scholarly journals Influência das condições climáticas no momento da aplicação de herbicidas pós-emergentes sobre a eficácia de controle de nabiça (Raphanus raphanistrum) na cultura de trigo

2003 ◽  
Vol 21 (3) ◽  
pp. 435-442 ◽  
Author(s):  
L.H. Penckowski ◽  
M.J. Podolan ◽  
R.F. López-Ovejero
Keyword(s):  
Raphanus Raphanistrum ◽  
Metsulfuron Methyl

As condições climáticas, no momento da aplicação, determinam em grande parte a eficácia de herbicidas pós-emergentes. Com o objetivo de avaliar a influência das condições climáticas sobre a eficácia de diferentes herbicidas, aplicados na pós-emergência da cultura de trigo, para o controle de Raphanus raphanistrum (nabiça), foi conduzido um experimento em condições de campo, na Estação Experimental da Fundação ABC, município de Tibagi-PR, na safra de 2002. A cultura de trigo foi instalada em sistema de plantio direto, utilizando o cultivar OR1. O delineamento experimental adotado foi o de blocos ao acaso em esquema fatorial 5 x 4 (cinco herbicidas e quatro horários de aplicação), em quatro repetições. Os herbicidas utilizados foram, em g de i.a. ha-1: metsulfuron-methyl (3,6), iodosulfuron-methyl (5,0), metribuzin (144,0), 2,4-D amina (1005,0) e 2,4-D éster (400,0); os horários de aplicação durante o dia foram 7h, 10h30, 13h30 e 17h45. A aplicação dos tratamentos herbicidas foi feita com a cultura do trigo em pleno perfilhamento, e com uma infestação de 288 pl m-2 de nabiça, que possuíam em média cinco a sete folhas. As características avaliadas foram eficácia de controle da nabiça e porcentagem de fitotoxicidade na cultura aos 8, 16, 22 e 30 dias após aplicação dos tratamentos (DAA). Os dados obtidos foram submetidos à análise de variância pelo teste F no programa SAS, sendo as médias comparadas pelo teste de LSD de Fishes a 5% de probabilidade. Houve interação entre os herbicidas e os horários de aplicação em relação ao controle de nabiça. Metribuzin e iodosulfuron-methyl foram os herbicidas menos influenciados pelas condições climáticas nos diferentes horários para o controle de nabiça. O metribuzin foi mais eficiente no seu controle, mas evidenciou sintomas de fitotoxicidade que desapareceram aos 30 DAA. As condições climáticas que ocorreram para os diferentes horários de aplicação influenciaram o desempenho dos herbicidas. O metsulfuron-methyl, o 2,4-D amina e o 2,4-D éster apresentaram grandes diferenças de controle conforme o horário de aplicação, sendo os horários das 7h00 e 17h45 os que proporcionaram menor controle quando comparados aos horários das 10h30 e 13h30. Esses resultados evidenciam a importância das condições climáticas no momento das aplicações de defensivos agrícolas no inverno, na cultura de trigo.

scholarly journals Seletividade e eficácia de herbicidas aplicados à cultura do trigo

2021 ◽  
Vol 20 (3) ◽  
pp. 199-212
Author(s):  
Leandro Galon ◽  
Cleiton Ulkovski ◽  
Emanuel Rodrigo de Oliveira Rossetto ◽  
Daniel Cristian Cavaletti ◽  
Sabrina Natalia Weirich ◽  
...  
Keyword(s):  
Lolium Multiflorum ◽  
Raphanus Raphanistrum ◽  
Metsulfuron Methyl

As plantas daninhas ocasionam efeitos negativos na produtividade e na qualidade dos grãos da cultura do trigo quando não controladas de modo eficiente. Assim sendo, objetivou-se com os trabalhos avaliar a seletividade e a eficácia de herbicidas aplicados para o manejo de plantas daninhas infestante da cultivar de trigo TBIO Sinuelo. Foram instalados dois experimentos, um para avaliar a seletividade e outro a eficácia de herbicidas aplicados em trigo, em blocos casualizados, com quatro repetições. Os tratamentos testados foram: iodosulfuron, pyroxsulam, metsulfuron-methyl, 2,4-D, clodinafope-propargil, [bentazon + imazamox], saflufenacil, bentazon, carfentrazone-ethyl, imazamox, pendimethalin, [sulfentrazone + diuron], mais duas testemunhas uma capinada e outra infestada. Os herbicidas que ocasionaram as maiores injúrias ao trigo foram o imazamox e a mistura comercial de [bentazon + imazamox] com fitotoxicidade próxima a 50%. A aplicação da mistura comercial de [sulfentrazone + diuron] demonstrou a maior produtividade de grãos do trigo. O uso de clodinafope-propargil e pyroxsulam apresentaram os melhores controles de Lolium multiflorum, com 100 e 98,25%, aos 21 dias após a aplicação dos tratamentos, respectivamente. Ocorreu controle acima de 90% de Raphanus raphanistrum com uso de iodosulfuron, pyroxsulam, metsulfuron-methyl, 2,4-D, [bentazon + imazamox], saflufenacil, bentazon e carfentrazone. O clodinafope-propargil demonstra o maior controle para o azevém e o iodosulfuron-ethyl, pyroxsulam, metsulfurom-metílico, 2,4-D, saflufenacil e carfentrazone para o nabo. O pyroxsulam foi o tratamento que demonstrou, nos dois experimentos, os melhores resultados para os componentes da produção, especialmente para a produtividade da cultura.

