Activity of essential oils of Lamiaceae on Ascosphaera apis and treatment of an apiary

The first part of the experiment consists of the measurement of fungistatic and fungicidal activities of essential oils of different Labiaceae: Origanum vulgare (2 varieties), Satureia montana (4 varieties), Thymus vulgaris . In vitro, the most effective oils generally have a rich carvacrol content (higher than 30%). The clone of thyme (number 133) shows anti-fungal properties relatively constant through time. The second part of the experiment is a field study to assay the therapeutic value of an oil, which is active and palatable for bees, the essential oil of savory (Satureia montana ), imported from Albania. This is mixed with sugar-candy (dilution: 0.1%; dose of 1 ml per colony) and fed at the end of wintering (February). Seven colonies were experimentally treated, 7 colonies were unfed and another 7 received simple sugar-candy. The evolution of chalkbrood was estimated by counting, two times a week, the dead larvae gathered at the entrance of the hive, during the 75 following treatment. Under these conditions, the efficacy of the essential oil of savory is significant.