Why Beekeepers Need to Consider Plan B for Varroa Control

[Allen Dick]

Why Beekeepers Need to Consider Plan B for Varroa Control

Dr. Medhat Nasr

Alberta Provincial Apiculturist, Crop Research and Extension,
Alberta Agriculture and Rural Development
Email: medhat.nasr@gov.ab.ca or bee@gov.ab.ca

Alberta beekeepers have been successfully applying Apivar application in spring for varroa control. In most years the surviving bee cluster usually covers 6-9 frames. In this situation an application of 2 Apivar strips provided excellent control of varroa. Beekeepers have been quite happy with the results. They report no to very little number of mites after treatment for 6 weeks.

This spring beekeepers have been reporting higher than usual varroa mite levels after the 6 weeks application of Apivar. They are concerned over the efficacy of Apivar strips and bee health. If varroa mites that survived the treatment build up their population through the summer, they will impact honey production, production of healthy bees for wintering, and increase levels of viruses in wintering bees. As a result, bee populations will most likely have higher winter kill next year. Moreover, if the varroa infestation level is high and may require treatment during the honey flow, it will be challenging. High risks of contaminating honey with residues from applied treatments will be expected.

Investigation of the causes of lower than expected efficacy showed that mild weather conditions through the last part of winter has helped the bees to: 1) have high level of survivorship, 2) have a large population of bees survived winter, 3) start production of brood earlier, and 4) have a higher than usual rate of bee population build up. Consequently, when beekeepers applied two strips of Apivar to their bee colonies in late March early April, they underestimated the size of the bee cluster. In fact at this time of the year some beekeepers had reported that bees had already covered up to 15 frames of bees in some colonies. Despite the large bee population beekeepers applied two strips per cluster. At this rate of application, treated bee colonies were under dosed. According to the label, beekeepers should apply one strip for every 5 frames covered with bees. Thus, it is clear that the applied dose was insufficient to control mites and varroa mites are not resistant to Apivar.

When asked what to do in this unusual season with unprecedented mite levels after the application of Apiver in the spring, beekeepers should check the bee cluster size to ensure the proper number of strips applied. However at this time of the season beekeepers need to consider plan B for varroa treatment. This plan will include several options as the following:

Option 1. Beekeepers adjust the dose of strips by adding new strips to ensure the total number of applied strips will meet the recommended proper dose (1 strip/5 frames of bees). Strips must be left for the full duration of 6 weeks and 2 more weeks optional if needed.

Option 2. All newly made splits placed in new apiary sites will get the proper does of Apivar strips. Strips will be left for the full treatment period. For the parent colonies you can use a similar treatment of Apivar or use formic acid application.

Option 3. All bee colonies and splits will get spring/summer formic acid treatments.

All be colonies must be monitored closely at the end of summer as early as August to determine varroa infestation levels. A fall treatment must be considered when varroa infestation reaches the economic threshold to ensure that bees going to winter with less than 1% varroa infestation.

Our program thanks all beekeepers who reported cases of varroa status this spring. It is a positive development to share information and stay proactive. Overall providing early warning for varroa population treatment will help beekeepers to improve their pest management practices, keep healthy bees and stay competitive.

[Colino]

As a side note, they also Mentioned that the provincial bee inspector has recommended an extra Apivar strip be added to hives because the mite counts this spring are so high. I have already thrown 2 in where 1 would have been needed by mistake because the clusters weren't that big, so I'm hoping I will be fine. I'll do some mite counts when it warms up.

That is very general advice, gleaned from reports all over Alberta, from all kinds of beekeepers.
I would suggest you check to see how many mites you actually have before you start overdosing with chemicals.
You are a small beekeeper and your hives are right nearby so you are able to monitor better than most beekeepers.

Thanks Allen, you're right. It's supposed to warm next week so I will do some mite counts on my over wintered hives. My packages should be okay for now but I could put some Thymol strips on them to be safe.

[Allen Dick]

We are encouraged to use IPM, then the word comes down to blanket treat and people interpret that as an edict to blanket-treat province wide.

IPM requires monitoring locally before treating and the warning is to know what you have.

The big problem is that what seem like very low levels in spring can become monster infestations by the time the crop is off at the end of summer.

Catch 22.

I was seeing some varroa between boxes during the early part of the treatment, but none now.

