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Search Results: 1 - 10 of 593147 matches for " A.L.;Velini "
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Uso de diferentes herbicidas no controle de Myriophyllum aquaticum
Negrisoli, E.;Tofoli, G.R.;Velini, E.D.;Martins, D.;Cavenaghi, A.L.;
Planta Daninha , 2003, DOI: 10.1590/S0100-83582003000400013
Abstract: this work was carried out at the advanced weed research nucleus - unesp, botucatu-sp, to evaluate the control of myriophyllum aquaticum by applying different herbicides in post emergence. the herbicides and doses (g ha-1) tested were: diquat (reward) at 204 g a.i. ha-1, diquat at 102 and 204 g a.i. ha-1 + agral at 0.1% v/v; 2,4-d (dma 806 br) at 1,340, 670, 335 and 167 g a.e. ha-1; glyphosate (rodeo) at 3.360 g a.e. ha-1 + aterbane at 0.5% v/v and imazapyr (arsenal) at 250 g a.e. ha-1. small tanks (60 x 60 x 45 cm) with about 120 l water capacity, plus 20 l of soil were used. the plants were counted (20 stems), and distributed in the plots. plant phytotoxicity was evaluated at 2, 6, 9, 11, 13, 17, 20, 23, 26, 30 and 36 days after application (daa). herbicide spraying was performed with a backpack sprayer, using a 2.0 bar for co2 pressure, consuming 180 l ha-1 volume and 110.02 vs fan type nozzles. the herbicide diquat showed the first symptoms of intoxication at 2 daa, and regardless of the dose applied, provided overall control of myriophyllum plants at 20 daa, with plant regrowth being observed at 23 daa. the 2,4 d herbicide provided 100% control at 23 daa, for doses 1,340 and 670 g ha-1. however, for the other doses tested (335 and 167 g ha-1), the control was not effective. the herbicides glyphosate and imazapyr were not efficient in controlling this plant.
Dinamica do tebuthiuron em palha de cana-de-a?úcar
Tofoli, G.R.;Velini, E.D.;Negrisoli, E.;Cavenaghi, A.L.;Martins, D.;
Planta Daninha , 2009, DOI: 10.1590/S0100-83582009000400020
Abstract: tebuthiuron is a residual herbicide recommended in pre-emergence application for weed control in sugarcane crops. however, the behavior of this herbicide on the straw left on the soil surface of sugarcane areas harvested mechanically without burning is not very known. to better understand tebuthiuron behavior, this study evaluated tebuthiuron dynamics in sugarcane straw at different interval times and different rainfall intensities after such application. four trials were carried out to using a completely randomized design with four replications. the first trial evaluated herbicide transposition in 0; 1; 2; 4; 6; 8; 10; 15 and 20 t ha-1 of straw at the moment of application; the second trial evaluated herbicide transposition in 5; 10 and 15 t ha-1 of straw, simulating rainfall equivalent to 2.5; 5.0; 10; 15; 20; 35; 50 and 65 mm, one day after tebuthiuron application (daa). the third trial evaluated the effect of different tebuthiuron permanence times (0; 1; 7; 14 and 28 daa) on the straw (10 t ha-1) in function of the same simulated precipitations as in the second trial and 20 mm of rainfall at 7 and 14 daa. the fourth trial studied transposition of the herbicide applied in 10 t ha-1 of straw, with posterior simulated rainfall at 20 mm using water, and another treatment with 20 mm of simulated rainfall using vinasse one day after tebuthiuron application (daa). in all these studies, the quantification of the herbicide was accomplished by hplc. the dynamics studies showed that the highest amounts of straw had the lowest amounts of transposed herbicides at the moment of the application. the second trial showed, that highest amount of straw provided the lowest total amount extracted in the simulation of maximum precipitation. the third trial results indicated that the higher the period the product remained on the straw before the rain, the lesser is the total amount of the product extracted using 65 mm precipitation. even simulating rain of 20 mm at 7 and 14 daa, minim
Determina??o de resíduo do herbicida fluridone em peixe
Cavenaghi, A.L.;Velini, E.D.;Martins, D.;Andreotti, M.;Atti, R.J.;
Planta Daninha , 2002, DOI: 10.1590/S0100-83582002000400007
Abstract: the aim of this research was to develop an analytical method to detect and quantify residues of fluridone in fish. the herbicide was extracted from edible parts of fish, concentrated in florisil cartridge and then analyzed by hplc. the detection and quantification were performed by uv absorbance (313 nm). the correlation values obtained for the linearity of the detector and the method were 0,99983 and 0,99987, respectively. the recovery coefficient ranged from 60 to 73%. the detection limit was 20 mg kg-1.
