Library · Bees & pollinators
Bee Disease Reference.
Bee Disease & Pest Reference
Diagnose what's wrong with your hive. Varroa is the king; foulbrood is the legal one. Plus identification, treatment, and when to report to state apiarist.
The big three concerns
| Threat | Severity | Why |
|---|---|---|
| Varroa mites | ★★★★★ Existential | Vectors viruses + weakens bees; untreated colonies die in 1-2 winters. The reason most amateur colonies die. |
| American Foulbrood (AFB) | ★★★★★ Reportable | Highly contagious bacterial disease. Spores survive 50+ years. Many states require burning infected equipment by law. ALWAYS report to state apiarist. |
| Pesticide exposure | ★★★★ Variable | Sublethal neonicotinoids cause subtle decline. Acute kills happen near monoculture spray operations. |
Varroa management — the universal protocol
| Step | When | How |
|---|---|---|
| Monitor | Monthly during active season | Alcohol wash or sugar shake — 300 bee sample. Threshold: 3 mites / 100 bees |
| Spring treatment | March-April | If mite count high entering spring; oxalic acid vaporization while broodless |
| Mid-season action | July (post-flow check) | If mite count rising, plan immediate post-honey treatment |
| Late summer treatment | August (CRITICAL) | After honey supers off; formic acid (Mite-Away Quick Strips) or thymol (Apilife Var) or amitraz (Apivar) |
| Fall verification | September-October | Mite count should be < 1%; if not, second treatment |
| Winter treatment | December-February | Oxalic acid vaporization while colony is broodless — most effective single treatment |
When to call the state apiarist
- Suspected American Foulbrood (AFB). Many states require reporting; some inspect for free. Ropy test + sour smell = call.
- Sudden mass die-off (overnight or within 24 hours). Pesticide kill suspected; document immediately for possible compensation/legal action.
- Disease you can't identify. Most state apiarists do free hive inspections.
- Importing bees / equipment from another state. Many states require inspection certificates.
- Buying used equipment. Inspect for AFB scale before introducing to your apiary.
Find your state apiarist: most state Departments of Agriculture maintain a list. The Apiary Inspectors of America (AIA) directory is a starting point.
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