A few days back Randy said he felt one of the hydrolysis products of amitraz was biologically active against mites and ticks and I expressed doubt that was so.  I was wrong.

Amitraz hydrolyzes to two different molecules.  One is called a formamide and it is pretty clear that one is biologically inactive as a pesticide.  The other is a formamidine and papers Randy kindly sent me and that he asked Peter to send me clearly show that molecule has about the same pesticidal activity as amitraz.  In fact two molecules of that formamidine are combined to make one amitraz molecule.  That formamidine is persistent in wax.

Does this make any difference to how I feel about the safety of amitraz?  Not really.  I have looked for papers that show the toxicity of both the formamide and formamidine and can not find a thing published.  Not even an LD50.  Yet, there simply had to be a lot of tox work done on both molecules as part of the amitraz registration package.  There is lots and lots of tox data generated every year on all kinds of chemicals and most never gets published.  In some cases it is not published because it is of no consequence.  In many cases the results are held as trade secrets rather than help a competitor even if the data is supplied to the EPA as part of a registration.  As the data is owned by the company that supplies it EPA is not free to make it public.  EPA says, "Adequate methods are available to enforce amitraz tolerances. Residues of amitraz and two of its metabolites are stable in several food commodities tested."

https://archive.epa.gov/pesticides/reregistration/web/pdf/0234fact.pdf

Obviously EPA is well aware of the two hydrolysis products and made the judgement that they do not present a health issue to humans based on the registration data submitted and as long as the residues are within the tolerances set.  I should point out that EPA runs several labs which buy food products or sample imported food products at the point of entry and look for all kinds of pesticide residues.  In the case of imports contamination with unregistered in the US pesticides or residues over the limit will result generally in that shipment being returned to the shipper at his cost.  In the case of US produced product that is out of the limits the supplier can be fined and ordered to recall the product and destroy it.  We likely have the safest food supply in the world as a result.

Does this mean these hydrolysis products are not a problem to honey bees?  Nope.  The laws that govern EPA say their job is to protect the applicators, consumers and environment.  They require what they feel are reasonable studies to show that non target organisms are not harmed excessively when the product is used according to the label.  But, we all know many registered pesticides will kill the whole hive if the bees are exposed.  In any application EPA also does not warrant in any way that the product will be effective at doing the job stated on the label.  They simply say that if used according to the label the product is safe to applicators, consumers and the environment. If you feel a product used according to label did not perform as advertised you are free to sue the manufacturer.  Farmers regularly sue pesticide manufacturers and get paid settlements for such failure to perform problems.  So, how can we judge if that formamidine residue in wax might have long term negative effects on queens?

We know that shortly after the apivar strips are pulled from the hive there is no more mite kill.  Do a spring treatment and you can drive mite counts below 1%.  Yet, by August those mite counts are high enough to be back in the danger zone.  We also know that mites are way more sensitive to this product than honey bees.  So, it sure does not seem obvious that the formamidine residues in wax are able to do a thing to control mites.  If they can not do a thing to control mites I personally doubt they could do much to queens.  Particularly when the queen was exposed to far more during the treatment period.  Now I will admit it would be a near impossible job to show that such exposures shortened a queens productive life by 10%.  It would be equally near impossible to show that sublimed oxalic shortened a queens life by 10%.  We can be pretty sure neither of them do the queen any good.  Our other choice is not treat and we know for sure that will result in harm.

Queen issues are not recent.  Peter from time to time has posted articles from over 100 years ago complaining about poor queen performance and early supersedure.  My 1972 version of the Root "ABC" book also addresses those complaints both current to the time of publication and historically.  Those articles sound just about like the complaints today.  I am not convinced we have more queen problems now than people had 100 years ago.  Yet no one to my knowledge has attempted a breeding program where long productive life was selected.  Rather, commercially the practice has long been to requeen yearly or even more often.  As I have said many times, you get what you select for.

I have no oar in any mite treatment boat.  All I want to see people do is take steps to maintain tolerable mite levels so come spring their hives are alive.  I know of people doing exactly that using various treatments other than apivar and year after year they have great survival.  Randy never uses apivar other than in studies and his survival is great.  I know of folks who use nothing but oxalic sublimation and they do great.  Ditto formic products.  We are lucky we have so many options that are effective.  I do feel we have relied too long on amitraz treatments.  Other parts of the world have seen resistance.  USDA gave a talk at the last ABF meeting on tests they had run and reported seeing mites from some commercial operations that took several times the normal dose of amitraz to drop them.  So, we have a good start on resistance in the US.  If you do use apivar I strongly suggest you rotate it with some other type of treatment as that can slow resistance development greatly.  If you do not wish to use the amitraz at all I have exactly zero problem as long as you control mites.

Dick

             ***********************************************
The BEE-L mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software.  For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html