The Signs of Mite Damage - How to Identify Progressed Varroosis?

Bee Informed Partnership    September 26, 2018

BIP Tech Transfer Team Member, University of Minnesota, Written by Garett Slater, posted by Anne Marie Fauvel

Varroa infested colonies entered the United States in ~1987, and changed beekeeping forever. Beekeeping has always been time consuming, difficult and experience oriented; however, beekeeping became even more challenging when beekeepers were called to eradicate a bug on another bug. Since its introduction in the US, beekeepers have reported high annual colony losses due to mites. In fact, some beekeepers report 60% losses due to this troublesome pest. While beekeepers have faced devastating challenges before, including American Foulbrood, Varroa mites has presented damages never before seen.

Varroa have become more difficult to manage since their introduction. The mites are seemingly embedded within the honey bee industry reality as nearly, if not all, colonies have Varroa. Like many beekeepers say: ” all my colonies have mites, I just cannot see them”. Even if alcohol washes do not reveal mites, Varroa is present in the brood or will be present soon due to infestation from surrounding colonies. As mites have become more widespread, they became a vector for a variety of viruses. In fact, researchers are finding more and more variants of Deformed Wing Virus (DWV), a virus that affects the honey bee’s essential flight capabilities. Research has shown that DWV-B (Deformed Wing Virus variant B) can be responsible for high over-winter losses.

The point here is that Varroa devastates colonies.  It would also seem that Varroa are transmitting more virulent strains of viruses with each passing year. Because of this, I recommend to keep mite levels below 1 mite/ 100 bees in the spring and below 3 mites/100 bees in the fall. With Varroa loads any higher, beekeepers risk high colony losses.

Monitor, Monitor, Monitor

Beekeepers must consistently monitor mites if they expect to have strong and healthy colonies. Beekeepers can monitor their mites in various ways, but I recommend both of these two methods: perform an alcohol wash (or other monitoring method) and observe the overt signs of mite damage. It is ideal to perform monitoring methods once a month, but we realize this is not always possible. Because of this, combining both monitoring and observation methods are recommended. Ideally, mites should be monitored at least 4 times a year.  As seen in Figure 1: population increase, population peak, population decrease, and fall dormant; it is essential to understand the seasonal changes. For example, brood density varies throughout the year, so certain treatments can be less effective at different times. By understanding seasonal cycles, beekeepers can better manage their mites. I understand Figure 1 does not reflect the reality of every region but it gives a good overall general idea.  Some regions have multiple population peaks due to large honey flows, so you will need to understand the honey bee seasonal phases in your region. But essentially, as the bee and brood population increase, so do the mites.

Figure 1: Honey bee seasonal phases – Beekeepers should monitor mites once a month, but if this is not possible, mites should be monitored at least 4 times a year: during the late winter-early spring dormant, population increase, population peak, population decrease, and fall dormant phases. I recommend alcohol washes (or another monitoring method) during these periods. Photo courtesy of the Honey Bee Health Coalition.

Mite Monitoring Techniques

I attached a chart outlining the 3 major mite monitoring techniques I recommend. Perform one of these techniques 4 times a year: Early spring, late spring, late summer and early fall. Each beekeeper has their preference, so use the method you feel the most comfortable with. I use alcohol washes, but I feel comfortable with sugar rolls or CO2 as well. As long as you monitor, there is not a wrong method!



Sugar Rolls

Known research on accuracy

Common method

May not kill bees


Hard to do on windy, rainy or humid days

More time consuming

Less accurate

Alcohol Wash

Well documented

Quicker than sugar rolls

Can be more accurate than sugar roll

Can be messy

Kills bees


Quickest method

Easy to do with multiple colonies

Kills the bees (most likely)

When monitoring for mites, beekeepers should review mite thresholds. I outline my recommended thresholds for each monitoring method below. If your colony is above threshold, I recommend taking actions. Mite thresholds are not an exact science, even if you have levels below the threshold, it is no assurance that your colonies will be healthy and successful. For example, I have sampled many commercial beekeepers with mite levels <0.5 mites /100 bees in the spring, and they eventually had huge losses. I typically see mite levels spike in the late summer because: A) summer treatment with honey supers are limited, B) Mites are often lurking in the brood, and C) Mites from other beekeepers nearby can (re)infest colonies. Because of this, always monitor and monitor again. Once mite levels do spike, they may be difficult to bring down. Too often, when you notice, the mite damage is already done. I should note that I recommend alcohol washes, powdered sugar rolls or CO2 over a sticky board. Sticky boards are not nearly as accurate, because they do not quantify the level of infestation. If a sticky board is your only option, you can attest that you have some mites or more mites, but you are not able to assess the level of infestation (1, 2, 3 mites/100 bees). Use other monitoring method options for more accurate results and an infestation level to compare with suggested thresholds. *These thresholds may vary per US regions. These are the threshold I recommend in the Midwest (MN & ND)

Monitoring Method

# of mites in early-spring

# of mites in mid-spring

# of mites in late-spring

# of mites in early-fall

# of mites in late-fall

Alcohol Wash


1 mite/100 bees

1 mite/100 bees

1 mite/100 bees

3 mite/100 bees

3 mite/100 bees

Powdered sugar roll

1 mite/100 bees

1 mite/100 bees

1 mite/100 bees

3 mite/100 bees

3 mite/100 bees


1 mite/100 bees

1 mite/100 bees

1 mite/100 bees

3 mite/100 bees

3 mite/100 bees

Sticky Board

9 mites/24 hours

9 mites/24 hours

9 mites/24 hours

12 mites/24 hours

12 mites/24 hours

Mite related Disease Progression 

I inspect and observe hundreds of colonies annually. When I enter a colony, I often immediately know whether it has (or did) have high mite levels simply by observing progressed signs of mite damage. Just observing progressed mite damage does not suffice, but it is a good start. By noting visual signs of Varroa, you will know just how important your mite levels are and the need for action. Monitoring is best but if you can recognize some of the visual signs, you will better understand the extend of the mite damage to your colony.

I outlined the 5 stages of mite damage, which I relay to my beekeepers. In the spring during population increase, I want to see colonies within the Stage 1- 2. While I hate to see mites in the spring, this is not always a bad sign. Even if I observe mites, the colony may be below the recommended threshold, so just continue to monitor that colony. During the late spring, summer and fall, I like to see colonies within Stage 1-3. Even if Chewed Down brood (CDB) (outlined below) and phoretic mites are seen, it does not mean that beekeepers have high levels. However, a combination of phoretic mites and CDB can signal worse mite issues. If these signs are seen, continue to monitor these colonies. As for Stage 4-5, I never want to see these stages, regardless of temporal period. Deformed Wing Virus (DWV) and Varroa Mite Syndrome (formerly Parasitic Mite Syndrome or PMS) can signify high mite levels.  Specifically for Varroa Mite Syndrome, it signifies very progressed mite damage, which often results in colony deterioration and eventual colony death. If colonies are in stage 4 or stage 5, monitor immediately to determine extent of damage. Action is often required, but may be too late.


Visual Signs


Stage 1

Zero signs of mites, brood diseases or viruses

Stage 2

Visual signs of phoretic mites on either workers or drones.


This does not necessarily mean a mite issue exists, but if mites are seen, monitor to determine extent of varroosis.


Stage 3

Chewed Down Brood and/or phoretic mites



Stage 4

Deformed Wing Virus (DWV) and/or Chewed Down Brood and/or signs of phoretic mites.

Visual signs of Deformed Wing Virus (DWV) can mean larger varroa issues. Obviously, this depends upon the number of bees with DWV and the number of phoretic mites seen, but mite monitoring is recommended to determined extent of varroosis. These signs signal a more progressed form of varroosis.

Stage 5

Varroa Mite Syndrome (VMS) and/or Deformed Wing Virus (DWV) and/or Chewed Down Brood and/or Phoretic mites

Visual signs of Varroa Mite Syndrome usually signal extreme issues with varroasis. If Varroa Mite Syndrome is seen, then mite levels are often a significant issue and has advanced to the most progressed stage of varroosis.

Visual signs

Phoretic Mite

Phoretic mites are Varroa mites seen on the abdomen of worker (or drone bees). Most phoretic mites, however, are found underneath the bee, more precisely tucked between the abdomen’s sclerites where they latch on and feed. Because of this, I typically inspect the ventral abdomen of several worker bees during inspections. This is why beekeepers “never see mites”, even if these beekeepers have higher mite levels. Visually inspect phoretic mites just on the workers, not the drones. If phoretic mites are seen on worker bees, then this represents a more progressed infestation of mites. Signs of phoretic mites indicate the colony is in Stage 2-5. Visually inspect other signs to further pinpoint extent of damage.

Phoretic mite on the thorax of a worker bee. Photo by Rob Snyde Chewed Down Brood (CDB)

Bees can sense mites in the brood. If sensed, bees will uncap and cannibalize the pupae. If CDB is seen, then mites may be at a high level, especially within the brood. CDB can indicate progressed mite damage, so continue to monitor and assess colony health.

