Atividade do óleo essencial extraído das acículas de Pinus spp. como controle da ação do fungo apodrecedor de madeira - Postia placenta (Fr.)

Abstract

Research related to the application of essential oils provides knowledge about their antimicrobial properties, providing important information for the generation of new products and their final use as a bioinsecticide in biological control. The objective of this work was to evaluate the antifungal potential of essential oil extracted from Pinus spp. in the control of the action of the wood rot fungus Postia placenta (Fr.). The samples were collected and prepared in the laboratory of the Federal Technological University of Paraná, Campus Dois Vizinhos. For the performance test of essential oil extracted from Pinus spp. 350 g of green needle mass sample was weighed on a semi-analytical scale, after which 1 liter of distilled water was added to the volumetric flask, which were subsequently subjected to hydrodistillation for four hours in a modified Clevenger-type extractor. Evaluating two different periods of needle collection to test its performance in extracting the essential oil from Pinus spp. needles. For the analysis of the vegetative structure of the fungus P. placenta, the microculture technique was used. To visualize the structures, spores and hyphae were observed with the aid of a Zen optical microscope through the ZENZEISS software, the reproductive structures of the fungus were observed on a 40x objective, and the structures of interest were thus photographed. In order to evaluate the antimicrobial potential of the essential oil against the fungus P. placenta, the methodology of Microdilution in Broth in Elisa Plates was used to determine the Minimum Inhibitory Concentration (MIC). Successive dilutions were carried out, removing 100 μL of extract from the firstcolumn and transferred to the second well, the solution was homogenized and again 100 μL was removed from the second well and transferred to the third. This process was repeated until the last well. With the diluted solutions, 20 μL of previously adjustedfungal solution was added to each well. The evaluations were carried out according to the color of the wells, where the pink color or with reddish tones indicate the cellular respiratory activity, suggesting the presence of active microbial. The study carried out through the accelerated rot test was conducted in accordance with ASTM D 2017 -05 with adaptations. Through the result of the calculation of the yield of the extraction of essential oils from Pinus ssp. needles, we recommend that you should proceed with the collection of needles in the morning and have already undergone the extraction process immediately. In the study, the spores and hyphae were observed with the aid of a microscope, making it possible to visualize the presence of vegetative structures of the fungus P. placenta, in addition to the presence of its well-defined hyphae and the presence of spores. Through the analysis of the Minimum Inhibitory Concentration -MIC it was verified that all the tested concentrations caused significant effects in the inhibitory control of the fungus P. placenta through the essential oil extracted from Pinus spp.. The used concentrations of essential oil extracted from Pinus ssp. needles showed significant effects in controlling the growth of the fungus P. placenta.