Antifungal action of essential oils on Colletotrichum musae in vitro

Abstract

Antifungal activity of essential oils on Colletotrichum musae in vitro

ABSTRACT - Among the phytosanitary problems finded by banana producers is anthracnose, one of the main post-harvest diseases of the crop and the use of fungicides has been the main management method. However, the search for healthy foods, free of chemical residues has increased among consumers. Therefore, the objective of this work was to evaluate in vitro the antifungal efficiency of essential oils from citronella (Cymbopogon nardus), lemon grass (Cymbopogon citratus), clove (Syzygium aromaticum) and basil (Ocimum basilicum) on the mycelial growth of Colletotrichum musae, causal agent of anthracnose in banana fruits. Essential oils were added to the Potato-Dextrose-Agar culture medium at concentrations of 0; 0.5; 1.0; 1.5; 2.0; 2.5 μLmL^-1 and distributed in Petri dishes (90 mm diameter). Mycelial disks (10 mm) from the fungus colony, with 7 days of growth, were inoculated to the center of the Petri dishes, which were incubated at 25ºC with a 12h photoperiod (light/dark) for 8 days. Daily evaluations of colony growth were performed to determine the percentage of mycelial growth inhibition, mycelial growth inhibition and colony diameter average. The experimental design was in randomized blocks, with six treatments (extracts concentrations) and four replications, each extract being evaluated separately. The essential oils from citronella, lemon grass and basil inhibited mycelial growth as the concentration increased, with total inhibition starting at 1.5 µLmL^-1 for citronella and lemon grass, and 2.5 µLmL-1 for basil. The clove essential oil inhibited completely the mycelia growth in the concentration of 0.5 µLmL-1. The essential oils tested showed in vitro antifungal activity against C. musae at different concentrations. Clove essential oil stands out for presenting greater inhibition of mycelial growth in low concentration.