Pathogenic fungi are a leading cause of crop disease and primarily spread
through microscopic, durable spores adapted differentially for both persistence
and dispersal. Computational Earth System Models and air pollution models have
been used to simulate atmospheric spore transport for aerial-dispersal-adapted
(airborne) rust diseases, but the importance of atmospheric spore transport for
soil-dispersal-adapted (soilborne) diseases remains unknown. This study adapts
the Community Atmosphere Model, the atmospheric component of the Community
Earth System Model, to simulate the global transport of the plant pathogenic
soilborne fungus Fusarium oxysporum, F. oxy. Our sensitivity study assesses the
model's accuracy in long-distance aerosol transport and the impact of
deposition rate on long-distance spore transport in Summer 2020 during a major
dust transport event from Northern Sub-Saharan Africa to the Caribbean and
southeastern U.S. We find that decreasing wet and dry deposition rates by an
order of magnitude improves representation of long distance, trans-Atlantic
dust transport. Simulations also suggest that a small number of viable spores
can survive trans-Atlantic transport to be deposited in agricultural zones.
This number is dependent on source spore parameterization, which we improved
through a literature search to yield a global map of F. oxy spore distribution
in source agricultural soils. Using this map and aerosol transport modeling, we
show how viable spore numbers in the atmosphere decrease with distance traveled
and offer a novel danger index for viable spore deposition in agricultural
zones