Ontario Treatment Recommendations
for Honey Bee Disease and Mite Control
Please contact apiary@ontario.ca
for the report in PDF format.
This document is intended as a guide for beekeepers in the management
of honey bee pests and diseases and includes recommendations for
both treatments and monitoring methods. Any recommended product
is to be used in accordance with label directions. The users assume
responsibility for any risk to persons or property arising from
the use of the recommended products.
Table of Contents
- General BMPs for the Control of Pests and Diseases
- American Foulbrood
- Chalkbrood
- European Foulbrood
- Nosema
- Sacbrood
- Small Hive Beetle
- Tracheal Mites
- Varroa Mites
General Best Management Practices (BMPs) for
the Control of Pests and Diseases
It is recommended that beekeepers implement the following best
management practices for the control of pests and diseases in Ontario
apiaries:
- Read product labels before applying disease or mite control
products.
- Follow treatment withdrawal times. Do not use treatments when
honey supers are on, unless specified on the product label.
- Follow safety precautions and use appropriate protective equipment
as recommended by the label directions when mixing and applying
treatments.
- The presence of multiple parasites/diseases may require treatment
below the recommended treatment threshold(s).
- Treat all colonies that require treatment in the yard at the
same time.
- Monitor colonies to determine the severity of varroa infestation.
- Rotate treatments for varroa management to prevent the development
of resistant varroa mites. For example, use synthetic mite-strips
in spring followed by a formic acid treatment in fall.
- When managing varroa, oxalic acid should be used as a follow-up
treatment in the late fall, after a primary early fall treatment.
- Use temperature-dependent treatments like formic acid and thymol
within recommended temperature thresholds.
- Treatment timing is important as treatments need to be applied
before infestations/infections reach damaging levels.
- The use of Ontario-bred disease resistant honey bee queens may
help colonies naturally resist some diseases and pests. However,
treatment will still be required.
- It is recommended to replace 2 to 3 old frames in the brood
chamber (typically the darkest) every year with newly drawn comb
or foundation. This practice will help to reduce the level of
pathogens and miticide residues in the hive.
American Foulbrood (Paenibacillus larvae)
American foulbrood (AFB) is a readily transmissible disease. There
is no cure for AFB. Action should be taken immediately after AFB
is found to prevent further spread of the disease. At any time when
honey bee colonies show signs of AFB, report the finding immediately
to the regional bee inspector, burn all infected equipment and kill
the bees.
Monitoring Method(s):
- Examine brood frames as colonies are opened.
- Signs of AFB include a scattered brood pattern and cappings
with a punctured, sunken, dark and greasy appearance.
- Infected larvae settle to the bottom of the cell wall in a sunken
gooey mass, beige to dark brown in colour.
- Insert a toothpick into the cell and draw out the contents.
AFB will draw out 1.25 cm and has the consistency of mucous.
- Check empty cells on brood frames for AFB scales (hardened dark
black masses of old dead larvae).
Treatment Method(s):
- All colonies in the yard should be treated at the same time,
see table below for specific recommendations.
- Other methods of application such as using pollen substitutes
as carriers or using the sugar syrup method are not recommended.
These methods can contaminate honey, are less effective and will
promote resistant AFB strains.
- Note: Oxytetracline is the only registered antibiotic
that may be used for treatment in spring. Honey from the brood
nest areas of the colonies treated with oxytetracycline should
not be harvested for human consumption.
- Note: Tylosin is the only registered antibiotic to be
used in fall. Tylosin should not be used in the spring as this
product may contaminate honey in spring and summer. Honey from
the brood nest areas of colonies treated with Tylosin should not
be harvested for human consumption.
Control Measures
| Treatment |
Timing |
Method |
| Burning |
Any time when signs of AFB are observed |
- Burn all frames, bottom boards and bees from infected
hives. Scorch empty bee boxes, inner covers and lids.
- Treat all remaining colonies with OXYTET-25-S or OXYSOL-62.5
powdered sugar mix (see below).
|
| Gamma Radiation |
Any time |
- Disinfect contaminated empty hive parts using irradiation
at 1.2 m rads.
