Evaluación de la actividad antifúngica in vitro de aceites esenciales microencapsulados frente a Cladosporium fulvum Cooke

Abstract

Tomato leaf disease caused by the phytopathogenic fungus Cladosporium fulvum Cooke is a high-impact phytopathological problem, especially in greenhouse production systems, where humidity favors its development. Both globally and in Ecuador, its control has traditionally been based on the application of chemical fungicides, contributing to the recurrent use of these products, generating resistance in the pathogen, increasing production costs, environmental risks, and affecting human and animal health. This situation highlights the need to implement sustainable alternatives for the management of leaf diseases. Among these alternatives, essential oils (EO) stand out, widely reported for their antifungal activity. However, their volatility and limited stability in aqueous media restrict their direct application. In response to this, this study evaluated the efficacy of microencapsulated essential oils (MEO) of basil and geranium, obtained by spray drying using a polymer mixture composed of 20% pure EO and 80% maltodextrin and gum arabic. Antifungal activity was determined by mycelial growth inhibition (MGI) in PDA medium and mínimum inhibitory concentration (MIC) using the microdilution method in PDB with Alamar Blue as a viability indicator. The results showed that both A.E.Ms were highly effective: basil A.E.M completely inhibited the growth of C. fulvum at 2.5%, while geranium A.E.M achieved 100% inhibition at 1.25%. The Alamar Blue microdilution method presented limitations due to interference from turbidity and phase separation of the microencapsulation. Overall, the results show that microencapsulated essential oils represent an ecological, efficient, and promising alternative for the sustainable management of gray mold in tomato cultivation.