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Updated: Mar 5, 2026
Measuring Volatile and Non-volatile Antifungal Activity of Biocontrol Products
Published on: December 5, 2020
Stonebrood and chalkbrood in Apis mellifera causing fungi: in vitro sensitivity to some essential oils
Simona Nardoni1, Carlo D'Ascenzi1, Guido Rocchigiani1
1a Dipartimento di Scienze Veterinarie , Università degli Studi di Pisa , Pisa , Italy.
Abstract:
Aim of the present study was to evaluate the in vitro antimycotic activity of 17 chemically defined essential oils (EOs) both alone and as a mixture, against agents responsible for stonebrood caused by Aspergillus flavus, and chalkbrood caused by Ascosphaera apis in European honeybees. Cinnamomum zeylanicum yielded the lowest MIC value against A. flavus, but was not effective against A. apis, while Litsea cubeba and Pelargonium graveolens appeared to be effective against all checked fungi. Aspergillus niger showed the lower sensitivity. Two mixtures composed by L. cubeba, C. zeylanicum and Cymbopogon flexuosus (M1) and by L. cubeba, C. zeylanicum, P. graveolens and C. flexuosus (M2), respectively, were tested, both resulting effective. The components of M1 showed a synergistic effect. The use of mixtures allowed to decrease the total amount of EOs. The use of these products could be of interest for an alternative natural approach in honeybee disease management.
Insights
Essential oils show promise for managing honeybee fungal diseases like stonebrood and chalkbrood. Certain essential oils and their mixtures effectively inhibit Aspergillus flavus and Ascosphaera apis, offering a natural alternative.
Area of Science:
- Mycology
- Apiculture
- Natural Product Chemistry
Background:
- Honeybee fungal diseases, including stonebrood (Aspergillus flavus) and chalkbrood (Ascosphaera apis), pose significant threats to European honeybee populations.
- Current disease management strategies may have limitations, necessitating the exploration of alternative, natural approaches.
Purpose of the Study:
- To evaluate the in vitro antimycotic activity of 17 chemically defined essential oils (EOs) against A. flavus and A. apis.
- To assess the efficacy of EO mixtures for honeybee disease management.
Main Methods:
- In vitro testing of 17 essential oils (EOs) individually and in mixtures against A. flavus and A. apis.
- Determination of minimum inhibitory concentration (MIC) values.
- Evaluation of synergistic effects in EO mixtures.
Main Results:
- Cinnamomum zeylanicum showed the lowest MIC against A. flavus but was ineffective against A. apis.
- Litsea cubeba and Pelargonium graveolens demonstrated efficacy against all tested fungi.
- Two EO mixtures (M1 and M2) were effective, with M1 exhibiting synergistic effects.
- Aspergillus niger displayed lower sensitivity to the tested EOs.
Conclusions:
- Essential oils, particularly Litsea cubeba and Pelargonium graveolens, show potential as natural agents against key honeybee fungal pathogens.
- EO mixtures can enhance efficacy and reduce the total amount of essential oil required.
- These findings support the use of essential oils as an alternative natural approach for managing honeybee diseases.
