Causal agent

Varroa destructor (was Varroa jacobseni)- Parasitic mite


Age group




Adult - worker







Yes ++


Clinical signs



The mites are classically seen in stressed hives in late Autumn


Drones are preferentially affected as they have a longer pupation and more mated females can be produced


Varroa mite and bee


Worker with mite to indicate size

A pupae removed from its cell with a mite on it.

Varroa dorsal view uk

Varroa ventral 4 legs

The dorsal surface of the mite    

Ventral surface of the mite – note 8 legs – member of the spider family not an insect.

Secondary infections

Colony Collapse Disorder


Bees infected early in life may have deformed wings – associated with Deformed Wing Virus

A number of other viruses are also associated with Varroa infestation.




The adult female mite infests a larvae as the larvae is about to be capped.

The larvae pupates and the mite feeds off the pupae haemolymph.  The mite lays eggs.  The first egg hatches is a male and the subsequent mites are female.  The male mates with his sisters.

The adult female mite can live for months when no brood is available to allow multiplication.  With brood the life expectancy is 27 days.

The Varroa mites can also infest other native bee species – Bumblebees (Bombus pennsylvanicus) for example. However, while they do not multiply on other bees, they can act as a transportation system – horizontal spread





Horizontal - Drifting and robbing.  Concentration of hives in an area.  Can live on other bees.

Vertical –through the brood



The Varroa mite appears to have jumped between bee species having originated in Apis cerana.   Apis cerana have various adaption’s to manage Varroa.   Only the drones are affected.   The capping of drone brood is hardened  and weak drones are unable to open the cocoon caps and the Varroa die in the capped cell.  The workers also seem able to detect the infected pupae and will uncap and remove the infected pupae.  Apis cerana also display a range of grooming more intensely than Apis mellifera and are able to remove or damage the mites.  In addition they perform a “dance” to call up help from other workers to remove the mites.  The combination of these factors enable Apis cerana to remove 98% of mites from their colonies.


Post-mortem Lesions



Presence of mite




Mite seen on the bee


Monitoring mites with a screened bottom board with a sticky surface – spray on cooking oil for example.  When the number of mites exceed 150 in a day – treat.


Take 500ml of car windscreen washer fluid (alcohol).  Shake around 500 bees into the solution (one frame).  Shake the fluid and bees.  The bees are killed in the fluid.  Count the mites which appear.   The mites will generally float to the top.  If less than 10 then hive infestation acceptable. If more than 40 the hive needs treatment.


Ether roll – Collect 200-300 bees into a jar and anaesthetise with ether – from an car store used in air to start engines.  Use 1-2 second blast.  Roll jar for 10 seconds, mites dislodge and adhere to side of jar.  Remaining bees can be spread on a white paper to see additional mites if required.


Icing sugar- Collect 200-300 bees in a jar. Replace the lid with another lid cut with #8 sieve in the top.  Introduce a 10g of icing sugar through the sieve.  Roll the jar around.  Allow the jar to sit for a couple of minutes.  Pour the sugar and mites out of the jar through the #8 sieve onto a clean sheet of paper.





None of the treatments achieve elimination only control



Tau-Fluvalinate (Apistan) or Flumethrin (Bayvoral) both synthetic pyrethroids Start treatment when sticky boards reveal over 200 mites after 3 days exposure. 

The strips are normally applied for up to 6 weeks

Note these chemicals can build up in the honey and eventually will affect the bees.  2 years of application has affected queen bee fertility.

These products may be more useful in the Autumn.


Apiguard – Thymol.  Once the temperature is above 15°C Thymol products can be used. Use two applications 10 to 15 days apart.

Api Life Var – Thymol, eucalyptus oil, menthol and camphor.    This is used two 14 days apart.



Organophosphates - Coumaphos (Checkmite+).The checkmite+ strip hangs down between frames in the broodnest so bees can walk on it and pick up minute amounts of the active ingredient.  Do not put the strip on the bottom board, tops of frames.


Apiguard in Autumn Varroa control UK



Mite control in Korea

Be careful when medicating with products that may affect honey quality


Organic acids treatments are being developed


Oxalic acid – This is not authorised in the UK.  Oxalic acid can kill brood and therefore has to be used in brood-less colonies – in the wintertime.

Mix 6% of oxalic acid with 30% sugar solution and apply by the trickling method.  Note the products have to be used fresh and breakdown products can be toxic to the bees –hydroxymethylfurfuraldehyde.    This product works by damaging the clapses of the proboscis of the Varroa mite.


Sucrose octanoaten – a sugar and soap solution. Need to repeat 3 times to kill mite eggs.


Formic acid can be used on the bottom boards.  This can be useful to control tracheal mite.  Administer 30 mls every week for 3 to 5 applications in the spring.   Then again in June.   Air temperature needs to be above 22°C but below 30°C



Drone brood sacrifice – drone trapping


Queen trapping


Artificial swarm technique


Shook swarm technique



Powdered sugar dusting (using icing sugar) – encourages better grooming of the bees.  Have sticky paper on the screening board to capture any falling mites.   The mites start appearing within 15 minutes of application.



Screening bottom boards – sticky boards.  With a moderate to heavy mite infestation the sticky board will have 150 to 500 mites stuck to it.



Use more resistant lines of bees –some subspecies have slightly shorter pupation periods which reduce the Varroa population and thus impact.



Reducing drifting


Common differentials



Braula coeca may resemble Varroa.  However, Braula is an insect with 6 legs whereas Varroa as a mite has 8.







Global distribution of Varroasis as of 2010

Varroa distribution 2010

The global distribution:  Positively confirmed countries/areas indicated in red
Life cycle of Varroa

Varroa life cycle

From this a generation time can be calculated:





7.5 days queen would emerge

3 days

Male laid

8 days

Male matures



Female laid

12.5 days

Females matures

12 days worker would emerge

6 days

Female laid

13 days

Females matures


7.5 days

Female laid

14.5 days

Females matures

14.5 days drone would emerge

9 days

Female laid

Female not mature in time to be mated


This explains why the queen larvae are rarely infested with Varroa mites, but the longer pupation of the drone allows for large number of mites to reach maturity and fertility.

On average, the female mite produces a new female (as well as herself) for each worker larvae infested and 2 female mites for each drone larvae infested.




Varroa management techniques over the year







Open Mesh Floor sticky paper





Drone brood removal







Drone comb trapping







Apiguard -  thymol products





Apistan/Bayvoral – tau-fluvalinate/flumathrin





Checkmite - Coumaphos





Oxalic acid





Icing Sugar Dusting






It is vital to read and follow all manufacture’s advice regarding withdrawal times and bee product sales.

Some of these techniques may not be legal in your area – check with your veterinarian first.


Using drone monitoring to decide on the appropriate level of control required:


Proportion of intested drone pupae

Spring/Early summer

Less than 2%

Less than 1 mite per 50 drones


More than 4%

More than 1 mite per 25 drones


Less than 3%

Less than 1 mite per 30 drones



More than 7%

More than 1 mite per 15 drones

Later summer

Less than 5%

Less than 1 mite per 20 drones


More than 10%


Action suggested:

No action

Light control/plan

Severe risk