Deformed Wing Virus (DWV)

Deformed Wing Virus (DWV) represents the next stage of varroosis progression. Bees with DWV are kicked out of the colony so if bees with DWV are seen than Varroa has become an issue. DWV does not signify un-manageable mite levels for the colony, but it is a more progressed sign of mite damage.

The bottom right corner contains a cell with chewed down brood (CDB). Bees begin chewing brood when they sense mites within the cell, so this can indicate larger mite issues. Photo by Rob Snyder

This bee has deformed wing virus, a debilitating virus than can easily deplete a colony. Oftentimes, bees with the virus are removed from the colony. So if bees with Deformed Wing Virus are seen, than this can indicate larger issues. Photo by Rob Snyder


Spotty brood and Varroa present on adult

Mites may be present on brood

Mites seen on open brood cells

Small population size

No odor present, just sunken brood

Varroa Mite Syndrome (VMS) is the most progressed sign of mite damage. If VMS mite is seen, than the damage is done. These colonies will likely collapse, and there is nothing a beekeeper can really do. At this stage, the colony has already dwindled and deteriorated. Photo by Rob Snyder

Varroa Mite Syndrome (VMS)

A pathogen has not been identified for this diseased, however mites are always present when this disease is seen. This brood symptom looks similar to other brood diseases except the larvae do not rope like foulbrood. Larvae do appear sunken to the side of the cell. If Varroa Mite Syndrome is observed, then colony has likely dwindled and deteriorated. Varroa Mite Syndrome is the most progressed sign of mite damage, and truly at a stage of no return. Even if low phoretic mites are seen, Varroa mite syndrome often means an end to your colony, even if treatment is applied.


All beekeepers should consistently monitor mites throughout the year. Even if mite levels are low at one point, it does not mean they will stay low. Mite levels can easily spike, so always be aware and monitor and re-monitor. Beekeepers should learn how to monitor and visually inspect for mites. By doing so, varroa mites can effectively be managed. Varroa mites are the most challenging issue beekeepers face, so make sure you know where your colonies stand. If you don’t, then you risk losing your colonies.

(Note: Thank you to Jaime E. Garza, Apiary/Agricultural Standards Inspector, Department of Agriculture, Weights & Measures, County of San Diego for the link and his quote, “With the lack of floral resources this year, Varroa mites may put more stress on your colonies. Hopefully the information will help give you a better idea of how to look for signs of Varroa mite infestations and encourage you to monitor and control them if you are currently not doing so.”)

Get Ready For The Mite-A-Thon! September 8 - 15, 2018

CATCH THE BUZZ     August 29, 2018

Spread The Word - Local Beekeeping Clubs And Associations Are Key To Making The Mite-A-Thon A Success!

September 8 to 15, 2018      

The Mite-A-Thon is a tri-national effort to collect mite infestation data and to visualize Varroa infestations in honey bee colonies across North America within a one-week window.  All beekeepers can participate, creating a rich distribution of sampling sites in Canada, the United States, and Mexico.       

OBJECTIVE: 1) To raise awareness about honey bee colony Varroa infestations in North America through effective monitoring methods. 2) Management strategies will be made available for discussion within bee organizations utilizing Mite-A-Thon partner developed information and outreach materials.     

PARTICIPANTS: All beekeepers in North America are encouraged to participate.


Encourage your members to participate in September, through meetings, newsletters, emails, social media etc. 

Teach new beekeepers how to monitor for mites in August.

Help your members prepare their monitoring materials.

Support your members in making sure they are able to monitor mites effectively and report their data.

DATA COLLECTION: Varroa monitoring data will be uploaded to  

CONTACT: or 415 362-1137

Get resources and stay up to date at!

Thank you,

The Mite-A-Thon Partners

How Do Varroa Mites Feed on Bees?

Western Apicultural Society FB Post  June 17, 2018

Sammy Ramsey, of the vanEngelsdorp Bee Lab, University of Maryland, spoke at the April meeting of the Alameda (CA) Beekeepers Association. This is a summary of his research findings, published in the most recent ABA newsletter.


Conventional wisdom is that Varroa mites feed on bees' hemolymph, which is like blood. When Sammy reviewed the research, he didn't think it actually supported that.

His PhD thesis was to determine how mites feed and what they feed on. He compared Varroa mites to other arthropods that feed of hemolymph or blood and found differences:
• Their digestive systems and excrement are quite different
• They are not closely related genetically

Next, he did an observational study of where on bees Varroa mites fed. Looking at mite placement, he found 99 percent of mites on the bottoms of the bees, wedging themselves under the plates called the metasomal sternites/tergites.

The mite pierce multiple layers of soft tissue in the membrane between sternites/tergites and then inserts its feeding tube to feed on the "fat body."

Bees typically have a long section of fat, the fat body, running along their undersides. This is an organ, not just a mass of tissue, with nine different functions, including growth and development; metamorphosis; metabolic activity; water and temperature regulation; protein synthesis; immune function; and synthesis of vitellogenin, the substance that allows some bees in the colony to overwinter.

When a mite has been feeding, it gets smaller and more dispersed. This indicates two things: The mite injects something into the bee to predigest tissue; and that fat is the mite's food.

Next, he stained the fat content and hemolymph of bees with specific stains that would fluoresce under a spectrophotometer. Then he put in mites and allowed them to feed. The mites consistently showed they had fed on fat.

Finally, he raised groups of mites off bees, feeding them on various combinations of fat body and/or hemolymph. Mites that were fed on fat body laid the most eggs. Mites fed only on hemolymph laid no eggs. Moreover, mites fed hemolymh died as quickly as those fed nothing. Those fed on fat body lived substantially longer.

His conclusion is that the mites feed on the fat body of the bee, not the hemolymph.

He has also found bacteria inside bees near the feeding wound, and the bee's immune system doesn't seem to attack them. The bacteria haven't been identified yet.

Mites that kill colonies the quickest are also the ones that have a better chance of dispersing into other colonies. He thinks beekeepers should treat or intervene in some way, for example, by removing drone comb right before the drones hatch. He advises using more than one type of treatment, so you reduce mites with different characteristics with the different methods.

Brood breaks are helpful, but there will still be mites on the adult bees.
His data shows that in four consecutive years, beekeepers who treated for Varroa lost fewer colonies than those who didn't treat.

Why does this matter? It shows:
• Need to update recommendations for treatment timing.
• Supplementing protein without controlling Varroa is not helpful.
• This info could lead to the development of systemic pesticides for Varroa.
• Important to make sure bees that will overwinter, which are developing in the cells in August, are not harmed by Varroa—so that's a good time to treat.

More about Sammy Ramsey:

Refrigerating Honey Bees to Fight Mites, Colony Collapse

Washington State University     By Scott Weybright, College of Agricultural, Human and Natural Resouce Sciences     April 23, 2018

PULLMAN, Wash. – Saving Honey Bees Is Easier When Varroa Mite Infestation Is Reduced. WSU Researchers Are Hoping Mid-Season Hibernation Can Help In The Fight Against The Mighty Mites.

The black bump on this honey bee's back is a varroa mite. Mites weaken bees’ immune systems, transmit viruses, and siphon off nutrients. Photo by Scott Bauer, USDA Agricultural Research Service.

Varroa Mites Are Pests That Weaken Bees’ Immune Systems, Transmit Viruses And Siphon Off Nutrients. They’re A Huge Factor In Colony Collapse Around The Country.

“Most Treatments Only Kill Varroa On Adult Bees, And Are Generally Only Effective For Three Days,” Said Brandon Hopkins, Assistant Professor Of Entomology And Manager Of The WSU Bee Program. “But A Lot Of Mites Live In The Brood, Which Are Under A Wax Cap That Treatments Can’t Touch. Those Bees Hatch Out And Are Already Afflicted.”

Currently, Treating For Mites Requires Three Treatments Over A 21-Day Period To Make Sure You Treat All The New Bees That Come Out Infested With Mites.

These Treatments Are Difficult And Expensive Because Beekeepers Must Treat All Their Colonies On A Specific Schedule. It’s Very Labor Intensive To Treat Thousands Of Colonies By Hand Three Times At Precise Timing Cycles, Hopkins Said.

Cold Storage

Bees Don’t Truly Hibernate, But They Do Change Their Behavior In Winter. Queens Stop Laying Eggs, So No New ‘Brood’ Is Created At That Time.

Last August, WSU Researchers Put 200 Honey Bee Colonies Into Refrigerated Storage. This Is A Time When Bees Are Still Active, But Have Finished Making Honey For The Season, And There Are No Crops That Require Pollination. It’s Also When Beekeepers Normally Do A Round Of Mite Treatments.

By Placing Colonies In Refrigerators, The Queen Stops Laying New Eggs, Which Stops The Production Of Brood. When The Bees Come Out Of Refrigeration, There Is No ‘Capped Brood’.