Be aware that the label permits leaving the strips in extra time (read it) if you move the strips. Of course, I have moved all mine

[Allen Dick]

Strips must be left for the full duration of 6 weeks and 2 more weeks optional if needed.

This is important. The strips at this point may be partially used up, but they do have some efficacy and they are in position -- at least I hope they are in the middle of the brood -- so they continue to work. Fears of resistance are overblown IMO.

Option 2. All newly made splits placed in new apiary sites will get the proper does (sic) of Apivar strips. Strips will be left for the full treatment period.

I think this is the panic button. Monitor, and if things are off the map, panic and do this. If not, chill out.

For the parent colonies you can use a similar treatment of Apivar or use formic acid application.

Yes. Do not lose your bees. BUT, monitor and think. Formic in spring can really damage your crop unless you are very capable -- and lucky.

Option 3. All bee colonies and splits will get spring/summer formic acid treatments.

Think. If you risk losing your bees, then do the math. Bees vs. honey. Honey vs. bees. $$$$. I know it is cruel, but you have to survive. If you don't, financially, then your bees are on their own.

All be colonies must be monitored closely at the end of summer as early as August to determine varroa infestation levels.

Amen.

A fall treatment must be considered when varroa infestation reaches the economic threshold to ensure that bees going to winter with less than 1% varroa infestation.

Hmmm. At 1% varroa in fall, I think the harm from treating exceeds the benefits.

I could accept 5% or more in some hives. Of course, if you have a yard of 40 hives, some hives will be at 0% and some at 15%. Will you poison the 0% hives just to make sure the 15% hives survive? I wouldn't.

Treatments are all poisons.

[Colino]

Alberta beekeepers have been successfully applying Apivar application in spring for varroa control. In most years the surviving bee cluster usually covers 6-9 frames. In this situation an application of 2 Apivar strips provided excellent control of varroa. Beekeepers have been quite happy with the results. They report no to very little number of mites after treatment for 6 weeks.

I guess I never made a mistake I just didn't remember the instructions right. My hives had 7 and 9 frames of bees so I'm well within the doseage. Bonus!

[Vance G]

I have the bee inspector coming on Tuesday. I may do some testing then or I may just keep my mouth shut and watch. My strips are all pulled now and it is time to see where I stand.

[Allen Dick]

The sugar shake is quite easy. The sugar shake does not get as many mites as the alcohol wash, however it gives a pretty good idea and does not destroy any bees. The trick is to leave the bees sitting in the sugar for a while, maybe 2 or 3 minutes, before shaking the sugar and mites out through the screen and counting the mites

[Vance G]

I use two wide mouth quart jars and put my sample in the first one and dose with sugar and roll and agitate for a minute and then set it in the shade of that hive and move on and do the next, then move back and put a sandwich baggie over the mouth of the screened jar and shake as much sugar out as I can. Then I put a tablespoon or so of water in to turn the sugar opaque and the mites stand out like lighthouses. I have never used the alcohol wash because I just don't want to kill that many bees. I know this is foolish but I plead guilty. It used to really bother me in the seventies to go down the line with my rose duster full of cyanide killing any colony that didn't weigh up. I still wonder why no beekeeper died when the commercial guys all had a can of cyanide under the seat we were bouncing along on.

[Allen Dick]

I feel the same about killing nurse bees just to sample for mites.

Accuracy is not all that important for what we are doing. Sugar gives us a good enough idea for our purposes. If we find something and want to get greater accuracy, then we can go back with alcohol.

FWIW, we used to handle calcium cyanide quite casually. I found a can in my garden she'd a few years ago and got rid of it, concerned that someone might open it and sniff it. Cyanide has a nice smell.

[Vance G]

Like almonds as I remember.

[Charlie]

I'm surprised that "oxalic acid" was not mentioned. Especially when you consider that Dr Medhat Nasr developed a delivery system for using it.
From http://scientificbeekeeping.com/oxalic- ... f-2-parts/

Oxalic Acid: Heat Vaporization and Other Methods:
Update 2009: Dr Medhat Nasr has developed a fan-forced vaporizer that uses oxalic acid “pills” that are easy to handle, and that give exactly the right dose. The design is an improvement over the Varrox, since it does not overheat the acid (and thus cause degradation), and the stream of warm air causes the cluster to open up so that the vapor can penetrate

