Conditionally pathogenic and pathogenic microflora negatively affects the general condition and productivity of animals, even with the provision of proper feeding and maintenance conditions. Significant damage to industrial farms is caused by fungal infections such as Aspergillus, Penicillium, Fusarium and Candida albicans which associate with using of different disinfectants.

The purpose of the work is to investigate and select the optimal concentrations of the Baresi preparation for effective disinfection of the cultures of Aspergillus, Penicillium, Fusarium and Candida albicans.

The tests were conducted in the State Scientific and Research Institute of Laboratory Diagnostics and Veterinary and Sanitary Expertise. We used bactericidal preparation "Barez" based on plant essential oils: thyme, fir, eucalyptus, nanoparticles of metals and benzalkonium chloride.

Work on the determination of the fungicidal action of different concentrations of "Barez" and parameters of using was done according to generally accepted recommendations. The study and determination of fungicidal concentrations of "Barez" were done by the following methods: suspension, paper disks. For this purpose, we prepared the following aqueous solutions of "Barez" 0.05; 0.1; 0.5; 1.0; 2.0; 3.0% and swabs of spore (120 spores per 1/5 cm³) from 7 day culture of Aspergillus, Penicillium, Fusarium from the SSRKIBSM museum (working dilution). Control was the culture of fungi with working dilutions.

After 30 and 60 minutes of exposure, solutions of Barez began to affect the growth of fungal cultures beginning from the 1.0% concentration causing inhibition. This concentration stopped the growth of micromycetes. A 0.5% concentration had positive effect on Candida albicans.

It should be noted the concentration 0.5% and 1.0% "Barez" actively inhibited the growth of Aspergillus and Penicillium, respectively (zone of inhibition of growth was > 5 mm). Zone of inhibition of Fusarium was 8 mm while using just 0.05% concentration of Barez.

On the tenth day Barez was very active in 0.05% concentration because zona of inhibition of Fusarium was 12 mm. Concentrations of disinfectant 1.0-2.0% gave the zone of inhibition near 20 mm. Increasing of concentration of Barez increased the zone of inhibition of Aspergillus, Penicillium, Fusarium, Candida albicans.

As a result of the tests it was found the disinfection Barez, at the recommended concentrations of 1.0 – 2.0%, has a fungicidal effect against fungi of the genera Aspergillus, Penicillium, Fusarium, Candida albicans.

Key words: micromycetes, disinfectant, essential oils, fungicide.