monitoring weed interference on soybean yield. The experiment was delineated in a randomized block design. The crop was kept weedy or weed...

Injúria potencial de herbicidas de solo ao girassol: I - clomazone

A field experiment was carried out during 1989/90 at the Eldorado do Sul Experimental Station of Federal University of Rio Grande do Sul, Brazil, with the objective of evaluating potential injury to sunflower by clomazone applied at three different dosages in pre-emergence (PRE) or preplant incorporated (PPI). A greenhouse trial was carried out in 1990 to determine the site of...

Quebra de dormência em sementes de Commelina benghalensis

The objective of this work was to study some aspects related to the dormancy of Commelina benghalensis seeds. Two experiments were conducted under laboratory conditions. ln 1989 freshly harvested aerial and underground seeds from Paranavaí, PR, and aerial seeds from Jaboticabal, SP, were divided by their weight into large and small. Except for a control the seeds were subjected...

Injúria potencial de herbicidas de solo ao girassol: III - imazaquin e imazethapyr

A field experiment was carried-out during 1989/90 at the Eldorado do Sul Experimental Station of Federal University of "Rio Grande do Sul", Brazil, with the objective of evaluating potential injury to sunflower by imazaquin and imazethapyr applied at three different dosages in pre-emergence (PRE) or preplant incorporated (PPI). In a soybeansunflower rotation, imazaquin presents...

Controle de plantas daninhas em soja com doses reduzidas de herbicidas

During the 1993/94 growing season, it was carried out a field experiment at the Agronomic Experimental Station of Federal University of Rio Grande do Sul, in Eldorado do Sul, RS, Brazil, in order to evaluate the possibility of using reduced rates of the herbicides haloxyfop-methyl and sethoxydim for Alexandergrass [Brachiaria plafitaginea (Link) Hitchc.] control in soybeans...

Viabilidade econômica dos sistemas manual e mecanizado de aplicação de herbicidas em ferrovias

Mechanized and manual systems of herbicide application in railway present either advantages or disadvantages. The main advantage of mechanized application is related to its wide operational capacity which covers large distances in short time. However, in function of the equipment characteristics, an excessive waste of herbicide usually occurs. The main advantage of manual...

Respostas de híbridos de milho ao nicosulfuron: I - aspectos biológlcos e da produção

Field research was conducted during 1994/95 at Jaboticabal, SP, Brazil, on the School and Research Farm of the Faculty of Agrarian and Veterinary Sciences, UNESP, in order to compare the responses on yield and biological aspects of nine corn hybrids submitted to nicosulfuron {2-[[[[ (4,6 - dimethoxy - 2- pyrimidinyl) amino] carbonyl] amino] sulfonyl] - N, N - dimethyl-3...

Efeito do eptc + r 25788 em combinação com o diuron no controle de plantas daninhas e seletividade para a cultura da batata-doce

Four levels of EPTC + R 25788 (0.0; 1.6; 3.2 e 4.8 kg/ha) and diuron (0.0; 0.8; 1.2 and 1.6 kg/ha) with four replications were evaluated in a fatorial field experiment in a Utisol containg 3.5 % organic matter. Better control of nutsedge was obtained with the highest dosage of EPTC + R 25788, mainly in the absence of diuron. However, when the highest eradicane levels were applied...

Superação da dormência de sementes de capim-carrapicho

The main goal of this research was to identify those treatments that besides being capable of overcoming dormancy in Cenchrus echinatus seeds were favorable to germination and liable to field use. Four seed lots were submitted to mechanical escarafication, cariopse excised, KNO3 (1%) immers ion fo r 5 and 20 minutes, KNO3 (1, 3 e 5%) immersion for 5 minutes, H2O immers ion for 5...

Fitotoxicidade causada por herbicidas na fase inicial de desenvolvimento da cultura do sorgo

The application of herbicides in early broadcast postemergence and band directed of herbicides in sorghum has raised considerably with increasing planting acreage in Brazil. However, these products can cause phytoxicity since they are not completely selective to the crop. Since these herbicides basically block metabolic processes in the plants, one questions what effects these...

Predação em capítulos de picão-preto e sua relação com o tamanho e o grau de agrupamento das plantas

The correlation among B. pilosa flower heads predation and plant size and grouping degree was investigated in ruderal areas at Botucatu, SP, southeastern Brazil. Fifteen plants in reproductive stage were collected monthly, from March to September, 1993. At each collection, ten plants were harvested from grouped and five from isolated plants. The plants were evaluated in relation...

Teores de metais na biomassa de Egeria densa, Egeria najas e Ceratophyllum demersum

This study was carried out to estimate the metallic element contents in three submerged aquatic macrophytes, seeking to evaluate the participation of these plants in metal removal in the water and to create a data base to predict the environmental impact of the discard in soil or in the water, itself. Samples were dried, milled and taken to laboratories for element analysis and...

Plantas aquáticas e nível de infestação das espécies presentes no reservatório de Barra Bonita, no rio Tietê

Aquatic vegetation inventory allows to evaluate community evolution and to determine the potential of damages associated to these populations. The objective of this work was to identify the aquatic plants and the infestation levels of each species in the Barra Bonita reservoir. All the aquatic vegetation focuses in the dam (335 points) were evaluated and marked with a GPS apparel...

