Alternaria Spore Forecasts Using the Atmospheric Dispersion Model SILAM: the First Trial

The SAPID -project of the Academy of Finland aims to add some pest and spore forecasts to the SILAM modelling system. Here we present the first attempt to forecast amounts of Alternaria spores in Europe using the atmospheric dispersion and composition model SILAM, which already includes several pollen types . The final goal after the project is a real operational warning system, which would be able to predict large pest insect migrations and plant pathogen dispersion in regional and continental scales in Europe.
Alternaria species are known as major plant pathogens. At least 20% of agricultural spoilage is caused by Alternaria species and the most severe losses may reach up to 80% of yield. Alternaria is also a common allergen in humans and numerical, model based forecasts that specify Alternaria could complement current forecasts.
A key tool in this study is the SILAM atmospheric dispersion model. The insect migration and plant pathogen model presented in this study will be constructed as a part of the SILAM modelling system. It includes both Lagrangian and Eulerian advection/diffusion formulations and wet and dry depositions.
Spore observations will be used from the University of Turku, the University of Worcester and from the EAN database.
The atmospheric dispersion and concentration of spores are predictable using mathematical-physical-biological models in the same way as pollen concentrations are: maps of source areas and flowering parameters with a flowering model in the SILAM constitute pollen emissions. After pollen release, the pollen grains disperse in the air and removal processes remove them from the atmosphere. As a result, the model gives pollen concentrations in the air (see http://silam.fmi.fi). In the case of Alternaria spores, the source areas (e.g. crop fields and grass areas), timing of spore release and favourable weather are the main parameters included in the model.

This work demonstrates the possibility and limitations of using the dispersion model with pollen sources for the new type of biogenic aerosols - the Alternaria spores.