Preventive control of post-harvest diseases in citrus (orange, mexican and lemon) using noni essential oil and Saccharomyces Cerevisiae

Citrus fruits (Citrus) are of great importance in the fruit production chain in Brazil. With a significant contribution to the country's economy. However, post-harvest diseases negatively affect the quality and quantity of fruits that would be marketed. Thus, the main objective of the work was to evaluate the effect of noni essential oil (Morinda citrifolia) and commercial Saccharomyces cerevisiae (Fleischmann) in the control of post-harvest diseases in citrus. The pathogenic isolates were obtained from diseased citrus fruits collected at the local market in the city of Gurupi-TO. Noni essential oil was extracted using the hydrodistillation method. In vitro tests with noni essential oil were performed at concentrations of 1.25; 2.5; 5; 10 and 30 mg mL-1 and a solution based on sterilized distilled water was prepared for the yeast at concentrations of 1%, 2%, 3%, 4% and 5% evaluated for 10 days with intervals of 48 hours maintained at 25 ± 1°C. The phytotoxicity test was evaluated at the same concentrations. For in vivo tests, the same concentrations as in vitro tests were used. The isolated pathogens that attack the fruits in the post-harvest are Penicillium sp., Guignardia sp. and Aspergillus sp. Etiology confirmed by pathogenicity test. By means of gas chromatography (GC/MS) the major compound identified in noni essential oil was octanoic acid (92.02%). The best in vitro fungitastic activity of noni essential oil was achieved at a concentration of 30 mg mL-1, inhibiting the mycelial growth of the pathogens Penicillium sp. and Guignardia sp. at 100%. S. cerevisiae showed better fungitastic activity from the concentration of 3%, 4% and 5% for the pathogen Penicillium sp. with inhibition of 76%, 87% and 88% and Aspergillus sp. with 100% inhibition at both concentrations (4% and 5%). The noni essential oil did not show phytotoxicity in the fruits. The two in vivo treatments showed protective action, especially the yeast S. cerevisiae. Based on the results we can conclude that the essential oil of noni and the yeast S. cerevisiae present themselves as a good alternative in the biological control of pathogens characteristic of post-harvest in citrus fruits.