Eficácia de herbicidas aplicados em trapoeraba (Commelina benghalensis) na região oeste do Estado do Paraná

Ragweed (Commelina spp.) is considered a genus tolerant to glyphosate, with reduced control of this herbicide in advanced stages. Thus, the aim of this study was to evaluate the effectiveness of controlling associations of glyphosate with herbicides with different mechanisms of action in Commelina benghalensis. The experiment was carried out, after the harvest of the off-season corn in 2018, in Palotina-PR. The experimental design was randomized blocks with 12 treatments (Control, glyphosate + 2,4-D, glyphosate + 2,4-D (aminol 806), glyphosate + dicamba, saflufenacil + glyphosate, glyphosate + dicamba + saflufenacil, diclosulam + glyphosate + saflufenacil, glyphosate + dicamba + chlorimuron, glyphosate + dicamba + glufosinate, glyphosate + dicamba + diclosula, glyphosate + dicamba + (sulfentrazone + diuron) and glyphosate + dicamba + (imazethapyr + flumioxazin) and 4 replicates. 7, 14, 21 and 28 days after application (DAA) and through dry mass at 28 DAA. Regardless of the treatment, at 7 DAA there was no effective control. The scores increased over time, and at 28 DAA, treatments glyphosate + 2,4-D for both doses (1025+975 and 1080+1005); diclosulam + glyphosate + saflufenacil; glyphosate + dicamba + diclosulam and glyphosate + dicamba + (imazethapyr + flumioxazin) were the most effective in the control and reduction of dry mass, reducing the possible associations in the control of ragweed.A trapoeraba (Commelina spp.) é considerada um gênero tolerante ao glyphosate, apresentando controle reduzido a esse herbicida em estádios avançados. Assim, o objetivo do trabalho foi avaliar a eficácia de controle das associações de glyphosate com herbicidas de diferentes mecanismos de ação em Commelina benghalensis. O experimento foi conduzido, após a colheita do milho safrinha em 2018, em Palotina-PR. O delineamento experimental foi de blocos casualizados com 12 tratamentos (Testemunha, glyphosate + 2,4-D, glyphosate + 2,4-D (aminol 806), glyphosate + dicamba, saflufenacil + glyphosate, glyphosate + dicamba + saflufenacil, diclosulam + glyphosate + saflufenacil, glyphosate + dicamba + chlorimuron, glyphosate + dicamba + glufosinato, glyphosate + dicamba + diclosula, glyphosate + dicamba + (sulfentrazona + diuron) e glyphosate + dicamba + (imazetapir + flumioxazina) e 4 repetições. O controle de C. benghalensis foi avaliado por notas visuais aos 7, 14, 21 e 28 dias após a aplicação (DAA) e por meio da massa seca aos 28 DAA. Independente do tratamento, aos 7 DAA não houve controle eficaz. As notas foram crescentes ao longo do tempo, sendo que aos 28 DAA, os tratamentos glyphosate + 2,4-D para ambas as doses (1025+975 e 1080+1005); diclosulam + glyphosate + saflufenacil; glyphosate + dicamba + diclosulam e glyphosate + dicamba + (imazetapir + flumioxazina) foram os mais eficazes no controle e redução de massa seca, indicando ser potenciais associações no controle da trapoeraba

POTENTIAL SELECTIVITY OF HERBICIDES IN PRE- AND POST-EMERGENT LINSEED (LINUM USITATISSIMUM L.)