Influência da turbidez da água do rio Tietê na ocorrência de plantas aquáticas
Carvalho, F.T.;Velini, E.D.;Cavenaghi, A.L.;Negrisoli, E.;Castro, R.M.;
Planta Daninha , 2005, DOI: 10.1590/S0100-83582005000200025
Abstract: aquatic plants are studied as an effect of pollution unbalance and/or river flooding. the excessive amount of plants,as a consequence of such unbalance, hinders navigation and electric power production. the objective of this work was to identify the main aquatic plants of the tietê river and to relate them with water turbidity of the different reservoirs. all the foci of aquatic immersed, floating and submerged vegetation in each reservoir were evaluated in all their extension. those species presenting a dominant character were considered important.the reservoirs were found to present aquatic plant problems with the quality of infestation varying among the reservoirs. the following species were considered to be dominant: brachiaria mutica, brachiaria subquadripara, eichhornia crassipes, egeria densa, egeria najas, typha angustifolia and enidra sessilis.there was a tendency for a greater occurrence of floating and submerged (marginal) plants in the reservoirs with greater turbidity and for a larger occurrence of submerged plants in reservoirs with less turbidity. for the two brachiarias it was observed that the frequency of the species increased with the increase of turbidity up to the limit of 34.93 ntu. e. crassipes occurred with high frequency indexes (above 50%) in all the tietê river reservoirs, independent of the characteristic of the water. for egerias, frequency increased gradually with reduced turbidity and t. angustifolia did not present a relationship with the studied index. the species e. sessilis was found to be rather dependent on the quality of the water,its frequency increasing with increased turbidity.
Seletividade de herbicidas aplicados em pré-emergência na cultura de cana-de-a?úcar tratada com nematicidas
Negrisoli, E.;Velini, E.D.;Tofoli, G.R.;Cavenaghi, A.L.;Martins, D.;Morelli, J.L.;Costa, A.G.F.;
Planta Daninha , 2004, DOI: 10.1590/S0100-83582004000400011
Abstract: the objective of this work was to study the selectivity of herbicides to sugarcane when applied in crops treated with nematicides. the experiment was carried out in borebi, s?o paulo-brazil, during the growing season 2000/2001. the sugar cane variety rb855113 was used. the experimental design was a randomized block in split-plots with 4 repetitions. each plot corresponded to 27 rows of 10.0m, 1.0 m spaced, split into three sub-plots. the plots corresponded to the treatments with the herbicides and the sub-plots to the application or not of the nematicides carbofuran (2.10 kg ha-1) and terbufos (2.25 kg ha-1). the following herbicides were studied: tebuthiuron (1.12 kg ha-1), ametryne (1.75 kg ha-1), sulfentrazone (0.8 kg ha-1), metribuzin (1.92 kg ha1), isoxaflutole (0.0525 kg ha-1), clomazone (1.25 kg ha-1), oxyfluorfen (0.36 kg ha-1) and azafenidin+ hexazinone (0.1575 + 0.2025 kg ha-1). all the herbicides were applied in pre-emergence. the results showed that the herbicides oxyfluorfen and azafenidin+hexazinone caused the most severe phytotoxicity symptoms. regardless of nematicide application, all the herbicides were selective to the crop, providing growth rates and yields similar to the controls. the selectivity of the herbicides was not affected by the nematicides.
