In reference to the patent: WO2015107233A1
We have published the first experiences with oxalic acid in cardboard strips made by Mr. Ricardo Prieto in August 2014. Mr. Prieto asked me how to disolve oxalic acid without water in 2013. I recomended him to use an alcohol because of its polarity and water affinity. We use ethyl alcohol and/or propylene glycol frequently to disolve propolis. Being glycerol cheaper than propylene glycol and with more hydroxyl groups and it is not volatile at normal pressure and temperature conditions we suggested to Mr. Prieto to use glycerol to disolve oxalic acid. He soaked cardboard strips into a solution of oxalic acid and glycerol. He made different essays hanging different sizes of strips into the brood chamber of the bee hives to test the mitecide effect of these strips. All of this was published in Espacio Apícola magazine #109 May-July 2014 ISSN 1850-0757 and the following editions.
On May 6th 2015 Mr. Ricardo organized a meeting in his farm with about 100 colleagues to share his experiences that we published in Espacio Apícola #112 ISSN 1850-0757..
Currently many beekeepers around the world are using this formula to prepare their own strips like a State of Art in Beekeeping Practice. There are not invention here. Oxalic acid is wellknown and for a long time recognized as an active substance against varroa mite and glycerol is a vehicle and the cardboard strip is a support.
We have published many articles about the use of oxalic acid in differents treatments against varroa. This cardboard strips is one of them.