In vivo evaluation of the efficacy of Cymbopogon citratus (lemongrass),Allium sativum (garlic), Leptospermum scoparium (manuka), and Litseacubeba essential oils on Varroosis and Nosemosis co-infection in honeybees under field conditions

In this study, the efficacy of four different essential oils; Cymbopogon citratus (CC,Lemongrass), Allium sativum (AS, Garlic), Leptospermum scoparium (LS, Manuka),and Litsea cubeba (LC) against mite and microsporidian infections was evaluated inhives simultaneously infested with Varroa destructor and Nosema spp. Changes inmite and microsporidian loads were analyzed to determine the biological controlpotential of these plant-based treatments. Forty-two hives were divided into sixgroups (four treatment, two control), each consisting of seven hives. Essential oilswere applied to the frames four times at weekly intervals using a spray method inthe treatment groups. The Nosema load was determined using the digestion method,and the Varroa load was determined using the powdered sugar method. The numberof falling mites was calculated using sticky paper placed on the bottom frame of thehive. Nosemosis treatment efficacy was 57.64% (CC), 58.97% (AS), 62.54% (LS),and 66.55% (LC). For Varroa, efficacy was 77.92%, 77.77%, 75.91%, and 79.42%,respectively. All treatment groups showed significant reductions in mite numbersfrom day 0 to 28 (p<0.001). Sticky board counts revealed a progressive declinebetween days 7 and 28 in AS, LS, and LC groups (p<0.001). Nosema spore countsalso significantly decreased in all treatment groups (p<0.001). In this study, essentialoils were found to be effective against Varroa infestation. Chemical residues in beeproducts, especially honey, can be prevented by using plant extracts instead ofchemical agents in Varroa infestations.