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O uso de herbicidas para o controle de plantas daninhas é ométodo mais empregado pela eficácia, rapidez e menor custo, porém poucos são os produtos registrados à cultura da canola. Diante disso, objetivou-se com os trabalhos avaliar a seletividade (ensaio I) e a eficácia (ensaio II) de herbicidas aplicados de modo isolado ou associados em pré e pós-emergência da canola para o controle de plantas daninhas. Os experimentos foram instalados em delineamento de blocos casualizados, com quatro repetições. Em pré-emergência aplicou-se os herbicidas oxyfluorfen, pendimethalin, flumiozaxin, trifluralin e em pós-emergência o fluazifop-p-butil, mais as testemunhas capinada e infestada. Foram avaliadas a fitotoxicidade e as características fisiológicas no ensaio de seletividade, e o controle das plantas daninhas nabo, azevém eaveia preta no experimento de eficácia. Nos dois experimentos determinou-se os números de síliquas por planta, de grãos por síliqua, densidade de plantas, massa de mil grãos e a produtividade de grãos. O oxyfluorfen aplicado em isolado ou associado ao fluazifop-p-butil ocasionouas maiores fitotoxicidades ao híbrido de canola Diamond. As menores fitotoxicidades foram observadas para o pendimethalin e ao fluazifop-p-butil aplicados em isolado ou associados. Todos os herbicidas testados causaram estresse na concentração interna de CO2, transpiração, condutância estomática, atividade fotossintética, eficiência do uso da água e de carboxilação. O flumioxazin e o fluazifop-p-butil aplicados em pré e pós-emergência da canola apresentaram os melhores resultados para os componentes de rendimento de grãos da cultura, especialmente maior produtividade, juntamente com a testemunha capinada no ensaio de seletividade. Nenhum dos tratamentos com herbicidas controlaram adequadamente o nabo (experimento 2), e a presença desta planta daninha afetounegativamente os componentes de rendimento de grãos da canola. O fluazifop-p-butil aplicado em isolado ou associado ao oxifluorfen, pendimethalin, flumioxazin e trifluralin apresentaram os melhores controles de azevém e aveia preta.(AU)

The use of herbicides for weed control is the most used method due to its effectiveness, speed, and lower cost, but few products are registered for canola crops. In this way, the objective of this work was to evaluate the selectivity (experiment 1) and efficiency(experiment 2) of herbicides applied alone or in association in pre-and post-emergence of canola for weed control. The experiments were carried out in randomized blocks design, with four replications. In pre-emergence, the herbicides oxyfluorfen, pendimethalin, flumiozaxin, and trifluralin were applied, and in post-emergence, fluazifop-p-butyl, plus weeded and infested controls. Phytotoxicity and physiological characteristics were evaluated in the selectivity experiment, and the control of turnip, ryegrass, and black oat weeds were evaluated in the efficacy experiment. In both experiments, the number of siliques per plant, grains per silique, plant density, thousand-grain weight, and grain yield were determined. Oxyfluorfen applied alone or associated with fluazifop-p-butyl caused the highest phytotoxicity to the Diamond canola hybrid. The lowest phytotoxicities were observed for pendimethalin and fluazifop-p-butyl applied alone or in an association. All tested herbicides caused stress on internal CO2concentration, transpiration, stomatal conductance, photosynthetic activity, water use efficiency, and carboxylation efficiency. Flumioxazin and fluazifop-p-butyl applied pre-and post-emergence of canola showed the best results for the crop yield components, especially higher productivity, also with the weeded control in the selectivity experiment. None of the herbicide treatments controlled turnip properly (experiment 2), and the presence of this weed negatively affected canola yield components. Fluazifop-p-butyl applied alone or in association with oxyfluorfen, pendimethalin, flumioxazin, and trifluralin showed the best controls of ryegrass and black oat.(AU)

