Sunday, 19 January 2020

7 Days After Oxalic Acid treatment......

So Yesterday I visited the hives....7 days after the oxalic acid treatment was is what I found on the varroa boards......

Hive 1. Treatment...oxalic acid 'trickle'
As you can see on this board there is 
a good varroa drop, this hive had not
been treated since winter 2018. This hive
swarmed naturally during summer 2019.
Hive 2, Treatment...Oxalic acid 'vaporiser'
This hive is the one I showed you last week.
I cleaned the board before putting it back
and still there is another significant drop.
This hive had not been treated since winter
2018. Artificial swarm control was carried
out on this hive in summer 2019.
Hive 3, Treatment...Oxalic Acid 'Trickle'
Still very little in the way of either varroa
or debris on this board but I can assure you
that there is an active colony within.
This hive was created when carrying
out swarm control on hive 2.
Hive 4, Treatment...Oxalic acid 'vaporiser'

This hive was a swarm caught and brought to the 
district apiary so I do not know its origin/history.
As you can see there appears to be very little drop.
however I wold like to point out the this is a 
wooden varroa floor and when I pulled it out
to check the wood had 'sucked' all the oil and the
board was dry so some varroa/debris could
easily have been blown away.

So as you can see there were mixed results but from hive to hive and not so much with the way in which the treatment was administered. Personally I am happier with the 'trickle' method and will continue to do this on my own hives but would happily carry out both methods again next winter should more members like to observe the process.
It's very interesting how both swarms have very little drop and I have some thoughts about this that can be covered maybe later on...of course if you have some theories on this I would love to hear them so please comment so we can see what others thoughts are too.

Tuesday, 14 January 2020

Oxalic acid treatment update

So yesterday morning whilst out walking the dog I thought I would have a quick peak at a couple of the varroa floors in the hives.

It states that oxalic acid treatments can take a week to 10 days to kill the mites off but that you can often see a very significant mite drop within 24 hours.

I only checked two hives when I went over....the two that were done with the vaporiser.

Hive 2 was the biggest hive, has two supers of honey and was a newly hatched and mated queen this year. This hive had not been treated for varroa since winter 2018.

As you can see from the board in just 48 hours there was a very significant drop. This hive was very strong throughout the summer, very easy to work with and showed no sign in the hive of deformed wing etc during inspections. The hive has a standard brood box.

The other hive I looked at was a little different. This is hive 3, a hive that I created from doing swarm control from hive 2 in May. No supers on and were fed syrup in the autumn and candy added in December...

As you can see from the's clean...I didn't see a single mite which to be honest I was very surprised with...many factors could be responsible for this.

Obviously as I carried out swarm control many mites would have been left in the parent hive. This is a national polystyrene hive...maybe better insulation helps the bees cope with the mite better?? This is just a possible thought and by no means substantiated anywhere...but none the less something to bear in mind. The other major thing is that they are in a 14 byt 12 brood box as opposed to a standard and I did leave 2 standard brood frames in the box that as drones were laid in them and capped off I then cleared out of the hive...a natural way to control varroa and the only one that was carried out over the summer period.
So this is what has been found so far...I will check the boards again next week and also check hives 1 
& 4 to see what we have on those boards too.

Sunday, 12 January 2020

Oxalic Acid Demonstration at the District Apiary

On Saturday 11/01/20 following a talk at the monthly meeting about the varroa mite we offered members to join us at the District Apiary to see a demonstration on the application of Oxalic Acid.

The Oxalic acid is readily available at Thornes and can either be 'trickled' into the hive using a solution of crystals in water (always check your labels for mixing instructions and doses) and sugar syrup or can be administered using a vaporizer (again, check instructions on how to use the vaporizer and what quantity to use.

It was a very blustery Saturday morning when we met but the air was dry and a little chilly (though colder would have been better) so we headed over to start the demonstration. We had quite a good turn out for the demonstration and although you can find info and videos on the internet about the procedure I personally like to see things first hand and be able to ask questions whist things are going on and this is the opportunity we wanted to give our members.

We demonstrated both the trickle and vaporiser method and talked through how each can be carried out...necessity of timings, health and safety procedure which should be followed, protective clothes (i.e. mask/goggles/full face masks) and which type of mask to purchase.
We then discussed  the importance of following instructions for mixing and weighing and the reasons why you may want to treat your hives.
Stewart Talking bout timings of burning
the oxalic acid crystals before starting
the procedure

  1. Add 2 grams per brood box, no matter the brood box size, of Oxalic Acid crystals to the head (pan) of your Oxalic Acid Vaporizer. You can use a ½ of a teaspoon (which is the equivalent of 2 grams) as a measuring tool.  For a nuc box, you would use 1 gram.
  2. Insert the vaporizer about ½ to ¾ of the way into hive from the front entrance.
  3. Seal any openings with cloths or foam.
  4. Don your respirator.
  5. Connect your vaporizer to the power source (12 volts) for two and a half minutes (Maximum three minutes – depends on battery capacity.)
  6. Disconnect power source.
  7. Wait 2-3 minutes and remove the vaporizer to prepare for the next hive.
Mask goes on...and timer started as
battery is attached!!

There are 4 hives at the district apiary and we treated two with vapour. One wooden hive and one Polystyrene hive. It is always important to wear suitable protective clothing when carrying out any procedure as there is generally a little seepage of vapour. It was very interesting though that during the treatment of the polystyrene hive there was zero percent of vapour leakage which did then spark up a discussion as to whether or not the poly hive fitted together better due to its materials not shrinking/swelling with weather conditions.

Opening up the top of the first hive to
demonstrate the 'trickle' method.
 As you can see the bees are quite lively...honestly I was relieved to see them so lively after the long wet spells we have had but this wasn't the best for trickling the oxalic acid...none the less....explanations were given and the demonstration went ahead. The temperature was about 7 degrees...ideally you would want to do this procedure at about 4 degrees so that the bees are still in a tight cluster and don't start flying.

The oxalic acid crystals for the trickle technique come
with a handy bottle which measure exactly the right
amount for each 'seam' of bees.
How do you prepare oxalic acid dribble?
Prepare solution
  1. Measure 600 ml of hot water into a non-reactive container.
  2. Add 35 grams of oxalic dihydrate crystals (wood bleach) into the hot water. Stir but do not shake.
  3. When the crystals are dissolved, add the 600 grams of sugar. Stir until dissolved.
  4. When cool use the included bottle to treat your hives so that you get the quantities correct.

Administering the oxalic acid. 

The last seam to be 'trickled' In all
the procedure takes about 30
to 40 seconds.

Oxalic acid is toxic!

  • The lethal dose for humans is reported to be between 15 and 30 g. It causes kidney failure due to precipitation of solid calcium oxalate.
  • Clean up spills of powder or solution immediately.
  • Take care not to inhale the powder.
  • Store in a clearly labelled container out of reach of children.
  • Wear gloves.
  • Do not use containers or utensils you use for food preparation. A carefully rinsed plastic milk bottle, very clearly labelled, is a good way to store the solution prior to use.
If anyone wants to treat their hives by either of these methods and needs any further help, advise or pointers then feel free to contact us.