The Beekeeper Blog

Varroa mite alert!

An important announcement from Dr. Ramesh Sagili:

Hope all of you had a relatively successful bee year with strong hives and significant honey production, and have prepared your hives for successful overwintering. I just wanted to take this opportunity to alert / caution you about possibility of high mite populations in the colonies this year due to an unusually long bee season. As you all are aware we had a long bee season this year (at least in the Willamette valley) as a result of warm weather that prevailed for almost more than 7 months. Longer brood cycle (abundance of larvae) usually results in higher mite populations, as the mites get a greater opportunity to breed and increase their populations relative to bees. Most of you might agree that this year was a year with longest brood cycle seen in the recent past (I have been in Oregon only for the past 6.5 years, so can’t go beyond that number). It has been reported that mite populations could increase exponentially (up to about 50 fold increase) in years when the brood is present in colonies almost round the year (Martin 1998).

The economic threshold to treat Varroa mites in general for temperate areas is considered to be about 3% or higher in Fall, but as economic threshold depends on several factors it is not ideal to always rely on this magic number. In Oregon during the past six years we have documented mite intensities ranging between 3 % and 5% in Fall (August sampling). We observed significantly higher mite intensities this year (2015). The average mite intensity observed in backyard beekeeper colonies was 7%, whereas average mite intensity documented in commercial beekeeper colonies was about 3%. In few backyard beekeeper colonies we observed mite intensities as high as 32%, which is alarming.

If you treated your colonies for Varroa on time during July or August then probably you may have your mite populations under control, but still I urge you to monitor mites one more time before overwintering to make sure that the treatments that you used were effective and your current mite populations are not at damaging levels. If your mite levels are still high then please consider using an oxalic acid treatment if feasible when there is no brood (possibly during November).

If you did not use any Varroa mite treatments yet, then please assess the mite populations using alcohol wash or powdered sugar method as soon as possible and consider treating your hives with oxalic acid when there is no brood in the colonies. Oxalic acid was recently approved by EPA and is available from the bee supplier Brushy Mountain Bee Farm (

Following are some consequences of inadequate or no Varroa mite control this fall:

a)      Bee population may decline significantly or the colonies might totally collapse.

b)      Colonies that survive the winter will start upcoming year / season with higher mite loads and hence could reach damaging levels soon by late spring or summer.

c)      High mite infested colonies may contribute to higher mite drifting via robbing bees to other beekeeper colonies and your existing healthy colonies, as your mite infested dead colonies may be robbed by other strong colonies and aid in greater mite dispersal.

Also, please continue feeding protein to your colonies if pollen stores are not adequate in the colonies. Protein feeding not only helps with brood rearing, but also helps boost the immune system of bees. We have observed colonies to consume protein until October 25 in the Willamette valley and few other locations in Oregon when the weather is still OK (temperatures around 55 to 60° F).

Following is a question relevant to Varroa mite biology that an Oregon beekeeper asked me few months ago.

Question: How many days is the female Varroa mite outside of the capped brood before it re-enters another cell for reproduction? Do the young female mites that emerge along with the new bees also take the same amount of time to re-enter another larval cell for reproduction?

Answer: The time a female Varroa takes to re-enter (re-infest) a new cell depends on the availability of older larva (ready to be capped) to enter, and also on the number of bees in the hive at that point of time. One study showed that on average female mites take about 4 to 6 days to re-infest new larval cells. In a lab study, female mites that were artificially reintroduced into new cells with appropriate aged larvae (ready to be capped) immediately after emergence from a cell were able to reproduce successfully without any problems. Young female mites that emerge along with the foundress mite (parent mite) need time to achieve full maturity and hence may take a little more time to enter a cell for reproduction than the parent mite. Research pertaining to these new young mites is scarce, hence providing an average time for infestation is difficult.


Ramesh Sagili

Oregon State University

Apprentice News

Friday in the Apiary: September 18, 2015

Topics for the September Friday in the Apiary include mites (again and always!) and preparing hives for winter. We will heft hives to get a feel for a good weight, we will "nuc" a queenless hive, and we'll discuss supplementary feeding. Please join us at the OSU apiary on Friday from 3-5pm. Email for directions. Bring your hat/veil and gloves.

Apprentice News

Journey Level fee increase

Are you a certified Apprentice? Have you been considering the Journey Level? The fee for the Journey Level will be increasing to $200 on Septemer 1, 2015! Sign up before Sept 1 to save $50.

For more information on what the Journey Level entails, please see the links on the left under Journey Program. You don't need experience beyond the Apprentice Level to enroll! Advanced training and community service are the focus of the Journey Level. We also offer many exciting events such as a Lab Day (see blog post below), Field Day, and Oregon Master Beekeeper Institute in November.

Questions? Contact us at

Apprentice News

Friday in the Apiary: August 21, 2015

Mites, mites, mites. It seems that's all we talk about these days. They sure take all the fun out of beekeeping! Join us on August 21 from 3-5pm at the OSU apiary as we go through the OMB colonies and sample for mites. The colonies have been treated with Mite Away Quick Strips and we want to know if our treatment was effective. 

We will also have a special guest, John Bassinette, OSU pesticide specialist and Journey-level participant, who will talk to us about using miticides safely.

Please email Carolyn Breece ( to RSVP and for directions. Bring your hat/veil and gloves and water.

Apprentice News

Central Oregon: Saturday in the Apiary!

On August 1, 2015, the first Saturday in the Apiary took place at the Central Oregon Agricultural Research Center (COARC) in Madras. Eight beekeepers braved the triple digit temperatures to look at the colonies at the Research Center's apiary. Heike Williams, OMB committee member and COARC research technician, led the group through colony inspections. Cathy Platin, a certified apprentice in the Oregon Master Beekeeper Program, describes her experience.


On Saturday Aug. 1st, I attended the first Saturday in the Apiary at the Central Oregon Agricultural Research Center in Madras. I almost did not attend due to the extremely high temperatures but am very glad I did.

Heike was a wealth of knowledge and guided us through many steps of beekeeping including how she lights her smoker, what to look for when observing a hive, and then going into the heart of the hive where we checked for its queen rightness, stores, egg laying patterns, how to balance a weak hive by taking a frame from a strong one and putting it inside. She showed us queen cages and the best ways to place them within the hive while addressing the best strategies for successful queen introduction. She invited many of us to open the hives and look at the frames, then telling her what we saw. Later we went back in the classroom and had a further question and answer time which allowed for individual beekeepers to address concerns they had in their own hives.

It was a very successful day. I was quite thankful to have Heike's knowledge and to have a forum where we could come together and improve our skills as beekeepers. I look forward to the next session...

The next Saturday in the Apiary will be combined with an advanced beekeeping workshop on August 29, 2015. September’s Saturday in the Apiary will be on September 26, 2015. Please contact Heike Williams for more information:

All photos copyright of Debra Hollern.

Apprentice News

Congratulations Max Kuhn!

Saturday, June 27, 2015, Max Kuhn successfully completed the Practical Exam, his final requirement, to become a certified Journey in the Oregon Master Beekeeper program.