Plant Essential Oils Used Against Some Bee Diseases

The most common honey bee diseases are American foulbrood (AFB) caused by the bacterium Paenibacillus larvae, Chalkbrood caused by fungus Ascosphaera apis and diseases caused by parasitic mites such as Acarapis woodi, Varroa destructor. These diseases and pests not only cause economic loss but also cause ecological problems related to the role of honey bees, as the most important pollinators on Earth. Synthetic acaricides and antibiotics are used to keep the diseases and mites in control. Use of the drugs lead to the development of drug-resistant organisms, detrimental effect on non-target organisms and the residue problem in bee products. For this reasons, the need for alternative control methods has become compulsory in recent years. It has been known that some plant oils used widely in perfumery and food industry for flavor and smell have been used as repellent to certain insects, bactericide and fungicide. Therefore, intensive studies have been carried out on plants with anti-mites, antibacterial and antifungal potentials and these studies are still going on. Recently, studies in this area have shown that essential oils of plants such as thyme, cloves, mint, lemon grass, cinnamon, grapefruit, rosemary, marigold, are lethal to some mites, bacteria and fungi. In addition, it has been reported that some components, isolated from these plants such as sanguinarine, thymoquinone, capsaicin, carvacrol, citral, eugenol, thymol, show these effects on the organisms. As a result, in countries rich in biodiversity due to endemic plant species, the essential oils used in control of these diseases should be favored instead of or in combination with conventional drugs in integrated the disease management programs because of the lack of harmful effects of essential oils on non-target organisms and environment.