RESUMO A amostragem é um dos procedimentos básicos (0,30; 0,40 e 0,50m Palavras-chave: MIP, pano-vertical, pano-de-batida,Anticarsia gemmatalis, Piezodorus guildinii. ABSTRACT Sampling is a key component in the Integrated

ResumoA espécie Conyza bonariensis (L.) Cronquist, conhecida por buva, pertence à família Asteraceae e é originária da América do Sul. Apresenta ciclo de desenvolvimento anual e é prolífica, podendo produzir até 200.000 sementes por planta, estabelece-se em diversas condições climáticas, apresenta boa adaptabilidade, sendo, geralmente, considerada planta daninha, mas também usada como medicinal. Para auxiliar na identificação precisa dessa espécie, este trabalho teve como objetivo realizar a caracterização citogenética, partindo de sementes coletadas em populações ocorrentes na região do planalto médio do Rio Grande do Sul. Para determinação do número de cromossomos, as sementes foram colocadas para germinar em placas de Petri com papel filtro duplo no germinador a 20 o C. As radículas com 2 a 5 mm de comprimento foram coletadas e submetidas ao pré-tratamento a frio (4 o C) por 18h, fixação em etanol: ácido acético (3:1) por 24h a temperatura ambiente e conservação em álcool 70% sob refrigeração até o uso. Para o preparo das lâminas, as radículas foram hidrolisadas em HCl 2N por 5 min, lavadas em água destilada e coradas com orceína acética (2%) pela técnica de esmagamento. As lâminas foram analisadas em microscópio ótico com auxí-lio da objetiva de 40x e 100x. Os resultados obtidos para as populações oriundas [39][40][41][42][43][44][45][46][47][48] 2012 40 de diferentes locais do RS foram 2n=4x=36 cromossomos para as populações de Júlio de Castilhos, Tupanciretã, Cruz Alta, Victor Graeff; e 2n= 5x= 45 para a população de Não-Me-Toque, correspondendo morfologicamente a Conyza bonariensis var. microcephala (Cabrera) Cabrera, com exceção da população de Tupanciretã, a qual se trata de Conyza bonariensis var. bonariensis. Palavras-chave: Asteraceae, buva, número de cromossomos, planta daninha. AbstractThe species Conyza bonariensis, known as hairy fleabane, belongs to the Asteraceae family and has its origin in South America. It has an annual cycle of life, being prolific and able to produce up to 200,000 seeds per plant. It occurs in various climatic conditions, showing good adaptability, and is generally considered weed, but also used as medicinal. To help on the identification of this species, the study aimed to perform cytogenetic characterization, starting from seeds collected of populations occurring in the higmedium plains region of Rio Grande do Sul. To determinate the number of chromosomes, the seeds were germinated and the root-tips with 2-5 mm in length were collected and subjected to cold pretreatment (4°C) for 18h, fixed in ethanol: acetic acid (3:1) for 24h and kept in 70% ethanol under refrigeration. For the preparation of slides, the root-tips were hydrolyzed in 2N HCl for 5 min and stained with acetic orcein (2%) by the squashing technique. The results were 2n = 36 chromosomes to populations of Julio de Castilhos, Tupanciretã, Cruz Alta, Victor Graeff; and 2n = 5x = 45 for the population of Nao-Me-Toque, morphologically corresponding to Conyza bonariensis var. microcephala, except the populatio...

Weed control using herbicides with the same mechanism of action can encourage the emergence of resistant biotypes or tolerant plants. An example of this is the occurrence of morning-glory (Ipomoea sp.) in soybean crops in southern Brazil. In this sense, the aim of this study was to quantify the losses arising from two species of morning-glory weeding coexisting with soybean crop. A field study was conducted in the 2013/2014 season. The experimental design was a randomized block with four replications, with treatments being distributed in a factorial arrangement (2x2x5), which assessed the effect of competition on two soybean cultivars (TEC6029 and TEC7849) of morning-glory species (I. triloba and I. purpurea) in different population (0, 4, 8, 16 and 32 plants m-2). The interaction of soybean with different densities of morning-glory affects yield components. The first eight morning glory plants have a more intense competition, reducing productivity by 45% and 27% for TEC6029 and TEC7849 cultivars, respectively.

