Varroa Mite Monitoring

Varroa mite monitoring methods

An important step to keeping your honey bees healthy is to monitor and control for varroa mites. It is the first step in implementing an IPM approach in mite management. It is extremely important to monitor mites on a monthly basis to determine the severity of varroa infestations and when to treat your colonies before numbers approach damaging thresholds. It is also a good idea to maintain written records and to monitor varroa levels before and after treatment(s) to evaluate treatment efficacy and management strategy. It is best to use a standard protocol procedure such as sugar shake (powdered-sugar rolls), alcohol wash or sticky board (mite fall). This  makes it easy to compare data to state-wide and/or national surveys and statistics. The powdered sugar roll is currently the most common and quickest tool to monitor mites. Research indicates that a reasonable threshold for mite treatment is about 5 mites per 100 bees for both alcohol and sugar rolls however, there is not a reliable threshold for mites per sticky boards although some research indicated a threshold of 60 mites/board. Below we have described the three most common methods used in apiculture to monitor mites: powdered sugar roll, alcohol wash and sticky board.

Powdered-Sugar Roll

Equipment

• Mason Jar with 1/8 inch mesh wire
• 1/2 measuring cup
• Powdered sugar
• [wash] tub to shake bees into
• water in a spray bottle (optional)

Inspect the colony to find a frame with open brood. Mites are more likely to be found on frames of brood where nurse bees are present as they enter and exit brood cells. DO not collect bees from the inner cover,  front of the hive or from a honey frame. These tend to be older bees and will be less likely to have mites.

1. Shake the frame of bees into the tub
2. Collect about ½ cup of bees (300 bees) from a frames(s) of brood into a mason jar with a mesh lid. Make sure the queen is not present on the frame that you sample, otherwise you risk damaging her.
3. Add 2-tablespoons of powdered sugar to coat the bees & shake the jar vigorously for 30 seconds
4. Let the jar and bees sit for about 2-4 minutes while the bees move about and mites are more likely to become dislodged from the bee
5. Invert the jar and shake vigorously over a tub or pan to catch the mites. The mites will appear as tiny reddish specs on the white paper. The sugar debris can be sprayed with water and it could be easier to spot the mites. The jar can be shaken over water which could make it easier to spot the mites.
6. Afterward, the bees can be released in front of the hive.

Alcohol wash

Equipment:

• [Mason] Jar with a solid lid
• 1/8 inch mesh wire
• 1/2 measuring cup
• 70% or higher alcohol (ethanol, ethyl alcohol, or isopropyl alcohol will work)
• [wash] tub to shake bees into
• [wash] tub or pan to pour alcohol solution into

Inspect the colony to find a frame with open brood. Mites are more likely to be found on frames of brood where nurse bees are present as they enter and exit brood cells. DO not collect bees from the inner cover,  front of the hive or from a honey frame. These tend to be older bees and will be less likely to have mites.

1. Shake the frame(s) of bees into the tub
2. Collect about ½ cup of bees (300 bees) from a frames(s) of brood into a jar with a solid lid. Make sure the queen is not present on the frame that you sample, otherwise you risk damaging her
3. Add just enough alcohol to completely submerge the bees,  add lid & shake the jar vigorously for 30 seconds
4. Let the jar and bees sit for about 2-4 minutes
5. Replace the lid with a mesh wire, invert the jar and pour the solution into a tub or pan. The mites will appear as tiny reddish specs in the solution.
6. After the alcohol is added, the bees in alcohol can be stored and shaken at a later date

Sticky Board

Sticky boards are an efficient method of monitoring mites over an extended period of time and before/after treatments(s) to determine efficacy and mite drop. There are two styles of sticky boards, full white and checkered sticky boards.

Sticky boards can be purchased or homemade. It is a cut piece of cardboard paper to fit under the screen bottom board and covered with a sticky substance.

1.      The sticky board is covered with a sticky substance (vegetable oil or petroleum jelly)
2.      Insert the board sticky-side up below screen bottom boards or for solid bottom boards, insert the board in the hive entrance with a screen cover on top to protect from bees
3.      As mites are dislodged during grooming or removal from the capped cells they will fall through the screen cover and adhere to the board
4.      The board is removed after 72 hours (3 days)
5.      Mites are counted, although there could be debris on the board that could have to be sorted through when counting

Written by Katy Ciola Evans

Photos by Katy Ciola Evans & Nick Sloff, Department of Entomology, Penn State University