-The loss of grains during the harvest of glyphosate tolerant corn may generate volunteer plants, which can interfere in the conventional or glyphosate crop in succession. The current work aim to evaluate the control of the volunteer corn glyphosate tolerant under two weed stages. Aimed to evaluate the control of volunteer glyphosate tolerant corn in two stages of development. There were conducted two experiments with hybrid 2B688 HR (lepidoptera and glyphosate tolerant), the application were at V 5 and V 8 stage. The experiment was randomized block design with four replicates, using the treatments: haloxyfop at 25, 50 and 62 g ha -1 alone and associated with 2,4-D at 670 g ha -1 or fluroxypyr at 200 g ha -1 . The standard was clethodim at 84 g ha -1 with 2,4-D and fluroxypyr at same rates. The applications of haloxyfop and clethodim both isolated or in a mixture with 2,4-D and fluroxypyr at V 5 stage showed total control (100%) at 32 and 39 days after the application, except for haloxyfop + 2,4-D (25 + 670 g ha -1 ) mixture, which did not provided adequate control. At Keywords: enetically modified, in tank mixture, ACCase inhibitors, auxin inhibitors, antagonism, and rampant weed. Palavras-chave: transgênico, mistura em tanque, inibidores da ACCase, inibidores de auxinas, antagonismo, planta daninha. RESUMO -Os

14, 21, 28, 35, 42, 49, 56, 63, 70, 77, 84, 91, 98, 105 and 112 days after emergence. The growth curve of susceptible and resistant biotypes were similar; however, the susceptible biotypes accumulated more leaf dry mass, while the resistant one accumulated more root dry mass. The resistant biotypes exhibited greater competitive efficiency and produced fewer tillers and inflorescences. The resistant biotype of D. insularis would have advantages over the original population of susceptible biotypes in an environment without application of glyphosate due to the low potential of aboveground biomass production and reproduction.Keywords: growth analysis, chemical control, sourgrass, weeds. de 14, 21, 28, 35, 42, 49, 56, 63, 70, 77, 84, 91, 98, 105 RESUMO -Objetivou-se neste estudo avaliar o crescimento e desenvolvimento de biótipos de

The effectiveness of a new product has a great importance to weed control, especially those that are difficult to control or resistant to, such as the sumatran fleabane (Conyza sumatrensis). The objective of this research was to evaluate the control of C. sumatrensis at different growth stages, using halauxifen-methyl in combination with other herbicides. The experimental design used was a randomized blocks in a 3x10 factorial scheme, with four replications. The plants of C. sumatrensis were evaluated at different growth: stage 1: plants with 8 leaves; Stage 2: plants with 19 leaves and stage 3: plants with 45 leaves fully expanded. The herbicides used were the association of glyphosate with the herbicides 2,4-D at 806, 943 and 1,209 g a.e. ha-1, halauxifen-methyl + diclosulam at 5.06 g a.e. ha-1 + 25.52 g a.i. ha-1 and 6.32 g a.e. ha-1 + 31.87 g a.i. ha-1, halauxifen-methyl + 2,4-D at 5.00 + 783 g a.e. ha-1 and 6,0 + 940 g a.e. ha-1 and halauxifen-methyl at 5.0 and 6.0 g a.e. ha-1 and untreated, totaling 10 treatments. The herbicides demonstrated satisfactory control of the plants in Stage 1 at 50 DAA, with the exception of the glyphosate + 2,4-D treatment at the lowest rate. However for Stages 2 and 3 the halauxifen-methyl + diclosulam in both rates, provided superior controls in relation to the other treatments. The control of sumatran fleabane was facilitated when their management occurs in the early stages of development, however independent of the development stage, the best controls obtained were with the treatment containing glyphosate + halauxifen-methyl + diclosulam at 1,440 g a.e. ha-1 + 6.32 g a.e. ha-1 + 31.87 g a.i. ha-1. Thus, combinations of herbicides containing halauxifen-methyl are another option to control C. sumatrensis in agricultural systems.

Recebido para publicação em 16.7.2015 ABSTRACT -Weeds have the potential to dramatically interfere in cassava cultivation, reducing its productive potential; however, there are few studies on the selective herbicides in this crop. Therefore, the objective was to evaluate in this work the selectivity and efficiency of sulfentrazone in cassava crops grown in sandy and clayey soils. Two experiments were carried out: The first one was carried out in sandy soil conditions in the conventional system; and the second one was carried out in clayey soil conditions in the no-tillage system. The experimental design was a randomized block with four replications. The treatments consisted in doses of 250, 500, 750 and 1,000 g ha -1 of sulfentrazone, and weeded and non-weeded controls. Sulfentrazone application in cassava crops has linearly reduced the production of roots in a proportion of 0.0153 and 0.0107 t ha -1 at each increment in grams of the active ingredient, respectively. It was concluded that sulfentrazone was not selective for cassava crops grown both in sandy and in clayey soil; however, it was highly effective in weed control in both soils.

