Evaluation of the antifungal activity of regional essential oils against Botrytis cinerea

ARECO, VANESSA A.; ACHIMÓN FERNANDA; ZUNINO, MARÍA PAULA; YARYURA PABLO

Congreso; XVIII Congreso Argentino de Microbiología General, SAMIGE 2022; 2022

Botryitis cinerea is a phytopathogenic, necrotrophic fungus, agent of gray mold, a disease that affects numerous species of agronomic importance and causes considerable economic losses. Its main method of control is carried out by chemical fungicides, but their improper use has led to the development of resistance. Then, new forms of control are needed to guarantee the maintenance of yields. Plant essential oils (EOs) have in their composition terpenic compounds, phenylpropanoids, among others, with functions linked to the body's defense against various pathogens. Its use as an alternative to chemical pesticides has multiple advantages, since they are biodegradable and safe for health. Aloysia polystachya is a herbaceous species, native of South America, whose EO is rich in oxygenated monoterpenes. The objective of the present work was to evaluate the antifungal activity of the EO of two populations of A. polystachya on B. cinerea.Materials and methods: The determination of the chemical composition of the EOs was carried out by GC/MS. The antifungal activity of the EO of both populations was evaluated by the fumigant method, using 5 concentrations (23.6, 47.2, 71, 94.5 and 189 µL/mL of air). In addition, the effect of the different concentrations of the EOs on the germination of conidia was evaluated and the morphology of the hyphae of B. cinerea under the different treatments was analyzed by means of scanning electron microscopy (SEM). The results were analyzed using one-way ANOVA and Kruskal-Wallis test using Infostat software. Results: It was determined that the EOs used correspond to two different chemotypes, one whose main component was carvone, and the other with thujone as the main constituent. The EO rich in carvone produced the inhibition of mycelial growth for all the concentrations studied, the MIC being 71 µL/mL of air. The antifungal activity of the thujone-rich chemotype was moderate, compared to the carvone chemotype, and itsMIC was determined for 189 µL/mL of air. All treatments significantly (P