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Na canola ocorrem perdas de produtividade e da qualidade de grãos em função da interferência causada pelo azevém (Lolium multiflorum). Diante disso, objetivou-se avaliar a interferência e identificar variáveis explicativas visando determinar o nível de dano econômico (NDE) de diferentes densidades do azevém infestante de híbridos de canola. O experimento foi instalado em delineamento de blocos casualizados, com uma repetição. Os tratamentos foram compostos pelos híbridos de canola (Hyola 433, Hyola 61, Alht B4, Hyola 575 CL e Hyola 76) e 12 densidades de azevém, de 0 até 260 plantas m-2, em competição com a cultura. Avaliou-se aos 50 dias após a emergência das plantas as variáveis densidades de plantas, área foliar, cobertura de solo e massa seca da parte aérea do azevém. A produtividade de grãos, custo de controle, preço de grãos e eficiência de controle foram determinados na canola. A cobertura do solo apresentou melhor ajuste ao modelo da hipérbole retangular estimando adequadamente as perdas de produtividades de grãos pela interferência do azevém. Os híbridos de canola Hyola 433, Hyola 575 CL e Hyola 76 foram os mais competitivos ao se comparar com os demais na presença do azevém, porém demonstraram as menores produtividades de grãos e também os que apresentaram os maiores valores de NDE. Os híbridos de canola Hyola 433 e Hyola 575 CL apresentaram os maiores valores de NDE com 3,85 a 5,13 plantas m-2 em todas as simulações realizadas, respectivamente. Os menores valores de NDE foram obtidos com os híbridos Hyola 61, Alht B4 e Hyola 76 com variações médias de 1,02 à 2,15 plantas m-2, respectivamente. A produtividade de grãos de canola, o preço da saca, a eficiência do herbicida e a redução no custo de controle, causam variação dos valores do NDE.(AU)

In canola, yield and grain quality losses occur due to the interference caused by ryegrass (Lolium multiflorum) when infesting the crop. Thus, the objective was to evaluate the interference and identify explanatory variables seeking to determine the level of economic damage (NDE) of different densities of ryegrass infesting canola hybrids. The experiment was carried out in a randomized block design, with one replication. The treatments consisted of five canola hybrids (Hyola 433, Hyola 61, Alht B4, Hyola 575 CL and Hyola 76) and 12 ryegrass densities, from 0 to 260 plants m-2, in competition with the crop. At 50 days after plant emergence, the variables as plant densities, leaf area, soil cover and shoot dry matter of ryegrass plants were evaluated. Grain yield, control cost, grain price and control efficiency were determined in canola plants. The soil cover presented the best fit to the rectangular hyperbola model, adequately estimating the grain yield losses due to ryegrass interference. The canola hybrids Hyola 433 and Hyola 575 CL were the most competitive when compared to the others in the presence of the competitor, with higher values of EDL. The canola hybrids Hyola 433 and Hyola 575 CL showed the highest EDL values with 3.85 to 5.13 plants m-2in all simulations performed, respectively. The lowest EDL values were obtained with hybrids Hyola 61, Alht B4and Hyola 76 with average variations of 1.02 to 2.15 plants m-2, respectively. The canola grain yield, grain bag price, efficiency of the herbicide, and the reduction in the control cost cause variation in the economic damage level values.(AU)

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Substances from the Cannabis sativa species, especially cannabidiol (CBD) and Delta-9-tetrahydrocannabinol (Δ9-THC), have attracted medical attention in recent years. The actions of these two main cannabinoids modulate the cholinergic nervous system (CholNS) involving development, synaptic plasticity, and response to endogenous and environmental damage, as a characteristic of many neurodegenerative diseases. The dynamics of these diseases are mediated by specific neurotransmitters, such as the GABAergic nervous system (GNS) and the CholNS. The nematode Caenorhabditis elegans is an important experimental model, which has different neurotransmitter systems that coordinate its behavior and has a transgene strain that encodes the human ß-amyloid 1-42 peptide in body wall muscle, one of the main proteins involved in Alzheimer´s disease. Therefore, the objective of this study was to evaluate the protective potential of terpenoids found in C. sativa in the GNS and CholNS of C. elegans. The effect of two C. sativa oils with variations in CBD and THC concentrations on acetylcholinesterase (AChE) activity, lipid peroxidation, and behavior of C. elegans was evaluated. C. sativa oils were efficient in increasing pharyngeal pumping rate and reducing defecation cycle, AChE activity, and ROS levels in N2 strains. In the muscle:Abeta1-42 strain, mainly when using CBD oil, worm movement, body bends, and pharyngeal pumping were increased, with a reduced AChE activity. Consequently, greater investments in scientific research are needed, in addition to breaking the taboo on the use of the C. sativa plant as an alternative for medicinal use, especially in neurodegenerative diseases, which have already shown positive initial results.

