IMPACT OF ACARICIDES ON VARROA DESTRUCTOR INFESTATION IN HONEYBEE COLONIES (APIS MELLIFERA) AND THEIR HISTOLOGICAL EFFECTS ON HYPOPHARYNGEAL GLANDS.

Abstract

This study aimed to determine the random role of some acaricides, which are the most commonly used in Egypt for controlling Varroa destructor on Hypopharyngeal Glands of honeybee. The acaricides used in this study were Varroakiller, Menthocaros, Amitraz, Varroby, and formic acid. Results showed that the total number of fallen mites was 53.5, 47, 28.6, 26, and 24.5 for Varroakiller, Menthocaros, Amitraz, Varroby, and formic acid, respectively, compared to 16 mites in the control group. For sealed worker brood areas (SWBA), the treatments included Varroakiller (129.125 in2), formic acid (90.125 in2), Varroby (87.50 in2), Menthocaros (51.07 in2), and Amitraz (40.05 in2), while the SWBA for control colonies was 17.65 in2. Histological studies of the hypopharyngeal gland showed that although, Varroakiller effectively controlled Varroa mites and had no direct impact on worker bees or egg-laying areas, it considerably impacted the hypopharyngeal glands, which could ultimately affect the bee colony. Moreover, formic acid recorded a lower number of fallen Varroa with acceptable outcomes for egg-laying areas and sealed workers. This, coupled with the fact that formic acid was deemed the most significant due to its effectiveness over a short period, resulted in a reduction percentage of 100% after 24 days.