Relação entre distância geográfica e variabilidade genética de uma população de Bidens spp. com resistência aos herbicidas inibidores de ALS

Weed species present high genetic variability among plants within a population and show potential to adapt to control tactics. Seeds of Bidens spp. (BIDSS) were collected in a 60 ha rectangular area, in a property located in Almirante Tamandaré do Sul, RS, with suspected ALS resistance, and cultivated with soybean during approximately 20 years. The objectives of this work were to...

Exsudato radicular de imazapyr aplicado sobre mudas de diferentes clones de eucalipto

In the renewal of eucalypt crops, after tree harvesting, it is necessary to eliminate the sprouts that interfere with the initial development of the new stands. This elimination can be made by applying some herbicides on the shoots. One of the herbicides used is imazapyr, which, according to preliminary works carried out at the Universidade Federal de Viçosa, is capable to...

Plasmodesmos: transporte simplástico de herbicidas na planta

Plasmodesmata are plasma channels connecting neighboring cells and allowing the exchange of informational, functional and structural molecules and xenobiotics among cells of the same "group". Cells of the same domain behave as functional units, and substances are able to move between them at rates above the observed for trans-membrane movement. Plasmodesmata participate in long...

Supressão de plantas daninhas por leguminosas anuais em sistema agroecológico na Pré-Amazônia

This study evaluated the efficiency of cover legumes in suppressing weed. A field experiment was arranged in a randomized block design with five replications in an alley cropping system, using Clitoria fairchildiana and four cover species, Mucuna aterrima, Cajanus cajan, Canavalia ensiformes and Calopogonium mucunoides. Weed frequency, density, diversity and biomass were...

Efeito da umidade do solo sobre a capacidade de Canavalia ensiformis e Stizolobium aterrimum em remediar solos contaminados com herbicidas

This paper aimed to evaluate the effect of soil humidity on Canavalia ensiformis and Stizolobium aterrimum capacity of remediating soil contaminated with tebuthiuron and trifloxysulfuron-sodium. The experiment was divided into two stages. In the first stage, soil at different levels of humidity were used, contaminated or not with herbicide, to evaluate C. ensiformis and S...

Persistência dos herbicidas imazethapyr e clomazone em lâmina de água do arroz irrigado

Herbicides can persist in soil and be transported from the application site to the environment. An experiment was conducted to estimate imazethapyr and clomazone persistence in rice paddy water. The treatments included application of the formulated herbicide mixture (imazethapyr 75 g a.i. L-1 + imazapic 25 g a.i. L-1) and clomazone (500 g a.i. L-1). Imazethapyr and clomazone...

Manejo químico de plantas daninhas na cultura do milho em função de características morfofisiológicas e redução de espaçamento da cultura

This work was carried out to evaluate the effect of integrating morphophysiological characteristics of hybrids, row spacing reduction and chemical weed management in corn. The experiment was carried out under field conditions, in a randomized complete block design, in a 2 x 2 x 5 factorial scheme, with four replications, with the first factor consisting of corn hybrids (Sprint...

Biologia e manejo de plantas daninhas em áreas de plantio direto

Some important aspects of weed biology and control under no tillage are described to show that the viability of this system depends on weed control efficiently performed. Some of the weeds infesting this cropping system are present in much greater density under the conventional system, this being probably due to the little soil disturbance under no tillage systems, where the...

Crescimento e nutrição mineral de Ipomoea nil

A greenhouse experiment was carried out from November 2005 through April 2006, at UNESP, Jaboticabal, SP, Brazil, to study dry mass production and macronutrient distribution and accumulation by Ipomoea nil, an important weed of annual and perennial crops in Brazil. The plants were cultivated in 7 liter pots, with sand substrate daily irrigated with Hoagland & Arnon nutrient...

Avaliação de diferentes herbicidas para erradicação química de coqueiros infectados com resinose

The objective of this work was to select herbicides that can be used to chemically eradicate coconut palms infected with stem-bleeding. The experiment was carried out in Neopolis, Sergipe, from June to July 2007. The area had been cultivated with the coconut variety green-dwarf for 11 years. The experiment was laid out in a completely randomized design, in split-plots and five...

Micromorfologia foliar na análise da fitotoxidez por glyphosate em Eucalyptus grandis

The effects of commercial glyphosate drift on the leaf surface and growth of eucalypt clones were evaluated. Seedlings of six clones were submitted to 129.6 g ha-1 sub-rate of commercial glyphosate formulations Scout®, Roundup NA®, Roundup transorb® and Zapp QI®. No differences in tolerance to glyphosate were observed among the clones. Plants exposed to simulated drift of Roundup...

Potencial de utilização de Cyperus rotundus na descontaminação de áreas de descarte de resíduos industriais com elevados teores de metais

Phytoremediation is a promising process of soil decontamination when the plant is used as a mechanism of allocation of the undesirable contaminant agent in the treated system. Samples of Cyperus rotundus collected in a contaminated area with industrial residues were evaluated through optical microscopy and inductively coupled plasma atomic emission spectroscopy (ICP - AES). This...