The influence of various plant protection systems on micromycetes in potato cultivation in the conditions of the lower Volga region

The research was carried out in order to compare the effect of various plant protection systems on the quantitative composition of soil micromycetes when growing potatoes in irrigated of the Lower Volga region. The work was carried out in 2021–2023 in the Volgograd region on light chestnut heavy loamy soils under irrigation by sprinkling in Gulliver cultivar plantings. The degree of infection of potato tubers was assessed on three variants of protection systems: I – biological; II – chemical (control); III – integrated. The experience was laid out in three–fold repetition, the accounting area of the plot was 294 m². In the pre-sowing soil samples, the number of saprophytic myrcomycetes was 71.93…91.8 %, among which the most common were fungi of the genus Penicillinum sp. (33.6…44.2 thousand CFU/g), and the rest are represented by fungi of the genus Thrichoderma sp. (0…2.5 thousand CFU/g), Aspergillus sp. (1,24…19,7 thousand CFU/g), and Rhizopus sp. (0…8.1 thousand CFU/g). Representatives of the genus Fusarium sp. are noted among the pathogens. (5,8…9,92 thousand CFU/g). A higher percentage of saprophytic (Penicillinum sp., Thrichoderma sp.) was observed in soil samples after the use of biological agents. Aspergillus sp., Rhizopus sp.) of micromycetes (73.9 %) than after the use of chemicals (61 %) and an integrated system (59.6 %). Thus, representatives of the genus Penicillinum sp. were 15.6 % more than with the use of chemicals, Thrichoderma sp. by 70 %, Aspergillus sp. by 77.8 %. The number of pathogenic micromycetes (Fusarium sp.) in soil samples after the use of biological compounds was 26.1 %, chemical compounds 38.9 %, integrated system 40.3 %. Thus, the use of biological protective agents in potato cultivation in the conditions of the Lower Volga region during irrigation contributes to an increase in saprophytivity and a decrease in the pathogenicity of soil microflora and is a promising technique.