Comparison of the efficacy of varroa treatment with rotenone in powder solution prepared by dilution of the powdered product 'Cube Powder Fish Toxicant, TIFA International LLC, with efficacy of varroa treatment with Check Mite+ and 'originally' packed rotenone in stripes in Rijeka, Croatia

Rotenone in stripes is considered (among some beekeepers in Croatia) as an effective drug against Varroa destructor. It is usually sold in the form of carton paper stripes previously dipped in 5% liquid rotenone (in further text “originally packed rotenone”). In this work, a rotenone solution was prepared by dilution of 50g of the powdered product „Cube Powder Fish Toxicant, ( TIFA International LLC, USA, with a rotenone content 6.8%) in 100 ml BAS 220 (Solvent naphtha heavy aromatic, Banner Chemicals Ltd., UK). After extraction period of 30 min, solution was filtered and used for dipping carton paper stripes, equal to those used for „originally“ packed rotenone. Obtained concentration of rotenone solution was 3, 4%. At the same apiary 5 colonies were treated with 3, 4% rotenone, 5 colonies were treated by Bayer drug „Check Mite+“ and 5 colonies with „originally“ packed rotenone in stripes, i.e. 5% rotenone solution. In colonies treated by Check mite + the Varroa infestation fell from initial 5, 76% to 0, 61%, in those treated by „original“ rotenone it fell from initial 3, 87% to 0, 16%, and in colonies treated by prepared rotenone it fell from 2, 18% to 1, 82%. Not even one colony from the group treated by Check mite+, or the group treated by Rotenone in stripes, according to the method described by Büchler et.al., ADIZ 2005., did not have infestation level higher than 2%, which would require additional treatment, but 2 out of 5 colonies treated by obtained rotenone solution had Varroa infestation level higher than 2%.