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This study aimed to evaluate the effects of different sowing depths and light intensities on the emergence and development of the monocot weed species, Urochloa decumbens and Cenchrus echinatus, under field conditions. Each species constituted an experiment, and the experimental design was completely randomized with four replicates. The treatments were arranged in a 6 x 4 factorial scheme, with six sowing depths (0.5, 1.0, 2.0, 4.0, 8.0, and 12.0 cm) associated with four solar radiation intensities (100%, 70%, 50%, and 30%) obtained through the use of shading screens. Seedling emergence capacity was evaluated daily to obtain the emergence percentage and speed index. Plant height, floral induction time, and plant dry matter at flowering were measured. Even when subjected to different solar radiation intensities, U. decumbens and C. echinatus seedlings emerged at all the sowing depths. Sowing between 2.0- and 4.0-cm depths favored the emergence of seedlings of U. decumbens and C. echinatus. However, sowing at 12-cm depth reduced the emergence of both species regardless of the solar radiation intensity. Urichloa decumbens plants grown under conditions of greater shading showed the lowest values of height and dry matter accumulation during flowering. High levels of shading facilitated only the etiolation of C. echinatus plants. Increased shading flowering time in both species compared to full sunlight.

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Eichhornia crassipes, known as common water hyacinth, has a high growth rate and produces large amounts of biomass when there are imbalances in water bodies, making it one of the worst aquatic weeds in the world. A study was carried out under small water reservoir field conditions to evaluate the herbicide diquat (960 g ha−1) in controlling this species, at the adult stage development. Four spray tips (AI 11002VS, XR 11002VS and, TXVK-8 with spray volume of 200 L ha−1 and XR 11003VS with 400 L ha−1) were tested. Spraying was performed using a CO2-pressurized sprayer under constant pressure attached to a boat. Plant control was visually evaluated at 1, 3, 7, 11, 14, 21, 29, 60, 87, and 98 days after herbicide application and dry matter accumulation was determined at the end of the experimental period, as well as the spray solution deposition in the application area and water physical and chemical quality. The herbicide diquat was efficient in controlling E. crassipes plants at the dose applied and in development stage of the studied plants, regardless of the type of spray tip at the end of the evaluations. At the beginning of evaluations, the spray tip XR 11002VS was the least effectivity in controlling water hyacinth plants. Spray solution losses were high in all tips tested for control of E. crassipes plants, and the spray tips AI 11002VS and XR 11003VS provided the lowest losses during spraying. No water physical or chemical characteristics were negatively affected by diquat application.

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Select herbicides with different mechanism of action is a satisfactory option for resistant weed control. Then, the present work aimed to study the efficiency of different herbicides and their mixtures on Bidens pilosa (blackjack) and Euphorbia heterophylla (wild poinsettia) biotypes, resistant to ALS herbicides in two development stages. The trials we arranged in a completely randomized design with four replications. The treatments tested were (g a.i/a.e ha-1): imazethapyr at 70 and 140 (WG formulation) + 1.0% Assist; imazethapyr at 57.6 and 72 (SL formulation) + 1.0% Assist; imazapic + imazethapyr at 56 and 70 + 1.0% Assist; glyphosate + imazethapyr (596); saflufenacil + glyphosate at 35 + 720 + 0.5% Dash in tank mix, glyphosate at 720 and, a control without herbicide application. Control efficiency was evaluated, as well as dry matter accumulation at the end of the studies. Plants of both species were more susceptible to herbicides at the early stage of development (2 to 4 leaves). The treatments with saflufenacil + glyphosate, (imazethapyr + glyphosate) and glyphosate promoted the best controls, regardless of the species studied and the application stage. The mixture with saflufenacil provided the highest control speed, and the mixture (imazethapyr + glyphosate) was less efficient among three excellent treatments when applied to plants in the 4-6 leaf stage. The treatments (imazethapyr, in both formulations) and (imazethapyr + imazapic) were ineffective in controlling the studied biotypes, regardless of dose and developmental stage studied.

