Comparison of thymol treatments for varroa

[Monbees]

As I only use thymol as my late summer/autumn varroa treatment, I found this article on the efficacy of the three main types of thymol treatment an interesting read.

https://www.beeculture.com/thymol-varroa-control

 

[echidna]

Thanks for that. My late August Apiguard failed last year so I put it on mid-August this year. It still failed even though it was well above 15 degrees at least for the first tray. Reading that encourages me to abandon Apiguard and try something else.

 

[Monbees]

Thanks for that. My late August Apiguard failed last year so I put it on mid-August this year. It still failed even though it was well above 15 degrees at least for the first tray. Reading that encourages me to abandon Apiguard and try something else.

I never got on very well with Apiguard - bees didn't seem to distribute it very well and was always a lot left on the trays after treatment, so last two years I've been using Apilife Var which works fine but is very fragile and easy to crumble accidentally, so this next season giving Thymovar a go as it seems more robust.

 

[Newbeeneil]

I never got on very well with Apiguard - bees didn't seem to distribute it very well and was always a lot left on the trays after treatment, so last two years I've been using Apilife Var which works fine but is very fragile and easy to crumble accidentally, so this next season giving Thymovar a go as it seems more robust.

I moved to Apigard because I found with Apilife Var that the some bees seemed to entomb the "biscuit" in propolis which made the treatment pretty ineffective. Next year I'm going to use sublimated OA base treatment on most of my hives.
Who would think we are all working with the same animal?

 

[North End Bees]

I moved to Apigard because I found with Apilife Var that the some bees seemed to entomb the "biscuit" in propolis which made the treatment pretty ineffective. Next year I'm going to use sublimated OA base treatment on most of my hives.
Who would think we are all working with the same animal?

I've found the same with Apilife Var. Just makes a mess. Also decided not to use Apivar again due to reported developing resistance.
I'm happy to continue with Apiguard in August as I've not had any problems with it.

I know some use OA as a sole treatment whatever season. Does anyone know of any studies which prove conclusively that OA also kills tracheal mites? I know there is anecdotal evidence. One of the reasons I use thymol in autumn is to also get any tracheal mites.

 

[Murox]

I know some use OA as a sole treatment whatever season. Does anyone know of any studies which prove inconclusively that OA also kills tracheal mites? I know there is anecdotal evidence. One of the reasons I use thymol in autumn is to also get any tracheal mites.

Some adverts say “the vaporization of the oxalic acid inside the hive is a proven method to kill tracheal and Varroa mites.” I am not aware of any studies that conclusively prove that OA does in fact kill tracheal mites.

I came across this in another .com forum.

- it probably COULD - but only under certain circumstances.
The much longer answer involves some biology and some chemistry: the biology relates to understanding the mode of entry of the tracheal mite.
The honey bee trachea is connected to the outside world by ten pairs of smaller diameter spiracles, and the pair of interest are the first of these which are hidden beneath the spiracle lobes, a large hair-fringed backward extension of the first thoracic segment. These are the spiracles which are invaded by tracheal mites.

Now the hairs seen in the picture above serve an important function - they prevent the bee from inhaling airborne dust of around 30 microns or larger, which brings us to the chemistry of Oxalic Acid.

Oxalic Acid exists in two forms: anhydrous Oxalic Acid (which I'll simply call OA) and Oxalic Acid Dihydrate (OA-D). The Dihydrate is the stable form, and the form most readily available. If a container of anhydrous (laboratory) OA were to be left open for any length of time, then OA-D would result, as moisture would be adsorbed from the atmosphere. Anyone who has used OA-D knows it to be a rather 'damp' material, with the crystals being prone to clumping together.

During the vaporisation process, water is initially driven off, with anhydrous OA vapour resulting, only for that emitted vapour to very quickly adsorb moisture again from the atmosphere, with a cloud of airborne OA-D dust resulting.

Now - if this dust had a particle size significantly less that 30 microns, then it could be 'inhaled' by the bee, would contact any mites present, and duly act as a miticide. So whether OA-D is an effective honey bee miticide or not depends upon it's particle size.

So - what size are the OA-D particles created by vaporisation ? No-one can ever determine this - because the resulting particle size depends upon the temperature and humidity at the moment the vaporisation takes place, as temperature and humidity combine to determine the amount of water which is available within the atmosphere to enable OA to revert to it's stable OA-D form.

Therefore on cold, dry days there is a greater chance (and I wouldn't put it any stronger than that) that OA-D particle size might be sub-30 microns, and thus able to to access the honey bee trachea and act as a miticide. On warm, humid days it certainly wouldn't.

Although this explanation doesn't answer your question, I hope it helps you to understand the issue - which unfortunately isn't a clear-cut one of being either "Yes or No".

 

[Curly green finger's]

Like Newbeeneil I've only ever used apilife var on two occasions much the same happened to me they entombed the biscuit, second time I had minimal mite drop, so I put apivar strips in and had 100s of dead mites.
I've this season and last winter been using OA via sublimation and will never turn back. I would like to try some home made OA strips but I need a bit more conclusive evidence first.


Im not a fan of thymol at all and to put it in syrup well that's just a no no for me.. Each to there own.

 

[Murox]

Like Newbeeneil I've only ever used apilife var on two occasions much the same happened to me they entombed the biscuit, second time I had minimal mite drop, so I put apivar strips in and had 100s of dead mites.
I've this season and last winter been using OA via sublimation and will never turn back. I would like to try some home made OA strips but I need a bit more conclusive evidence first.


Im not a fan of thymol at all and to put it in syrup well that's just a no no for me.. Each to there own.

The amitraz based products are effective, but amitraz is a widely used active ingredient and some resistance to it seems to be be developing. thymol does seem to deal with tracheal mites and being both antibacterial, and antifungal I believe is effective against chalk brood and it probably increases hygienic behaviours. So thymol has its uses as a tool.