Med. Weter. 68 (10), 607-611, 2012

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Howis M., Chorbiński P., Nowakowski P.
Physical damage to the chitin plate and position of Varroa destructor on hive bottoms after use of different varroacidal treatments
The aim of research was to characterize the share of physical damage to the chitin plate and the position of fallen mites on hive boards after use of different varroacidal treatments. Bee colonies (Apis mellifera carnica) were not treated or treated with organic acids (formic, lactic and oxalic), Beevital Hive Clean (F&B Ges. m. b. H., Austria) and Apiwarol AS (Biowet – Poland) – 10 colonies per treatment. Mites that fell on paper with glue on solid boards after varroacidal treatments (n = 200 mites/group) were analyzed for physical damage to the chitin plate (indentation or rupture) and position of the mite’s body after fall (natural – with legs directed to the bottom or upside down). Natural fall of mites in bee colonies without any treatment characterized with approximately 20% of mites with physical damage to chitin plate and with nearly 50:50 share of mites in the natural position (45.5%) vs. upside down (54.5%). The fall of mites from bee colonies differed due to the use of varroacidal treatment. Significant differences in physical damage share to mites’ chitin plate were observed after use of Apiwarol AS, formic acid, lactic acid, oxalic acid and Beevital Hive Clean preparation; respectively 1.5, 17.0, 12.0, 33.0 and 31.0% (P≤0.05). The high incidence of physical damage to the chitin plate while using oxalic acid and Beevital Hive Clean indicate the direct activity of bees in removal of mites. The share of the mite fall position on the bottom (natural and upside down) did not differ to the natural fall of dead mites after use of oxalic acid (49.0 vs. 51.0 %) and Beevital Hive Clean preparation (51.5 vs. 48.5%) in contrast to fallen mites obtained after use of Apiwarol AS (13.5 vs. 86.5%), formic acid (25.5 vs. 74.5%) and lactic acid (38.5 vs. 61.5%). Significant differences observed in the picture of the mite fall may be used as a diagnostic tool for discriminating between different varroacidal treatments used in field examinations.
Key words: Varroa destructor, Apiwarol AS, formic acid, lactic acid, oxalic acid, Beevital Hive Clean, mite plate damage, mite fall