Coffee Science_v.16, 2021
URI permanente para esta coleçãohttps://thoth.dti.ufv.br/handle/123456789/12727
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Item Effectiveness and selectivity of herbicides applied under pre-emergence conditions in weed management for coffee crop(Editora UFLA, 2021) Gonçalves Netto, Acácio; Presoto, Jéssica Cursino; Resende, Laís Sousa; Malardo, Marcelo Rafael; Andrade, Jeisiane de Fátima; Nicolai, Marcelo; Carvalho, Saul Jorge Pinto de; Rodrigues, Matheus Rossi; Marçal, Marcela Borges TomásThe coffee plant is sensitive to weed competition, which negatively affects its growth and development. Thus, the proper and safe use of herbicides is extremely important for weed management to allow the crop to develop its maximum productive potential. The objective of this study was to evaluate the control efficacy of different herbicides under pre-emergence conditions and assess their selectivity for coffee crops. Two experiments were carried out in the field, in randomized block designs, with four replicates and eight treatments, totaling 32 experimental plots. The treatments were: unweeded control; weeded control; sulfentrazone + diuron 1.4 L ha-1; sulfentrazone + diuron 1.7 L ha-1; sulfentrazone + diuron 2.0 L ha-1; sulfentrazone + diuron with indaziflam 1.4 + 0.15 L ha-1; respectively, indaziflam 0.15 L ha-1; and oxyfluorfen + chlorimuron 3.0 L ha-1 + 0.08 kg ha-1, respectively. The treatments were applied prior to the emergence of weeds in a directed spray between the crop rows. Evaluations of weed control in the area, phytotoxicity to the crop, branch length, and internode distance of coffee were conducted at 30, 60, 90, and 120 days after treatment application (DAA). In general, all treatments guaranteed greater than 80% efficacy up to 60 DAA. After this, some treatments suffered reductions in efficacy, and did not guarantee satisfactory con trol up to 120 DAA. For Digitaria nuda, the most effective treatments were those that contained indaziflam alone or in combination with sulfentrazone + diuron, and oxyfluorfen + chlorimuron for 60 DAA. In both experiments and the two species analyzed, the indaziflam treatments guaranteed efficacy percentages above 80%, even at 120 DAA. All treatments were equally selective for the coffee plants under the conditions evaluated.Item Resistance and effect of insecticide-treated coffee berries of different varieties to the penetration of Hypothenemus hampei (Coleoptera: Curculionidae: Scolytinae)(Editora UFLA, 2021) Davi Júnior, Salmo de Melo; Soares, Walyson Silva; Celoto, Fernando Juari; Fernandes, Flávio Lemes; Oliveira, Mariana Martins Fernandes; Botrel, Gabriel Buso BorgesThe control of Hypothenemus hampei, coffee berry borer (CBB) is difficult as the insects infest inside coffee berries and are thus protected from agrochem icals. Coffee varieties with an increased penetration time by H. hampei can help control this pest tends to be exposed insecticide action for long time. Therefore, this study aimed to determine the time taken by H. hampei to entirely penetrate berries of different coffee varieties and whether insecticides have any influence on the penetration time. Thus, twenty five berries of 27 coffee varieties in the green phenological stage were introduced in rubber caps, with the berry crown exposed.. From this experiment, seven varieties were selected for another bioassay, with insecticides being sprayed on the berries. Copulated female H. hampei were released on the berry, and the penetration time was assessed. Finally, a free-choice test to verify H. hampei food preference was performed, using the same seven coffee varieties. The insects took longer to penetrate the Arara, Catuaí Vermelho IAC 144, and Guará coffee-variety berries. Moreover, all coffee varieties treated with the insecticide cyantraniliprole inhibited penetration by H. hampei. Most coffee varieties treated with insecticides showed a prolonged penetration time by H. hampei compared to the same untreated ones, except for the chlorpyrifos insecticide in the Catuaí IAC 144 and IAC 62 varieties. Additionally, H. hampei showed no feeding preference among the different tested coffee varieties.Item Control of Digitaria insularis resistant to glyphosate using a combination of herbicides in coffee farms(Editora UFLA, 2021) Onofre, Luís Carlos; Onofre, Thiago Borba; Rezende, Tiago TeruelCoffee has a significant economic, social, and cultural impact on Brazilian society, generating jobs for thousands of Brazilians. Good management practices such as weed control have direct and indirect benefits on coffee yield and quality. Currently, there is an increase in the infestation rate of Digitaria insularis in coffee plantations due to chemical resistance to glyphosate. In the literature, the study of the combination of glyphosate with different herbicides has been investigated, aiming at improving the efficiency of the control of D. insularis. The objective of this work was to evaluate the efficiency of control of the D. insularis in a coffee farm using a combination of glyphosate with clethodim and phenoxaprope-p-ethyl. Trials were conducted in a commercial coffee farm in southern Minas Gerais in a field with a two-year-old cultivar IAC Catuaí 144. The experiment was conducted under a completely randomized design with five treatments and four replications, totaling 20 experimental plots. Thirty and ninety days after application, the number of plant were counted. The results show that the use of glyphosate alone was not efficient to control of D. insularis. The results show that the herbicide mixtures were efficient in the control.