N. D. Shamaev
All-Russian Research Institute of Experimental Veterinary Medicine named after K. I. Skryabin and Ya. R. Kovalenko of the Russian Academy of Sciences, Moscow, Russia
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Volume 26 No. 8
Date of paper submission: 30.12.2025, date of review: 25.02.2026, date of acceptance: 02.04.2026.
Published: 08/31/2026
Abstract. The number of pathogen spores in soil, plants, and insects varies significantly depending on the specific pathogen, its life cycle, and the environment. The presence and concentration of these spores are crucial for understanding the mechanisms of disease transmission and pathogen control. Under conditions of intensified agricultural production, liming rates may decrease, and the carbonate balance in the soil may become negative, which can affect interactions with the soil environment and play a decisive role in the persistence and further dissemination of spores. The purpose of the study is to assess seasonal changes in the quantitative distribution of microsporidia spores of the genus Nosema in leached soil. Methods. Soil, vegetation, and worker bee samples were collected monthly from each of the 10 hives participating in the study. Using statistical data on the number of rainy days and precipitation totals, a linear model was constructed and an analysis of variance was performed. Results. According to our calculations, the highest average spore counts of microsporidia of the genus Nosema in worker bees (47 × 103 spores) and in leached soil (10.75 × 104 spores) occurred in March. In vegetation, spores were first detected only in May (5.1 × 103 spores). Significant differences were found only between the spore counts obtained from March to July and from July to September (p < 0.05). In a soil column experiment with simulated precipitation, spores traveled a distance of 16 cm in leached soil over 23 days and decreased in number by 94.13 %, from 38.41 × 103 to 4.14 × 103 . In the control column without simulated precipitation, spore movement was not observed, and the number of spores in the soil at a depth of 2 cm from the 2nd day to the 23rd day of the experiment decreased by only 17.02 %. Based on the observations, it can be assumed that spores are unstable to the specific features of the environment of leached soils in the presence of precipitation, since this implies their movement deeper into the soil layer and, probably, activation of decomposition processes by the soil environment. Even under conditions of precipitation and leaching, the bees themselves play a major role in the distribution and circulation of Nosema sPp. spores; vegetation and soil can remain reservoirs provided that bees infected with spores are present, which was observed during the spring-summer-fall study period. Scientific novelty. For the first time, a comprehensive assessment of the seasonal dynamics of Nosema sPp. spores in the bee-soil-plant system on leached black soil was carried out.
Keywords: Nosema sPp. microsporidia, honey bees, Apis mellifera, leached black soils, quantitative distribution of spores
Acknowledgments. This study was carried out within the framework of state contract FGUG-2025-0006 in accordance with the approved research plan of the All-Russian Research Institute of Experimental Veterinary Medicine named after K. I. Skryabin and Ya. R. Kovalenko of the Russian Academy of Sciences for 2026.
For citation: Shamaev N. D. Assessment of seasonal distribution and movement of Nosema sPp. spores in the leached black soil. Agrarian Bulletin of the Urals. 2026; 26 (08): 1539‒1549. https://doi.org/10.32417/1997-4868-2026-26-08-1539-1549 (In Russ.)
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