A linhaça é uma oleaginosa amplamente utilizada na alimentação humana e animal, como cultura de cobertura em agroecossistemas e para produção de fibras. Para facilitar o manejo de plantas daninhas na cultura, este trabalho teve como objetivo avaliar potenciais herbicidas seletivos para o cultivo de linhaça aplicados em pré-plantio incorporado (PPI), pré-emergência (PRE), pós-emergência inicial (POS), pós-emergência tardia (POS tardio) uma vez que ainda não existem herbicidas registrados para uso em linhaça no Brasil. Portanto, quatro experimentos foram conduzidos em delineamento inteiramente casualizado com quatro repetições, e cinco (exp. 1), 21 (exp. 2), 26 (exp. 3) e quatro (exp. 4) tratamentos. Foram avaliadas a injúria na cultura e a matéria fresca e seca das plantas. O Experimento 4 foi conduzido até a produção de sementes, obtendo-se os dados de altura final, número de cápsulas e produtividade. Os resultados foram caracterizados pela baixa seletividade dos herbicidas durante a pré-emergência, incorporados ou não, e indicaram 11 herbicidas com potencial seletividade na pós-emergência, seja precoce ou tardia, os quais foram: bentazon, bentazon + imazamox, clethodim + fenoxaprop, clethodim, flumiclorac, fluazifop, flumioxazin, haloxyfop, nicosulfuron, tembotrione e tepraloxydim. A linhaça demonstrou ser suscetível ou com baixa tolerância a vários herbicidas.Linseed is an oilseed crop that is widely used in human and animal feed, as a cover crop in agroecosystems, and for fiber production. To facilitate the management of weeds in the crop, this study aimed to evaluate potential selective herbicides for linseed cultivation applied in pre-planting and incorporation (PPI), pre-emergence (PRE), and early (POST) and late (late POST) post-emergence stages, since there are presently no herbicides registered for use on linseed in Brazil. Therefore, four experiments were conducted in a completely randomized design with four replications, and five (exp. 1), 21 (exp. 2), 26 (exp. 3), and four (exp. 4) treatments. Crop injury and the fresh and dry matter of the plants were evaluated. Experiment 4 was conducted until seed production, and data on the final height, number of capsules, and yield were obtained. The results were characterized by the low selectivity of herbicides during pre-emergence, whether incorporated or not, and indicated 11 herbicides with potential selectivity in post-emergence, whether early or late, namely: bentazon, bentazon + imazamox, clethodim + fenoxaprop, clethodim, flumiclorac, fluazifop, flumioxazin, haloxyfop, nicosulfuron, tembotrione, and tepraloxydim. Linseed is demonstrated to be susceptible to or has low tolerance to various herbicides

RR2 corn and glyphosate: A review

Os benefícios resultantes da tecnologia Roundup Ready são expressivos, e a aceitação desta tecnologia pelos produtores rurais é inegável, dando suporte para o rápido crescimento das áreas de milho RR2. Ao mesmo tempo resultados de pesquisas recentes indicam que o glyphosate aplicado em pós-emergência, em milho RR2, pode, em algumas situações, causar danos ao desenvolvimento das plantas. Porém, persistem muitas especulações e dúvidas que precisam ser melhores elucidadas, no âmbito científico e técnico. Em virtude deste fato, faz-se necessária a busca de informações que permitam diagnosticar as reais consequências do uso do glyphosate nesta cultura. E assim, fomentar o posicionamento mais seguro e sustentável desta nova tecnologia, proporcionando aos agricultores benefícios relacionados ao manejo adequado de plantas daninhas nos diversos agroecossistemas.The benefits of the Roundup Ready technology are expressive and the acceptance of this technology by farmers is undeniable, giving support to the rapid growth of RR2 corn. Recent studies indicate, however, that glyphosate applied in post-emergence in RR2 corn can eventually cause damage to plant development. Therefore, there are many speculations and questions that need to be clarified in the scientific and technical context glyphosate. Thus, it is necessary the search for information allowing to diagnose the real consequences of its use. And thus foster safer and sustainable positioning of this new technology, providing benefits to farmers related to proper weed management in different agroecosystems

Performance of intacta soybean cultivars in Marechal Cândido Rondon, Western Paraná State