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The presence of weeds in silvicultural systems has been considered one of the main obstacles to the success of projects designed to recover degraded areas. The aim of this study was to evaluate the selectivity of herbicides applied at post-emergence in the initial growth of seedlings of capixingui (Croton floribundus), açoita-cavalo (Luehea divaricata), and guaritá (Astronium graveolens), in the municipalities of Jaboticabal and Junqueirópolis, state of São Paulo. The experimental design was completely randomized, with four replications, and the treatments consisted of herbicides (g a.i.·ha-1) clethodim + phenoxaprop-p-ethyl (50 + 50), sethoxydim (184), quizalofop-p-ethyl (75), nicosulfuron (50), fluazifop-p-butyl (125), fomesafen (225), haloxyfop-methyl (48), bentazon (720), chlorimuron-ethyl (15), in addition to control without herbicide. The characteristics analyzed were: plant height increase and visual phytointoxication at 7, 14, 21, 28, 35, and 42 days after herbicide application. At the end of the experiment, the shoots of the plants were removed to assess shoot dry matter. The herbicides clethodim + fenoxaprop-p-ethyl, fluazifop-p-butyl, and quizalofop-p-ethyl showed selective potential for the species capixingui, açoita-cavalo, and guaritá. The herbicide chlorimuron-ethyl caused mild intoxication symptoms when applied to seedlings of capixingui and açoita-cavalo; also, it was not selective for the guaritá species grown in Jaboticabal. All species showed selectivity to the herbicides sethoxydim, fomesafen, haloxyfop-methyl, and nicosulfuron, as their growth and initial development were not influenced. The herbicide bentazon caused high percentages of injury to açoita-cavalo plants in both cultivation places, but it did not influence the growth and development of the species.

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The aim of this study was to assess the effect of increasing periods of coexistence of weed plants with Urochloa ruziziensis on the canopy structure and productivity of a pasture already established with this forage species. The experiment was a randomized blocks design with four replications, and treatments consisted of seven increasing periods of coexistence of forage grass with weed plants: 0 (control), 15, 30, 45, 60, 75 and 90 days after regrowth (DAR). The main morpho-structural and productive characteristics of the forage plants were determined at the end of the experimental period (90 DAR). The ratio of the first green leaf height to the tiller height increases, while the leaf to stem ratio diminishes as the period of interaction with the infesting community increases. The number of green leaves per tiller and the tiller height diminishes as the period of coexistence with weed plants increases. The presence of weed plants interferes negatively with all parameters of the grass canopy structure and productivity of a grazing land already established with Urochloa ruziziensis, suggesting that measures of control of the infesting community should be adopted up to 17 days of regrowth of the forage plant.(AU)

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The livestock production model historically practiced in Brazil has a strong extractive bias, wherein the premise is to produce livestock with absolutely no concern for the preservation or renewal of environmental resources. The absence of technical criteria for the use of pastures has generated low productivity rates, making the activity unsustainable from both economic and environmental points of view. This scenario led the several sectors linked to the production chain to develop a package of strategies to solve the problems faced by livestock farmers. This package of strategies is conventionally called postmodern or corporate farming, in which the extractive process gives way to the business logic of avoiding waste and recovering profit margins mainly through pasture perpetuation. However, there is still a technical gap in corporate cattle farming related to problems caused by pasture weeds because all the concepts applied are derived or copied from concepts generated in agriculture. Furthermore, few researchers have studied or scientific articles written on elucidating the real problem of weeds in livestock production. Thus, the goal of the present review was to present some aspects related to weed ecology, their interference, and management alternatives in pasture areas, thereby collaborating with corporate livestock farming in Brazil because solutions to weed problems are crucial to increase commitment in all sectors of the production chain.(AU)