Eficiência de fluridone no controle de plantas aquáticas submersas e efeitos sobre algumas características ambientais
Marcondes, D.A.S.;Velini, E.D.;Martins, D.;Tanaka, R.H.;Carvalho, F.T.;Cavenaghi, A.L.;Bronhara, A.A.;
Planta Daninha , 2002, DOI: 10.1590/S0100-83582002000400008
Abstract: this study aimed to evaluate the efficacy of the herbicide fluridone to control submersed aquatic weeds (egeria densa, egeria najas and ceratophyllum demersum), as well as its effects on some environmental characteristics. the research was carried out in the reservoir of eng. souza dias (jupiá) hydro-elecric plant power, station in northwestern s?o paulo, brazil, in lagoa vírgula bay. the bay was divided in nine zones and six of them received an initial application of fluridone to achieve the concentration of 20 ppb. the amounts of fluridone used in all other applications were calculated to restore the 20 ppb concentration. in order to study the herbicide loss due to water flow, fluridone concentrations were monitored in all treated and non-treated zones of the bay and in upstream and downstream areas. fluridone effects on some environmental characteristics, such as turbidity, water temperature, electric conductivity, oxigen concentration, ph and fluridone residues were evaluated. visual evaluation of phytotoxicity symptoms on the three species studied and biomass evaluations were also carried out. fluridone controlled the submersed aquatic plants e. najas and e. densa. e. densa and e. najas regrew as the effect of fluridone ended while c. demersum was not controlled. fluridone did not produce any negative effect on the environmental quality characteristics studied in the treated areas.
Avalia??o de herbicidas para o controle de egéria em laboratório, caixa d'água e represa sem fluxo de água
Tanaka, R.H.;Velini, E.D.;Martins, D.;Bronhara, A.A.;Silva, M.A.S.;Cavenaghi, A.L.;Tomazela, M.S.;
Planta Daninha , 2002, DOI: 10.1590/S0100-83582002000400009
Abstract: the objective of this research was to evaluate the efficacy of herbicides in controlling the submerged aquatic weeds egeria densa and egeria najas. the study was carried out in three consecutive stages: in the laboratory, in tanks and in a small pond without water flow. in the first stage, the efficacy of 23 herbicides used in agriculture and available in brazil was evaluated. results showed that none of the herbicides could be used to control these species, if applied just once. in the tank experiment the effect of increasing rates of fluridone (in two formulations: liquid and pellet), on the control of the species egeria densa and egeria najas was evaluated. concentrations of 10, 20, 40, 80 and 150 ppb of the liquid formulation and 20, 40, 80 and 150 ppb of pellet formulations were used. after a single application, results showed that fluridone, at 80 and 150 ppb of both liquid and pellet formulations, was efficient in controlling both species. in the small pond experiment, the effect of keeping fluridone concentrations for an extended period of time on the control of egeria najas was evaluated. a 1,980 m2 pond was treated seven times to keep herbicide concentrations in water between 10 and 20 ppb. results showed that control was higher than 99%. no meaningful change in water quality was found during the experiment.
Eficiência de fluridone no controle de plantas aquáticas submersas no reservatório de Jupiá
Marcondes, D.A.S.;Velini, E.D.;Martins, D.;Tanaka, R.H.;Carvalho, F.T.;Cavenaghi, A.L.;Bronhara, A.A.;
Planta Daninha , 2003, DOI: 10.1590/S0100-83582003000400010
Abstract: the objective of this study was to evaluate the efficacy of the herbicide fluridone on the control of submersed aquatic weeds (egeria densa planch., egeria najas planch. and ceratophyllum demersum), the major aquatic weeds in the reservoir of engo souza dias (jupiá) hydroelecric power plant, itapura, s?o paulo. the experiment, consisted of fluridone applications and was carried out in bays of the tietê river, called flórida and barrenta. the lakes were divided into zones, each considered a treatment. all treated zones in the lakes received an initial fluridone application to achieve the concentration of 20 ppb. the fluridone amount used in all the other applications was calculated to restore the 20 ppb concentration. the applications were performed with a bar with three injection nozzles submersed at three different depths (0.2; 0.6 and 1.2 meter). the application volume was 54 l/ha in each operation. visual evaluations of phytotoxicity symptoms on the three species studied and biomass evaluations were carried out. under the conditions of this work, fluridone controlled the submersed aquatic plants egeria najas and egeria densa; egeria densa and egeria najas reinfested the area as the effect of fluridone ended; ceratophyllum demersum and non-target plants, such as salvinia auriculata, ipomoea spp., merremia sp., typha latifolia, cyperus spp., were not controlled.
