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Research article2025Peer reviewedOpen access

Temporal dynamics of airborne fungi in Swedish forest nurseries

Larsson, Rebecca; Menkis, Audrius; Olson, Ake

Abstract

In Sweden, reforestation of managed forests relies predominantly on planting nursery-produced tree seedlings. However, the intense production using containerized cultivation systems (e.g., high seedling density, irrigation from above, regular fertilization) creates favorable conditions for fungal infections. Despite the harmful role of diseases in forest nurseries, the origin and dispersal factors of fungal pathogens remain largely unknown. A better understanding of the airborne spread of pathogens could improve the prediction of fungal infection, ultimately optimizing preventative methods and decreasing the use of fungicides. This study investigated the temporal dynamics of airborne fungi in forest nurseries, with a focus on fungal pathogens. Airborne fungi were monitored in four Swedish forest nurseries over two growing seasons using spore traps and high-throughput sequencing. Fungal pathogens were identified using bioinformatics and quantified with quantitative PCR. Results showed strong temporal shifts of airborne fungal diversity and community composition following the growing seasons. The airborne spread included high abundances of important fungal pathogens (e.g., Cladosporium sp., Botrytis cinerea, Alternaria sp., Sydowia polyspora, and Melampsora populnea) with individual temporal and spatial variations. In general, the deposited spore loads of nursery pathogens correlated positively with increased temperature and negatively with higher precipitation. This was expressed the strongest for Cladosporium sp., Alternaria sp., and M. populnea, which suggests a higher availability of fungal inoculum in warm and dry periods. This study highlights the influence of seasonality on the temporal dynamics of economically important fungal pathogens in Swedish forest nurseries, which should be considered in the development of a local decision support system.

Keywords

conifer seedlings; Diplodia sapinea; fungal pathogen; Picea abies; Pinus sylvestris; spore trap

Published in

Applied and Environmental Microbiology
2025, volume: 91, number: 2, article number: e01306-24
Publisher: AMER SOC MICROBIOLOGY

SLU Authors

Global goals (SDG)

SDG15 Life on land

UKÄ Subject classification

Forest Science

Publication identifier

  • DOI: https://doi.org/10.1128/aem.01306-24

Permanent link to this page (URI)

https://res.slu.se/id/publ/140500