Nosema: The Silent Stressor in the Hive Part 3: How Beekeepers Are Managing It Today

If you’ve followed our series so far, you know that Nosema isn’t just a seasonal nuisance—it’s a parasite that slowly chips away at your colony’s strength. By now, you also understand how it can open the door to higher viral loads that may contribute to colony collapse. In this final part, we’re focusing on what you can do about it.

Start with Prevention

The best way to manage Nosema is to prevent it from gaining a foothold. Infections usually take off when bees are already stressed by poor forage, damp hives, weak queens, or overcrowding. Here’s what works in real-world apiaries:

• Feed Well: Make sure your bees have access to a well-rounded diet, especially during spring buildup and fall preparation. When natural pollen is limited, supplement with protein patties that contain 20–25% protein. We’ve found that higher-protein diets may help bees better withstand Nosema pressure—a topic we’ll explore in more detail in an upcoming article.

• Keep Hives Dry and in the Sun: Moisture worsens Nosema’s effects. Sunlight not only helps bees take cleansing flights but also reduces moisture-related stress.

• Rotate Out Old Comb: Spores cling to wax and residual fecal material. Regular comb replacement is a simple, cost-effective insurance policy.

• Use Moisture Boards or Insulated Lids: In areas prone to cold and damp conditions, these can help reduce condensation inside the hive.

• Don’t Overcrowd Your Yard: Excessive hive density increases drifting and robbing, which spread Nosema spores.

• Practice Good Apiary Hygiene: Wear nitrile gloves when inspecting your hives, and disinfect your hive tools between colonies by either flaming them or dipping in a 5% bleach solution.

Homemade protein patty and Nozevit syrup, used to support colony health under Nosema pressure.

Test Before You Treat

It’s important not to rush into treatments without knowing what you’re dealing with. The only reliable method is to test your colonies. If you can’t do microscopy yourself, send your samples to a reliable lab (like BVS, Inc.). If a colony shows a spore count of more than 1 million spores per bee—and it’s also underperforming—it may be time to consider intervention.

Natural Approaches That Beekeepers Are Using

With fumagillin falling out of favor, many beekeepers are turning to more natural methods to support colony recovery and resilience:

Thymol

Derived from thyme oil, thymol offers antifungal properties and may help lower Nosema levels when added to syrup or patties. It isn’t a cure-all, so be sure to use it in measured doses; too much can deter bees from feeding, or even kill them.

Probiotics & Supplements

Some beekeepers incorporate probiotic blends, vitamins, or amino acid-based feeds into their regimens. These supplements don’t directly reduce Nosema spores, but they can support gut health and immune function after periods of stress or high infection.

Nozevit

Nozevit, an extract made from oak bark, has been used in Europe for years to manage Nosema. Whether sprayed on bees or mixed into feed, many treatment-free beekeepers report anecdotal success with it, especially when used preventively during the fall or spring.

For Heavily Infected Colonies

If a colony is badly infected and you prefer to avoid chemical treatments:

• Perform a “Shook Swarm”: Shake the bees onto new, clean foundation, leaving behind all the old brood comb. This method removes a significant amount of the accumulated spore load.

• Feed Immediately: Provide plenty of syrup and protein so the bees can quickly rebuild comb and recover.

• Sanitize Old Equipment: Dispose of or properly disinfect old frames and tools to prevent future contamination.

What About Fumagillin?

Fumagillin was once the go-to treatment for Nosema. However, its use has declined for several reasons:

• It’s no longer approved in the EU and has limited availability in the U.S.

• There are concerns over residues in honey.

• It may harm queens and young bees if overused.

• Its effectiveness—especially against Nosema ceranae—is inconsistent.

For most beekeepers today, fumagillin isn’t part of routine management. If you decide to use it and it’s legally available in your area, follow label instructions carefully and avoid using it during honey flows.

Final Takeaway

Nosema may be a silent invader, but its impact is anything but silent. It shortens bee lifespans, weakens colonies, and opens the door to dangerous viral infections. The key is to stay proactive: maintain strong colony practices, test regularly, and use natural interventions when possible. With the right management, you can keep Nosema under control and give your colonies a better chance to thrive—even in tough times.