At That Point, Hopkins And His Team Apply A Varroa Treatment On The Adult Bees.

The Initial Results Were Overwhelmingly Positive. Researchers Found An Average Of Five Mites Per 100 Bees On The Control Colonies (Not Refrigerated) One Month After The Normal Three-Cycle Mite Treatment.

The Refrigerated Colonies Had An Average Of 0.2 Mites Per 100 Bees One Month After The Single Mite Treatment.

“That’s A Significant Decrease,” Hopkins Said. “Refrigeration Is Expensive, So We Need To Do More Work To Prove The Cost Is Worth It For Beekeepers, But We’re Really Excited So Far.”

Additionally, The Infestation Levels Varied Tremendously From Colony To Colony In The Control Samples. That’s Because Of The Difficulty In Treating Colonies Consistently Over Three Cycles. The Colonies That Had The Refrigeration Treatment Had Consistent Mite Numbers With Little Variation.

Doubling Down

Brandon Hopkins in his bee lab.

After Hearing About This Research, A Few Beekeepers Approached The WSU Scientists About Doing A Similar Round Of Refrigeration In The Early Spring. Most Commercial Beekeepers In The U.S. Take Their Colonies To California For Almond Pollination In February And March. But There’s A Time Gap Between The End Of The Almond Pollination Season And The Start Of Pollination Season In The Northwest.

“Beekeepers Generally Have Two Periods Of Time For Mite Treatments, Before The Bees Make Honey And After,” Hopkins Said.

Once Bees Have Mites, The Infestation Increases During The Pollination And Honey Production Months.

“But If They Can Start With Low Mite Numbers, The Bees Are Healthier During The Honey Production Period,” Hopkins Said. “A Lot Of Varroa Damage Comes While The Bees Are Making Honey.”

Calculated Risk With 100 Colonies

This Spring, Belliston Bros., A Commercial Idaho Beekeeper, Donated 100 Honey Bee Colonies To Do A Refrigeration Study Just Like The One Done In August Last Year.

“It’s A Big Risk For Them,” Hopkins Said. “But If It Works, Beekeepers Would Have Significantly Better Varroa Control While Using Fewer Chemicals. And They’ll Have Better Colony Survival During The Following Pollinating Season. It’s A Win All-Around.”

Nobody Really Knows How Bees Will React To Being Put Back Into Their Winter Mode In What Is Normally The Middle Of Their Active Season, He Said. But That’s What Science Is All About. And If This Works, It Could Be A Major And Environmentally Sound Victory In The Great Varroa Mite Battle That Beekeepers Have Been Waging For Decades.

“We’re Hopeful,” Hopkins Said. “We Won’t Have Results Back For Several Months, But We’re Excited We May Have A Way To Help Beekeepers Keep Their Colonies Strong And Stable.”

Scientific Beekeeping: Research on Oxalic Acid

Scientific Beekeeping     By Randy Oliver     February 22, 2018

 Hi All,

Thanks so much for your feedback on the mite model--I received over 700 responses, many with constructive comments that I forwarded to the class.  Voting went overwhelmingly to the original graph--596 for it; 26 for the individual graphs; 11 for both.  I suggested to the class a way to present all options--taking first-time users step-by-step, with options.

I'm heartened by the number of you worldwide who have already used the mite model.  Your feedback and notes of appreciation make my day!

I'm currently deep into cage trials to attempt to determine the optimal formula for the extended-release oxalic acid treatment.  I'm trying different ratios of OA to glycerin, as well as using the very similar food-grade solvent propylene glycol.  I'm finding that both humidity and degree of saturation of the towels can make huge differences in whether the treatment hurts the bees.

I've also figured out how to quantify the precise amount of oxalic acid on the bees' bodies using titration:

I'm able to accurately quantify the amount of OA to less than 1/10,000th of a gram!  I now know how much OA is harmful to the bees, and will soon resume testing to see how little is necessary to kill the mites.

I've recently posted three new articles:

Not surprisingly, the first is Progress Report #3 on the above topic of the extended-release oxalic treatment.

The next two are numbers 14 and 15 in my "The Varroa Problem" series.
One discusses in-hive virus dynamics and the need for early mite treatment.
The other models the expected effect of various mite treatment options, especially repeated oxalic acid vaporizations (would also apply to sugar dusting).

Here at home, our beekeeping season is well underway.  Almond bloom in California is nearing an end, just as frosty air moved in to threaten the nutlets with freezing.  We've suddenly gone from a balmy early spring, to winter conditions.  Indeed, we started grafting queen cells as it was snowing.  My sons Eric and Ian are doing a great job at taking over the operation--we went to almonds with our highest colony count yet, and graded at over 15 frames average in those orchards that got graded per contract--giving them a nice bonus!

Happy Beekeeping to All!


(Please note: Randy Oliver's research on oxalic acid is supported entirely by donations from beekeepers.)

Accidental Discovery Could Save Bees From Their Greatest Threat

Real Clear Science     By Ross Pomeroy     January 15, 2018

Agricultural Research ServiceGerman scientists primarily based out of the University of Hohenheim have stumbled upon a simple solution that could deal a blow to honeybees' greatest threat. They've found that a tiny dose of the compound lithium chloride kills Varroa destructor mites without harming bees.

The scientists detailed their incredible findings in the January 12th publication of Scientific Reports.

V. destructor, more commonly known as the Varroa mite, is a scourge of honeybees across the globe. Upon infiltrating a colony, the mites latch on to bees, sucking their hemolymph (essentially blood) and spreading the diseases they carry. According to the USDA, 42 percent of commercial hives in the U.S. were infested in summer 2017, and 40 percent of beekeepers said the parasite seriously harmed their colonies. By comparison, only 13 percent reported harm from pesticides.

Chemical compounds exist to combat the parasites but they are outdated and growing increasingly ineffective, the researchers write, adding that no new active compounds have been registered in the last 25 years.

The dearth of options prompted scientists at The Hebrew University of Jerusalem to experiment with a technique called RNA interference. In their study, they fed bees double-stranded RNA via a sugar solution to knockout vital genes in Varroamites. The mites ingested the lethal RNA via bees' hemolymph and subsequently died.

Inspired by those results, the German researchers sought to replicate them by repeating the experiment with slightly tweaked methods. Indeed, mites infesting bees that were fed sugar water with the designed RNA rapidly died, but so did mites in a control group given another RNA that should have been ineffective. The astonishing results prompted the researchers to suspect that the lithium chlorideused to produce the RNA – and thus present in the sugar water – was actually killing the parasites. A battery of subsequent examinations confirmed their hypothesis.

The scientists then carried out numerous experiments testing lithium chloride against Varroa mites, including ones that approximated field studies. They found that feeding honeybees minuscule amounts of lithium chloride (at a concentration of no more than 25 millimolar) over 24 to 72 hours wiped out 90 to 100 percent of Varroa mites without significantly increasing bee mortality. (Below: The figure shows the surviving proportion of bees and mites fed lithium chloride compared to those not fed lithium chloride.) Ziegelmann et al. / Scientific Reports

According to the researchers, lithium chloride could be put to use very quickly as it is easily applied via feeding, will not accumulate in beeswax, has a low toxicity for mammals, and is reasonably priced. However, wider studies on free-flying colonies testing long-term side effects are required first, as well as analyses of potential residues in honey.

Francis Ratnieks, a Professor of Apiculture at the University of Sussex, expressed skepticism about the new finding.

"We can kill 97% of the Varroa in a brood less hive with a single application of oxalic acid, which takes five minutes to apply and is already registered and being used by beekeepers," he told RCScience via email. "I think it will be difficult in practice to apply lithium salts to colonies to kill varroa and get the same level of control... There are also the wider issues of registration and potential contamination of the honey with a product that would not normally be there."

It should be noted that studies have shown oxalic acid to be inconsistent at managing mites during the summer months as well as in colonies with capped broods

Regardless, the Hohenheim researchers are pressing forward. They're already speaking with companies to get a lithium chloride treatment refined, approved, and in the hands of beekeepers.

"Lithium chloride has potential as an effective and easy-to-apply treatment for artificial and natural swarms and particularly for the huge number of package bees used for pollination in the United States," they conclude.

Source: Bettina Ziegelmann, Elisabeth Abele, Stefan Hannus, Michaela Beitzinger, Stefan Berg & Peter Rosenkranz. "Lithium chloride effectively kills the honey bee parasite Varroa destructor by a systemic mode of action." Scientific Reports 8, Article number: 683 (2018) doi:10.1038/s41598-017-19137-5

*Article updated 1/15 to include Professor Ratnieks' statement and to include information about oxalic acid.

*An earlier version of this article mistakenly reported that the researchers are based out of the University of Hoffenheim. They are from the University of Hohenheim.