- Supers with frames without bees should be placed in containers
that are inaccessible to honey bees ("bee tight")
for irradiation.
|
Preventative Actions
| Treatment |
Timing |
Method |
| OXYTET-25-S or OXYSOL-62.5 powdered sugar mix |
Spring and fall |
- Follow label directions.
- Label must indicate that the mixture can be used for honey
bees.
- Apply the powdered sugar mix along the margins of the
brood chamber, avoid applying powdered mix directly on open
brood.
- Repeat 3 times at 4-5 day intervals in the spring and
in the fall. Stop treating 4 weeks before the main honey
flow.
|
| Tylan 100 Soluble (Tylosin) |
Fall |
- Follow label directions.
- Label must indicate that the mixture can be used for honey
bees.
- Apply the powdered sugar mix along the margins of the
brood chamber, avoid applying powdered mix directly on open
brood.
- Colonies should receive three treatments administered
as a dust in confectioners/powdered sugar. The 200 mg dose
is applied over the top bars of the brood chamber weekly
for 3 weeks.
|
Chalkbrood (Ascosphaera apis)
Chalkbrood is a readily transmissible disease. Spores are highly
infectious and are carried in contaminated pollen by infected foraging
bees. There is no cure for Chalkbrood.
Monitoring Method(s):
- Examine brood frames as colonies are opened.
- Signs of disease include dead and dried larvae covered in a
hard white or black fungus with the tip of the larvae protruding
from the cell (also known as "chalkbrood mummies").
Treatment Method(s):
- Registered chemical treatments are not available for Chalkbrood.
Control Measures
| Treatment |
Timing |
Method |
| New queens |
Spring and summer |
- Maintain strong, healthy colonies and requeen with queens
from hygienic stocks.
|
European Foulbrood (Mellisoccus pluton)
European foulbrood (EFB) can occur when colonies are stressed
or have inadequate nutrition. Larvae are most susceptible to infection
when they are less than 48 hours old.
Monitoring Method(s):
- Examine brood frames as colonies are opened.
- Signs of disease include dead larvae that appear yellowish or
brown in color and are found curled in a C-shape at the bottom
of the cell and is often accompanied by a sour odor which is distinct
from AFB.
Treatment Method(s):
- Requeen or replace infected combs with new non-infected combs
or foundations. It is unnecessary to kill bees.
Control Measures
| Treatment |
Timing |
Method |
| Replace infected combs |
Any time when signs of EFB are observed |
- Burn or irradiate at 1.2 m rads all infected combs.
- Treat all remaining colonies with OXYTET-25-S or OXYSOL-62.5
powdered sugar mix (see below).
|
Preventative Actions
| Treatment |
Timing |
Method |
| OXYTET-25-S or OXYSOL-62.5 powdered sugar mix |
Spring and fall |
- Follow label directions.
- Label must indicate that the mixture can be used for honey
bees.
- Apply the powdered sugar mix along the margins of the
brood chamber, avoid applying powdered mix directly on open
brood.
- Repeat 3 times at 4-5 day intervals in the spring and
in the fall. Stop treating 4 weeks before the main honey
flow.
|
| Pollen supplements |
Spring and fall |
- Provide supplemental feed after intensive berry pollination.
|
| New queens |
Spring and fall |
- Requeen colonies with new queens from mite and disease
resistant hygienic stocks.
|
Nosema (N. apis and N. ceranae)
Nosema are single-celled parasites of the honey bee that are classified
as fungi and infect and damage the mid-gut tissue.
Monitoring Method(s):
- Testing by a qualified laboratory is necessary to diagnose
the presence of nosema.
- Collect 50 adult bees from the front entrance of suspected colonies
and send to a bee testing laboratory for diagnosis.
Treatment Method(s):
- Requeen colonies with new queens from hygienic stocks. See table
below for specific recommendations.
- Other methods of application such as using barrel feeding are
not recommended. These methods do not provide a standardized dosage
as the Fumagilin-B will settle.
Preventative Actions
| Treatment |
Timing |
Method |
| Fumagilin-B |
Spring and fall |
- Follow label directions.
- Label must indicate that the mixture can be used for honey
bees.
- Use only if colonies are exhibiting a significant infection
(> 1 million spores/bee).
