Effect of seasons on chemical composition and fungitoxicity of Cymbopogon citratus (DC) Staf essential oil

The study aimed to evaluate the chemical composition and the fungitoxicity of Cymbopogon citratus (DC) Staf essential oil, obtained in different seasons of the year. Therefore, C. citratus leaves were harvest at four seasons (summer, fall, winter and spring) and essential oil extracted by hydrodistillation of freshly harvested and dried leaves, with a total of eight samples. Yield was expressed in percentage and the fungitoxicity was evaluated in vitro on Colletotrichum gloeosporiodes (Penz.) Penz. & Sacc the causal agent of anthracnose at different concentrations (0, 0.25, 0.5, 0.75 and 1 µL mL-1, respectively). The qualitative analysis of essential oil samples was made using gas chromatography coupled to mass spectrometry (GC-MS). The essential oil of freshly harvested leaves had a higher yield (0.25%) in the summer, whereas the essential oil of dried leaves had a better yield (0.48%) in the fall. In in vitro tests, concentrations of 0.75 and 1 µL mL-1 significantly inhibited mycelial growth and sporulation, in all samples. In the quantitative analysis, there was a variation in the levels of oil compounds observed in the different seasons. The most abundant compound in essential oil was citral (neral and geranial mixture) and myrcene. However, the variation in the compounds’ levels had no influence on the fungitoxicity of C. gloeosporiodes (Penz.) Penz. & Sacc. Key words: Lemongrass, citral, anthracnose, seasons, yield.