Teor do óleo essencial de Croton pulegiodorus Baill de diferentes locais de coleta e controle in vitro de fitopatógenos

Abstract

The Croton species originating in the Northeast are known with the popular names of limb, cinnamon and candles and poseen essential oils of economic interest, due to their antimicrobial action. Various pathogenic fungi are responsible for production losses in agriculture, such as: Aspergillus sp. and Fusarium sp. Therefore, proposing innovations with essential oil in the control of pathogenic fungi becomes of great value in efficient productive agroecosystems, since they generate natural products that help in the self-regulation of agriculture. Thus, the study aimed to verify the essential oil content of Croton pulegiodorus and the in vitro activity in the control of phytopathogens Aspergillus welwitschiae and Fusarium oxysporum sp. cubense. The work was carried out at the Photochemical Laboratory of block L in Center for Agricultural, Environmental and Biological Sciences/CCAAB, of the Federal University of Recôncavo da Bahia/UFRB. The essential oils were extracted in a Clevenger apparatus, using the hydrodistillation method, for 2.5 hours. In vitro tests were carried out (mycelial growth inhibition test) with different concentrations of essential oil of Croton pulegiodorus (0.5; 1.0; 2.0; 4.0; 6.0; 8.0 and 12 μL.mL-1) proving the direct effect of the treatments on the fungi. The data obtained were analyzed using the statistical software R. The essential oil content of Croton pulegiodorus was 2.56%. In the antifungal assays, the phytopathogens A. welwitschiae and F. oxysporum present a minimum inhibitory concentration (MIC) of 4 and 8 μL.mL-1. A. welwitschiae subjected to the volatile method, the best result is obtained at a concentration of 12 μL. In the method of diffusion in medium, the best results of fungistatic effect were observed in the concentration of 2.0 μL.mL-1 for the two phytopathogens. The fungicidal effect is obtained at a concentration of 4 μL.mL-1 in both phytopathogens. Complete inhibition of fungi in direct contact with essential oil diluted in PDA medium was 4 μL.mL-1 for both phytopathogens. The levels of essential oils were influenced by collection locations and light intensity. The results obtained indicate that the essential oil of Croton pulegiodorus is effective in the control of phytopathogens that cause red pudrición del Sisal and fusariosis in banana.