- Feed bees a mix of Fumagilin-B with sugar syrup and apply
using direct-to-colony feeding techniques such as bag or
pail feeding.
- Ensure medicated sugar syrup does not come in contact
with direct sunlight.
|
| New queens |
Spring and summer |
- Requeen colonies with new queens from mite and disease
resistant hygienic stocks
|
Sacbrood
Sacbrood is caused by a viral infection. In larvae, the virus can
cause mortality when in the brood cell.
Monitoring Method(s):
- Affected larvae can be identified by the presence of a fluid
filled sac that can be removed from the brood cell, often intact.
- Testing by a qualified laboratory is necessary to diagnose the
presence of Sacbrood.
Treatment Method(s):
- Registered chemical treatments are not available for Sacbrood.
Preventative Actions
| Treatment |
Timing |
Method |
| New queens |
Spring and summer |
- Maintain strong, healthy colonies and requeen with queens
from hygienic stocks.
|
Small Hive Beetle (Aethina tumida)
The Small Hive Beetle (SHB) is an apiary pest damaging stressed
colonies by destroying wax comb and honey bee brood in addition
to spoiling honey. At any time when SHB is suspected, report the
finding immediately to the regional bee inspector.
Monitoring Method(s):
- Examine the top of brood frames for the presence of SHB adults
immediately after the lid is removed.
- Adult and larval beetles may also be encountered on the surface
of brood frames among the worker bees.
- A variety of mechanical traps, such as chemical-free oil traps,
are commercially available to monitor for SHB. Traps will not
control SHB populations.
Treatment Method(s):
- The effects of small hive beetle can be mitigated by following
best management and biosecurity practices.
Preventative Actions
| Treatment |
Timing |
Method |
| Best management and biosecurity practices |
Any time |
|
Tracheal Mites (Acarapis woodi)
Tracheal mites are internal parasites of honey bees that live and
reproduce in the tracheae.
Monitoring Method(s):
- Tracheal mites are very small and can only be observed with
a microscope.
- Tracheal mite infestation lack unique physical symptoms and
can only be diagnosed by the mites and eggs, and evidence of scarring
detected in the dissected trachea.
- Collect 150 adult bees from the suspected bee yard or 50 bees/colony
and send to a bee testing laboratory for diagnosis.
Treatment Method(s):
- It is recommended that bees be treated when the tracheal mite
infestation is >10%.
- If colonies are being treated with formic acid for varroa management,
further treatments for tracheal mites are unnecessary.
Control Measures
| Treatment |
Timing |
Method |
|
65% liquid formic acid
(35 ml multiple application)
|
Spring and fall |
- Colonies must have 6 or more frames of brood covered
with bees to use this treatment.
- Follow label directions, seal all holes in the hive box
except for the main entrance and utilize personal protective
equipment.
- Use a single 35 ml pad per hive and place on the top bars
close to the brood area for 3 applications, 4 days apart.
- For really small colonies, move the brood to the side
of the hive and place absorbent pad in the middle of the
tops of the frames in the brood chamber.
|
| Mite Away Quick Strips™ (MAQS™) |
Spring and fall |
- Colonies must have 6 or more frames of brood covered
with bees to use this treatment.
- Follow label directions, seal all holes in the hive box
except for the main entrance and utilize personal protective
equipment.
- Treatment period is 7 days in length.
|
Preventative Actions
| Treatment |
Timing |
Method |
| New queens |
Spring and summer |
- Requeen colonies with new queens from mite and disease
resistant hygienic stocks.
|
Varroa Mites (Varroa destructor)
Varroa mites are an external parasite of honey bees and elevated
levels of infestation may result in symptoms of stress in the colony
during the active season.
Monitoring Method(s):
- Colonies can be monitored for varroa using three methods: sticky
board, ether roll or alcohol wash.
- After applying varroa treatment in June, August and early fall,
check all bee yards (at least 5 hives in each) using the monitoring
method of your choice to determine the efficacy of the treatment.
- For more information, please see the Varroa
Mite Sampling and Monitoring infosheet at www.ontario.ca/beekeeping.
Treatment Method(s):
- Treat colonies when the varroa mite infestation is > 2% of
bees in the spring and >3% of bees in late summer / fall.