Related articles/info:

Samuel Ramsey - 2017 UMD Three Minute Thesis Winner

(Note from LACBA: Back in October 2017, we posted this note: "Through our volunteer efforts at the Bee Booth at the LA County Fair the Los Angeles County Beekeepers Association supports research through Project Apis m. Take a few minutes and vote for Samuel Ramsey @" Note from Project Apis m.: "Thank you for your support! This project alone has pretty big implications for our understanding of Varroa mites- beekeeper enemy #1! - Project Apis m. funded this important project, please vote and help Samuel Ramsey win this contest for his great work!")


2017 UMD Three Minute Thesis Winner is Samuel Ramsey

Interesting new research concerning Varroa mites. They seem to feed primarily on the fat body rather than on hemolymph (bee blood). This may influence control strategies in the future.

'Varroa Destructor Virus-1: It’s Here…'

By Karen Rennich  October 10, 2017

One of the best things about working in research is that it never fails to surprise – for good or for bad. And occasionally, it is not until much later that the surprise comes. In this case, the “surprise” arrived in the form of another Varroa-vectored, RNA virus, Varroa Destructor Virus-1, or VDV1.

Our University of Maryland lab has been leading the APHIS National Honey Bee Pest and Pathogen survey since 2010. During those years, we have processed thousands of samples from across most states for nosema spore load, Varroa load, pesticides, and viruses with the primary goal to survey whether exotics, not known to be in the US, are here or not. Secondarily, but almost as importantly, we also use the survey results to establish a nationwide honey bee health baseline. It cannot be overstated how important that baseline is, nor how vital archiving all of those samples are. In the case of viral samples, they are archived in a large -80C freezer at the USDA-ARS Beltsville Lab just down the road from us.

Dr. Eugene Ryabov, working at USDA-ARS with Dr. Jay Evans, decided to take a look into our archive freezer with the intent of re-processing those archived samples for VDV1. And we are glad that he did.  After doing a sweep of 2016 samples, he found VDV1 in >64% of all samples, making it just less prevalent and second only to Deformed Wing Virus (currently found in ~90% of all colonies). Reaching further back into that freezer, Dr. Ryabov found that only 2 colonies were positive from our 2010 survey samples – 1 in Indiana and 1 in Pennsylvania, and that temporal snapshot [below] shows the spread of this virus in just 6 years.


VDV1 is a species of RNA viruses under the genus iflavirus. Other iflaviruses include Sacbrood virus, Slow Bee Paralysis virus and its closest relative, Deformed Wing virus. Because we have methodically stored all historic samples, it will be possible, looking at the variants of this virus in the US and the world, to possibly help resolve how and when this virus arrived on our shores.  It is important to note that this virus is also present in Hawaii (the Big Island) so it has already migrated beyond the lower 48 states.

In addition to field samples, the APHIS National Survey also asks beekeepers to report colony loss numbers for the 3 months prior to being sampled. Using those losses, it may be possible to correlate those losses now with VDV1 infections and/or the levels of the virus present. This finding, and the further research it demands, provides a unique window into the forensics of this infection.

Additional information about this virus, the details used to screen for it and the possible risks to US honey bee colonies will be published in “Ryabov, E.V., Childers, A.K., Chen, Y., Madella, S., Nessa, A., vanEngelsdorp, D., Evans, J.D. (2017) Recent spread of Varroa destructor virus-1, a honey bee pathogen, in the United States. (Submitted)”.

The notice below was sent to all members of the Apiary Inspectors of America (AIA) and American Association of Professional Apiculturists (AAPA) on October 2nd.

Presence of Varroa destructor virus in the U.S.

Using RNA sequencing methods, the honey bee virus Varroa destructor virus-1 (VDV1, also known as Deformed wing virus strain B) was discovered in US honey bee samples by Dr. Eugene Ryabov, while working in the USDA-ARS Bee Research Laboratory (BRL) under the supervision of Drs. Jay Evans and Judy Chen. With guidance from the Bee Informed Partnership (University of Maryland, Dr. Dennis vanEngelsdorp) and USDA-APHIS (Dr. Robyn Rose), the BRL screened an extensive set of research samples along with U.S. bee samples collected during the USDA-APHIS National Honey Bee Disease survey.  This screening confirmed that VDV was widespread in the US in 2016 and far less common in 2010. Thanks to stored samples from the National Honey Bee Disease survey, it will now be possible to track the spread of this virus in the US and guide work for virus control in order to assure the good health of honey bees and maintain them as the primary pollinator of agricultural crops. There is no indication that VDV1 is significantly more virulent than DWV in US honey bees, and the advice to reduce levels of Varroa mites remains the same for both viruses. We are seeking to inform colleagues of this discovery primarily since VDV1 is not detectable using current genetic markers for DWV, and therefore laboratory methods will need to be tailored to detect this virus. Those involved with the National Honey Bee Disease Survey will notice that VDV1 is now a reported agent in this survey.

Mite-A-Thon has Begun!


By The Bee Informed Team   BLOG  September 9, 2017

Mite-A-Thon, the first ever national event to capture and collect Varroa mite infestations in North America has started! Please dust off your sugar shake jars, grab some powdered sugar and join us in the colonies starting today and lasting until September 16th (we hope you continue to monitor your colonies beyond this drive as is always open and your data is always welcome).

Add your data to this map and make it light up! Look at the data and see what management practices are being used around the country. If you have questions about what management or treatment strategy you should use, please see this valuable Varroa guide from the Honey Bee Health Coalition.

MiteCheck National Map (found at

If you don’t have a sugar roll jar, please see our previous BIP blog on how to make one and then how to administer a sugar roll test. Read more about sugar roll tests in general and for ways to interpret your data, please read another BIP blog here.

There are still time to purchase ready-made MiteCheck kits (everything you need in 1 bucket!). Please think about buying one from these bee supply houses, Brushy Mountain Bee Farm and Mann Lake.

Please get out, enjoy the wonderful fall weather and contribute to a HUGE citizen science project. You’ll learn how healthy your bees are heading into winter and you’ll make a difference in this valuable research effort. We thank you. Fight the mites.

Varroa Mites - Bees' Archenemies - Have Genetic Holes in Their Armor

Michigan State University Environment + Science & Technology     August 14, 2017

Contact(s): Layne Cameron, Zachary Huang

National Honeybee Day is celebrated Aug. 19, but MSU scientists work year-round to protect these important pollinators. Varroa mites have decimated honeybee populations and are a primary cause of colony collapse disorder. Researchers have now found genetic holes in the seemingly indestructible pest's armor that could potentially reduce or eliminate the marauding invaders.

Varroa mites attached to honeybees. Photo by Zachary Huang

The team’s results, published in the current issue of the Journal of Insect Science, have identified four genes critical for survival and two that directly affect reproduction.

“The Varroa mite is the worst threat to honeybee health worldwide,” said Zachary Huang, MSU entomologist. “They have developed resistance to many pesticides, so it’s urgent that we explore and target these genes to develop better control methods.”

The mite sucks the blood of honeybees and transmits deadly viruses. Its lifecycle consists of two phases: one where they feed on adult bees, called the phoretic phase, and a reproductive phase that takes place within a sealed honeycomb cell, where the mites lay eggs on a developing bee larva.

Varroa mites' lifecycle consists of two phases: one where they feed on adult bees, called the phoretic phase, and a reproductive phase that takes place within a sealed honeycomb cell, where the mites lay eggs on a developing bee larva. Photo by Zachary HuangHaving the double-whammy of eating bees and spreading disease makes Varroa mites the number-one suspect of honeybee population declines worldwide.

Controlling pests like Varroa mites succeeds by either eliminating them or reducing their ability to reproduce. The team used RNA interference to identify the key genes, which could achieve these outcomes. They injected the mites with double-stranded RNA, or dsRNA.

Interfering reduces transcription of a specific gene, the first step of making a gene, a piece of DNA, into a protein. This process, also known as “gene knockdown,” has been successful in reducing the mating success and the number of eggs produced by cattle ticks, which threaten cows and other livestock around the world.

This bee is suffering from deformed wing virus, which is transmitted by Varroa mites. Photo by Zachary Huang

Using this approach, the team identified two genes that caused high mortality in Varroa mites – Da and Pros26S. In fact, Da killed more than 96 percent of mites. They also identified four genes – RpL8, RpL11, RpP0 and RpS13 – that control reproduction.

Earlier researchhas shown that a combination of dsRNAs can be fed to bees at the colony level. Varroa mites absorb the “genetic cocktail” via bee blood and their population was reduced. Future research will explore whether a single-gene approach can be scaled up and achieve the same effect at a colony-wide setting. Using a single gene with a known mechanism will be more cost effective and safe to the honeybees.

The results may have applications beyond honeybees, too.

“It’s worth noting that Da reduced reproduction in species of mosquitoes and Drosophila,” Huang said. “Future research could help not only protect honeybees, but also reduce disease-carrying mosquitoes or crop-damaging pests.”