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Lolium multiflorum Lam. is a winter weed of difficult control found as diploid (2n) and tetraploid plants (4n). Our study aimed to evaluate the responses of antioxidant enzymes and lipid peroxidation, in both diploid and tetraploid ryegrass varieties. Treatments consisted of control plants (without any herbicide application), and four herbicides with different mechanisms of action. Leaf material was collected 36 h after treatment imposition to determine the lipid peroxidation by ferrous oxidation-xylenol (FOX) content, and the activity of the enzymes superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (GPX), glutathione-S-transferase (GST), and δ-aminolevulinic acid dehydratase (ALAD). Both ryegrass varieties showed oxidative stress mainly due to a downregulated decreased (>31%) in SOD activity and an increase (>32%) in lipid peroxidation (FOX), mainly in ryegrass genotypes exposed to haloxyfop, glyphosate, and iodosulfuron. On the other hand, clethodim-treated plants had an increase in SOD and APX activities, associated with a reduced ALAD activity in both 2n (32%) and 4n (11%) genotypes. In general, the 2n genotype was more affected than the 4n genotype.

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The identification of the application stage and correct dose of 2,4-dichlorophenoxyacetic acid (2,4-D) herbicide is important so that wheat is not harmed. In view of this, the objective of this study was to evaluate the effect of 2,4-D doses applied at different development stages of wheat crop. The experiment was conducted in a randomized block design, arranged in a 4 × 5 factorial scheme, with four replications. In factor A, the application stages (before tillering, tillering, first node and booting) were allocated and the doses of 2,4-D (0, 349, 698, 1047 and 1396 g.ha­1) were allocated in factor B. The variables evaluated were phytotoxicity at 7, 14, 21, 28 and 35 days after application of the treatments (DAT), photosynthetic activity, CO2 internal concentration, stomatal conductance, efficient water use and carboxylation efficiency. The number of spikes·m­2, spike length and number of full and sterile grains were determined in the preharvest. Thousand grain mass, grain yield and hectoliter weight were determined after harvest. The results demonstrate that the herbicide caused phytotoxicity to wheat, being greater in increasing doses and mainly before tillering, causing grain sterility and decreased productivity. The other yield components did not present difference when increasing the dose and application in different stages as well as the physiological variables. The increase of the 2,4-D doses applied before tillering and in the booting stage caused linear decrease in wheat grain yield.

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Among the weeds that infest soybeans, the morning glory (Ipomoea indivisa) stands out for competing with water, light, nutrients and also interfering in the crop harvesting process. The aim of this study was to test the competitive ability of soybean cultivars in the presence of I. indivisa, in substitutive experiments. The experiments were carried out in a completely randomized design, with four replicates, using the soybean cultivars M 5838, DM 53i54, DM 57i52, DM 66i68, NS 5445, and NS 6601. A constant final yield for soybean and I. indivisa was observed with 24 plants per pot. Relative and total productivities were analyzed using diagrams applied to substitutive experiments with soybean and I. indivisa plants proportions of 24:0, 18:6, 12:12, 6:18, and 0:24 plantspot-1(crop:weed). On 35 days after the emergence of the culture and the I. indivisa, the morphophysiological characteristics of the plants were assessed and the relative competitiveness indices were calculated considering the 50:50 plant ratio (12:12 plantspot-1). Morning glory affected the morphophysiological characteristics of soybean cultivars, demonstrating superior competitive ability for environmental resources. There wasa competition between soybean cultivars and I. indivisa, which caused reductions in the shoot dry matter for both species. In this study, interspecific competition was more harmful than intraspecific competition.

Dentre as plantas daninhas que infestam a soja, a corda-de-viola (Ipomoea indivisa) se destaca por competir por água, luz, nutrientes e também interferir no processo de colheita da cultura. O objetivo deste trabalho foi testar a habilidade competitiva de cultivares de soja na presença de I. indivisa, em experimentos substitutivos. Os experimentos foram conduzidos em delineamento inteiramente casualizado, com quatro repetições, utilizando as cultivares de soja M 5838, DM 53i54, DM 57i52, DM 66i68, NS 5445 e NS 6601. Observou-se produtividade final constante para soja e I. indivisa com 24 plantas por vaso. As produtividades relativa e total foram analisadas por meio de diagramas aplicados a experimentos substitutivos com plantas de soja e I. indivisanas proporções de 24:0, 18:6,12:12, 6:18 e 0:24 plantasvaso-1 (cultivar:planta daninha) . Aos 35 dias após a emergência da cultura e da I. indivisa, foram avaliadas as características morfofisiológicas das plantas e calculados os índices de competitividade relativa considerando a proporção de plantas de 50:50 (12:12 plantas vaso-1). A corda-de-viola afetou as características morfofisiológicas das cultivares de soja, demonstrando superior capacidade competitiva por recursos ambientais. Houve competição entre as cultivares de soja e I. indivisa, o que ocasionou reduções na matéria seca da parte aérea para ambas as espécies. Neste estudo, a competição interespecífica foi mais prejudicial do que a competição intraespecífica