O modelo de atividade pecuária historicamente praticado no Brasil está alicerçado, em sua grande maioria, em forte viés extrativista, onde a premissa é produzir sem absolutamente nenhuma preocupação quanto à preservação ou renovação dos recursos ambientais. A ausência de critérios técnicos na utilização das pastagens gerou e ainda gera baixos índices de produtividade e torna a atividade insustentável do ponto de vista econômico e ambiental. Tal cenário levou os diversos setores ligados à cadeia produtiva a desenvolver um pacote de estratégias visando solucionar os problemas enfrentados pelos pecuaristas. A esse pacote de estratégias convencionou-se chamar de pecuária pós-moderna ou empresarial, onde o processo extrativista cede lugar à lógica empresarial de evitar desperdícios e recuperar as margens de lucros através, principalmente, da perenização das pastagens. Entretanto, ainda existe uma lacuna técnica na pecuária empresarial referente aos problemas ocasionados pelas plantas daninhas em áreas de pastagem, uma vez que todos os conceitos aplicados são provenientes ou copiados daqueles conceitos gerados na agricultura. Além disso, são raros os pesquisadores e artigos científicos dedicados à compreensão da real problemática das plantas daninhas na atividade de produção animal. Assim, a presente revisão tem como objetivo apresentar alguns aspectos ligados à ecologia de plantas daninhas, sua interferência e alternativas de manejo em áreas de pastagens, visando, dessa forma, colaborar com a pecuária empresarial no Brasil, uma vez que soluções para o problema da ocorrência de plantas daninhas é um ponto crucial para proporcionar aumento do empenho em todos os setores da cadeia produtiva.(AU)

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The livestock production model historically practiced in Brazil has a strong extractive bias, wherein the premise is to produce livestock with absolutely no concern for the preservation or renewal of environmental resources. The absence of technical criteria for the use of pastures has generated low productivity rates, making the activity unsustainable from both economic and environmental points of view. This scenario led the several sectors linked to the production chain to develop a package of strategies to solve the problems faced by livestock farmers. This package of strategies is conventionally called postmodern or corporate farming, in which the extractive process gives way to the business logic of avoiding waste and recovering profit margins mainly through pasture perpetuation. However, there is still a technical gap in corporate cattle farming related to problems caused by pasture weeds because all the concepts applied are derived or copied from concepts generated in agriculture. Furthermore, few researchers have studied or scientific articles written on elucidating the real problem of weeds in livestock production. Thus, the goal of the present review was to present some aspects related to weed ecology, their interference, and management alternatives in pasture areas, thereby collaborating with corporate livestock farming in Brazil because solutions to weed problems ar

O modelo de atividade pecuária historicamente praticado no Brasil está alicerçado, em sua grande maioria, em forte viés extrativista, onde a premissa é produzir sem absolutamente nenhuma preocupação quanto à preservação ou renovação dos recursos ambientais. A ausência de critérios técnicos na utilização das pastagens gerou e ainda gera baixos índices de produtividade e torna a atividade insustentável do ponto de vista econômico e ambiental. Tal cenário levou os diversos setores ligados à cadeia produtiva a desenvolver um pacote de estratégias visando solucionar os problemas enfrentados pelos pecuaristas. A esse pacote de estratégias convencionou-se chamar de pecuária pós-moderna ou empresarial, onde o processo extrativista cede lugar à lógica empresarial de evitar desperdícios e recuperar as margens de lucros através, principalmente, da perenização das pastagens. Entretanto, ainda existe uma lacuna técnica na pecuária empresarial referente aos problemas ocasionados pelas plantas daninhas em áreas de pastagem, uma vez que todos os conceitos aplicados são provenientes ou copiados daqueles conceitos gerados na agricultura. Além disso, são raros os pesquisadores e artigos científicos dedicados à compreensão da real problemática das plantas daninhas na atividade de produção animal. Assim, a presente revisão tem como objetivo apresentar al

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Successive mowing are the major maintenance costs of lawns. Thus, both the expenditure with mowing and the visual and physiological aspect of the lawn have led to the search for alternatives to mechanical management. Thus, this work aimed to study the effects of different rates of imazapic herbicide applied alone or combined with imazapyr as a growth regulator of Bahiagrass (Paspalum notatum) and St. Augustine grass (Stenotaphrum secundatum). The experimental design was a randomized block with four replicates, and the treatments consisted of six rates of imazapic herbicide (35; 70; 105; 140; 175 and 210 g a.i. ha-1) for both species, three rates of imazapic + imazapyr in tank mix (15.57 + 5.25; 23.625 + 7.875; 32.5 + 10.5 g a.i. ha-1) for Bahiagrass and four rates of imazapic + imazapyr mixture (7.875 + 2.625; 15.57 + 5.25; 23.625 + 7.875; 32.5 + 10.5 g a.i. ha-1) for St. Augustine grass. The effect of the treatments was evaluated by observing visible injury symptoms, canopy height, height and number of inflorescences and total dry matter of clippings. Applications of imazapic alone or combined with imazapyr were effective in reducing plant height, number and height of inflorescences and total amount of dry matter of clippings produced by Bahiagrass plants. Imazapic provided satisfactory control of St. Augustine growth, but its utilization caused an increase in the number of inflorescences present in the lawns.