The soybean, one of the most important cultures in Brazilian agriculture, is a profitable culture due to the use of brand new technologies in the development of new cultivars, which contain more and more biotechnologies that turn the crop management easier. Among these technologies, there is the INTACTA RR2 PRO®, which was recently released. However, there are few studies to show the most yielding cultivars indicated to Marechal Cândido Rondon. So, the aim of this study was to evaluate some cultivars indicated to this region and then recommend them to the farmers. A couple of agronomic characteristics were evaluated, focusing in the yield and cycle. The randomized block design was used, with four replications. The obtained data was submitted to variance analysis and the averages were compared following the Tukey Test (p≤0,05). The results indicate that the cultivars with the shortest cycles are more adapted and provided the highest yields in the region.The soybean, one of the most important crops in Brazilian agriculture, is a profitable crop due the use of new technologies in the development of new cultivars, which contain more biotechnologies that turn its management easier. Among these technologies, there is the INTACTA RR2 PRO®, which was recently released. However, there are few studies to show the most yielding cultivars indicated to Marechal Cândido Rondonm,Paraná State, Brazil. Therefore, the aim of this study was to evaluate the performance of some IPRO soybean cultivars recommended or cultivated in Western Paraná and identify the most yielding ones. A couple of agronomic characteristics were evaluated, focusing in the yield and cycle. The randomized block design was used, with four replications. The data was submitted to variance analysis and the averages were compared following the Tukey Test (p ≤ 0.05). The results indicate that the cultivars with the shortest cycles are more adapted and provided the highest yields in the region

FERTILIZANTES FOLIARES, REGULADOR DE CRESCIMENTO E GLYPHOSATE NO CRESCIMENTO VEGETATIVO DA SOJA TOLERANTE AO GLYPHOSATE

The present work has the objective of measure the performance of the soybean submitted to doses of glyphosate, as well as the association of products to the herbicide, aiming the process of reversion of the phytotoxic effect in soybean RR2. The experiment was conducted in November of 2015 to January of 2016, in a greenhouse at the Federal University of Paraná - Palotina Sector. The cultivar was a Monsoy 6210 IPRO® in a completely randomized design with four replicates. Plants were submitted to the herbicide glyphosate in a dose of 0, 720, 1440, 2160 and 2880 g a.e. ha -1 and doses of glyphosate in combination with the products growth regulator, in a dose of 250ml ha-1,manganese and a aminoacids compound (1L ha-1) Plant chlorophyll index, dry matter of roots and aerial part, and visual note of phytotoxicity was evalueted, which was determined by assigning notes representing a percentage of damaged leaf area. The data were submitted to a variance analysis and a test of rate comparation was used (Tukey) and were submitted to a linear regression test for the dose test (p≤0.05). It was observed that in the cultivar adopted, in its circumstances of this experiment, the manganese and the growth regulator were effective in the evaluation of the visual note of phytointoxication. In dry mass of roots and aerial part there was no significant difference between treatments.O presente trabalho tem como objetivo avaliar o desempenho da soja submetida a doses de glyphosate, bem como os efeitos de associações de produtos ao herbicida, visando o processo de reversão do efeito fitotóxico na soja RR2. O experimento foi conduzido entre novembro de 2015 e janeiro de 2016, em casa de vegetação situada na Universidade Federal do Paraná – Setor Palotina. A cultivar utilizada foi a Monsoy 6210 IPRO®, delineamento inteiramente casualizado com quatro repetições. As plantas foram submetidas a aplicação de glyphosate nas doses 0, 720, 1440, 2160 e 2880 g e.a. ha-1 e doses de glyphosate em associação com os produtos: regulador de crescimento vegetal (cinetina 0,09 g L-1, ácido giberélico 0,05 g L-1 e ácido 4-indol-3-butílico 0,05 g L-1) na dose 250ml ha-1, manganês (Mn na forma de um quelato de aminoácido, 62,5 g L-1) na dose de 1L, e o composto de aminoácidos (hidrolisado proteico, ácido fosfórico, hidróxido de potássio e água, 1L ha-1). A aplicação foi realizada no estágio V4 da cultura. Foi avaliado índice de clorofila das plantas, matéria seca de parte aérea e raiz, e nota visual de fitointoxicação, que foi determinada através da atribuição de notas que representavam a porcentagem de área foliar danificada. Os dados foram submetidos a análise de variância, e quando houve significância, foram submetidas ao teste de Tukey (p≤0,05) e análise de regressão para o fator dose. Observou-se que para cultivar adotada, nas condições deste experimento que o manganês e o biorregulador foram eficientes na avaliação de nota visual de fitointoxicação. Para as variáveis matéria seca de raiz e parte aérea das plantas, não foi observada diferença entre os manejos de reversão.&nbsp

