Prevalence of Brood Diseases in Indian Honey Bee (Apis cerana indica) Colonies: A Kerala Study

Abstract

Aim: The study aimed to assess brood disease incidence in Apis cerana indica colonies across Kerala, analyze seasonal variation, and evaluate the effect of weather and hive conditions on disease prevalence for the management of brood diseases in Indian bee colonies. Study Design: Purposive survey, Correlation (regression) analysis, Temporal/seasonal assessment. Place and Duration of Study: "The survey was conducted in apiaries across Kerala, India, with fieldwork carried out at sites managed by local beekeepers under the academic guidance of the Department of Agricultural Entomology, Kerala Agricultural University, College of Agriculture Vellayani. The study was carried out over a period from February 2024 to March 2025. Methodology: The study involved a purposive one-year survey (Feb 2024-Mar 2025) across Kerala based on the disease incidence information from beekeepers. Geographical data and weather parameters such as temperature (̊C) and relative humidity (%), brood disease incidence, symptoms, & prophylactic management practices followed by the beekeepers were recorded. Observations on the number of infected colonies, its colony strength and infected brood cells were recorded and was correlated with weather parameters of apiary. Results: Of the 1143 colonies surveyed in Kerala, brood diseases were found in 329 colonies (28.78%) with the highest incidence in Kondazhy (90%) of Thrissur and lowest in Muthalamada (4.0%) of Palakkad. Brood disease incidence peaked during the dearth season, followed by brood-rearing and honey flow season. Regression analysis showed a weak negative correlation with temperature (-0.507) and a weak positive correlation with relative humidity (0.191) in the apiaries. Hive temperature showed a strong negative correlation (-12.482), while relative humidity had positive correlation (0.612) with percentage brood disease incidence (%BDI). The symptoms recorded were unsealed brood pattern, young larvae (4–5 days) lying flat in melted condition with degraded tissue, and pre-pupal stages ceasing development with their heads upright in position Conclusion: The study reveals significant brood disease incidence in Apis cerana indica colonies, influenced by environmental factors and colony strength. Hygienic behavior and diverse management practices helps to avoid spread and support recovery from the diseases. These findings highlight the need for integrated, climate-adapted disease management to sustain colony health and optimize honey production in Kerala. Further research is needed to validate and refine these approaches for sustainable apiculture.