Of all the brood diseases, American foulbrood is the most destructive. It may not be as common as varroa mite or small hive beetle, but it should be the most feared.
Beekeepers have limited options when treating AFB, so they’re best to focus on preventative measures. While there are no guarantees your hives will remain AFB-free, you’ll improve the odds of keeping healthy honey bees.
8 ways to reduce the risk of American foulbrood
To lessen the chance of getting AFB beekeepers should sterilize used equipment and tools and check hives containing brood thoroughly from suppliers. Avoiding feeding bees with external sources of honey and thoroughly cleaning shared extraction equipment will also help. The use of hard chemicals like Oxytetracycline should be used responsibly to avoid resistance.
1. Sterilize second-hand equipment and tools
One of the benefits of the ever-popular Langstroth hive is that its parts have standardized measurements. Used parts are easy to source and save money, but they could be infected with inactive AFB spores. Paenibacillus bacteria can survive for decades on old hive equipment before activating, and there is no way to test for the presence of spores.
To prevent foulbrood and other types of bacteria, the safest option is to sterilize everything before use. Gamma irradiation is a reliable method of killing off AFB, and honey bees are happy to use the equipment after they’re clean and disease-free. Read more about how to irradiate American foulbrood here.
Not all beekeepers have access to irradiation services, and some won’t think the added cost is worthwhile. In this case, a separate area should be established away from any existing hives. Mixing up hive parts straight away is risky and may contaminate healthy bees.
2. Be scrupulous when buying hives with bees
If you’re starting beekeeping or looking to expand your operation, buying a hive with bees is an option. While there are other ways to do this, acquiring a “turnkey setup” means the bees don’t have to start building from scratch.
Buying a hive with bees comes with risks attached. Always inspect comb for American foulbrood. Whenever possible, vet the goods before making payment to avoid getting lumped with a colony that must be destroyed.
Newcomers to beekeeping may get a headstart buying a hive with bees but seeking advice from an experienced beekeeper is a must. They should understand the symptoms of American foulbrood to avoid any false negatives or positives.
Once your order arrives, keep everything separate from existing hives and equipment. Positioning the new colony away from the others for 2-3 months is a sensible way to monitor for symptoms. During this time, keep different tools and equipment for old and new colonies.
3. Avoid feeding bees with outside food sources
Feeding bees with honey and pollen from another beekeeper is risky business. They may contain AFB spores that end up getting fed to larvae. A sugar and water solution is safer and easy to make.
Tip: In some states, pollen must be gamma irradiated if introduced from an external source.
4. Use caution sharing extraction equipment
Extraction equipment is expensive and sharing the cost between multiple beekeeping operations makes financial sense. However, honey can transfer foulbrood spores, which introduces the risk of spreading amongst hives.
While sterilization isn’t necessary, thoroughly cleaning extraction equipment is vital. That includes tools like uncapping knives. Traces of propolis, wax, or honey should be removed and then rinsed with fresh water.
5. Consider preventative antimicrobials
Depending on your location, Oxytetracycline may be an option. This antibiotic can be administered prophylactically as a preventative measure. A healthy colony dosed with this chemical can kill off the infection before unwanted spores form.
Oxytetracycline should be used responsibly and sparingly. Overuse of antimicrobials will lead to disease resistance.
6. Implement a hive barrier system
Hive barrier systems are a practical approach to reducing the spread of American foulbrood in commercial apiaries. Hobbyists won’t need to worry about this, but operations with 50 or more hives should consider dividing them into groups.
Physically distance each cluster of hives and restrict tools, hive parts, and comb to those hives. This practice will significantly reduce disease spread.
7. Taking advantage of genetics
Some bee breeds have a genetic disposition to hygienic behavior. They are better able to detect infected brood, uncap it, and remove the sick or dead larvae. You can learn more about the traits of different bee races here.
Choosing a type of honey bee with good hive hygiene, like Italian bees, may inhibit AFB to a small extent. However, they won’t obstruct an outbreak of AFB, especially if beekeepers reinfect the colony with contaminated equipment.
8. Try essential oils
Researchers are looking at natural ways to prevent American foulbrood. One approach is using essential oils like lavender, lemon, and verbena. Studies have shown promising results, and there is scope for future research into this topic. Source.
Related reading: What other threats do honey bees face?
How common Is American foulbrood?
American foulbrood is rare compared to other brood diseases like chalkbrood, sacbrood, and European foulbrood. Although not an everyday type of bacteria, it has a devastating effect on hives and should be taken seriously by beekeepers. Regular inspections will assist with early identification.
Beekeepers should do everything possible to prevent American foulbrood from infecting their colonies. Good hive practices and sterilizing equipment from external sources will help. Careful inspection of outside brood and used hive parts is also essential.
American foulbrood is tough to spot, and even the best prevention techniques won’t make a hive impervious to the disease. If you see the tell-tale signs of diseased larvae, act without delay to stop the spread.
Studies have shown that early detection and quarantine strategies can reduce the spread of infection through large-scale operations. Source. These learnings can also be applied by hobbyist beekeepers.
We also recommend reading up on what causes AFB to learn more about how it gets transferred.