Control Measures
| Treatment |
Timing |
Method |
|
65% liquid formic acid Single application:
- 250 ml pad in pin-prick perforated bag
Multiple applications:
- 30 - 40 ml pad for two-story colony
- 15 - 20 ml pad for one-story colony
|
Spring and fall |
- Colonies must have 6 or more frames of brood covered with
bees to use this treatment.
- Follow label directions, seal all holes in the hive box
except for the main entrance and utilize personal protective
equipment.
- Apply pad and place on the top bars close to the brood
area. Treatment may be repeated up to 6 applications at
3 to 5 day intervals. Leave treatment in for 21 to 30 days.
- Only use this product when the air temperature is between
10 to 26 °C. Remove pads from the hives if the daily
temperature highs exceed 30°C.
- For really small colonies, move the brood to the side
of the hive and place absorbent pad in the middle of the
tops of the frames in the brood chamber.
|
| Mite Away Quick Strips™ (MAQS™) |
Any time |
- Colonies must have 6 or more frames of brood covered with
bees to use this treatment.
- Follow label directions, seal all holes in the hive box
except for the main entrance and utilize personal protective
equipment.
- Treatment period is 7 days. Allow for a minimum of 1 month
between applications.
- Only use this product when the air temperature is between
10 to 26 °C. Pre-harvest interval honey should not be
extracted sooner than 2 weeks following the treatment.
- May be used during the honey flow or at any time during
the active beekeeping season.
|
Synthetic mite strips
Apivar®*,Apistan® or Bayvarol® |
Spring and fall |
- Follow label directions, label must indicate that the
mixture can be used for honey bees.
- Use 1 strip for every 5 frames of bees for Apivar®
and Apistan®. Use 4 strips per brood chamber for Bayvarol®.
- If treating when air temperatures are low, ensure the
strips are positioned in the colony in contact with the
cluster.
- Remove strips at the conclusion of the treatment period
and do not reuse strips.
|
| Thymovar |
Spring and fall |
- Follow label directions, label must indicate that the
mixture can be used for honey bees.
- Two consecutive applications are required for full treatment.
- Only use this product when the air temperature is between
13 to 30 °C.
|
| Drone trapping |
Late spring and summer |
- Insert 1-2 frames with drone foundation or empty drone
comb into the brood chamber.
- Do not leave drone combs to hatch inside colonies. Remove
combs containing drone cells from the brood chambers after
the cells are capped and before adult drones emerge (approximately
21 days).
- Repeat until the drones are evicted from the colony in
early fall.
|
| Screened bottom board |
Spring and fall |
- Incorporate 8 mesh screens into bottom boards (8 squares
per 2.54 cm).
- 2.54 x 1.27 cm spacing is needed between the screen and
bottom board separate varroa from the bees.
- This method may enhance varroa control but will not substantially
reduce mite infestations without additional treatment methods.
|
Oxalic acid
(trickle method) |
Late fall |
- Apply when varroa monitoring indicates treatment is necessary.
- Use in conjunction with an early fall treatment and only
when little or no brood is present. Do not use when honey
supers are in place.
- Follow label directions and utilize personal protective
equipment.
- Dissolve 35 g of oxalic acid dihydrate in 1 L of warmed
premixed syrup made from a 1:1 solution of sugar to water
(weight:volume) and agitate thoroughly. Smoke bees down
from the top bars. Trickle 5 ml of oxalic acid solution
directly onto the bees between the frames using a syringe.
- Apply on a cool day when the bees are clustered in the
hive.
- The maximum dose is 50 ml per colony (same dose for nucs,
single or multiple brood chambers).
- Oxalic acid may stress the colony or cause mortality when
colonies are weak or are experiencing unfavorable overwintering
conditions.
|
Preventative Actions
| Treatment |
Timing |
Method |
| New queens |
Late spring and summer |
- Re-queen colonies with new queens from mite and disease
resistant hygienic stocks.
|
Additional Resources
Authors
Paul Kozak (OMAFRA), Les Eccles, Melanie Kempers, Devan Rawn, Brian
Lacey (Ontario Beekeepers' Association Technology Transfer Program)
and Dr. Ernesto Guzman (University of Guelph)
