oxalic acid reacts with amitraz

[tristan]

i can't remember if this was discussed years ago.

Understanding amitraz & oxalic acid interaction in varroa treatments - Veto Pharma Blog

Are you applying amitraz strips right after an oxalic acid treatment? While this may sound like a good idea, it may actually reduce the efficacy of your amitraz treatment against varroa mites.

www.blog-veto-pharma.com

" their combination can lead to reduced efficacy due to the rapid degradation of amitraz in acidic environments."

https://www.sciencedirect.com/science/article/abs/pii/S0039914098002379 Kinetics and mechanism of amitraz hydrolysis in aqueous media by HPLC and GC-MS
"Amitraz is unstable in the whole pH range, undergoing faster hydrolysis at acidic pH values (at pH<2 the degradation is almost instantaneous)."

so not a good idea to use amitraz treatment (apivar/apitraz/amiflex) as well as any acid treatment (oxalic, formic, thymol etc) together and to leave enough time for one to dissipate before using the other.

 

[Alastair]

Thanks that is handy to know!

I think there are a lot of beekeepers do exactly that, ie, put in amitraz strips for a while then put in OA strips.

 

[Stephen Horsley]

Damn! Just put in Apitraz yesterday, but removed older oxalis strips before doing so. I guess a few minutes isn't enough time for the acids to dissipate. Fortunately one hive had a zero wash number five days ago but the other had a 30 count so not happy about that. Will monitor and maybe do a wash in a couple of weeks.

 

[tristan]

Damn! Just put in Apitraz yesterday, but removed older oxalis strips before doing so. I guess a few minutes isn't enough time for the acids to dissipate. Fortunately one hive had a zero wash number five days ago but the other had a 30 count so not happy about that. Will monitor and maybe do a wash in a couple of weeks.

i don't think that will be to bad. acid level will probably be low and will be completely gone in a day or so. its only those bees that get a dose of both at the same spot where it won't work. i don't think that will be a problem overall.
doing both in at the same time is problematic.

your 30 count unlikely to survive especially using apitraz, as that tends to work slow and huge amounts of damage is already done. bayvarol or apistan is better in those situations but even then its doubtful.
whats more important is how the levels got to be that high. spring treatment failure?
my hives at home got similar issues. they had mid season staples and had 15 mites/300 a few weeks ago. probably from someone's hives failing nearby.

 

[tristan]

Thanks that is handy to know!

I think there are a lot of beekeepers do exactly that, ie, put in amitraz strips for a while then put in OA strips.

with the staples i think the acid on the surface gets cleaned off very quickly and it causes the acid level in the hive to go to a very large peak (which is why you want the strips well drained so you don't get excess acid on the surface) which would react with the first lot of amitraz to get on the bees. reducing the effectiveness of both treatments.

plus having so many strips in the brood will reduce brood area by a lot which will impact bee numbers.