Economic Benefits of Using Essential Oils in Food Stimulation Administrated to Bee Colonies

Bees are the most important pollinators of agricultural plants. The decline of bee colonies is caused by a multitude of factors of which diseases, pesticides, and climate change seem to be the most important. Losses can be huge when several factors act together. In recent years, there has been a growing interest in the use of alternative sources such as medicinal plants in the form of extracts or essential oils. The purpose of our research was to evaluate the economic efficiency of the use of essential oils of basil (<i>Ocimum basilicum</i>), cinnamon (<i>Cinnamomum veruum</i>), clove (<i>Syzgium aromaticum</i>), juniper (<i>Juniperus communis</i> L.), oregano (<i>Oreganum vulgare</i>), mint (<i>Mentha piperita</i>), rosemary (<i>Rosmarius officinalis</i>), and thyme <i>(Thymus vulgaris</i> L.) in the additional feeding of bee colonies in the spring. Ninety colonies of <i>Apis mellifera</i> bees were used, which were additionally fed with sugar syrup and one of the essential oils. Our results showed strong positive correlations between the total number of germs in the gut of worker bees and the number of brood cells when using the essential oil of oregano (<i>Oreganum vulgare</i>) (R² = 0.786) and thyme <i>(Thymus vulgaris</i> L.) (R² = 0.729), and between the total number of germs and the yield of honey obtained at the first harvest in the case of the essential oil of basil (<i>Ocimum basilicum)</i> (R² = 1), mint (<i>Mentha piperita</i>) (R² = 0.718), oregano (<i>Oreganum vulgare</i>) (R² = 0.621), and Thyme <i>(Thymus vulgaris L)</i> (R² = 0.859). The best profit from the sale of honey was obtained in the case of the use of essential oils of mint, oregano, thyme, and basil, in a range of EUR 139.16–144.73/bee colony.