Effect of Different Plant Protection Schemes on Soil Micromycetes Under Conditions of Potatoes Growing in the Volga Region

The effects of various plant protection schemes (PPS) applied for potato production on the quantitative composition of soil micromycetes have been compared under conditions of the Volga region. The study was carried out in 2021–2023 in Volgograd oblast on light-chestnut heavy loamy soils under conditions of a sprinkler irrigation using a potato cultivar (Gulliver). The level of infection of potato tubers is evaluated for three protection schemes: biological, chemical (control), and integrated. The percentage of saprophytic micromycetes in the mycoflora of soil samples collected prior potato planting is 71.93–91.8%. The most common fungi belong to the genus Penicillium (33 600–44 200 CFU/g); in addition, the genera Trichoderma sp. (0–2500 CFU/g), Aspergillus sp. (1240–19 700 CFU/g), and Rhizopus sp. (0–8100 CFU/g) are revealed, as is pathogenic Fusarium fungi (5800–9920 CFU/g). After protective biopreparations are applied, a higher percentage of saprophytic micromycetes (Penicillium sp., Trichoderma sp., Aspergillus sp., and Rhizopus sp.) is observed in soil samples compared with the use of chemical preparations or integrated scheme of protection (73.9, 61, and 59.6%, respectively). The presence of Penicillium sp., Trichoderma sp., and Aspergillus sp. fungi in the case of biological protection exceeds that for the chemical treatments by 15.6, 70, and 77.8%, respectively. The percentage of pathogenic micromycetes (Fusarium sp.) in soil samples treated with biological compounds is 26.1%, while for the chemical treatment and integrated protection scheme, it is 38.9 and 40.3%, respectively. The use of biopreparations for potato protection under conditions of sprinkling in the Volga region can be considered a promising approach to increase saprophytic activity and reduce the pathogenicity of soil microflora.