Seemingly indestructible Varroa mites. Photo by Zachary Huang

Additional MSU researchers contributing to this study include Guowu Bian and Zhiyong Xi. Xianbing Xie, with Nanchang University (China), also was part of this paper.

This study was supported by the Almond Board of California, the Foundation for the Preservation of Honey Bees, the National Honey Board, MSU’s Project GREEEN, Michigan Beekeepers Association, National Natural Science Foundation of China, General Project of Jiangxi Provincial Department of Education and a fellowship from the China Scholarship Council.

Get Ready for the Mite-A-Thon

Varroa mites are one of the greatest threats to honey bee health, honey production, and pollination services. The Honey Bee Health Coalition has been proud to equip beekeepers with the information, tools, and resources they need to detect, monitor, and manage these destructive mites.

We are proud now to share information about the first ever Mite-A-Thon, supported by the Pollinator Partnership and the many partners listed below.

Read on or click HERE for more information about this exciting event

The first annual Mite-A-Thon will take place Saturday, September 9, to Saturday, September 16, and we invite you to participate!

Local beekeeping clubs and associations are key to making Mite-A-Thon a success!

The Mite-A-Thon is a national effort to collect mite infestation data and to visualize Varroa infestations in honey bee colonies across North America within a one week window.  All beekeepers will be asked to participate, creating a rich distribution of sampling sites in Canada, the United States, and Mexico.  Their Varroa monitoring data will be uploaded to

OBJECTIVE: 1) Raise awareness about honey bee colony Varroa infestations in North America through effective monitoring methods. 2) Management strategies will be made available for discussion within bee organizations utilizing Mite-A-Thon partner developed information and outreach materials.

PARTICIPANTS: All beekeepers are welcome to participate – we need bee associations to help lead this effort!

PARTICIPANTS: All beekeepers are welcome to participate – we need bee associations to help lead this effort!


Encourage your members to participate in September, through meetings, newsletters, emails, social media etc. -

Teach new beekeepers how to monitor for mites in August.

Help your members prepare their monitoring materials.

Support your members in making sure they are able to monitor mites effectively and report their data.

DATA COLLECTION: Participants will monitor the level of mites (number of mites per 100 bees) using a standardized protocol utilizing two common methods of assessment (powdered sugar roll or alcohol wash) and then enter data, including location, total number of hives, number of hives tested, local habitat, and the number of Varroa mites counted from each hive. The published information will not identify individual participants.

CONTACT: or 415-362-1137

Learn more and stay up to date at
Thank you,

The Mite-A-Thon Partners

Bees in Peril - Working Together to Find a Solution

Costco Connection   July 2017 Edition     By Stephanie E. Ponder

(NOTE: Thank you very much to Costco Connection and Stephanie E. Ponder for permission to include this excellent article on honey bees in peril and the many issues facing beekeepers who are striving to keep their bees alive and thriving. The Los Angeles County Beekeepers Association would like to extend our gratitude to Costco for their generous donations to honey bee research. Since 2012, Costco has made contributions totalling over 2.3 million dollars to PAm.) Read at Costco Connection: Bees in Peril.   

DID YOU KNOW that, through pollination, bees play a vital role in roughly one out of three bites of food we take, including nuts, these industrious and beneficial insects are being reduced in number and ravaged by pests and other problems.

Here’s a look at the issues facing bees and beekeepers, and what’s being done to help them.

An ominous sign
According to the not-for-profit group Bee Informed Partnership (, beekeepers lost more than 40 percent of their honeybees between April 2015 and April 2016. It’s a trend of loss that has held a steady course since 2006.

Almond growers were among the first to see a decline in the number of bees. It’s little surprise considering that, according to the Almond Board of California, almond pollination requires two-thirds of the nation’s commercial honeybees. The pollination average for almond orchards is two hives per acre. In the 2015–2016 growing season, California had nearly 900,000 acres of almond trees, translating to a need for almost 2 million hives.

Bee colonies in winter holding yard in central California waiting to go into almond orchards for pollination. Photo above and below Project Apis m BEES © IRSN-K/SHUTTERSTOCK

Honeybees pollinate flowers while they’re out collecting nectar. Pollen from the flower’s stamen sticks to the hairs on the bee’s body, and when she—all pollinating honeybees are female—visits the next flower, some of the pollen rubs off, allowing for the fertilization of the plant.

Robert Huckaby, vice president, farm services, for Costco supplier Wonderful Orchards of Shafter, California, tells The Connection that back in 2006 the company was having “a difficult time meeting the number of bees that [we] needed in the orchard.”

As almond farmers struggled to source the necessary quantity of bees, they also started talking to beekeepers, who reported a significant loss of bees during the year and didn’t have enough for the pollination season, which meant a crop loss.

“That was kind of the [indicator] that there was an issue. It wasn’t just something that was a short trend or an anomaly,” Huckaby says.

A beekeeper opening a brood comb for signs of Varroa mitesSearching for answers

At the same time that almond growers saw a problem, they found an ally in the nonprofit organization Project Apis m. (PAm; project, whose name was inspired by the scientific name for the European honeybee, Apis mellifera. PAm’s mission is to fund and direct research to enhance the health and vitality of honeybee colonies while improving crop production.

When PAm joined forces with almond growers in 2006, the biggest issue facing honeybees was colony collapse disorder (CCD), which happens when the worker bees leave the hive, abandoning the queen, young bees and plenty of food.

A decade ago no one was really thinking about bees, and there was little awareness about bees’ place in the food chain. But as CCD spread, the plight of bees made headlines across the country.

Danielle Downey, PAm’s executive director, says there were also few funds for research in 2006, and there was certainly no real clearinghouse for information. So the almond growers and beekeepers said they’d put up money and support research projects to happen right now, instead of putting out a proposal that might take over a year waiting for funds. Says Downey, “It was really kind of a guerrilla tactic to get some answers, so we’ve always been working closely with beekeepers, researchers and almond growers.”

As for the current research, Downey explains that CCD isn’t something they’re seeing these days. But bees are still in trouble. “We don’t see those same symptoms, and yet beekeepers are losing 40 percent of their hives every year. If you had 100, in that year you will get down to 60 and have to rebuild.

BEE: © MARCEL JANCOVIC / SHUTTERSTOCK, MITES: © KUTTELVASEROVA STUCHELOVA / SHUTTERSTOCK“The single worst thing that has tipped those losses so much higher is the Varroa mite. The Varroa mite arrived from Asia; it jumped from one species to another, and it kills our bees if we don’t do anything about it,” she continues.

These tiny pests lay eggs that develop within the honeybee brood and grow up to pierce an adult honeybee’s exoskeleton and feed off its internal fluid and fat. As if that’s not enough, the Varroa mite can also infect bees with deadly viruses.

PAm, with the help of Costco (see “Bee students”), is helping to fund research to combat the problem, including researching honeybees that are resistant to the Varroa mite.

Addressing the issues

Unfortunately, the Varroa mite (pests) is just one of the “four P’s” facing honeybees; the other three are pathogens, pesticides and poor nutrition.

While research is ongoing into pathogens and pesticides, when it comes to poor nutrition, almond growers are taking an active role by planting bee-friendly flowers among their rows of almond trees to help facilitate a diverse diet for honeybees.

Martin Pohl, a founder of Costco supplier Hughson Nuts of Hughson, California, compares a honeybee’s diet during pollination to that of a human who is given only steak for every meal for weeks on end. It’s boring and lacks nutrition. “Almond trees don’t have a lot of nectar,” says Pohl, who explains that he and his fellow farmers have been planting more flowers and letting weeds and grass grow between their trees. “You have to feed the bees if you want good bees.”

It’s not just the practice of planting only one crop that limits a honeybee’s diet. “Now people spray their yards to get rid of clover, but clover is something that bees love, so it’s not only the agricultural side, but it’s also on the everyday side that we’ve eliminated what bees are eating,” says Downey.

Bee-ing proactive

Planting wildflowers that all bees enjoy is one action that nonexperts can undertake to help honeybees. But what else can be done to help?

First, it’s important to know that buying and consuming honey is good for bees.

It used to be that beekeepers made their money from the sale of honey. These days, beekeepers travel with their bees, following the pollination seasons—including those of almonds, blueberries and cranberries—before getting honey from the bees in the fall.

“Beekeepers need your support,” says Downey. “Beekeepers have it harder than ever, trying to keep bees healthy in this country, and having those strong markets makes a big difference in what they’re able to do.”

Brent Barkman, of Kansas-based Barkman Honey, one of Costco’s Kirkland Signature™ Honey suppliers, adds that selling honey helps beekeepers take care of their bees and fund research that helps to keep their bees healthy.

“The beekeeping industry cannot survive on honey production alone anymore,” Barkman says. “About half of [beekeepers’] operating income comes from pollination practices—not just almonds, but other foods that pay for pollination.”