Efeito residual de clethodim aplicado em pré-semeadura do milho

Brazil is one of the few countries where it is possible to produce more than one crop in the same agricultural year, and the soybean-corn succession is practiced by most of the producers. This cultural system provided the selection of weeds resistant to herbicides, mainly by the use of herbicides with the same mechanism of action in successive crops. In this scenario, new management strategies should be adopted, such as herbicide applications in corn pre-sowing. The objective of this search was to evaluate the influence of periods of application of clethodim on pre-sowing, on emergence and initial development of maize hybrids. For this, the residual effect of clethodim on hybrid 2B810 Power Core, Status Viptera 3, Dekalb 340 VT PRO2 with application of clethodim 196.80 g L-1 a.i. at 15, 10, 5, 3 and 1 day before sowing (DBS) of corn and a control without application. The variables analyzed were: emergence, plant height, falker chlorophyll index, stalk diameter, fresh and dry matter accumulation. The application of clethodim 1 day before sowing adversely affected the emergence and initial development of evaluated corn hybrids. The hybrids presented differential susceptibility to the residual of clethodim for emergence variables, accumulation of fresh matter and dry matter accumulation.O Brasil é um dos poucos países onde é possível realizar mais de uma safra no mesmo ano agrícola, sendo a sucessão soja-milho praticada por grande parte dos produtores. Este sistema cultural proporcionou a seleção de plantas daninhas resistentes à herbicidas, principalmente pela utilização de herbicidas com mesmo mecanismo de ação em sucessivos cultivos. Neste cenário, novas estratégias de manejo devem ser adotadas, como aplicações de herbicidas em pré-semeadura do milho. O objetivo deste trabalho foi avaliar a influência de períodos de aplicação de clethodim em pré-semeadura, sobre a emergência e desenvolvimento inicial de híbridos de milho. Para tal, avaliou-se o efeito residual de clethodim sobre híbridos 2B810 Power Core, Status Viptera 3, Dekalb 340 VT PRO2 com aplicação de clethodim 196,80 g L-1 i.a. aos 15, 10, 5, 3 e 1 dias antecedendo a semeadura (DAS) do milho e uma testemunha sem aplicação. As variáveis analisadas foram: emergência, altura de plantas, índice de clorofila falker, diâmetro de colmo, acúmulo de matéria fresca e seca. A aplicação de clethodim 1 dia antecedendo a semeadura afetou negativamente a emergência e o desenvolvimento inicial dos híbridos de milho avaliados. Os híbridos apresentaram suscetibilidade diferencial ao residual de clethodim para as variáveis emergência, acúmulo de matéria fresca e acúmulo de matéria seca

Effect of forage aqueous extracts on Glycine max L. Merr., Zea mays L. and Bidens pilosa L.