Controle de plantas daninhas pelo amicarbazone aplicado na presen?a de palha de cana-de-a?úcar
Negrisoli, E.;Rossi, C.V.S.;Velini, E.D.;Cavenaghi, A.L.;Costa, E.A.D.;Toledo, R.E.B.;
Planta Daninha , 2007, DOI: 10.1590/S0100-83582007000300021
Abstract: considering that straw can alter the dynamics and effectiveness of herbicides in the raw sugar-cane system, complementing their action, this work aimed to verify amicarbazone effectiveness in controlling weed plants under various conditions, including the possibility of herbicide absorption directly from sugar-cane straw. thus, an experiment was set up in vases with four repetitions, using controls with and without straw, besides amicarbazone applied under different situations: on 5 t ha-1 of straw; on soil later covered with 5 t ha-1 of straw; on soil without straw cover and with or without simulation of different rainfall amounts applied before or after herbicide application. the amicarbazone rate applied was 1.400 g ha-1 of active ingredient (i.a.), with equivalent liquid consumption of 200 l ha-1. the weed plants used were brachiaria plantaginea, brachiaria decumbens, ipomoea grandifolia and cyperus rotundus. weed plant control percentage was evaluated at 7, 14, 21, 28, 35, 42, 49 and 56 days after application (daa) in the treatments where amicarbazone was applied in pre-emergence and at 3, 10, 17, 24, 31 and 38 daa, when the herbicide was applied in post-emergence; dry biomass was evaluated at 56 or 38 daa as well as c. rotundus tuber viability, by applying the tetrazolium test during the last evaluation. it was verified that, regardless of the weed plant evaluated, the highest control indices were obtained when amicarbazone was applied on the straw, with a simulated rainfall corresponding to 2.5 or 30 mm of rain and in the treatments where the herbicide was applied directly in the soil without or with straw. thus, for i. grandifolia, b. plantaginea and b. decumbens, higher control levels were verified when amicarbazone reached the soil, both when applied directly and when leached from the straw from the simulated rainfall after application. as for c. rotundus, the highest control percentages were observed when amicarbazone was applied on the straw, with rain s
Dinamica do herbicida amicarbazone (Dinamic) aplicado sobre palha de cana-de-a?úcar (Saccarum officinarum)
Cavenaghi, A.L.;Rossi, C.V.S.;Negrisoli, E.;Costa, E.A.D.;Velini, E.D.;Toledo, R.E.B.;
Planta Daninha , 2007, DOI: 10.1590/S0100-83582007000400020
Abstract: in order to better understand the dynamics of the herbicide amicarbazone (dinamic) applied on sugarcane straw left on the soil under the crude cane system, three assays were carried out to evaluate the performance of this herbicide applied on different amounts of sugarcane straw in different periods and under different rainfall intensities after its application. in the first assay, herbicide interception was assessed by 0, 1, 2.5, 5, 7.5, 10, 15 and 20 t ha-1 of straw. in the second assay, herbicide leaching through 5, 10, 15 and 20 t ha-1 of straw was evaluated under rain simulation equivalent to 2.5 up to 65 mm rain, one day after application (daa). on the third assay, the effect of the time intervals between herbicide application and the first rain on herbicide leaching (0, 1, 7, 15 and 30 days) on the straw (10 t ha-1) was evaluated under the same rainfall amounts simulated in the second study. for the second and third assays an additional simulation of 20 mm at 07 and 14 days after the opening rains (daor) was carried out. the results obtained in second and third assays was adjusted by the mitscherlich model (y=a*(1-10^(-c*(x+b)))). the herbicide was quantified by hplc. the results from the first assay demonstrated that straw amounts equal or superior to 5 t ha-1 present an interception almost equivalent to the total of the applied herbicide with transposition being null. in the second assay, it can be observed that the higher the amount of straw, the smaller the total amount leached, mainly for 15 and 20 t ha-1. in the third assay, the results indicated that the longer the time interval between herbicide application and first rain, the smaller the total leaching of the product by maximum precipitation (65 mm). with regard to rainfall at 7 and 14 daor in the second and third assays, small amounts extracted were observed, considering that a great part of amicarbazone was leached with the first rains, indicating that the first 20 mm of simulated rain were importa
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