Chilean Aloysia essential oils: A medicinal plant resource for postharvest disease control

Plant pathogenic fungi, such as Botrytis cinerea and Monilinia spp., cause substantial pre- and post-harvest losses, raising food safety concerns due to mycotoxin production [ 1 ]. Current control methods using synthetic fungicides face increasing resistance and environmental risks. This necessitates exploring sustainable alternatives like essential oils from medicinal plants for safer and more effective disease management. Essential oils from medicinal and aromatic plants are emerging as a promising alternative due to their lower toxicity and biodegradability. This research focuses on Aloysia citriodora (Lemon Verbena) and Aloysia polystachya (Burrito), South American aromatic plants with antifungal and antibacterial potential [ 2 ] [ 3 ]. However, there is a lack of information regarding the chemical composition and biological activities of their essential oils in combating postharvest fungi, especially in specimens cultivated in the central arid zone of Chile, justifying the need for further investigation. In this study, the chemical composition and efficacy of essential oils extracted from A. citrodora and A. polystachya and their respective major compounds against postharvest rot fungi in stone fruits were investigated. The GC-MS analysis of essential oils revealed compositional differences. A. citrodora is characterized by spathulenol and caryophyllene oxide as major components, along with smaller amounts of geraniol and farnesol. Conversely, A. polystachya is distinguished by the dominance of carvone, followed by dihydrocarvone and limonene. The antifungal activity of the essential oils and their major compounds was evaluated, highlighting the effectiveness of A. citrodora oil and farnesol against M. fructicola and B. cinerea . Against M. fructicola , A. citrodora oil and farnesol exhibited EC50 values of 61.89 ug/mL and 72.18 ug/mL, respectively, with conidial inhibition exceeding 75%. Against B. cinerea , the EC50 values were 85.34 ug/mL ( A. citrodora oil) and 47.6 ug/mL (farnesol), with conidial inhibition surpassing 50%. These results suggest that A. citrodora oil holds significant potential for application in the agricultural industry. Given its comparable effectiveness to natural fungicides like BC1000, its action could be further enhanced by loading it onto nanoemulsions and combining it with farnesol to potentiate its activity. Publication History Article published online: 05 March 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany