Beekeeping is a rewarding pursuit, whether you’re a beginner tending your first hive or a seasoned apiarist managing dozens of colonies. The hum of a healthy hive, the golden bounty of honey, and the vital role bees play in pollination make it a deeply satisfying endeavor. However, beekeeping comes with its challenges, and one of the most insidious threats to honey bee colonies is Bee Parasitic Mite Syndrome (BPMS). This complex condition, closely tied to the notorious Varroa mite, can devastate even the strongest hives if left unchecked. Understanding BPMS—its causes, symptoms, treatments, and prevention strategies—is essential for every beekeeper who wants to protect their bees and ensure the longevity of their apiary.
In this guide, we’ll dive deep into the world of BPMS, breaking down everything you need to know in a way that’s accessible to novices and insightful for experts. We’ll explore what BPMS is, how to spot it in your hives, the best ways to treat it, and proactive steps to prevent it from taking hold. By the end, you’ll be equipped with the knowledge and tools to safeguard your bees from this pervasive threat. Whether you’re inspecting your hives for the first time or troubleshooting a mysterious decline, this article is here to help you navigate the complexities of BPMS with confidence.
What is Bee Parasitic Mite Syndrome (BPMS)?
Bee Parasitic Mite Syndrome (BPMS), sometimes referred to as Parasitic Mite Syndrome (PMS), is not a single disease but a constellation of symptoms that emerge in honey bee colonies heavily infested with Varroa mites (Varroa destructor). Unlike bacterial diseases such as American Foulbrood or European Foulbrood, BPMS doesn’t have a single identifiable pathogen driving it. Instead, it’s a syndrome—a collection of signs and effects—strongly correlated with high Varroa mite populations and the viruses they transmit. This makes BPMS a multifaceted challenge, as it blends physical damage from mites with secondary infections that amplify the harm.
Varroa mites are external parasites that feed on the fat bodies of honey bees, weakening both adult bees and developing brood. While the mites alone can cause significant stress, BPMS arises when their presence triggers a cascade of health issues, including viral infections like Deformed Wing Virus (DWV) and Acute Bee Paralysis Virus (ABPV). The result is a colony that deteriorates rapidly, often collapsing entirely if intervention doesn’t occur in time. For beekeepers, BPMS is a red flag that mite management has failed, signaling an urgent need for action.
The Role of Varroa Mites
To understand BPMS, you must first understand the Varroa mite’s life cycle and impact. These tiny, reddish-brown parasites—about 1.5 mm wide—attach to adult bees and infiltrate brood cells to reproduce. Female mites enter cells just before they’re capped, laying eggs that hatch and feed on the developing pupae. This not only weakens the emerging bees but also provides a vector for viruses to spread. As mite populations grow, the damage compounds, leading to the symptoms we recognize as BPMS. While the exact causative agent of the brood symptoms remains unidentified, the consistent presence of Varroa mites in affected colonies is undeniable.
Why BPMS Matters
BPMS isn’t just a minor inconvenience—it’s a colony killer. Left untreated, it can wipe out a hive within months, leaving behind empty combs and a dwindling population. For commercial beekeepers, this translates to lost income from honey and pollination services. For hobbyists, it’s the heartbreak of losing a thriving colony they’ve nurtured. Beyond individual losses, BPMS contributes to broader declines in bee populations, threatening food security given bees’ role as pollinators. Understanding BPMS is thus not only about saving your hives but also about contributing to the health of the global bee community.
Bee Parasitic Mite Syndrome (BPMS) Symptoms
Spotting BPMS early is critical, but its symptoms can mimic other brood diseases, making diagnosis tricky. A keen eye during hive inspections is your best tool. Here’s a detailed breakdown of what to look for, divided into brood-related and adult bee symptoms, so you can confidently identify BPMS in your colonies.
Brood-Related Symptoms
- Spotty Brood Pattern: One of the hallmark signs of BPMS is an irregular, patchy brood pattern. Unlike the uniform capped cells of a healthy hive, BPMS-affected combs show a scattered mix of capped and uncapped cells. This occurs as worker bees detect and remove infested or diseased brood, leaving gaps.
- Chewed-Down Larvae and Pupae: Look closely at open brood cells. You might see white larvae that appear pecked or partially chewed by hygienic bees attempting to remove mite-infested brood. Pupae may have their faces bitten down, exposing them prematurely. This is a desperate attempt by the colony to curb the mite population.
- Sunken or Melted Larvae: Infected larvae often appear slumped or melted against the cell walls, sometimes with debris at their posterior ends. While this can resemble European Foulbrood, BPMS lacks the ropy consistency when probed with a twig—a key differentiator.
- Discoloration and Odor: As secondary bacterial infections set in, chewed-down brood may turn yellow, brown, or gray and emit a faint sour smell. This isn’t as pungent as foulbrood but is noticeable with close inspection.
Adult Bee Symptoms
- Rapid Population Decline: A sudden drop in adult bees is a red alert. With BPMS, foragers and nurse bees die off faster than the colony can replace them, leaving the hive eerily quiet despite ample honey stores.
- Deformed Wing Virus (DWV): Adult bees with crumpled, shriveled, or thread-like wings are a common sight. This viral infection, vectored by Varroa mites, is a frequent companion of BPMS and renders bees unable to fly or work effectively.