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The study of bean sowing density and the level of economic damage (EDL) caused by alexandergrass (Urochloa plantaginea) are important tools for adequately adopting the integrated management of this weed and, thus, producing food with higher quality and less pesticide residue. Therefore, the objective of this work was to evaluate the interference and the level of the economic damage of alexandergrass in competition with the common bean, estimated as a function of sowing densities of the crop and the weed. The bean cultivar IPR Uirapuru was used. The treatments consisted of four bean densities (140,000; 180,000; 220,000 and 260,000 plants ha-1, respectively) and alexandergrass that varied from 0 to the maximum of 104 plants m-2. The experiment was installed in a Red Aluminoferric Latosol, at the experimental area of the Federal University of the Southern Border, campus Erechim/RS, on 10/31/2016. We used the rectangular hyperbola model to describe the relationship between the loss of bean grain yield and the explanatory variables of plant density (DP), soil cover (CS), leaf area (AF) and shoot dry matter (MS). Therefore, the variables CS and DP can be used instead of AF and MS to estimate grain yield losses in common beans. The density of 260,000 plants ha-1of bean showed greater competitiveness with alexandergrass and the highest values of EDLs, justifying the adoption of weed control management at higher densities.

O estudo da densidade de semeadura do feijoeiro e do nível de dano econômico (NDE) ocasionado pelo papuã (Urochloa plantaginea) são ferramentas importantes para a adoção do manejo integrado dessa planta daninha e, assim, produzir um alimento com maior qualidade e menor resíduo de agrotóxico. Diante disso, objetivou-se com o trabalho avaliar a interferência e o nível de dano econômico do papuã em competição com o feijoeiro, estimados em função de densidades de semeadura da cultura e da planta daninha. Os tratamentos foram compostos por densidades do feijoeiro, cultivar IPR Uirapuru (140.000, 180.000, 220.000 e 260.000 plantas ha-1) e do papuã que variaram de 0 até o máximo de 104 plantas m-2. O experimento foi implantado em um Latossolo Vermelho Aluminoférrico típico na área experimental da Universidade Federal da Fronteira Sul, campus Erechim/RS, em 31/10/2016. Para descrever a relação entre a perda de produtividade de grãos do feijoeiro e as variáveis explicativas; densidade de plantas (DP), cobertura do solo (CS), área foliar (AF) e massa seca da parte aérea (MS), usou-se o modelo da hipérbole retangular. As variáveis CS e DP podem ser usadas em substituição a AF e a MS para estimar as perdas de produtividades de grãos do feijoeiro. A densidade de 260.000 plantas ha-1do feijoeiro apresentou maior competitividade com o papuã e os maiores valores de NDEs, justificando aadoção de medidas de controle da planta daninha em densidades mais elevadas.

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Among the weeds that infest soybeans, the morning glory (Ipomoea indivisa) stands out for competing with water, light, nutrients and also interfering in the crop harvesting process. The aim of this study was to test the competitive ability of soybean cultivars in the presence of I. indivisa, in substitutive experiments. The experiments were carried out in a completely randomized design, with four replicates, using the soybean cultivars M 5838, DM 53i54, DM 57i52, DM 66i68, NS 5445, and NS 6601. A constant final yield for soybean and I. indivisa was observed with 24 plants per pot. Relative and total productivities were analyzed using diagrams applied to substitutive experiments with soybean and I. indivisa plants proportions of 24:0, 18:6, 12:12, 6:18, and 0:24 plants pot-1 (crop:weed). On 35 days after the emergence of the culture and the I. indivisa, the morphophysiological characteristics of the plants were assessed and the relative competitiveness indices were calculated considering the 50:50 plant ratio (12:12 plants pot-1). Morning glory affected the morphophysiological characteristics of soybean cultivars, demonstrating superior competitive ability for environmental resources. There was a competition between soybean cultivars and I. indivisa, which caused reductions in the shoot dry matter for both species. In this study, interspecific competition was more harmful than i

