How to use Randy’s Handy mite wash cup
Tips for Using the XXX cup for Monitoring Varroa
TAKING THE SAMPLE
- Use an 18-quart dishwashing tub and a stainless-steel half cup (125 mL) measuring cup (for measuring live bees, a deep cup is more accurate than a shallow cup).
- Take the bee sample from a frame (or frames) adjacent to the broodnest, but not containing open brood — this will greatly reduce the chance of the queen being on the frame (check for her), and the sample will be most representative of the colony as a whole.
- Use a snap shake or brush to dislodge the bees from the frame into the tub (young bees hang on tighter than do old bees).
- Wait about 30 seconds for the older bees to fly off, shaking the tub, if necessary, to distribute the bees evenly. If more than a cup of bees remain in the tub, scoop out the excess so that you can more easily spot an inadvertently-shaken queen (the young bees will generally spread out evenly over the tub).
- Tilt and tap the tub firmly to shake the bees into a pile along one edge, and tip/scoop your half-cup sample of them into the cup. For the most accurate reading, use your finger to level them off before dumping them into the wash cup (young bees don’t sting).
PERFORMING THE WASH TO SEPARATE THE MITES
We don’t like to kill a bee any more than you do, but feel that any colony would gladly sacrifice a handful of workers in order to prevent facing an ugly death due to a varroa/virus overload. Our favorite agitation solution to use for separating the mites from the bees is Dawn Ultra detergent (2 tsp/quart water), but the XXX cup will also work with alcohol (use 90+% for highest mite recovery), or powdered sugar for dry shaking (this does not kill the bees, but produces inconsistent recovery).
For either Dawn or alcohol, first fill the cup to the line with solution, dump in the bee sample and immediately snap on the lid. Allow one minute for the mites to release from the bees, then gently swirl (don’t shake) the cup for a minute to precipitate the mites down through the bee bodies. Swirl just strongly enough so that all the bee bodies are in motion – vigorous agitation is counterproductive, since it keeps the mites stirred back up in the bees!
For a sugar shake, first place a tablespoon of powdered sugar into the cup, add the bees, snap on the lid, and then invert the cup back and forth until the bees are evenly coated. Wait a minute, then holding the cups upside down vigorously shake them up and down for a minute. Then pull off the outer cup and invert the inner cup over a white tub of water, and continue to shake it and the bees over the water until no more sugar (and mites) fall. The sugar will quickly dissolve into the water, leaving the mites temporarily floating on the surface for counting. The shaken bees can be returned to their hive.
DETERMINING THE MITE COUNT AFTER A WASH
Once you have separated the mites from the bees, remove the inner cup and discard the bees (compost them on the ground or save them for nosema microscopy). Then put on your reading glasses and lift the cup to view the bottom to count the mites. Better yet, hold the cup 4 inches above a 10x magnifying mirror to enlarge the mites for easy identification. This will be your “mite count” (you can divide the count by 3 to approximate the “percentage mite infestation rate if you wish).
TREATMENT THRESHOLDS FOR COLONY HEALTH AND SURVIVAL
So long as a colony’s mite count is below 2, varroa and its associated viruses have little impact upon colony health. Viruses begin to become a problem at counts above 6 mites, and colony performance declines noticeably once the count exceeds 15. A count above 40 will likely result in imminent colony collapse.
The key concept is to be proactive and stay ahead of the exponential rate of mite reproduction — the higher the mite count, the faster the rate of increase! When colonies are rearing brood, expect the mite count to double each month. Don’t be fooled by low counts in April – at that time most of the mites are hidden in the brood, and won’t show up in a mite wash!
To maintain optimal colony health, your treatment threshold counts would be:
January – April: zero-2 mites.
June-July: no more than 6 mites.
Mid-August: zero out the mites in preparation for their critical autumn brood rearing.
October – November: colonies may survive if they enter the winter in November with a count of up to 10 mites, but they’ll have a better chance if you get the count down to the zero-2 range (an oxalic acid or Hopguard treatment once they go broodless really helps).
Depending upon how many months the bees engage in brood rearing in your area, it will take one to three 95% reductions of the mite population (by whatever means) over the course of the season to maintain the above low levels of infestation. Your bees will thank you for helping them!