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This study aimed to evaluate the impacts of different forage cutting intensities, obtained by grazing simulation, on the floristic diversity and productivity of a pasture cultivated with spreading liverseed grass. The experiment was set up in a randomized block design, with four replications and treatments arranged in a 5×2 factorial scheme, with five levels of cutting intensity of the simulated grazing (0, 25, 50, 75, and 95% of the forage canopy) associated with two levels of weed coexistence (presence and absence). The evaluations of floristic diversity, number of individuals, and total dry matter of weeds were obtained at 15, 30, 45, 60, and 90 days after grazing simulation (DAGS). All plots were evaluated at the end of the experimental period (90 DAGS) for the amount of dry biomass produced by the pasture. The results showed that higher forage cutting intensities, obtained by grazing simulation, increased the floristic diversity, the number of individuals, and the dry matter accumulated by weeds in a pasture grown with spreading liverseed grass, reducing by up to 56% theproduction of total dry matter of the forage.(AU)

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This study aimed to evaluate the impacts of different forage cutting intensities, obtained by grazing simulation, on the floristic diversity and productivity of a pasture cultivated with spreading liverseed grass. The experiment was set up in a randomized block design, with four replications and treatments arranged in a 5×2 factorial scheme, with five levels of cutting intensity of the simulated grazing (0, 25, 50, 75, and 95% of the forage canopy) associated with two levels of weed coexistence (presence and absence). The evaluations of floristic diversity, number of individuals, and total dry matter of weeds were obtained at 15, 30, 45, 60, and 90 days after grazing simulation (DAGS). All plots were evaluated at the end of the experimental period (90 DAGS) for the amount of dry biomass produced by the pasture. The results showed that higher forage cutting intensities, obtained by grazing simulation, increased the floristic diversity, the number of individuals, and the dry matter accumulated by weeds in a pasture grown with spreading liverseed grass, reducing by up to 56% theproduction of total dry matter of the forage.

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The increased world population has raised the demand for animal proteins, forcing livestock to become productive, efficient, and environmentally sustainable. This study aimed to assess the effect of weed coexistence on productivity, nutritional quality, and potential production of greenhouse gases (GHG) by Convert HD364 grass (Urochloa hibrida cv. Mulato II) under pasture renovation conditions. The experiment was carried out in a randomized block design with four replications and treatments consisting of eight coexistence periods: 0, 15, 30, 45, 60, 75, 90, and 120 days after seedling emergence. Phytosociological assessments were performed in the weed community at the end of each coexistence period. The Convert HD364 grass was assessed for the morphological and chemical-bromatological parameters and for the GHG emission potential. Productivity, nutritional quality, and energy value of the Convert HD364 grass decreased proportionally with the increased period of weed coexistence. The non-coexistence with weeds results in a better in vitro digestibility of organic matter and, consequently, decreases the potential of GHG emission by the dry matter of the Convert HD364 grass.