I also believe "oxalic acid" was recently approved in the US for mite treatments. I currently use "Apivar" in my hives. However at the price of Apivar I did go looking for alternatives. Oxalic Acid seems to be a good organic solution, when you consider Dr Medhat Nasr and Randy Oliver (two the best bee people that I know of) seem to support "oxalic acid vaporization" so much so that I just bought a vaporizer and oxalic acid off of eBay.
After reading what Allen has posted I am having second thoughts on whether or not I miss something. The reasons I chose this method are as follows:
1. Pennies per treatment
2. Very high mite falls I’m not sure that it kills mites as much as makes them fall off.
3. Can be done at any time with or without honey
4. Very low risk to the Queen if not zero
5. I also understand it can potentially be done weekly
I realize that screen bottom boards or sticky boards may be required at the same time as treatment and I would imagine that it will be 5 to 10 minutes to treat each hive which may be prohibitive if you’re trying to treat thousands of hives.
Vaporizers can expensive and I did buy one from eBay to prove the concept (has not arrived) but looking at the pictures of the various vaporizers they appear just to be a tray for Oxalic Acid that is heated by a glow plug for a diesel engine with a handle and the wires to connect to the battery. I would imagine the total cost would be less than $50 Canadian to build one. Considering Oxalic Acid is dirt cheap ($10.50 US 500 g) with very little downside risk I’m wondering why it wasn’t listed as one of the options.

Also from http://agresearchmag.ars.usda.gov/1997/aug/mitesmoke/

After 30 seconds, smoke from the grapefruit leaves knocked down 90 to 95 percent of the mites in the cage test. With grapefruit leaves, however, few of the mites are killed. Most simply fall off the bees.

It seems to me and I’m guessing here that if we put leaves in our smokers that are high in “Oxalic Acid” we could be knocking the mites down every time we work the bees. Personally I’m looking at rhubarb leaves. I don’t know if this’ll work. I would think something as simple as this would be common knowledge and the United States Department of Agriculture did publish this small article on it. However I’m concerned that I have been unable to find any reliable sources for or against this concept since the Department of agriculture publish the article. I realize there is no money to be made by anybody by smoking grapefruit or rhubarb leaves. (I’m so sorry that sounds like it’s from the 70s ) So it’s unlikely that there be any real research done. It does make me wonder why somebody has not come up with a simple additive for smoker fuel that works in this manner. It could be the next "Flow Hive"$$$$$$$$

Would someone point out any errors in my thinking.

[karen]

I also believe "oxalic acid" was recently approved in the US for mite treatments.

Each individual state has to approve oxalic, it is put under a Section 18 which is a pesticide emergency exemption. Right now Maine doesn't have a section 18 on oxalic. They are working on it.

A local beekeeper is making vaporizers. It is an stainless rod with an aluminum base and a glow plug as you said. It will hook to a car battery. He has sent me pictures and offered me one to try out. I am sure they will make it so we have to purchase the oxalic from some expensive source, not the local hardware store. They have to make their money some how. Of course you don't have to follow the rules but if you sell your honey to the public following the rules keeps you out of trouble.

I have been treating for mites twice, late winter with Apivar and fall with a thymol treatment. Along with that and keeping my bees well fed it has helped me be abnormal, I am not one of the statistics we are talking about in the thread about losses, my bees did well.

[Allen Dick]

For those who care to dig, I have documented my experience with OA in the diary, complete with varroa counts of various sorts, and my experience with several ways to evaporate and the use of drizzle. I have not collected the links, so some searching will be required if anyone is interested. If someone does that, please post a list here.

Start here: http://tinyurl.com/ml4nolr

OA works, but is not as uniform in results as Apivar. The hive geometry and the idiosyncrasies of clusters and amount of brood at the time affect the results.

For the record, Medhat did not originate the evaporator he promotes, but refined one designed by Cor Dewitt that is shown in the diary back around 2002 with Cor's co-operation.

I have some evaporators hanging downstairs and have not used them for a while. OA is easy to obtain and when used in a drizzle is undetectable moments after application. The drizzle method requires careful mixing to get the right dose, but the acid in the syrup drizzle is quite dilute and therefore harmless to the person handling it but reports are that this method cannot be used repeatedly without harm to the colony. That said, a beekeeper in Florida says he does repeated applications without apparent harm.

