Coffee Science_v.15, 2020
URI permanente para esta coleçãohttps://thoth.dti.ufv.br/handle/123456789/12726
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Item Effect of the impact of rigid rods on coffee fruit detachment efficiency by mechanical vibrations(Editora UFLA, 2020) Gomes, Ely Queiroz; Santos, Fabio Lúcio; Nascimento, Moysés; Velloso, Nara SilveiraThe mechanization of field activities has been the response of coffee producers to the labor shortage, especially for fruit harvesting. The use of mechanical harvesters allows greater harvesting efficiency and ensures the economic viability of coffee plantations, which currently depend mainly on the reduction in production costs. The principle used for mechanized coffee harvesting is based on the principle of mechanical vibration. The objective of this study was to analyze the dynamic behavior of the coffee fruit-peduncle-branch system under mechanical vibration and the impact of the vibrating rods on the fruit detachment process in association with this behavior. Fragments of coffee branches containing fruits in the unripe and ripe stages were used in this experiment. These samples were subjected to different frequencies (20, 30, 40, and 50 Hz) and amplitudes (0.002, 0.003, and 0.004 m). Another variable analyzed was the form of vibration transmission to the fruits, with the vibrations being transmitted to the samples with or without the impact of the fiberglass rods. The fruit detachment efficiency increased as the ripening stage progressed from unripe to ripe. A higher detachment efficiency occurred with the increase in vibration frequency and amplitude because of the higher vibrational energy imposed on the fruit. The detachment efficiency was low when the vibration was transmitted without the impact of the rods. Conversely, the vibration in combination with impact achieved a mean detachment efficiency of approximately 90%.Item In vivo compatibility between Beauveria bassiana (Bals.) Vuillemin and castor oil on Hypothenemus hampei (Ferrari)(Editora UFLA, 2020) Celestino, Flávio Neves; Pratissoli, Dirceu; Santos Junior, Hugo José Gonçalves dos; Machado, Lorena ContariniThe degree of in vivo compatibility between the entomopathogenic fungi Beauveria bassiana (Bals.) Vuillemin (Ascomycota: Hypocreales) and castor oil is important, as the interaction can be additive, synergistic or antagonistic. Thus, the objective of this study was to evaluate the in vivo compatibility between castor oil and B. bassiana on the coffee berry borer. The CCA-UFES/Bb-4 isolate of B. bassiana was used in concentrations of 0.0 (control), 1 x 104, 1 x 105, 1 x 106 and 1 x 107 conidia mL-1. The concentrations of castor oil were: 0.0 (control), 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0% v v-1. The total and confirmed mortality were evaluated, and data submitted to variance analysis. To verify the effect of B. bassiana and castor oil concentrations, the data were submitted to regression analysis at 5% probability. Castor oil had an antagonistic effect on B. bassiana reducing the mortality of coffee berry borer. The mortality of H. hampei reduced caused by interaction between B. bassiana and castor oil, due to increasing concentration of castor oil. Lower interference of castor oil was observed for high concentrations of B. bassiana. Based on the results, management of H. hampei cannot be normally performed using the association between castor bean oil and B. bassiana, except if the economic viability of the higher concentrations justified.