Management of ecto-parasitic mite, Tropilaelaps mercedesae Anderson and Morgan in honeybee, Apis mellifera Lin. colonies in the mid-hill areas of Nepal

The ecto-parasitic mite, Tropilaelaps mercedesae Anderson and Morgan is one of the major limiting factors for both subsistence and commercial Apis mellifera Lin. beekeeping in Nepal. Its management by the beekeepers with chemical application regularly causes resistance in mite and contamination in bee products. So, an investigation was undertaken to explore the acaricidal properties of commonly available organic acid, plant and animal products as alternative methods for honeybee mite management. The ten-frame Langstroth colonies [7-frame honeybees with 5frame brood] were randomly selected and divided into five groups (treatments) with four colonies in each treatment. The treatments were: formic acid (FA) (65% @ 3 ml/frame), glucose powder (GP) (@ 4 g/frame), neem seed powder (NSP) (@ 3 g/frame), 100% cow urine solution (CUS) (@ 5 ml/frame), and control from third week of May to first week of July in the mid-hill areas of Lalitpur district for two consecutive years, 2017-018. The honeybee mite infestation was determined in randomly selected fifty sealed worker brood cells on 1st, 3rd, 6th, 10th and 15th day. The parameters as percent brood infestation by honeybee mite, percentage reduction of mite infestation, efficacy of different treatments, median lethal time in days (LT50) of the treatments and survivable of honeybee mites in different treatments were recorded. The population of mites before the treatment application was found non-significant, while after treatment application mite population varied significantly among the treatments. However, the interaction between year and treatments during entire observation dates were non-significant. In case of honey yield, it was highly significant among the treatments with the highest yield in FA treated colonies. The highest honeybee mite count on brood cells was observed on control colonies (37.37) and the lowest on FA treated colonies (3.62) followed by CUS (7.87), NSP (11.0) and GP (23.38), respectively, on the 15th day after the treatment. Similarly, the percent reduction of honeybee mite was noticed the highest in FA (91.01%) followed by CUS (81.02%), NSP (71.72%) and GP (40.85%) treatments, respectively. Among the acaracidal material evaluated against honeybee mite, the efficacy of FA was found better which increased from 43.08% on the 1st day to 90.52% on the 15th day of observation. All these evidences indicate superiority of FA over other materials investigated for the management of honeybee mite. This was further strengthened with the lowest LT50 value of FA (0.72 days) as compared to other treatments, NSP (0.80 days), CUS (1.34 days) and GP (2.56 days). All these evidences elucidate the use of FA for the sustainable management of honeybee mite, T. mercedesae in A. mellifera colonies, whereas Published with Open Access at Journal BiNET Vol. 23, Issue 02: 1944-1956 Journal of Bioscience and Agriculture Research Journal Home: www.journalbinet.com/jbar-journal.html Ecto-parasitic mite in honeybee, Nepal. 1945 Published with open access at journalbinet.com. EISSN: 2312-7945, © 2020 The Authors, Research paper. application of CUS and NSP are also advisable in the mid-hill areas. FA does not contaminate honey as it is volatile, but precaution should be taken during its application.