[Charlie]

Here's the first five links, there is a lot of reading here.

http://www.honeybeeworld.com/diary/articles/cor.htm
http://www.honeybeeworld.com/diary/arti ... c_drip.htm
http://www.honeybeeworld.com/diary/files/drop.htm
http://www.honeybeeworld.com/formic/oxalictrans.htm
http://www.honeybeeworld.com/diary/arti ... Safety.htm

[Charlie]

Here is the second batch of five links

http://www.honeybeeworld.com/diary/arti ... orator.htm
http://www.honeybeeworld.com/diary/file ... 202009.pdf
http://www.honeybeeworld.com/diary/file ... _engl2.pdf
" viewtopic.php?t=289&start=100 "
http://www.honeybeeworld.com/diary/2011/diary101011.htm

[Colino]

I bought a vaporiser from Heilyser technology last fall. It is a well built unit and is easy to use. I procrastinated in using it and only did 2 treatments. The 1st time I got a drop of ~300 mites per hive and the 2nd time ~50. The weather closed in on me and I didn't get the 3rd most important one in my opinion when they would have been broodless in late Nov. This year I'm starting out with Apivar, then late summer I am going to use Thymol strips like Karen and starting in October do some OA vaporization. I also have some stuff called "Bee Tea" which is a derivative of Thyme that is mixed with syrup that I'll feed in the fall. I'm hoping this will be enough. This all depends of course on how good/bad my mite counts are.
http://www.members.shaw.ca/orioleln/vaporizer.html

[Vance G]

If a person doesn't take these mites serious, he will be a customer of a bee supplier! Every time I think of my waste of 25% of my wintered bees because I was chasing miticide treatment free style points, I figure I should sit on a nail to drive the point home that mites need killed! I will leave the creation of mite resistant bees to those younger and endowed with my tax dollars.

[buzz1356]

FROM BeeL


Dear all

I am sharing the last update that we made in this treatment against Varroa
spp. For Your Information.

We are using carboard strips soaked with a solution of oxalic acid into
glycerol.
Mr. Ricardo Prieto, Queen bees breeder from Junin (Buenos Aires province,
Argentina), is maintaining 400 beehives with less than 1% of varroa with
these strips since June 2014 up to now. Ricardo, Juan Manuel (his son) and I
we share enough information last saturday with some friends in Ricardo's
farm.

The following is an abstract that published in TECA exchange group answering
to a
colleague

Preparation
Heat 1 kg of glycerol (food grade) up to 65ºC add 600 g of Oxalic acid
dihydrate stirring it.
The temperature will fall to near 35ºC then you need to maintain heating and
stirring up to the mixture become crystalline around 55ºC-58ºC

Soak the strips in this product when it is tepid, not warm, for about one
day and a half. Cardboard strips of 1,5 mm thick 30 mm wide and 350 mm long
will get around 19 g of the product each.

Then allow strips to drain for a day or less until they are not wet before
it use.

As you can see I am talking about a "product" not only a solution.

We are trying to check what is it happening. I found that with this method
we can distilled formic acid and
the product that is intermediate is glyceryl mono oxalate.
It seems that the main product that we produce is this glyceryl mono
oxalate.
We are trying to find a lab to check it. If you can help please contact me.

We talk about to register these strips but we are beekeepers we are not
lawyers.
We think that we can spray this method as State of the Art. We published it
in "Espacio Apicola" No. 109 (June 2014) ISSN 1850-0757

The treatment

It seems also that it work by contact.
The bees begin to gnaw the strips until they are removed from the hive.
Then if population and brood is too high the bees will removed the strips in
less than two month.

With more than 10% of infestation according the size of the swarm we put
from 6 to 8 strips per brood chamber and we found excellent results in a
week.
I don't know about you but in our area we catch some swarms in spring some
times from migrations of abandoned colonies. Especially these last ones with
high percentage of varroa.

Now next to the winter we have 3 strips into the brood chamber. During the
expansion of the brood nest we suggest to use 5 strips per brood chamber.
Then if population and brood is high the strips will be removed from the
beehive before two month. You need to maintain 5 new strips into the colony
after the final of the crop. Later when population decreased we are
maintaining 3 strips, it seems to be enough. You need to make your own
experience.

best regards
Fernando
Córdoba - Argentina

[Vance G]

Would glycerin and glycerol be one and the same?

[Allen Dick]

nomenclature - is there any difference between glycerin and glycerol? - Chemistry Stack Exchange
http://chemistry.stackexchange.com/ques ... d-glycerol