Installing a beehive in your backyard may not be the best way to help honeybees. Downey makes this comparison: “ ‘Pandas are in trouble; I’m going to get one.’ This makes no sense at all, but people often think that keeping bees is the only way to help them … unfortunately it’s not simple to keep bees alive and thriving, and if the colony is dead a year later, nobody wins. Providing habitat and supporting research are good ways to help.”

Lack of proper care can also create a host for pests to grow in; then those pests can move to another bee colony, Barkman says.

Future buzz?

Perhaps you’ve seen the quote, falsely attributed to Albert Einstein, that if the bees disappear, then so will we. Downey offers a counter version of a bee-less future: “If bees disappear, we will still have food. We won’t have the variety. It won’t be affordable. It will definitely change our quality of life and change our choices.”

Despite the very real issues facing bees and beekeepers, both Downey and Barkman stand firm that bees and beekeepers will prevail.

“As beekeepers, we’re still in business, and we’re still continuing. … We don’t see a doomsday. Bees are very resilient, and they proliferate very quickly,” says Barkman.

Huckaby, from Wonderful Orchards, adds: “It’s kind of mind-boggling just how much bees actually do for us. We know we need the bees, and we rely on them. I think there are a lot of farmers and a lot of people who are behind the research to make sure that we do have bees in the future.”  


FROM THE beginning of the Kirkland Signature honey program, Costco corporate foods buyer Shauna Lopez knew there were issues in the bee and honey industry that needed to be addressed. The Costco buying team set out to find a nonprofit organization that shared their priorities. Enter Project Apis m. (PAm). “PAm stood out as a clear front-runner,” says Lopez, who adds that PAm already had deep connections within the industry, along with an international scope, and was already set up to fund research projects.

Costco Photo StudioSince 2012, Costco has made a contribution to PAm for each Kirkland Signature honey item sold, totaling more than $2.3 million.

Some of the donated funds facilitate stock improvement to help breed honeybees that are resistant to Varroa mites, limiting mite reproduction. There is also a project supporting a repository for bee germplasm—reproductive genetic material—to help increase and preserve honeybee genetic diversity in the U.S.

Money has also helped fund several tech transfer teams who help beekeepers maintain their colonies. The teams perform a lot of work that beekeepers might not be able to do on their own, including collecting disease and pest samples and sampling colonies for stock improvement.

A honey bee carrying pollenCostco and PAm also award scholarships and fellowships to fund bee research at the Ph.D. level. The current scholarship winner is Morgan Carr-Markell at the University of Minnesota, St. Paul, who is studying the potential benefits of native prairie flowers on honey bees. She’s receiving $50,000 for three years.

Rodney Richardson, a student at Ohio State University, will also receive $50,000 for three years to study immune functions in honeybees along with molecular identification of bee-collected pollen.

Cameron Jack, at the University of Florida, received $15,000 for one year to support his studies on methods to rear Varroa mites in vitro, and to facilitate research on integrated pest management.

“There’s a lot of misinformation out there about bees and beekeeping, and that’s why I like that we’re fostering research that can be verified and shared,” Lopez tells The Connection. “I suggest that people visit PAm’s website [project] or the Honey Bee Health Coalition []. If people want to help, I suggest supporting organizations that understand the crisis and the issues.”—SEP

Read and download Costco Connection: Bees in Peril

View online (includes video):


No Offense, American Bees, But Your Sperm Isn't Cutting It

NPR The Sale    By Ryan Bell    July 13, 2017

With an American honeybee queen for a mother and a European honeybee drone for a father, this worker bee has a level of genetic diversity unseen in the U.S. for decades. Researchers at Washington State University hope a deeper gene pool will give a new generation of honeybees much-needed genetic traits, like resistance to varroa mites. The parasite kills a third of American honeybees each year. Megan Asche/Courtesy of Washington State University

Editor's note: This story is for mature bees only.

Seducing a honeybee drone – one of the males in a colony whose only job is to mate with the queen – is not too difficult. They don't have stingers, so you just pick one up. Apply a little pressure to the abdomen and the drone gets randy, blood rushing to his endophallus, bringing him to climax.

"They're really accommodating," says Susan Cobey, a honeybee breeder on Whidbey Island, Wash. "One ejaculate is about 1 microliter, and it takes 10 microliters to artificially inseminate a queen."

Since 2008, Cobey has done her share of bee abdomen rubbing as part of a research team from Washington State University traveling through Europe and Asia. They've collected sperm from native honeybees in Italy, Slovenia, Germany, Kazakhstan and the Republic of Georgia – countries where honeybees have favorable genetic traits, like resistance to the varroa mite. The deadly parasite has been cited as a major factor in bee deaths, along with genetics, poor nutrition and pesticide exposure, according to a major report from the USDA and EPA in 2013.

Varroa mites are an invasive parasite from Asia that sucks hemolymph (bee blood) from adult and larval honeybees, weakening their immune systems and transmitting deadly pathogens, like bent wing virus. If left untreated, a varroa infestation can kill a colony in one year. First detected on U.S. soil in 1987, varroa has spread quickly, infesting upwards of 50 percent of American hives. Last year, 33 percent of U.S. honeybee hives died. That's troubling for the plight of honeybees and U.S. agriculture, which relies on pollinators to produce one-third of the food we eat.

The buzz on American bees: too much inbreeding

According to the WSU research team, the root cause of the U.S. honeybees' vulnerability to varroa is a dwindling gene pool that has left them short on genetic traits that help honeybees resist varroa elsewhere in the world.

"Honeybees aren't native to America," Cobey says. "We brought them here. But the U.S. closed its borders to live honeybee imports in 1922, and our honeybee population has been interbreeding ever since."

WSU has monitored the genetic diversity of honeybee queens in Washington and California since 1994, showing a steady decline. Dr. Brandon Hopkins, the team's expert in freezing and thawing bee sperm, likens honeybee breeding to a poker game played with an incomplete deck of cards. "There's no way to get a four-of-a-kind if there aren't four aces in the deck," Hopkins says.

Brandon Hopkins, a cryopreservation specialist, works in Washington State University's fruit tree orchard in Pullman, Wash. As a doctoral student at WSU, Hopkins perfected a system of freezing and thawing bee semen for use in artificial insemination. Shelly Hanks/Courtesy of Washington State University

The imported semen has restacked the deck. WSU's crossbred honeybees already test positive at a higher level of genetic diversity than the first queens tested in 1994. "This doesn't mean they are superior in performance to the other bees," Hopkins says. "It means we have a better chance of finding rare and unique traits."

It used to be that honeybee breeders selected for bees that produced more honey, grew more populous hives, and were gentler to handle. Now, they want honeybees that can resist varroa. Without it, beekeepers must rely on costly "miticide" treatments to control varroa.

However, studies suggest the mites are developing resistance to pesticides and the chemicals may be harming honeybees, compounding the problem of widespread bee deaths known as Colony Collapse Disorder.

"I lost 40 percent of my colonies to varroa last fall," says Matthew Shakespear, whose company, Olson's Honeybees, raises 16,000 hives in central Washington. "I'm not taking any more chances. We've already done five treatments, compared with the two treatments we applied this time last year."

A problem that blooms in almond orchards

Pollination services like Olson's Honeybees are the cornerstone of a $15 billion segment of U.S. agriculture. A hefty share of that is the almond industry, whose trees are completely reliant on honeybees for pollination. It's also the industry most susceptible to fallout from the varroa epidemic in bees: California's almond groves serve as an incubator for the growth and spread of varroa mites across the United States.

"There are 800,000 acres of almonds in California," says Patrick Heitkam, owner of Heitkam's Honey Bees in Orland, Calif. "It takes two hives to pollinate one acre, so that's a need for 1.6 million hives. There are only 500,000 hives in the state, so the rest are trucked in from around the country."

Almond trees bloom in January, a time of the year when most honeybee varieties are dormant in their hives. But an Italian species of honeybee, Apis mellifera linguistica, which evolved in the warm Mediterranean climate, is active when the first almond blossom pops in late-January, making them the most popular variety in the U.S.

The trouble is, Italian honeybees are extremely susceptible to varroa mites, because their hives grow so big, so fast and so early.

"Italian honeybees rear their babies and varroa mites nearly one-for-one," says Dr. Robert Danka, a research entomologist at the USDA's Honey Bee Breeding, Genetics and Physiology Research Unit in Baton Rouge, La.

Lessons from mighty Russian stingers

Like the WSU team, Danka has also looked to the Old World for an answer to varroa mites. Between 1994 and 2000, he traveled to the Russian far east, where a local honeybee, Apis mellifera, has developed resistance to varroa. They are descended from European honeybees brought by Russian settlers traveling the Trans-Siberian Railway at the turn of the 20th century. The journey inadvertently transplanted the honeybees into the native range of varroa mites in east Asia, where they evolved resistance to the pest.

These Russian bees groom themselves, biting and crushing the mites. They also have a prevalent genetic trait called varroa sensitive hygiene (VSH), aborting larval honeybees infested with mites and removing them from the hive before the parasite can spread.