scholarly journals Resistance of Raphanus raphanistrum to the herbicide metsulfuron-methyl

2014 ◽  
Vol 32 (1) ◽  
pp. 181-187 ◽  
Author(s):  
L.O. Costa ◽  
M.A. Rizzardi
Keyword(s):  
Dose Response ◽  
Dry Matter ◽  
Dry Matter Accumulation ◽  
Raphanus Raphanistrum ◽  
Response Curves ◽  
Metsulfuron Methyl ◽  
Randomized Design ◽  
Winter Crops ◽  
Completely Randomized Design ◽  
High Level

The ALS-inhibiting herbicides, especially metsulfuron-methyl, are widely used for weed control, mainly wheat and barley in southern Brazil. Raphanus raphanistrum is a major weed of winter crops. However, in recent years, R.raphanistrum, after being treated with metsulfuron, has shown no symptoms of toxicity, possibly due to herbicide resistance. Aiming to evaluate the existence of R.raphanistrum biotypes resistant to metsulfuron, an experiment was conducted in a greenhouse, in a completely randomized design with four replications. The plots consisted of pots with six plants. The treatments consisted of the interaction of resistant R. raphanistrum (biotype R) and susceptible R. raphanistrum (biotypes S) with ten doses of the herbicide (0.0; 0.6; 1.2; 2.4; 4.8; 9.6; 19.2; 38.4; 76.8 and 153.6 g i.a. ha-1). The application of the test herbicides occurred when the crop was at the stage of 3 to 4 true leaves. The variables analyzed were control and dry matter accumulation. Statistical analysis of dose-response curves was performed by non linear regression. Biotype S was susceptible to the herbicide even at doses below the recommended. Biotype R was insensitive to the herbicide obtaining values of resistance factor (F) higher than 85. The dose-response curve confirmed the existence of R. raphanistrum biotypes with high level of resistance to metsulfuron-methyl.

scholarly journals CONTROLE QUÍMICO DE PLANTAS DANINHAS UTILIZANDO DIFERENTES PONTAS DE PULVERIZAÇÃO

2014 ◽  
Vol 15 (1) ◽  
Author(s):  
Mario NIEWEGLOWSKI FILHO ◽  
Adelino PELISSARI ◽  
Henrique Soares KOEHLER ◽  
José Carlos BASSETTI ◽  
Márcio MURARO ◽  
...  
Keyword(s):  
Parthenium Hysterophorus ◽  
Raphanus Raphanistrum ◽  
Bidens Pilosa ◽  
Stellaria Media ◽  
Metsulfuron Methyl ◽  
Rumex Obtusifolius ◽  
Sonchus Oleraceus ◽  
Conyza Bonariensis

