AZEVEDO, P. T. M.; http://lattes.cnpq.br/5702967752747651; AZEVEDO, Plínio Tércio Medeiros de.
Resumo:
This work evaluates the fungitoxic potential of essential oils blends of lemon 'Thaiti',
sweet orange, and mandarin on Colletotrichum gloeosporioides. The experiments
occurred in a completely randomized design in a 7x8 + 2 factorial scheme, with seven
formulations of essential oils (4 mixtures and 3 pure essential oils used as comparatives)
in eight concentrations each (0.0125, 0.025, 0.05, 0.1, 0.2, 0.25, 0.5, and 1.0%), one
negative control (0.0%), and one positive control (commercial Thiram fungicide at the
concentration recommended by the manufacturer - 1 mL L-1 ), with 5 repetitions each.
The different treatments were incorporated into PDA culture medium (Potato Dextrose
Agar) and poured into Petri dishes. The plates containing the treatments were inoculated
with C. gloeosporioides and incubated for seven days at 27±2°C. Growth was measured
daily to calculate the percentage of mycelial growth inhibition and the mycelial growth
rate index. All concentrations of citrus essential oils and the blends inhibited the mycelial
growth of C. gloeosporioides. The pure essential oils of lemon, orange, and tangerine
provided the greatest inhibitions, with average values of 67.7, 56.1, and 55.9%,
respectively. The blends promoted lower inhibitions than the treatment with the
commercial fungicide. We recommend to carry out in vivo tests to verify if the blends of
citrus essential oils have better control over the growth of C. gloeosporioides under field
conditions.