- Crawling Bees: Near the hive entrance, you may notice bees crawling aimlessly, unable to fly. This behavior often accompanies DWV or other mite-related stress, signaling a colony in distress.
- Supersedure Cells: In severe cases, bees may attempt to replace their queen, building emergency queen cells. This reflects the colony’s recognition that conditions are unfit for brood rearing, often due to high mite loads.
Differentiating BPMS from Other Diseases
BPMS shares symptoms with diseases like American Foulbrood (AFB) and European Foulbrood (EFB), but key differences help distinguish it. AFB features a strong, foul odor and sticky, ropy larvae, while EFB affects younger larvae with a twisted, rubbery appearance. BPMS brood, by contrast, doesn’t rope and often shows mite-related damage like chewed pupae. Checking for Varroa mites on bees or in cells—visible as tiny reddish dots—confirms BPMS as the likely culprit.
Bee Parasitic Mite Syndrome (BPMS) Treatment
Once BPMS is identified, swift action is essential to halt the decline. Treatment focuses on reducing Varroa mite populations, as they’re the root cause. Here’s a comprehensive look at your options, from chemical treatments to natural methods, tailored for beekeepers of all levels.
Chemical Treatments
- Amitraz (Apivar): Plastic strips impregnated with amitraz are hung between frames, releasing the miticide over weeks. It targets phoretic mites (those on adult bees) and is highly effective, though resistance is a growing concern. Follow label instructions and remove strips after 42 days to avoid residue buildup.
- Formic Acid (Formic Pro): Applied as gel pads or liquid-soaked pads, formic acid penetrates capped cells to kill mites during reproduction—a rare advantage. It’s temperature-sensitive (best between 50-85°F) and can be used during honey flow, making it versatile. Wear gloves and a mask for safety.
- Oxalic Acid: Delivered via vaporization or dribbling a sugar syrup solution, oxalic acid is a natural compound effective against phoretic mites. It’s ideal during broodless periods (like late fall) since it doesn’t penetrate capped cells. Vaporization requires specialized equipment but offers quick results.
Natural and Mechanical Methods
- Drone Brood Trapping: Varroa mites prefer drone brood due to its longer development time. Insert a frame of drone comb, let the queen lay, and remove it after capping but before emergence (about 10-14 days). Freeze or destroy the comb to eliminate mites.
- Brood Breaks: Temporarily caging the queen or performing an artificial swarm interrupts brood production, forcing mites onto adult bees where treatments are more effective. Combine with oxalic acid for a powerful one-two punch.
- Thymol (ApiGuard): Derived from thyme, thymol gel is placed on top bars, releasing vapors that kill mites. It’s less harsh than synthetic chemicals but requires warm temperatures (above 60°F) and can disrupt brood rearing if overused.
Monitoring and Follow-Up
Post-treatment, monitor mite levels using an alcohol wash or sugar roll (aim for less than 2 mites per 100 bees). BPMS symptoms should subside as mite numbers drop, but persistent issues may indicate reinfestation from nearby hives. Rotate treatments annually to prevent resistance, and always adhere to local regulations on chemical use.
How to Prevent Bee Parasitic Mite Syndrome (BPMS)
Prevention is the best defense against BPMS. By keeping Varroa mite levels low year-round, you can stop the syndrome before it starts. Here’s how to build a resilient apiary, with strategies for every season.
Regular Monitoring
- Mite Counts: Check mite levels monthly using a sticky board, alcohol wash, or sugar roll. Spring and late summer are critical times, as mite populations surge with brood rearing. A threshold of 3 mites per 100 bees signals the need for action.
- Brood Inspections: During routine checks, examine brood frames for early BPMS signs. Catching chewed larvae or spotty patterns early lets you intervene before collapse.
- For detailed instructions on how to regularly monitor your hives, check out article: How to Perform a Hive Inspection
Cultural Practices
- Hygienic Bee Strains: Breeds like Varroa Sensitive Hygienic (VSH) bees naturally detect and remove mite-infested brood, reducing BPMS risk. Source queens from reputable breeders to introduce these traits.
- Screened Bottom Boards: These allow mites to fall out of the hive, lowering reinfestation rates. Pair with a sticky board to track drop-off and assess mite pressure.
Seasonal Strategies
- Spring: Treat early if winter mite counts are high, using oxalic acid during low brood periods. Split strong colonies to disrupt mite cycles. See our checklist for beehive management in the Spring.
- Summer: Use drone trapping during peak brood season. Avoid overcrowding, which stresses bees and boosts mite spread.
- Fall: Reduce mite loads before winter bees emerge (August-September). Formic acid or amitraz can protect the colony through cold months.
Community Cooperation
BPMS often spreads via drifting or robbing bees from nearby infested hives. Collaborate with local beekeepers to monitor and treat mites collectively, creating a buffer zone of healthy colonies.
Final Thoughts
Bee Parasitic Mite Syndrome is a formidable adversary, but it’s not unbeatable. Armed with knowledge of its symptoms—spotty brood, deformed bees, and dwindling populations—you can catch it early. With a toolbox of treatments, from formic acid to drone trapping, you can fight back effectively. And by embracing prevention through monitoring, hygienic bees, and seasonal care, you can keep BPMS at bay. Beekeeping is as much about resilience as it is about reward, and tackling BPMS head-on strengthens both your hives and your skills. As you tend your bees, remember: every inspection, every treatment, and every preventive step is an investment in their future—and yours.