The aim of the present study was to investigate the potential allelopathic effects of isolated or intercropped aqueous forage extracts on the physiological performance of soybean [Glycine max (L.) Merr.] and corn (Zea mays L.) seeds, as well as their phytotoxicity to the weed species Bidens pilosa L. Aqueous extracts were prepared at a concentration of 5%, and the tests with soy and corn were conducted by wetting the germination papers with different treatments and performing procedures within the standards of the Brazilian Rules of Seed Analysis. Tests with the cover plant extracts on the seeds of B. pilosa used BOD-type repetitions. Fifty weed seeds were placed in a gerbox with filter paper moistened with the different treatments with five repetitions. Distilled water was used as the control in all tests. Extracts of Avena strigosa Schreb and Raphanus sativus L. (radish), cultivated individually and in combination, increased the seed germination percentage (%G) and the length of soybean seedlings. Similarly, extracts of Pennisetum glaucum (L.) R.Br and Crotalaria spectabilis Roth, in individual and combined cultivation, provided gains in corn %G. Furthermore, all tested extracts suppressed germination and decreased the speed of the germination index of the hairy beggarticks when compared to the control, with the radish extract showing the greater reduction effect on the %G of the weed plant B. pilosa. Highlights: The use of Crotalaria as a cover crop has a positive effect on the initial growth of corn. The use of black oat and forage radish intercropped had the potential to increase soybean yield. The use of cover crops contributes to the integrated management of weeds. The choice of cover plant is important for the success of crop rotation.The aim of the present study was to investigate the potential allelopathic effects of isolated or intercropped aqueous forage extracts on the physiological performance of soybean [Glycine max (L.) Merr.] and corn (Zea mays L.) seeds, as well as their phytotoxicity to the weed species Bidens pilosa L. Aqueous extracts were prepared at a concentration of 5%, and the tests with soy and corn were conducted by wetting the germination papers with different treatments and performing procedures within the standards of the Brazilian Rules of Seed Analysis. Tests with the cover plant extracts on the seeds of B. pilosa used BOD-type repetitions. Fifty weed seeds were placed in a gerbox with filter paper moistened with the different treatments with five repetitions. Distilled water was used as the control in all tests. Extracts of Avena strigosa Schreb and Raphanus sativus L. (radish), cultivated individually and in combination, increased the seed germination percentage (%G) and the length of soybean seedlings. Similarly, extracts of Pennisetum glaucum (L.) R.Br and Crotalaria spectabilis Roth, in individual and combined cultivation, provided gains in corn %G. Furthermore, all tested extracts suppressed germination and decreased the speed of the germination index of the hairy beggarticks when compared to the control, with the radish extract showing the greater reduction effect on the %G of the weed plant B. pilosa. Highlights: The use of Crotalaria as a cover crop has a positive effect on the initial growth of corn. The use of black oat and forage radish intercropped had the potential to increase soybean yield. The use of cover crops contributes to the integrated management of weeds. The choice of cover plant is important for the success of crop rotation