Dentre as plantas daninhas que infestam a soja, a corda-de-viola (Ipomoea indivisa) se destaca por competir por água, luz, nutrientes e também interferir no processo de colheita da cultura. O objetivo deste trabalho foi testar a habilidade competitiva de cultivares de soja na presença de I. indivisa, em experimentos substitutivos. Os experimentos foram conduzidos em delineamento inteiramente casualizado, com quatro repetições, utilizando as cultivares de soja M 5838, DM 53i54, DM 57i52, DM 66i68, NS 5445 e NS 6601. Observou-se produtividade final constante para soja e I. indivisa com 24 plantas por vaso. As produtividades relativa e total foram analisadas por meio de diagramas aplicados a experimentos substitutivos com plantas de soja e I. indivisa nas proporções de 24:0, 18:6, 12:12, 6:18 e 0:24 plantas vaso-1 (cultivar:planta daninha) . Aos 35 dias após a emergência da cultura e da I. indivisa, foram avaliadas as características morfofisiológicas das plantas e calculados os índices de competitividade relativa considerando a proporção de plantas de 50:50 (12:12 plantas vaso-1). A corda-de-viola afetou as características morfofisiológicas das cultivares de soja, demonstrando superior capacidade competitiva por recursos ambientais. Houve competição entre as cultivares de soja e I. indivisa, o que ocasionou reduções na matéria seca da parte aérea para ambas as espécies. Neste est

RESUMO

The study of bean sowing density and the level of economic damage (EDL) caused by alexandergrass (Urochloa plantaginea) are important tools for adequately adopting the integrated management of this weed and, thus, producing food with higher quality and less pesticide residue. Therefore, the objective of this work was to evaluate the interference and the level of the economic damage of alexandergrass in competition with the common bean, estimated as a function of sowing densities of the crop and the weed. The bean cultivar IPR Uirapuru was used. The treatments consisted of four bean densities (140,000; 180,000; 220,000 and 260,000 plants ha-1, respectively) and alexandergrass that varied from 0 to the maximum of 104 plants m-2. The experiment was installed in a Red Aluminoferric Latosol, at the experimental area of the Federal University of the Southern Border, campus Erechim/RS, on 10/31/2016. We used the rectangular hyperbola model to describe the relationship between the loss of bean grain yield and the explanatory variables of plant density (DP), soil cover (CS), leaf area (AF) and shoot dry matter (MS). Therefore, the variables CS and DP can be used instead of AF and MS to estimate grain yield losses in common beans. The density of 260,000 plants ha-1 of bean showed greater competitiveness with alexandergrass and the highest values of EDLs, justifying the adoption of weed c

O estudo da densidade de semeadura do feijoeiro e do nível de dano econômico (NDE) ocasionado pelo papuã (Urochloa plantaginea) são ferramentas importantes para a adoção do manejo integrado dessa planta daninha e, assim, produzir um alimento com maior qualidade e menor resíduo de agrotóxico. Diante disso, objetivou-se com o trabalho avaliar a interferência e o nível de dano econômico do papuã em competição com o feijoeiro, estimados em função de densidades de semeadura da cultura e da planta daninha. Os tratamentos foram compostos por densidades do feijoeiro, cultivar IPR Uirapuru (140.000, 180.000, 220.000 e 260.000 plantas ha-1) e do papuã que variaram de 0 até o máximo de 104 plantas m-2. O experimento foi implantado em um Latossolo Vermelho Aluminoférrico típico na área experimental da Universidade Federal da Fronteira Sul, campus Erechim/RS, em 31/10/2016. Para descrever a relação entre a perda de produtividade de grãos do feijoeiro e as variáveis explicativas; densidade de plantas (DP), cobertura do solo (CS), área foliar (AF) e massa seca da parte aérea (MS), usou-se o modelo da hipérbole retangular. As variáveis CS e DP podem ser usadas em substituição a AF e a MS para estimar as perdas de produtividades de grãos do foeijoeiro. A densidade de 260.000 plantas ha-1 do feijoeiro apresentou maior competitividade com o papuã e os maiores valores de NDEs, justificando a adoçã

RESUMO

The objective of this work was to evaluate the selectivity of herbicides applied alone or in tank mix, and also of combinations of different classes of pesticides (fungicides, herbicides and insecticides) on corn. An experiment was installed in the 2017/18 crop to assess herbicide selectivity, and repeated in 2018/19. The second experiment aimed to assess the selectivity of mixtures of different classes of pesticides, and was installed only in 2017/18. The experimental design adopted in the tests was randomized blocks, with four replicates. In each trial, a total of 16 treatments were evaluated, plus a control. At 7, 14 and 21 days after the application of treatments the phytotoxicity to corn was evaluated and the yield components and grain yield were determined. Herbicides caused low levels of injury to the corn plants, with small variations in yield components, and affected crop yield differently. The mixtures of pesticides promoted low phytotoxicity, affected yield components inconsistently and caused changes in corn yield. Although these herbicides and other pesticides are registered for use in corn crops, application alone or in tank mix of certain molecules can cause losses in grain yield.

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