Danka brought back 360 queens, the basis for what is now a robust Russian honeybee population in the United States. While their prowess as mite biters continues, Russian honeybees haven't proven up to task as commercial pollinators. The queens are used to long Russian winters, so they are slow at building up their hives, meaning only a small number are ready to fly in the almond groves come January.

Survival of the fittest bees

Still, Danka says the Russian honeybee offers proof that a European subspecies can develop varroa mite resistance through natural selection. That evolutionary process is interrupted in commercial beehives, because of the "prophylactic use of miticides," Danka says. "We're maintaining varroa-susceptible bees through chemistry. If we took away all those pesticide treatments – and to be clear, I'm not advocating for this – the results would be horrific. But in a rather short period of time, only varroa-resistant bees would be left." And those bees could be the basis of a new population.

Matthew Shakespear, the commercial honeybee keeper in Yakima, Wash., would rather not spend money treating his hives for varroa mites. Starting last year, he diversified his business to include hives of Carniolan honeybees, Apis mellifera carnica, a subspecies native to Eastern Europe.

The queens he bought were the great-great-great granddaughters of a honeybee drone that Susan Cobey found in the mountains of Slovenia.

"Maybe these new genetics can deal with the varroa mites naturally, rather than having to rely on chemicals," Shakespear says. "It's time to start widening our gene pool.

Bee Hive Thermal Industries, Breaking News, Saving Honey Bees Organically

Bee Hive Thermal Industries   Press Release     June 21, 2017

PAGELAND, S.C., June 21, 2017 /PRNewswire/ -- An organic and noninvasive solution in targeting and killing Varroa Mite infestations, that are killing honey bees, was developed by the joined forces of, Bee Hive Thermal Industries ( and OVEN Industries (, experts in temperature control.

Even if you're not in the bee keeping business, commercially or as a Hobbyist, you may have heard that, "honey bees are in trouble". There are a few main reasons that we could list in this dilemma and most experts will most likely agree that the Varroa Mite is near or at the top of that list. Bee Hive Thermal Industries designed this Thermal System utilizing an industrial grade heater blanket and electronic controls which are easily installed and removed from the hive. The end goal of the product is to raise the temperature of the hive to a programmed temperature, killing the mites without harming the bees based on studies done in Europe. To see the game changing product in action, click the link and view the video.

In the fight against today's Varroa Mites, beekeepers are often, if not always, resorting to pesticides as the solution. Bees have many other predators and hardships to endure, including weather related issues such as cold temperatures, moisture and diseases. The effect of the Mite on the overall colony is paralyzing to both general activity and honey production within the hive.  This revolutionary product is showing positive results in killing and controlling mites and hive beetles, with only a few applications annually.

Bee Hive Thermal Industries, located in beautiful Pageland South Carolina, is to be recognized as a global leader in the design, development and distribution of organically suitable products for the bee industry globally. The company strives daily to provide unique and safe solutions for bee keepers everywhere, providing them with high quality, value and reliability. Caring for our bees is very important to the mission of Bee Hive Thermal Industries.

To view the original version on PR Newswire, visit:

Can Mushrooms Save the Honey Bee?

bioGraphic     Produced by Louie Schwartzberg    April 25, 2017

A blood-sucking mite is wreaking havoc on honey bees - but scientists have discovered a surprising new way to fight back.

A decade ago, honey bee populations around the world began declining at an alarming rate. In the early years of this trend, beekeepers lost 60 percent or more of their hives to a mysterious phenomenon that came to be known as “colony collapse disorder” (CCD). In each of these cases, worker bees simply disappeared, and it doesn’t take long for a colony to collapse without workers to provide food and to care for the young. Although this trend seems to have leveled off somewhat in recent years, the current average rate of 30 percent annual mortality is still nearly double the average rate reported prior to 2006.

Honey bees (Apis mellifera) are native to Europe, western Asia and Africa, but have also been introduced to many other parts of the world to serve as pollinators of agricultural crops. Today, honey bees pollinate one-third of all the crops we consume—nearly a thousand varieties in all—and are by far the world’s most important and economically valuable pollinators for commercial agriculture. In the U.S. alone, their annual value is estimated at $5–14 billion.

Since the first reports of dead and dying honey bee colonies began to stream in, scientists have scrambled to determine the cause, or causes, of CCD. One threat in particular stood out as a major cause of honey bee declines: varroa mites (Varroa destructor). These tiny parasitic arachnids weaken adult and juvenile bees by sucking their blood. They also transmit a number of viruses that can spread throughout a colony like wildfire. To make matters worse, the mites reproduce quickly and, because of this, can rapidly evolve resistance to traditional chemical pesticides.

While many scientists have continued to search for causes of honey bee declines, others have turned their attention to developing new, more sustainable solutions to these threats. One of the more surprising and promising of these strategies is the use of compounds produced by a widely-distributed mushroom (Metarhizium anisopliae) that is known to parasitize a number of different insects. Researchers from Washington State University have found that spores and extracts from this mushroom are particularly toxic to varroa mites but—in low doses—leave bees unharmed. In fact, bees in hives treated with Metarhizium tend to be much healthier and live longer than those in untreated hives. While large-scale trials are just now being implemented, early results suggest that a common mushroom may hold the answer to at least one major driver of honey bee declines.

How the Varroa Mite Co-Opts Honey Bee Behaviors to Its Own Advantage

Entomology Today    By Entomology Today   May 10, 2017

While the Varroa destructor mite is not a highly mobile insect on its own, it takes advantage of the behaviors of honey bees in managed beekeeping settings to spread. In particular, bee colonies in close proximity to each other and less swarming allow mite populations to grow, according to new research. (Photo credit: Scott Bauer, USDA Agricultural Research Service,

As the managed honey bee industry continues to grapple with significant annual colony losses, the Varroa destructor mite is emerging as the leading culprit. And, it turns out, the very nature of modern beekeeping may be giving the parasite the exact conditions it needs to spread nearly beyond control.

In an article published yesterday in Environmental Entomology, researchers argue that the Varroa mite has “co-opted” several honey bee behaviors to its own benefit, allowing it to disperse widely even though the mite itself is not a highly mobile insect. The mite’s ability to hitchhike on wandering bees, the infections it transmits to bees, and the density of colonies in managed beekeeping settings make for a deadly combination.

“Beekeepers need to rethink Varroa control and treat Varroa as a migratory pest,” says Gloria DeGrandi-Hoffman, Ph.D., research leader and location coordinator at the U.S. Department of Agriculture-Agricultural Research Service’s Carl Hayden Bee Research Center in Tucson, Arizona, and lead author of the research.

In the wild, bee colonies tend to survive despite Varroa infestations, and colonies are usually located far enough apart to prevent mites from hitching rides to other colonies on foraging bees. Wild bee colonies’ natural habit of periodically swarming—when the colony grows large enough that a portion of its bees splinter off to create a new colony elsewhere—also serves as a mechanism for thinning out the density of mite infestations and their associated pathogens. In managed honey bee settings, though, these dynamics are disrupted, DeGrandi-Hoffman says. Colonies are kept in close proximity, and swarming is prevented.

DeGrandi-Hoffman, USDA-ARS colleague Henry Graham, and Fabiana Ahumada of AgScience Consulting, conducted an 11-month study of 120 honey bee colonies in one commercial bee operation, comparing those treated with mite-targeting insecticide (miticide) in the spring and fall with those treated only in the fall, and they found no significant difference in the results: more than half of the colonies were lost across the board. This aligns with what has been seen by beekeepers and researchers alike in recent years: Varroa populations continue to grow even after being treated with effective miticides. But why? The answer may be in its dispersal mechanisms.

The researchers also conducted mathematical simulations of Varroa mite population dynamics to examine the effects of both migration of foragers between colonies and swarming. When bees can wander into other colonies—either to “rob” them of their honey or because they’ve simply lost their way—Varroa populations across colonies climb. Likewise, prohibiting colonies from splintering periodically via swarming also leads mite populations to rise.

In the wild, DeGrandi-Hoffman and her colleagues note, driving a colony to collapse is against Varroa mites’ own interest; if the colony dies, the mites die with it. But in commercial beekeeping settings, increasing infestation of a colony activates the dispersal mechanisms the mites need to spread. Weakened foragers are more likely to wander to other colonies, and weakened colonies are more likely to see foragers from healthy colonies visit to rob them of honey. In both cases, mites can hitch a ride from one colony to another.

It all adds up to a critical point for managed honey bee industry. The researchers cite the need for new integrated pest management strategies to treat Varroa destructor as a migratory pest, as well as for further research into the specifics of Varroa dispersal.

“Colony losses in the U.S. are at unsustainable levels for commercial beekeepers. These beekeepers supply colonies for the pollination of crops that represent one-third of U.S. agriculture and are essential components of heart healthy and cancer-prevention diets,” says DeGrandi-Hoffman. “This research provides evidence that the tried and true ways of controlling Varroa are no longer feasible, and that new methods that are designed for control of a migratory pest are required.”