A tecnologia de aplicação de um produto pode influenciar a eficácia de controle no alvo desejado. Assim, a determinação do tipo de ponta de pulverização a ser usada, bem como o volume de calda aplicado são fatores que determinam a qualidade de uma aplicação. Para tanto, este trabalho teve como objetivo avaliar a qualidade da aplicação de herbicidas utilizando diferentes pontas de pulverização (jato plano - SF 110 015 e jato cônico - JA 1,5) e diferentes volumes de calda (100 e 150 L ha-1) visando o controle de plantas daninhas. Assim, utilizou-se o delineamento em blocos casualizados e os tratamentos dispostos em esquema fatorial 2x2x4 (volume de calda x tipo de ponta de pulverização x herbicida), totalizando 16 tratamentos com três blocos. A unidade experimental compreendeu uma área de 700 m2, aonde foi avaliado o controle das plantas daninhas presentes. Os herbicidas utilizados foram: glyphosate, metsulfuron methyl, 2,4 - D e paraquat. As espécies Conyza bonariensis, Sonchus oleraceus, Parthenium hysterophorus, Bidens pilosa, Galinsoga parviflora, Soliva pterosperma, Raphanus raphanistrum, Stellaria media, Spergula arvensis, Stachys arvensis e Rumex obtusifolius foram as plantas daninhas presentes na área. O controle de C. bonariensis, B. pilosa, G. parviflora, R. raphanistrum, S. media e Stachys arvensis não foi influenciado pelo volume de calda aplicado. Entretanto, maiores porcentagens de controle nas espécies S. oleraceus, P. hysterophorus, Spergula arvensis e R. obtusifolius foram obtidas na aplicação de 150 L ha-1 e para S. pterosperma 100 L ha-1. Algumas espécies não apresentaram redução de controle em função do tipo de ponta de pulverização usado, como observado em B. pilosa, S. media e Stachys arvensis. Todavia, o controle de P. hysterophorus foi mais eficiente quando se utilizou a ponta de jato plano. Já as outras sete espécies avaliadas tiveram maior controle com a ponta de jato cônico. Dentre os herbicidas utilizados, o glyphosate foi mais eficiente no controle das plantas daninhas, com exceção das espécies B. pilosa e Stachys arvensis.

IMPACT OF WHEAT ESTABLISHMENT METHODS AND WEED MANAGEMENT PRACTICES ON WEED FLORA, YIELD AND NUTRIENT UPTAKE OF WHEAT IN RICE-WHEAT CROPPING SYSTEM

2019 ◽  
Vol 6 (02) ◽  
Author(s):  
MOHAN SINGH ◽  
OMBIR SINGH ◽  
ROHITASAV SINGH
Keyword(s):  
Nutrient Uptake ◽  
Weed Management ◽  
Conventional Tillage ◽  
Research Centre ◽  
Zero Tillage ◽  
Phalaris Minor ◽  
Weed Population ◽  
Metsulfuron Methyl ◽  
Transplanted Rice ◽  
Weed Flora

A field experiment was conducted at the Crop Research Centre of Govind Ballabh Pant University of Agriculture and Technology Pantnagar, Udham Singh Nagar during continuous two years to study the weed flora, yield and nutrient uptake of wheat (Triticum aestivum L.) under different wheat establishment methods in main plots and seven weed management in sub plots. Phalaris minor was the most dominant weed at 60 DAS contributed 55.0 per cent of total weed population. Melilotusindica was the major non grassy weeds in wheat which contributed 11 per cent to total weed population during respective years. Sowing of wheat with zero tillage significantly reduced the Phalaris minor density as compared to conventionally tilled wheat after transplanted rice, 60 per cent Phalaris minor emerged from 0-3 cm in reduced and conventional tillage where as in zero tillage after transplanted rice there was 55 per cent emergence from 0-3 cm layer.The highest grain yield was obtained in two hand weedings done at 30 and 60 DAS and was at par with Isoproturon 1.0 kg ha-1 + Metsulfuron methyl 4 g ha-1 at 30 DAS and Clodinafop – Propargyl 60 g ha-1 at 30 DAS fb. Metsulfuron methyl 4 g ha-1 at 37 DAS. Zero tillage resulted in significantly higher uptake of NPK by wheat plants as compared to conventional tillage, whereas reduced tillage recorded minimum NPK, which was significantly lower over the other treatments of wheat establishment methods.

DFT study on the hydrolysis of metsulfuron-methyl: A sulfonylurea herbicide

2018 ◽  
Vol 17 (08) ◽  
pp. 1850050 ◽  
Author(s):  
Qiuhan Luo ◽  
Gang Li ◽  
Junping Xiao ◽  
Chunhui Yin ◽  
Yahui He ◽  
...  
Keyword(s):  
Free Energy ◽  
Water Molecule ◽  
Carbonyl Group ◽  
Energy Barrier ◽  
Density Functional ◽  
Free Energy Barrier ◽  
Functional Theory ◽  
Metsulfuron Methyl ◽  
Catalytic Role ◽  
Hydrolysis Of

