A system for real-time spore monitoring that can be expanded by the user to detect additional sporangia

Abstract

Fungal diseases such as downy mildew (Plasmopara viticola) have a negative impact on grapevine yield. These invisible, airborne sporangia infect the vines. The infection only becomes apparent once symptoms appear. By then, it is already too late to control the infection. Real-time monitoring of sporangium concentration in the air within the vineyard makes this key information available for estimating the risk of infection. Spore pressure can thus be measured and, together with temperature, humidity and the growth cycle, a measurement and well-founded prognosis of the risk of infestation becomes possible.

There are many different relevant spores that cause plant diseases. Monitoring of relevant sporangia for viticulture has recently been validated (Malvessi Cattani et al., 2026). The aim is to enable a rapid expansion of the range of spores that can be detected. This is the subject of this article.

The relationship between spore pressure and severity of infection is yet poorly understood. (Malvessi Cattani et al., 2026) investigated this for downy mildew. In doing so, they developed a classifier for Plasmopara viticola that runs on a spore sensor. This is made possible by a framework for spore monitoring. It includes everything necessary to enable the user to extend the classifier so that additional sporangia can be detected. The framework consists of a spore sensor: SwisensPoleno Jupiter; an AI classifier; a spore aerosol generator for generating measurement data to train the classifier; and a classifier architecture freely available to users, including the development toolchain. To empower the user, training is provided for the development of classifiers.

Once a new classifier is available validation under real-world conditions is recommended. This requires an independent measurement of spore concentration to have a reference. Methods exist for this. (Malvessi Cattani et al., 2026), for example, used two approaches: Hirst spore traps with manual spore counting and qPCR. This allows daily average spore concentrations to be determined. Experience shows that concentrations greater than 25 spores per m³ yield good validation results. One challenge are low concentrations, which must be measured reliably due to the detection limit of, for example, the Hirst-based method which has a detection limit of 25 spores per cubic meter (Malvessi Cattani et al., 2026).

In summary, it can be said that users can expand spore monitoring themselves. The greatest challenge for expanding spore monitoring currently lies in validation. Research activities should aim to simplify the validation method.

References

Malvessi Cattani, A., Zeder, Y., Graf, E., Schwendimann, A., Coronelli, R., Smit-Sadki, T., Burdet, J.-P., Alfonso, E., Jaccard, A., Niederberger, E., & Rienth, M. (2026). Automated air-flow cytometry enables real-time monitoring of Plasmopara viticola sporangia in vineyards. Applied and Environmental Microbiology, 92(4), e02152-25. https://doi.org/10.1128/aem.02152-25