Read More:
Are Dispersal Mechanisms Changing the Host–Parasite Relationship and Increasing the Virulence of Varroa destructor (Mesostigmata: Varroidae) in Managed Honey Bee (Hymenoptera: Apidae) Colonies? “Are Dispersal Mechanisms Changing the Host–Parasite Relationship and Increasing the Virulence of Varroa destructor (Mesostigmata: Varroidae) in Managed Honey Bee (Hymenoptera: Apidae) Colonies?”  Environmental Entomology

Scientists Say Agriculture is Good for Honey Bees    By Ginger Rowsey    May 2, 2017

In a recent study, researchers with the University of Tennessee Institute of Agriculture found the overall health of honey bees improved in the presence of agricultural production, despite the increased exposure to agricultural pesticides. Credit: Scott Stewart While recent media reports have condemned a commonly used agricultural pesticide as detrimental to honey bee health, scientists with the University of Tennessee Institute of Agriculture have found that the overall health of honey bee hives actually improves in the presence of agricultural production.

The study, "Agricultural Landscape and Pesticide Effects on Honey Bee Biological Traits" which was published in a recent issue of the Journal of Economic Entomology, evaluated the impacts of row-crop agriculture, including the traditional use of pesticides, on honey bee health. Results indicated that hive health was positively correlated to the presence of agriculture. According to the study, colonies in a non-agricultural area struggled to find adequate food resources and produced fewer offspring.

"We're not saying that pesticides are not a factor in honeybee health. There were a few events during the season where insecticide applications caused the death of some foraging bees," says Mohamed Alburaki, lead author and post-doctoral fellow with the University of Tennessee Department of Entomology and Plant Pathology (EPP). "However, our study suggests that the benefits of better nutrition sources and nectar yields found in agricultural areas outweigh the risks of exposure to agricultural pesticides."

Alburaki and fellow researchers established experimental apiaries in multiple locations in western Tennessee ranging from non-agricultural to intense agricultural production. Over the course of a year, colonies were monitored for performance and productivity by measuring colony weight, brood production and colony thermoregulation. Colony thermoregulation, or the ability to maintain an optimal temperature within a hive, is an important factor in brood development and the health of the resulting adult bees.

According to the study, hives located in areas with high to moderate agricultural vegetation grew faster and larger than those in low or non-agricultural areas. Researchers suggest the greater population sizes enabled better colony thermoregulation in these hives, as well.

Meanwhile, bees located in a non-agricultural environment were challenged to find food. Although fewer pesticide contaminants were reported in these areas, the landscape did not provide sustainable forage. In fact, during the observations, two colonies in the non-agricultural areas collapsed due to starvation.

Disruptions and fluctuations in brood rearing were also more notable in a non-agricultural environment. Interestingly, brood production was highest in the location that exhibited a more evenly distributed mix of agricultural production, forests and urban activity.

"One possible explanation for this finding could be the elevated urban activity in this location," says Alburaki. "Ornamental plantings around homes or businesses, or backyard gardens are examples of urban activity that increase the diversity of pollen in an area. Greater pollen diversity has been credited with enhancing colony development."

Researchers also evaluated trapped pollen from each colony for pesticide residues. Low concentrations of fungicides, herbicides and insecticides were identified, but at levels well below the lethal dose for honey bees. Imidacloprid was the only neonicotinoid detected, also at sub-lethal levels.

Agricultural pesticides, particularly neonicotinoids, are considered by some to be a key factor in declining honeybee populations. The UTIA study found that higher exposure to pesticides in agricultural environments did not result in measurable impacts on colony productivity.

"We train agricultural producers on careful selection and conscientious application of pesticides to reduce bee exposure," says Scott Stewart, Integrated Pest Management Specialist with UT Extension, "but it's becoming more clear that the influences of varroa mite and food availability are more important factors in honey bee health than agricultural pesticides."

 Journal reference: Journal of Economic Entomology

Beyond Taktic

Scientific Beekeeping    By Randy Oliver    First published in: American Bee Journal, January 2017

The miticide Taktic has been the savior of the commercial bee industry since the early 2000s. But it may be time to move on. I’ve been experimenting with a promising potential replacement.

Our Situation

As I recently pointed out, there are signs that mites in areas of the U.S. are exhibiting some degree of resistance to Taktic’s active ingredient–amitraz. And since Taktic has been pulled from the U.S. market, some beekeepers are justifiably concerned that the EPA may stop looking the other way about them illegally using the product (Canada’s already hit one beekeeper with a hefty fine; no telling when some State enforcement branch will make an example of a U.S. beekeeper).

I’m freshly returned from the California State Beekeepers Assoc. conference, where Dr. Juliana Rangel presented the findings of her student Liz Walsh (who previously found negative effects on queens from residues of miticides in the comb). Liz recently found that field-realistic residues of amitraz in queen cell wax appeared to reduce the egg laying rate of queens reared in those cells. I’ve suspected something like this, since queen problems appear to have increased since the widespread adoption of amitraz as a miticide. Of further concern is that amitraz residues are increasingly being detected in U.S. honey. In any case, commercial beekeepers are (or I suspect will soon be) looking for alternatives to Taktic.

The Ideal Treatment

In this same issue of ABJ, I’m pushing our industry to get serious about shifting to mite-resistant stocks so that we can give up treatments altogether. But I know that my own operation would collapse if I were to attempt an abrupt transition, and have no doubt that most others would too. So although I don’t use amitraz in my own operation, I have a common interest with my professional brethren to find mite treatments that are cheap, don’t harm the bees, queen, or brood, and don’t get into the honey.

Continue reading the full article at:


Honey Bee Health Coalition Unveils Videos to Help Beekeepers Combat the Devastating Parasites

 ABJ Extra   December 1, 2016
Videos Complement Coalition’s Tools for Varroa Management Guide, Provides Step-By-Step Demonstrations of Utilizing an Integrated Pest Management Strategy of Monitoring, Treatment
[KEYSTONE, Colorado, Dec. 1, 2016] — The Honey Bee Health Coalition released a series of videostoday to help beekeepers promote colony health and combat costly and destructive Varroa mite (Varroa destructor) infestations. The videos can be found on the Coalition website at and provide detailed step-by-step instructions on how to monitor hives for varroa and when levels get too high, safely treat. The videos complement the Coalition’s wildly popular Tools for Varroa Management Guide.
“The Honey Bee Health Coalition’s Tools for Varroa Management Guide has provided beekeepers in the US and Canada with invaluable tools and techniques to confront destructive Varroa mite infestations,” said Mark Dykes, Apiary Inspectors of America. “These videos will show beekeeper real world application techniques that will help them correctly apply treatments.”

The videos provide helpful visual aids and step-by-step directions on how beekeepers can monitor and control Varroa mites through an Integrated Pest Management strategy. The videos cover a range of strategies and tools, including the uses of formic acid, essential oils, and other synthetic miticides.

“Healthy bees support our world’s food supply and farmers everywhere. A single untreated colony can transmit Varroa mites to other nearby hives and threaten honey bee health across large geographic regions,” said Danielle Downey, Project Apis m. “Beekeeping is becoming very popular, and often keeping the bees healthy is a mysterious learning curve. These important 'how to' videos bring the Coalition’s Tools for Varroa Management Guide to life — and will amplify its impact in the United States, Canada, and around the globe.”
The Coalition’s Tools for Varroa Management has given beekeepers the tools they need to measure Varroa mite infestations in their hives and select appropriate control methods. The guide, which has been downloaded more than 5,500 times since its release, has been updated 4 times with continued refinements and details.


Greg Hunt Bites Back Against Mites

INternational Bee Research Association - IBRA    November 17, 2016

Dr Greg Hunt from Purdue UniversityMany honey bee breeders today focus on selecting for varroa mite resistance. Dr Greg Hunt is a honey bee specialist in the Entomology Department at Purdue University in Indiana, USA. At Purdue, he and his team have been breeding a line of varroa resistant “Mite Biter” bees. Learn more about his work in our Scientist behind the Science interview published in the latest issue of Bee World.

The team is selecting for bees that groom varroa mites from themselves. Hunt says: “It’s based on the proportion of chewed mites falling from the bees, because we found that correlates with the bee’s ability to groom mites off. You can find this trait in stocks of bees that seem resistant, more tolerant of mites.”

He finds great interest among beekeepers, and they seem to want locally reared queens: “There is an interest in getting local queens, because we find that they survive our winters better than queens we buy from out of state. They have lower mite levels. Hobbyists want to buy their queens locally. We need to increase production capacity from what they call micro-breeders – like micro brewers.”

You can read the full article by Kirsten S. Traynor here (free to view):…/…/10.1080/0005772X.2016.1242948

IBRA Members also have access to all other papers in issue 93(2), and have full access to all articles in the Bee World back catalogue to Volume 1 in 1919:. You can join IBRA here:…/2014-12-12-12-06-01