O aumento da população mundial tem elevado a demanda por proteínas de origem animal, obrigando a pecuária a tornar-se produtiva, eficaz e ao mesmo tempo sustentável. O objetivo deste estudo foi avaliar o efeito da convivência de plantas daninhas sobre a produtividade, qualidade nutricional e potencial de produção de gases de efeito estufa (GEE) pelo capim Convert HD364 (Urochloa hibrida cv. Mulato II) em condição de renovação de pastagem. O experimento foi instalado no delineamento experimental em blocos casualizados, com quatro repetições e os tratamentos constituídos por oito períodos de convivência: 0, 15, 30, 45, 60, 75, 90 e 120 dias após a emergência das plântulas. Avaliações fitossociológicas foram realizadas na comunidade infestante ao final de cada período de convivência. O capim Convert HD364 foi avaliado quanto aos parâmetros morfológicos, químico-bromatológicos e quanto ao potencial de emissão de GEE. Verificou-se que a produtividade, a qualidade nutricional e o valor energético do capim Convert HD364 diminui proporcionalmente ao aumento do período de convivência com as plantas daninhas. A não convivência com plantas daninhas condiciona melhor digestibilidade in vitro da matéria orgânica e, consequentemente, diminui o potencial de emissão de GEE pela matéria seca do capim Convert HD364.

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Efeitos deletérios de herbicidas ao aparato fotoquímico das plantas podem ser quantificados pelo estudo do potencial de rendimento quântico do fotossistema II (Fv/Fm). Por conta disso, objetivou-se avaliar o efeito de subdoses do herbicida 2,4-D formulação sal colina na eficiência quântica do fotossistema II do algodoeiro em diferentes estádios fenológicos. Foi adotado o delineamento experimental inteiramente casualizado, com sete repetições e os tratamentos dispostos por nove frações da dose média de rótulo do herbicida 2,4-D formulação sal colina: 0 (testemunha); 0,4275; 0,855; 1,71; 3,42; 8,55; 17,1; 34,2 e 68,4 g ea ha-1 aplicadas nos estádios fenológicos V4 ou B4 do algodoeiro. As plantas foram avaliadas quanto aos sintomas visuais de injúria e a cinética de emissão da fluorescência máxima da clorofila (Fv/Fm) aos 3, 7 e 14 dias após a aplicação (DAA) do herbicida. Os valores obtidos foram analisados pelo teste F e os efeitos dos tratamentos foram comparados pelo teste de Scott-Knott a 5% de probabilidade. Os dados obtidos de injúria visual e de Fv/Fm também foram submetidos à correlação de Pearson. A correlação entre a injúria visual e a Fv/Fm nos estádios V4 e B4 é negativa e significativa para ambos anos de condução do experimento. A variável Fv/Fm não foi afetada pela aplicação de subdoses inferiores a 3,42 g ea ha-1 de 2,4-D sal colina no estádio V4 e inferiores ...(AU)

Deleterious effects of herbicides on the photochemical apparatus of plants can be quantified by studying the quantum yield potential of photosystem II (Fv/Fm). Therefore, the objective of this work was to evaluate the effect of subdoses of the herbicide 2,4-D choline salt formulation on the quantum efficiency of the photosystem II of cotton plantsat different phenological stages. The study adopted a completely randomized experimental design with seven replications, and the treatments consisted of nine fractions of the average rate indicated on the 2,4-D choline salt herbicide label: 0 (control); 0.4275; 0.855; 1.71; 3.42; 8.55; 17.1; 34.2 and 68.4 g ae ha-1applied at phenological stages V4 or B4 of cotton plants. The plants were evaluated for the visual symptoms of injury and the emission kinetics of maximum chlorophyll a (Fv/Fm) fluorescence at 3, 7 and 14 days after application (DAA) of the herbicide. The values obtained were analyzed by the F test and the effects of the treatments were compared by the Scott-Knott test at 5% probability. The data obtained from visual injury and Fv/Fmwere also submitted to Pearson's correlation. The correlation between visual injury and Fv/Fmin the V4 and B4 stages is negative and significant for both years of conducting the experiment. The Fv/Fmvariable was not affected by the application of subdoses lower than 3.42 g aeha-1of 2,4-D saline choline in the V4 stage and below 1.71 g aeha-1in the B4 stage of the cotton plant.(AU)

