CSBA Issues
Pests & Disease
The unexpected emergence of Colony Collapse Disorder (CCD) in 2006 brought the plight of honey bees to global attention, highlighting numerous challenges faced by beekeepers.
While scientists and beekeepers now agree that CCD was caused by a combination of environmental and biological factors and is no longer a primary cause of colony loss, the issue of high colony losses persists worldwide.
It is not uncommon for the national average honeybee colony loss to reach 50%, with the most recent reports citing losses up to 70% over the 2024-2025 season.
Colony losses stem from a multitude of causes. Honeybees are subject to a wide range of pests, pathogens, viruses and bacteria. But the parasitic Varroa mite (Varroa destructor) remains the most significant challenge for beekeepers. This mite feeds on the fat bodies of both developing and adult bees, suppressing their immune response and making them more susceptible to other stressors.
Furthermore, Varroa mites are vectors for pathogens, particularly viruses, with over 40 identified as being associated with honey bees. The Varroa-vectored Deformed Wing Virus is particularly devastating, leading to significant colony losses worldwide. This virus causes wing deformities in bees, preventing them from performing essential tasks like foraging.
Beekeepers often rely on miticides to manage Varroa infestations. However, resistance to the few available miticides is rapidly developing, exacerbating the problem. In response, researchers and beekeepers are working together to develop sustainable solutions, including novel miticides and delivery systems, temperature manipulation and breeding programs for Varroa-resistant or tolerant honey bees.
Honey bee colonies can also harbor other pests, such as small hive beetle and wax moth.
Bacterial diseases of honey bees include American Foulbrood and European Foulbrood. To prevent antibiotic resistance, beekeepers have needed veterinary prescriptions or veterinary feed directives.
This requirement has complicated rapid disease management, as it necessitates a veterinarian-patient relationship. Veterinary education in the U.S. rarely includes apiculture training, leaving few professionals equipped to provide these services. Universities are now developing programs to train veterinarians in bee biology and beekeeping practices.
Parasitic microsporidia from the genus Vairimorpha (Nosema spp.) also impact honey bee health, attacking gut cells and reducing nutrient uptake. This infection leads to the eventual death of individual bees and, potentially, entire colonies. Preliminary testing among California beekeepers indicates low levels of Nosema infection, but larger-scale studies are needed to understand its epidemiology better.
Fungal diseases like chalkbrood (Ascosphaera apis) often arise in stressful conditions, such as increased humidity or poor nutrition. With no effective treatments available, management focuses on prevention and sanitation.
The beekeeping industry also faces constant risks from emerging threats due to global mobility. One such threat is the Tropilaelaps mite (Tropilaelaps spp.), currently found in Asia but spreading to the Middle East, Africa, and Papua New Guinea. Like Varroa mites, Tropilaelaps mites have the potential to devastate beekeeping unless proactive measures are taken. Research is urgently needed to study dispersal patterns, biology, and management, as well as to implement rigorous monitoring programs.