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George Imirie's PINK PAGES
March 2000

Using Powdered Sugar to Detect Varroa Mites

While seeking new ways to recover Varroa mites from bees for laboratory assays, Paula Macedo, a University of Nebraska Graduate Student, found a new way to check colonies for Varroa mites that is more efficient than ether roll, and NOT necessary to kill bees to conduct the test.

You will need the following:

  1. A wide mouth canning jar (quart or pint) with a two piece lid.
  2. #8 mesh hardware cloth (or any mesh that will retain bees, but pass Varroa
  3. Window Screen (or any fine mesh that will retain Varroa, but pass powdered sugar)

Retain the metal ring of the two piece lid and discard the center portion. Cut a circle of #8 mesh hardware cloth to fit the inside of the ring. Collect 200-300 bees in the jar. Add powdered sugar (enough to coat the bees, about I tsp. to I tbsp.) through the #8 mesh hardware cloth lid. Roll the jar about to distribute the sugar. Allow the jar to sit for a few minutes (NOT just a few seconds). Then invert the jar over a piece of paper and shake to recover the mites. The bees will remain in the jar, but the mites and sugar will pass through the #8 mesh to the paper. The sugar will make it difficult to count the mites. Hence, pour the sugar and mites into another jar with a fine mesh lid. Shake again and allow the sugar to escape through the mesh. A brief shaking will usually recover about 70% of the mites, but longer shaking will produce about 90% recovery. Dump the mites on a clean sheet of paper and count them.

There are three possible reasons for the efficacy of this technique:

  1. Varroa mite legs have a sticky pad called the empodium that helps them adhere to their host bee. The presence of powdered sugar could make it difficult for mites to adhere to their host bee.
  2. Powdered sugar stimulates the bees' natural grooming behavior.
  3. The powdered sugar on the mite's body stimulates mites to release from feeding on the host bee to groom themselves.

Plans for future studies: Powdered sugar applied to a whole colony will dislodge a few mites from their host bees, but it is not efficient. Furthermore, the mites will eventually recover and return to their hosts. However, when bees are isolated from nest materials, the might recovery from exposing them to powdered sugar is impressive. Hence, in the future, we will examine the efficiency of the technique in bulk bee cages. One limitation to using this technique is that it is only efficient when brood is not present. When brood is present, 70-80% of the mites will be in sealed brood cells.

We know that the powdered sugar technique of Varroa detection is a safe, inexpensive, and highly efficient way to check adult bees for mites. We hope that you can find creative ways to use the technique to lower Varroa mite infestations and reduce the frequency of chemical treatments. Dare we even dream of eliminating them altogether?

Editor's Note: In a private communication to me, Dr. Marion Ellis, Extension Apiculture Specialist for Nebraska, told me that he uses this survey method for varroa detection and prefers it to any other method. I will test it in my apiary on July 1st with Sticky Boards used as Controls and publish my results in August. I strongly suggest that you try it too.


If you have not heard about the excitement, research, and writings about Integrated Pest (mite) Management over the past year, you must read only the Sport Pages or the Comics. It s a major undertaking by our Mid-Atlantic Apiculture Research and Extension Consortium (MAAREC) including our Beltsville Bee Research Lab.

Confined to the house because of the. darn snow, I carefully examined the Internet Bee-Line for something exciting; and I FOUND IT! One of our most respected scientist (and my friend), Dr. Medhat Nasr, Research Scientist of University of Guelph in Ontario, Canada, had replied to someone on the subject of "Robust Varroa Management". Medhat had written a quick, "off the-top-of- his-head" reply, and he gave me his permission to publish it in my PINK PAGES. Here it is, with minor grammatical changes:

My definition of robust varroa management is an integrated mite management system. In Ontario, we have been using, annually, a combination of several methods for management of both varroa and tracheal mites. These methods include:

  1. requeening colonies every TWO years with tracheal mite-resistant hygienic bee stock (1/2 of the operation each year)
  2. spring treatment of formic acid in a mite-away pad (a single application formic acid pad that was developed and LEGALLY used in Ontario since 1996-97).
  3. use of 1-2 frames of drone foundation to trap mites in drone brood in the summer and early fall, if needed. (Ed: Several bee equipment houses can supply)
  4. fall treatment with APISTAN.