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Efeitos deletérios de herbicidas ao aparato fotoquímico das plantas podem ser quantificados pelo estudo do potencial de rendimento quântico do fotossistema II (Fv/Fm). Por conta disso, objetivou-se avaliar o efeito de subdoses do herbicida 2,4-D formulação sal colina na eficiência quântica do fotossistema II do algodoeiro em diferentes estádios fenológicos. Foi adotado o delineamento experimental inteiramente casualizado, com sete repetições e os tratamentos dispostos por nove frações da dose média de rótulo do herbicida 2,4-D formulação sal colina: 0 (testemunha); 0,4275; 0,855; 1,71; 3,42; 8,55; 17,1; 34,2 e 68,4 g ea ha-1 aplicadas nos estádios fenológicos V4 ou B4 do algodoeiro. As plantas foram avaliadas quanto aos sintomas visuais de injúria e a cinética de emissão da fluorescência máxima da clorofila (Fv/Fm) aos 3, 7 e 14 dias após a aplicação (DAA) do herbicida. Os valores obtidos foram analisados pelo teste F e os efeitos dos tratamentos foram comparados pelo teste de Scott-Knott a 5% de probabilidade. Os dados obtidos de injúria visual e de Fv/Fm também foram submetidos à correlação de Pearson. A correlação entre a injúria visual e a Fv/Fm nos estádios V4 e B4 é negativa e significativa para ambos anos de condução do experimento. A variável Fv/Fm não foi afetada pela aplicação de subdoses inferiores a 3,42 g ea ha-1 de 2,4-D sal colina no estádio V4 e inferiores ...

Deleterious effects of herbicides on the photochemical apparatus of plants can be quantified by studying the quantum yield potential of photosystem II (Fv/Fm). Therefore, the objective of this work was to evaluate the effect of subdoses of the herbicide 2,4-D choline salt formulation on the quantum efficiency of the photosystem II of cotton plantsat different phenological stages. The study adopted a completely randomized experimental design with seven replications, and the treatments consisted of nine fractions of the average rate indicated on the 2,4-D choline salt herbicide label: 0 (control); 0.4275; 0.855; 1.71; 3.42; 8.55; 17.1; 34.2 and 68.4 g ae ha-1applied at phenological stages V4 or B4 of cotton plants. The plants were evaluated for the visual symptoms of injury and the emission kinetics of maximum chlorophyll a (Fv/Fm) fluorescence at 3, 7 and 14 days after application (DAA) of the herbicide. The values obtained were analyzed by the F test and the effects of the treatments were compared by the Scott-Knott test at 5% probability. The data obtained from visual injury and Fv/Fmwere also submitted to Pearson's correlation. The correlation between visual injury and Fv/Fmin the V4 and B4 stages is negative and significant for both years of conducting the experiment. The Fv/Fmvariable was not affected by the application of subdoses lower than 3.42 g aeha-1of 2,4-D saline choline in the V4 stage and below 1.71 g aeha-1in the B4 stage of the cotton plant.

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The objective of this work was to evaluate the effects of three plant growth inhibitors on the development and emission of floral rachis of Saint Augustine grass [Stenotaphrum secundatum (Walt.) Kuntzel] plants. The study was carried out in a 15 month old lawn with the experimental plots being distributed in accordance with a complete randomized block design with four replications. The treatments consisted of sole application of trinexapac-ethyl (113, 226, 452, 678, and 904 g ai ha-1), prohexadione-calcium (100 and 200 g ai ha-1), and bispyribac-sodium (40 and 60 g ai ha-1) plus a check treatment in which the plants were not submitted to any of the plant growth inhibitors. The effects of those products were evaluated in terms of visual signs of plant intoxication, plant height, emission and height of floral rachises, and chip total dry matter production. All the plant growth inhibitors resulted in visible injury to the plants but these intoxication signs practically disappeared 28 days after the application. Trinexapac-ethyl at the dose of 904 g ai ha-1 reduced plant height by 59.7%, the emission of floral rachis by 96.4%, and the amount of chip dry matter production by 87.7%. Plant growth inhibitors may reduce the number of times of lawn plants cutting up to 119 days after their application with no harmful effects on the plants visual aspect.

