SYNERGISTIC ACARICIDAL ACTIVITY OF MELIA AZEDARACH AND NIGELLA SATIVA AGAINST VARROA DESTRUCTOR IN APIS MELLIFERA: AN IN VIVO STUDY

Abstract

Varroa destructor is a major ectoparasitic mite threatening Apis mellifera colonies worldwide, causing colony weakening and significant economic losses. With increasing resistance to synthetic acaricides and concerns over chemical residues in hive products, there is a growing need for sustainable and eco-friendly control strategies. This study evaluated the acaricidal and repellent potential of methanolic extracts of Melia azedarach leaves and Nigella sativa seeds, individually and in combination, against Varroa destructor under controlled laboratory conditions. Contact toxicity bioassays revealed dose-dependent mite mortality, with M. azedarach showing the highest efficacy (60–100%) but moderate honeybee toxicity, while N. sativa exhibited moderate mite mortality (22.7–49.3%) with minimal bee mortality. Notably, combined extracts demonstrated synergistic effects, achieving greater-than-predicted mite mortality (53.3%) at lower concentrations, suggesting enhanced efficacy and safety. Repellence assays indicated strong avoidance behavior, particularly for M. azedarach, highlighting the potential dual mode of action. These findings indicate that botanical combinations can serve as effective, environmentally safe alternatives to conventional acaricides, contributing to integrated Varroa management and sustainable apiculture.