The Microorganisms Isolated from the Mites Varroa Destructor and the Verification of Their Pathogenity

Our research was concentrated on the finding one of Varroa destructor mite with pathological symptoms and on the isolation of its microorganisms. The dead mites were collected from sticky boards in beehives and observed under the stereomicroscope. The mites suspected of dying caused by pathological process were examined by means of bacteriological and mycological methods. The pathogenity of isolated microorganisms was verified in the following tests. Females with black formations in the gut ́s area and with white colored mycosis in the idiosoma and on its surface were found during the research. The bacteria Enterobacter cloacae, Staphylococcus albus haemolyticus and the fungi Aspergillus flavus, Penicillium multicolor and P. simplicissimum were isolated from the individuals with black patches and the bacteria Enterobacter cloacae and the fungi Mucor ramosissimus, M. indicus and M. hiemalis from the mites with mycosis. The laboratory tests for verification of pathogenity of isolated microorganisms were performed in laboratory cages with 40 bees and 15 females of mite Varroa destructor. The laboratory cages with bees infested by Varroa destructor were sprayed by an inoculum and by sterile saline (in control cages). The experiments proceeded at the temperature of 35°C. The laboratory tests proved the pathogenity only in bacteria Enterobacter cloacae, which constrained the mortality of mites average of 77,4 p.c. in the laboratory cages. The mortality in the control cages was average in 15,9 p.c. . The statistical difference with the control cages by the tests of other microorganisms was not proved. The mites infected by Enterobacter cloacae died with characteristical pathological changes in Malpighian tubules (macroscopicaly observed as the enlargement of these organs and of the idiosoma) and the membrane between genital and sternal or metapodal shields usually burst. However, the black patches were not observed in our laboratory tests.