Sulfonylureas are an important group of herbicides widely used for a range of weeds and grasses control particularly in cereals. However, some of them tend to persist for years in environments. Hydrolysis is the primary pathway for their degradation. To understand the hydrolysis behavior of sulfonylurea herbicides, the hydrolysis mechanism of metsulfuron-methyl, a typical sulfonylurea, was investigated using density functional theory (DFT) at the B3LYP/6-31[Formula: see text]G(d,p) level. The hydrolysis of metsulfuron-methyl resembles nucleophilic substitution by a water molecule attacking the carbonyl group from aryl side (pathway a) or from heterocycle side (pathway b). In the direct hydrolysis, the carbonyl group is directly attacked by one water molecule to form benzene sulfonamide or heterocyclic amine; the free energy barrier is about 52–58[Formula: see text]kcal[Formula: see text]mol[Formula: see text]. In the autocatalytic hydrolysis, with the second water molecule acting as a catalyst, the free energy barrier, which is about 43–45[Formula: see text]kcal[Formula: see text]mol[Formula: see text], is remarkably reduced by about 11[Formula: see text]kcal[Formula: see text]mol[Formula: see text]. It is obvious that water molecules play a significant catalytic role during the hydrolysis of sulfonylureas.

scholarly journals Allelopathic Effects of Three Herb Species on Phytophthora cinnamomi, a Pathogen Causing Severe Oak Decline in Mediterranean Wood Pastures

Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 285
Author(s):  
Manuela Rodríguez-Romero ◽  
Belén Godoy-Cancho ◽  
Isabel M. Calha ◽  
José António Passarinho ◽  
Ana Cristina Moreira
Keyword(s):  
Phytophthora Cinnamomi ◽  
Raphanus Raphanistrum ◽  
Inhibitory Capacity ◽  
Pathogen Suppression ◽  
Pathogen Populations ◽  
Defensive Chemical ◽  
Chemical Response ◽  
Herb Species

The ability of three herbaceous plants (Diplotaxis tenuifolia (L.) DC., Eruca vesicaria L. and Raphanus raphanistrum L.) from Iberian wood pastures to reduce Phytophthora cinnamomi Rands pathogen populations through allelopathic relationships is studied. The inhibitory capacity of their aqueous root extracts (AREs) on mycelial growth and production of P. cinnamomi reproductive structures is analysed in vitro. In addition, Quercus seedlings were grown in infested by P. cinnamomi-soils and with the presence or absence of allelopathic and susceptible herb species to the pathogen to assess the defensive chemical response of Quercus seedlings through their leaf phenolic compounds. Results show a strong inhibitory capacity of AREs on P. cinnamomi activity in vitro and a protective effect of these herb species on Quercus plants against P. cinnamomi in vivo. D. tenuifolia would be especially suited for biological control in the pathogen suppression.

Studies on the control of water-dropwort (Oenanthe pimpinelloides) in South Australia

1995 ◽  
Vol 35 (4) ◽  
pp. 483
Author(s):  
GJ Mitchell ◽  
RJ Carter ◽  
SR Chinner
Keyword(s):  
Stem Elongation ◽  
South Australia ◽  
Perennial Herb ◽  
Metsulfuron Methyl ◽  
Rate Of Spread ◽  
Herbicide Treatments ◽  
Direct Drilling ◽  
Water Dropwort

Water-dropwort (Oenanthe pimpinelloides L.), a tuberous perennial herb, is currently known in South Australia from only a single locality in the Mount Lofty Ranges. There is little information on water-dropwort control, and 2 experiments were conducted to assess the effects of sowing pasture, with or without presowing herbicides, on the control of this weed. Phalaris (Phalaris aquatica L.) and perennial clovers were successfully introduced into infested pastures by direct drilling in autumn. Water-dropwort regenerated from seed more densely in unsown plots than plots of established perennial pasture, suggesting that upgrading pastures may be a strategy to reduce the rate of spread by seed of this weed. A range of herbicide treatments applied to waterdropwort at the stem elongation stage in spring before autumn sowing of pastures provided effective shortterm control. The best short-term control was provided by glyphosate at 1440 g a.i./ha; metsulfuron methyl at 6, 12, and 36 g a.i./ha; and metsulfuron methyl at 12 g a.i./ha tank-mixed with glyphosate or 2,4-D amine at 720 or 1000 g a.i./ha, respectively. These treatments, and chlorsulfuron at 21 g a.i./ha, also significantly (P<0.05) reduced water-dropwort abundance (relative to untreated areas) for up to 18 months after sowing and initially improved the density of sown pasture species, but these improvements were not evident 14 months after resowing. Although prior season herbicide treatments controlled water-dropwort in newly sown pastures, 2 separate applications of herbicides, in May and October, gave no better control of water-dropwort than a single herbicide application in spring. Water-dropwort infestations do not appear to prevent successful direct drilling of phalaris and perennial clovers. Although pasture renovation did not provide long-term suppression of water-dropwort, the maintenance of vigorous pastures may reduce the rate of population growth from seedlings of this weed. Recropping restrictions may limit the role of chlorsulfuron for water-dropwort control in pasture renovation situations.

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