Varroa mites (Varroa destructor) are small, reddish-brown tick like pests which feed on the hemolymph (“blood”) of the honey bees. It will create cuts on your bees that can gain infection as well as transmit viruses.
- The reproduction of the mite is directly tied to bee reproduction.
- Female mite enters cell of maturing bee before it is capped
- She waits 60 hours before laying eggs (lays an additional egg every 30 hours)
- First egg will be male and subsequent eggs will be female
- Mites will feed on the pupating bee
- Infect bee with viruses and causes infection
- Female mites will exit with adult bee
There are two widely used methods to assess the mite levels in your hive.
Corex Sheet. This is a sheet which slides under a screened bottom board. Spray the corex sheet with a cooking oil so when the mites fall from the hive they stick to the sheet and can then be counted. Insert the sheet for 3 days and then remove it to count the mites. Once you have a total, divide it by 3 to get the average mite drop in a 24 hour period.
Sugar Shake. Place a few table spoons of powdered sugar in a mason jar and gently "slosh" some bees (about ½ cup) around ensuring they are fully coated. Replace the lid with #8 hardware cloth and the sugar will dislodge the mites allowing them to fall through the screen.
Below is a very general guide to determine if the colony should be treated. However, the prevailing thought is if you have a window of opportunity to treat your colony you should treat.
|Corex Sheet||5-10 mites||50-60 mites|
|Sugar Shake (per 100 bees)||3-4 mites||3-4 mites|
Integrated Pest Management (IPM) methods work with the behavior and biology of the target pest to aid in its control. Several methods that can control the mite population include:
- 1. A screened bottom board which allow the mites to fall out of the hive
- 2. Drone trapping/Varroa trapping using a Drone frame or Drone foundation Remove frame after cells have been capped and freeze for 48 hours. Reinstall frames after thawing.
IPM methods often are not a sufficient form of control and pesticides need to be used. We, and many in the scientific community, strongly encourage the use of “soft chemicals”. These are naturally occurring products and many naturally existing in honey. The two most common are Api Life VAR and MiteAway Quick Strips. Api Life VAR is made with thymol, which is used in mouthwash, and other essential oils. Evaporative wafers are placed on the hive and the thymol vapor kills the varroa. MiteAway Quick Strips use food grade formic acid, which naturally occurs in honey. For other methods of control see ourmedication table.