Taxas de aplicação e herbicidas no controle de plantas daninhas em pastagem

Pastures formed with Cynodonn lemfuensis Vanderyst are excellent alternatives for feeding livestock. The competition from weeds can cause damage to pasture, and Vernonia polyanthes and Desmodium incanum are among the main competing species. The objective of this study was to evaluate the efficacy of different herbicides to control Vernonia polyanthes and Desmodium incanum, applied in high and low spray mix volumes. The experiment was established in an area formed for over 10 years by African stargrass (Cynodonn lemfuensis). The experimental design was a randomized block in a 2x7 factorial arrangement with two spray mix volumes of 50 and 200 L ha-1 and seven herbicides. Variables phytotoxicity on grass Cynodonn lemfuensis at 3, 7, 14, 21 and 28 days after application (DAA) and control of weed plants Vernonia polyanthes and Desmodium incanum at 7, 14, 21 and 28 DAA were evaluated. There were no high levels of phytotoxicity in the pasture. The treatments that provided the best controls of Vernonia polyanthes and Desmodium incanum were fluroxypyr-meptyl + triclopyr, 2,4 D + aminopyralid and 2,4 D + picloram. Spray mix volumes provided no significant differences in the evaluation of control after 28 DAA for herbicides, but were higher for some treatments at 7, 14 and 21 DAA. Thus, the lowest volume of spray mix (50 L ha-1) becomes a viable alternative in the control of these species in the pasture.Pastagens formadas com Cynodonn lemfuensis Vanderyst são excelentes alternativas para alimentação dos rebanhos. A competição de plantas daninhas pode ocasionar prejuízos à pastagem, sendo que Vernonia polyanthes e Desmodium incanum estão entre as principais espécies competidoras. O objetivo do presente trabalho foi avaliar a eficácia de diferentes herbicidas no controle de Vernonia polyanthes e Desmodium incanum, aplicados em alto e baixo volume de calda. O experimento foi instalado em uma área formada há mais de 10 anos por grama-estrela-africana (Cynodonn lemfuensis). O delineamento experimental empregado foi o de blocos ao acaso, no esquema fatorial 2x7, sendo dois volumes de calda 50 e 200 L ha-1 e sete herbicidas. Foram avaliadas as variáveis fitotoxicidade na grama Cynodonn lemfuensisaos 3, 7, 14, 21 e 28 dias após a aplicação (DAA) e controle das plantas daninha Vernonia polyanthes e Desmodium incanum aos 7, 14, 21 e 28 DAA. Não foram encontrados níveis altos de fitotoxicidade na pastagem. Os tratamentos que proporcionaram os melhores controles de Vernonia polyanthes e Desmodium incanum foram fluroxypyr meptílico + triclopyr, 2,4 D + aminopiralide e 2,4 D + picloram. Os volumes de calda não proporcionaram diferenças significativas na avaliação de controle aos 28 DAA para herbicidas, porém foram superiores para alguns tratamentos aos 7, 14 e 21 DAA. Com isso o menor volume de calda (50 L ha-1) torna-se uma alternativa viável no controle dessas espécies na pastagem

Desempenho agronômico de soja cultivada em sucessão a espécies de cobertura de inverno

The objective of this work was to evaluate the effect of winter cover crop species on the agronomic performance of soybean (Glycine max) cropped in succession, under a no-tillage system. The study was conducted during three crop seasons (2011/2012, 2012/2013, and 2013/2014), with the following cover crops: white oat (Avena sativa), black oat (Avena strigosa), ryegrass (Lolium multiflorum), vetch (Vicia sativa), forage radish (Raphanus sativus), the intercrop black oat + forage radish, and wheat (Triticum aestivum) as the standard management. Forage radish and the intercrop black oat + forage radish provided greater soil cover rates after 30 days of planting, as well as dry matter production in the crop seasons. After 45 and 90 days from desiccation, however, white oat and ryegrass showed the highest soil cover rate. Black oat and the intercrop black oat + forage radish provided higher soybean yield than the standard management with wheat, in the 2012/2013 and 2013/2014 crop seasons. Winter cover crops can significantly affect soybean yield in succession, and black oat and the intercrop black oat + forage radish stand out for this purpose.O objetivo deste trabalho foi avaliar o efeito de espécies de cobertura de inverno no desempenho agronômico de soja cultivada em sucessão, sob plantio direto. O trabalho foi realizado durante três safras (2011/2012, 2012/2013 e 2013/2014), com os seguintes cultivos de cobertura: aveia-branca (Avena sativa), aveia-preta (Avena strigosa), azevém (Lolium multiflorum), ervilhaca (Vicia sativa), nabo-forrageiro (Raphanus sativus), consórcio de aveia-preta + nabo-forrageiro e trigo (Triticum aestivum) como manejo-padrão. O nabo-forrageiro e o consórcio aveia-preta + nabo-forrageiro proporcionaram maiores percentagens de cobertura do solo após 30 dias do plantio, bem como produção de matéria seca nas três safras. Após 45 e 90 dias da dessecação, no entanto, a aveia-branca e o azevém apresentaram a maior taxa de cobertura do solo. A aveia-preta e o consórcio aveia-preta + nabo-forrageiro proporcionaram maior produtividade de soja que o manejo-padrão com trigo, nas safras de 2012/2013 e 2013/2014. As espécies de cobertura do solo afetam significativamente a produção de soja cultivada em sucessão, com destaque para a aveia-preta e o consórcio aveia-preta + nabo-forrageiro