Common Diseases and How to Diagnose Them

If you suspect or confirm any of the following diseases, report your findings to the MDAR apiary program (bees@mass.gov). 
View videos showing how to identify abnormal brood and take a disease sample.

Varroa 

Learn more about managing Varroa here: http://ag.umass.edu/resources/pollinators/varroa 

• Varroa levels cannot be diagnosed by sight. In order to accurately assess infestation levels, use an alcohol wash.  
• How to conduct an alcohol wash [VIDEO]: Identify a frame with open brood. Shake bees off of the frame into a bin. Scoop a ¼ cup of bees and place in a jar with 50-80% ethanol. Return remaining bees to hive. Shake jar for 1 min and replace solid lid with mesh lid. Shake jar upside-down over bin to release mites. If there are over 6-9 mites in the bin, the hive is over the treatment threshold for Varroa.  
• If you want to double-check Varroa counts, gather a sample for the Beltsville Bee lab: Identify a frame with open brood. Shake bees off of frame into a bin. Scoop a ¼ cup of bees into a sealed container (plastic bag, plastic jar, or glass jar) and cover with 50-80% ethanol.  
• Fill out a Sample Identification Form, with contact information for you and the beekeeper (indicate that you would like the sample tested for Varroa)  
• Mail the sample using standard ground shipping to the USDA Bee Lab in Maryland:  
  Bee Disease Diagnosis 
  Bee Research Laboratory 
  10300 Baltimore Ave. BARC-East 
  Bldg. 306 Room 316 
  Beltsville Agricultural Research Center - East 
  Beltsville, MD 20705 
• TIP: The same adult-bee sample can be analyzed for both Varroa and Nosema. 

Parasitic Mite Syndrome 

• Parasitic Mite Syndrome (PMS) has a number of symptoms, including punctured pupal cappings, chewed-down pupa, and “melty” dead larvae which remain pearly white. For photos, visit https://beeinformed.org/2013/10/15/parasitic-mite-syndrome-pms/ 
• Basic prevention/treatment: PMS is caused by Varroa mites. The only way to treat/prevent PMS is to make sure that Varroa populations are under control. Conduct an alcohol wash (more info above), and recommend treatment if mites are above the treatment threshold. Find treatment info

Nosema  

See the fact sheet for info about Nosema biology, symptoms and treatment 
 
 

• Nosema cannot be easily diagnosed by eye. For common symptoms, consult a disease guide or https://www.mass.gov/doc/nosema-fact-sheet/download. If Nosema is suspected, submit a sample to the USDA bee lab. 
• How to take a sample [VIDEO]: Gather ~50 adult bees from the top of the hive using a ¼ or ½ cup measuring cup. Alternatively, use leftover dead bees from an alcohol wash. Place bees in a sealed container (ideally a 50ml plastic tube, but you could also use a plastic bag, plastic jar, or glass jar) and cover with 50-80% ethanol or rubbing alcohol.  
• Fill out a Sample Identification Form, with contact information for you and the beekeeper (indicate that you would like the sample tested for Nosema) 
• Mail the sample using standard ground shipping to the USDA Bee Lab in Maryland:   

Bee Disease Diagnosis 
Bee Research Laboratory 
10300 Baltimore Ave. BARC-East 
Bldg. 306 Room 316 
Beltsville Agricultural Research Center - East Beltsville, MD 20705 

• Basic prevention/treatment:  
  • Mild infections may clear up with a good nectar flow and/or feeding 
  • Replace contaminated equipment o Replace the queen 

European Foulbrood

See the fact sheet for info about EFB biology, symptoms and treatment  

• European foulbrood causes open larvae to become yellowed and twisted along the sides of the cell. Consult a bee disease field guide or for photos. If you suspect EFB, submit a sample to the USDA lab 
• How to take a sample [VIDEO]: 
  • Remove a discolored larva using a Q-tip or toothpick and place it in a paper bag.  
  • Place the paper bag in a cardboard mailer 
  • Fill out a Sample Identification Form and include it in the mailer.  The sample form should include contact information for you and the beekeeper, and indicate that you would like the sample tested for EFB/AFB)  
• Mail the sample using standard ground shipping to the USDA Bee Lab in Maryland:   

Bee Disease Diagnosis 
Bee Research Laboratory 
10300 Baltimore Ave. BARC-East 
Bldg. 306 Room 316 
Beltsville Agricultural Research Center - East 
Beltsville, MD 20705 

• Inform the beekeeper. Sanitize all equipment. EFB can be spread between hives by contaminated equipment, but is not nearly as contagious or damaging as AFB (below) 
• Basic prevention/treatment:  
  • Feeding/nutrition o Re-queening 
  • Terramycin 

American Foulbrood

See the fact sheet for info about AFB biology, symptoms and treatment

• American foulbrood causes young bees to die in the pupal stage. It causes pupal cappings to sink and break. If you insert a toothpick into the cell and remove it, AFBkilled larvae will “rope out”. It has a distinctive “sweaty foot” smell. Consult a bee disease field guide or https://www.mass.gov/doc/american-foulbrood-factsheet/download for photos. If you suspect EFB, submit a sample to the USDA lab. This is the most serious disease that you could encounter, so make sure to take adequate biosecurity precautions (link).  
• How to take a  sample [VIDEO]: 
  • Remove a discolored larva using a Q-tip or toothpick and place it in a paper bag.  
  • Place the paper bag in a cardboard mailer
  • Fill out the Sample Identification Form and include it in the mailer 
•  Mail the sample using standard ground shipping to the USDA Bee Lab in Maryland:   

Bee Disease Diagnosis 

Bee Research Laboratory 

10300 Baltimore Ave. BARC-East 

Bldg. 306 Room 316 

Beltsville Agricultural Research Center - East Beltsville, MD 20705 

• Immediately inform the beekeeper, and instruct them to leave the hive closed until you receive results 
• Immediately inform MDAR (bees@mass.gov) 
• If the hive is positive for AFB, it must be burned as soon as possible. Inform MDAR immediately, and they will contact the beekeeper and take care of hive disposal.    

Chalkbrood 

Info about chalkbrood biology, symptoms and treatment

• Chalkbrood is identifiable by sight. For photos, consult a bee disease field guide, or https://beeinformed.org/2013/11/01/chalkbrood/  
• Basic prevention/treatment:  
  • Moving the hive to a drier location 
  • Increasing ventilation (for instance, by installing a screened bottom board) o Feeding 
  • Re-queening 

Sacbrood

For information about sacbrood, visit:  https://beeinformed.org/2013/10/29/sacbrood-virus-sbv/  

• Sacbrood is identifiable by sight. For photos, consult a bee disease field guide or https://beeinformed.org/2013/10/29/sacbrood-virus-sbv/   
• Basic prevention/treatment: Sacbrood is a virus, which is transmitted by Varroa. The only way to treat/prevent sacbrood is to make sure that Varroa populations are under control. Conduct an alcohol wash (more info above), and recommend treatment if mites are above the treatment threshold.