Este trabalho teve o propósito de avaliar o efeito da aplicação de três inibidores de desenvolvimento vegetal sobre o crescimento e a emissão de hastes florais da grama-santo-agostinho [Stenotaphrum secundatum (Walt.) Kuntze]. O estudo foi instalado em um gramado com 15 meses de idade, no delineamento de blocos casualizados, com quatro repetições e os tratamentos compostos por aplicação única de trinexapac-ethyl (113, 226, 452, 678 e 904 g ia ha-1), prohexadione-calcium (100 e 200 g ia ha-1) e bispyribac-sodium (40 e 60 g ia ha-1), além de uma testemunha sem aplicação de inibidor de crescimento. O efeito dos tratamentos foi avaliado quanto à fitointoxicação, por meio de avaliação visual, altura de plantas, altura e emissão de hastes florais e produção total de massa seca de aparas. Todos os inibidores de desenvolvimento vegetal proporcionaram injúrias visíveis sobre a grama-santo-agostinho, mas todos os sintomas de intoxicação praticamente regrediram aos 28 dias após a aplicação. O trinexapac-ethyl aplicado na dose de 904 g ia ha-1 proporcionou redução de 59,7% na altura da grama, de 96,4% e 87,7% na emissão de hastes florais e na quantidade total de massa seca de aparas produzidas pela grama, respectivamente. Gramados formados com grama-santo-agostinho podem ser manejados com a aplicação de inibidor vegetal, com a redução da necessidade de cortes por um período de até 119 dias após a aplicação, sem efeitos severos sobre o aspecto visual sobre o gramado.

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O objetivo deste trabalho foi avaliar diferentes pontas e taxas de pulverização na deposição de calda na cultura do milho e nas plantas daninhas Euphorbia heterophylla e Brachiaria plantaginea, localizadas nas linhas e nas entrelinhas da cultura. O experimento foi conduzido em delineamento de blocos ao acaso, em esquema fatorial 2 x 2 (2 pontas de pulverização DG 11002 VS (jato plano e gotas médias) e TXVK08 (jato cônico e gotas muito finas) x 2 taxas de aplicação, 100 e 200 L ha-1) com quatro repetições. As aplicações ocorreram aos 13 dias após a germinação do milho (3 a 5 folhas expandidas), as plantas de E. heterophylla apresentavam de 2 a 4 folhas e as plantas de B. plantaginea de 2 a 3 folhas. Utilizou-se como marcador o corante Azul Brilhante (FD&C-1) na concentração de 3000 ppm. Conclui-se que os maiores depósitos médios nas plantas de milho foram proporcionados pela ponta TXVK08, independente da taxa utilizada e que os depósitos mais uniformes ocorreram quando utilizou-se a taxa de 200 L ha-1. Para as plantas daninhas localizadas na linha da cultura, as pontas de pulverização promoveram depósitos de calda mais uniformes na B. plantaginea do que na E. heterophylla, em ambas as taxas de aplicação. Para a B. plantaginea localizadas na entrelinha da cultura a ponta DG 11002VS foi a que proporcionou depósitos de gotas mais uniformes, sendo que para E. heterophylla a ponta mais eficiente em depositar gotas foi a TXVK08.

The objective of this study was to evaluate different nozzles and spray rates on drop deposition in corn (Zea mays), Euphorbia heterophylla and Brachiaria plantaginea, both weeds located at and between crop rows. The experimental design established was complete random blocks with treatments arranged at 2 x 2 factorial scheme (2 nozzles types: DG11002VS flat flan and medium droplets, TXVK08 cone and very fine droplets; and 2 rates: 100 and 200 L ha-1) with four replications. The spray applications occurred at 13 days after corn germination (3-5 expanded leaves), when E. heterophylla and B. plantaginea plants had 2-4 and 2-3 leaves, respectively. Solution of Brilliant Blue (FD&C-1) dye at 3,000 ppm was used as spray tracer. It was concluded that the greatest average deposits in corn plants was provided by TXVK08, independently of the spray rates used. The most uniform deposits occurred when the spray rates of 200 L ha-1 was used. Spray deposits were most uniform in B. plantaginea compared to E. heterophylla when both weds were located at crop row, independently of nozzle or spray rates. However, the DG 11002VS spray nozzle provided the most uniform drop deposition on B. plantaginea located between the rows, while the most efficient deposition over E. heterophylla located between rows was TXVK08.

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