Seasonal Dynamics of Varroa Mite Infestation and Its Impact on Honey Production in Apis mellifera Beekeeping of Chitwan, Nepal

Abstract

Honeybee colony health and productivity are influenced by Varroa mite (Varroa destructor) infestations, which remain one of the most significant challenges in apiculture. To assess Apis mellifera beekeepers’ perceptions of mite infestation across different seasons, honey yield losses due to infestation, and the management practices adopted, a survey was conducted in the Chitwan district of Nepal. A total of 120 beekeepers were selected as respondents, and information on beekeeping was gathered using a pre-tested semi-structured questionnaire. Beekeepers perceived that the prevalence of Varroa mite infestation and honey production varied considerably by season. The majority of respondents reported that mite infestation was higher in spring and summer, when honey production was minimal. Thereafter, infestation gradually decreased, reaching its low level in autumn (10.40%), when honey production increased to 22.60%. In winter, however, mite infestation began rising again, alongside a peak in honey production. The gradual rise in winter mite infestation may be linked to abundant forage availability and increased brood levels. Most beekeepers experienced honey yield losses of 5-15% due to mite infestation, with average losses of approximately 10%, highlighting the considerable impact of mites on honey yield. In terms of colony losses, 25% of beekeepers reported experiencing them, underscoring the persistent threat posed by mites. Regarding management practices, formic acid was the most widely used treatment, followed by combinations of formic acid with local methods. Overall, the findings highlight that mite infestation, though often manageable, reduces honey yield and poses ongoing risks to apiculture.