The experiment was conducted in a protected cultivation in the Marechal Cândido Rondon, PR, Brazil. The experimental design was constituted of randomized blocks with six piggery wastewater doses (0, 25, 50, 100, 200 and 400 m³ ha-1) in four repetitions. The variables evaluated were: number of tillers, plant height, dry matter, leaf area, leaf number, potassium content, phosphorus content and crude protein in the culture, leachate and soil analysis. The number of tillers increased linearly with the addition of SRW doses. At the beginning of the development of millet culture, swine raising wastewater (SRW) application causes a decrease in plant height; however, over the course of time, this management increases those values. There was an increase in the number of leaves at the beginning, and leaf area at the end of the development of millet crop. The SRW doses applied did not cause increase in phosphorus and potassium contents in plants, raising only the crude protein. The dry mass is highly influenced by the increase in SRW doses, with their highest levels in a dose of 319.75 m³ ha-1. The SRW doses cause reduction in soil pH and its constituents are not leached.

No abstract

The intensive use of glyphosate can select resistant populations. This study aimed at evaluating the occurrence of glyphosate resistance in populations of D. insularis in agricultural areas. Three experiments were conducted in randomized block experimental design with four replications. The Resistance Degree (RD) was determined by a dose-response curve in the evaluated populations: Experiment 2012, São Camilo (R01 and R02) and Palotina (R03, R04 and S05-susceptible); Experiment 2013 Palotina (R06 and R12), Katueté/Paraguay (R07), Toledo (R08 and R10), Cascavel (R09), São Miguel do Iguaçu (R11), Dom Eliseu/Pará (S13-susceptible); Experiment 2015 Nova Aurora (R14), Iracema do Oeste (R15 and R16), Jesuitas (R17 and R18), Tupãssi (R19), Jotaesse (R20), Espigão Azul (R21) and Palmitopolis (S22- susceptible). In 2012, it was possible to confirm a moderate resistance (RD = 1.1 to 5.0) only in R03; and populations R01, R02 and R04 were highly resistant (RD>5.0). In 2013, populations R09, R10, R11 and R12 showed resistance, while R06, R07 and R08 were highly resistant. In 2015, the R14, R16, R18, R19 and R20 populations showed moderateresistance, and R15 and R18 were highly resistant. Only R21 was susceptible. It was found that 83% of producers use the no-tillage system, 100% use the succession soybean/corn with 90% transgenic varieties, 45% of producers cannot explain the procedure regulation/sprayer calibration. Around 62% use practices to prevent the selection of resistant biotypes. Resistance was confirmed in 89.5% of the populations. The adopted agronomic practices may explain these results.

RESUMOEste estudo objetivou avaliar a fitotoxidez do herbicida mesotriona no desenvolvimento inicial do milho inoculado com Azospirillum brasilense, associado à adubação nitrogenada. O delineamento utilizado foi o de blocos casualizados, em esquema fatorial 2x3, representado por milho com e sem aplicação do mesotriona (192 g ha) e os tratamentos: 1-inoculação das sementes com A. brasilense; 2-aplicação em cobertura de 140 kg ha -1 de N; e 3-A. brasilense + 140 kg ha -1 de N em cobertura aplicado aos 26 dias após a semeadura (DAS). A aplicação do mesotriona foi realizada aos 21 DAS, com avaliações realizadas por 28 dias após a aplicação (DAA). Aos 7 DAA constatou-se redução da taxa de assimilação líquida de CO 2 em 35% nas plantas que receberam aplicação de mesotriona, bem como aumento da atividade da peroxidase e maior degradação de carotenoides. Aos 14 DAA de mesotriona resultou em redução na taxa de assimilação líquida de CO 2 e na transpiração, enquanto aos 28 DAA foi verificado menor altura de plantas, área foliar e massa seca de parte aérea nas plantas com herbicida. A inoculação com A. brasilense + N elevou a atividade das peroxidases aos 7 DAA e auxiliou a manutenção da taxa transpiratória aos 14 DAA. Conclui-se que a inoculação com A. brasilense + N pode minimizar os efeitos danosos causados pelo mesotriona no desenvolvimento inicial do milho.Palavras-chave: bactérias promotoras de crescimento vegetal; herbicida; inibidor dos carotenoides; trocas gasosas Phytotoxicity of mesotriona in corn with Azospirillum brasilense associated nitrogen fertilization ABSTRACTThis study aimed to evaluate the phytotoxicity of the mesotrione herbicide in the initial development of maize inoculated with Azospirillum brasilense and associated with nitrogen fertilization. The treatments were: randomized blocks in a 2x3 factorial scheme, represented by maize with and without mesotrione application (192 g ha -1 ) and treatments: 1-inoculation of the seeds with A. brasilense; 2-Application in coverage of 140 kg ha -1 of N; And 3-A. brasilense + 140 kg ha-1 of N in cover applied at 26 days after sowing (DAS). The application of mesotrione was performed at 21 DAS, with evaluations performed up to 28 days after application (DAA). At 7 DAA a reduction of the net assimilation rate of CO 2 in 35% in the plants with mesotrione was observed, as well as increase of the peroxidases activity and greater degradation of carotenoids in the mesotrione plants. At 14 DAA the mesotrione reduced the rate of CO 2 net assimilation and transpiration, while at 28 DAA, lower plant height, leaf area and shoot dry mass were verified in herbicide plants. The inoculation with A. brasilense + N increased peroxidase activity at 7 DAA and helped maintain the transpiratory rate at 14 DAA. It is concluded that inoculation with A. brasilense + N can minimize the harmful effects caused by mesotrione in the initial development of corn.