Our research results for evaluating the efficacy of applying this system showed that:

  1. the use of tracheal mite-resistant h ienic bees slows the mite development in bee colonies. Tracheal mite population will build very slowly and it will take more than two years to reach a damaging level. Hygienic bees which are able to remove greater than 75% of freeze killed drone brood are able to reduce the varroa mite population by 30%
  2. the use of a single application of formic acid in the spring is good for a full year for tracheal mite control, and good to kill the varroa in the spring without the need to use any Apistan strips in the spring.
  3. using this system has helped Ontario beekeepers to achieve the following:
    1. Reduction of the annual colony mortality from 25-40% to less than 10%
    2. No sign of varroa mites developing resistance to Apistan which has been used in Ontario for 8 years. We tested varroa mite resistance to Apistan, which showed Apistan is still effective and kills >95% of varroa mites.
    3. No Apistan residues have been found in honey samples; and we are now in the' process of testing for Apistan residues in the wax.
    4. Beekeepers diversified their management and activities. We have a group of queen producers of Buckfast, Carniolan, And Ontario bees who are involved in the breeding program to measure mite resistance. These beekeepers make their income from selling more than 15,000 queens/year and 6,000 'nucs'/year.
    5. The total number of bee colonies is increasing for the past two years.
    6. Honey production per colony has been increased by 10-20%.

When you total the costs of colony replacement (killed by mites), 2 Apistan treatments, and loss of honey production before this new "robust mite management" program, this new method is economically viable and sustainable. This system is far more robust than relying on the use of the same miticide (Apistan or Coumaphos) year after year. Also, this program maintains healthy producing colonies year after year.

Cheers, from Medhat Nasr

Proper Supering

I can hear the screams now: "What the hunk does George mean when he says "proper"? Doesn't he think I know what I am doing?"

Year after year, I hear of people who have lost their honey crop because their bees swarmed, or their brood chamber was honey bound, or their foundation was all sealed together by burr comb and bridge comb. In most instances, the blame was placed on all kinds of crazy or wrong reasons, because the real reason was IMPROPER supering. Although well discussed in previous PINK PAGES, I will repeat the cardinal points about supering, including WHEN to super, HOW MANY supers, DRAWN COMB or FOUNDATION, and bee ENTRANCES.

FOUNDATION can NOT be used like drawn comb! When using foundation there MUST be IO frames of foundation (NEVER NINE) in a super to get it PROPERLY drawn. If you have less than I 0, you have violated "bee space" and the bees will build bridge comb, burr comb, and all kinds of strange comb in between the frames. Further, you can NOT put on MORE THAN ONE super of foundation at a time. At least 6 or 7 frames of foundation must be drawn and almost filled before you move the undrawn frames into the center position and then add a second super, and likewise with the 3rd super, and the 4th, etc. Obviously, it is easier to use DRAWN COMB. After the bees have drawn comb, it is YOUR JOB to protect it from damage by wax moths or mice, because it is the beekeeper's MOST VALUABLE ASSET.

WHEN to super: In Maryland, I install my FIRST super on April I st with NO QUEEN EXCLUDER under it. On April 1 5th (Income Tax Day), that first super should have 6-7 of the frames filled with nectar or may )e even vouna hrnnri (larvae or eggs). I very full make sure the queen is NOT in that super (but down below in the brood chamber area) and place a queen excluder under that super. Then I add 4 more supers of rawn omb plus 2 Imirie Shims on top of the first super. By putting the supers in place ALL AT ONE TIME stimulates the bees hoarding instinct making them work harder ' but much more important, multiple supers provides LOTS of storage room for them to store the thin wate ectar until they have time to ripen it into honey.

In you are normal, you don't like to get hung up in a traffic jam or wait in line to get into a movie, so you try to avoid traffic congestion or lines of people. Bees do the same thing. The forager age bee (over 19 days of age) does little more than forage, and does not do much work in the brood chamber (bee nursery). That forager bee gets irked battling through that highly congested brood chamber with all those nurse bees feeding larva, building cell cappings, cleaning cells for the queen to lay eggs, guarding the front entrance, etc, and would use another entrance to go to and from the super area if it was available. That is the exact purpose of the Imirie Shim a nd the upper entrance in the edge of the inner cover. An lmirie Shim is NEVER,

EVER used anywhere on a colony except in between supers (never in the brood area). I put a Shim between the I st and 2nd supers and another one between the 3rd and 4th supers; and hence my foraging bees have 3 entrances to use other than the bottom board entrance: 2 lmirie Shims + the entrance cut in the inner cover.

Even if you think it won't work, your bees will swarm anyhow, that is not the way TOM, DICK, or HARRY supers their bees, and surely not the way DADDY used to keep bees, why don't you stop talking and just try it. You might find out how I rarely have any swarms and average 130 pounds of honey each year per colony in MARYLAND where the official average yield is a paltry 29 pounds. I have led you to the water, now you must decide whether to drink or not.

George Imirie
Certified EAS Master Beekeeper