Integrated management practices should be recommended to avoid damage of glyphosate-resistant hairy fleabane [Conyza bonariensis (L.) Cronquist] on the soybean. This study aimed to evaluate the effect of soil cover plants and chemical control on the glyphosate-resistant hairy fleabane. Field experiment was performed in a randomized block design, with treatments arranged in a factorial scheme (3x10), using subdivided plots and four replicates. The main factor was composed by three types of soil cover (black oat, wheat and fallow), and on the subplots were evaluated the glyphosate+2,4-D amine in a tank-mix applied at 14 DBS (days before sowing) with sequential application of paraquat+diuron at 01 DBS; burndown performed at 07 DBS using glyphosate alone or applied in a tank-mix with clorimuron-ethyl, diclosulan, imazethapyr, sulfentrazone, and flumioxazine; glyphosate alone applied at the V 4 phenological development stage of the soybean, and control without application on Roundup Ready ® soybean. The hairy fleabane sensitivity to glyphosate was previously evaluated by the dose-response curve. Hairy fleabane demonstrated low sensibility to glyphosate, with 17,280 g a.e. ha-1 needed for a 90% reduction of dry weight. Wheat or black oat reduced the hairy fleabane population density by 95% and its plants height by 90% when compared to fallow, allowing the increased herbicide efficacy, regardless of the tank-mix. For the fallow, the tank-mix of glyphosate+2,4-D amine (1,080+1,340 g a.e. ha-1) herbicides with a sequential application of paraquat+diuron (200+100 g a.i. ha-1) provided a better control level during the evaluated period, protecting the yield potential.

The objetive of this study was to identify the effects of aluminum concentrations and pH levels of solution on germination of Echium plantagineum L. seeds. Three different experiments were carried out in completely randomized design with four repetitions. In the first experiment, we used aluminum sulfate solutions in concentrations of 0.0; 0.3; 0.6; 1.0; 2.0; 3.0; 4.0; 5.0; 6.0 and 7.0 cmolc L -1 and in the second experiment, solutions with different pH, 3.0; 4.0; 5.0; 6.0; 7.0; 8.0; 9.0 and 10.0. In the third experiment, we carried out a factorial (4x4) with aluminum sulfate solutions (0.0; 2.0; 4.0 and 6.0 cmolc L -1 ) and pH (4.0; 5.0; 6.0 and 7.0). It was evaluated the germination of Echium plantagineum L. at four and 14 days after seeding (DAS), germination speed index, primary root length, aerial part and dry mass of seedlings. The presence of aluminum reduced the germination by 27 and 40% at four and 14 DAS, respectively, in concentrations superior to 3.0 cmolc L -1 . The three growth parameters presented linear reduction with the increase of aluminum concentrations. In the second experiment, the solutions with pH of 3.0 and 10.0 provided increases in germination, length of root and aerial part, and little influence in the dry mass of seedlings. In the third experiment, there was significant interaction between the aluminum concentrations and pH levels of substrate. The presence of aluminum in the substrate presented toxic effect on germination of seeds, length of seedlings and dry mass. The pH of the solution has little effect in germination of seeds and in the growth of seedlings of E. plantagineum.

Italian ryegrass (Lolium multiflorum Lam.) is a troublesome weed widely found in temperate Brazilian fields with several herbicide-resistant populations. Soil seed bank is the main source of future infestations and can be strongly affected by agricultural practices, such as crop rotation and tillage system. Therefore, this study evaluated the long-term effects of different crop rotation and tillage systems on the seed bank of Italian ryegrass. Data were collected in 2012 and 2013 in a field managed since 1985 under conventional-tillage and no-tillage and subjected to three cropping systems (monoculture, total, and partial rotation) compared to the control plot. The samples were collected at three soil depths (0-5, 5-10, and 10-20 cm) using a cylindrical soil sampler, and infestations in the field were evaluated with a sample frame of 1 m 2. All cropping systems reduced the soil seed bank of Italian ryegrass, regardless of soil management and sampling depths comparing to the control plot. Total and partial rotation were more effective than soil tillage to reduce the seed bank. A larger number of seeds was observed on the surface layer (0-5 cm) for all cropping systems with more uniform distribution in the soil profile in conventional-tillage. Infestation of Italian ryegrass was greater for monoculture under no-tillage in both years, whereas in total and partial rotation, regardless of soil tillage, infestations remained below 40 seedlings m-2. Thus, strategies to reduce the soil seed bank and infestations of Italian ryegrass should focus on cropping systems with crop rotation and no-tillage.