VIRTUAL SPEAKER - Optimizing Invasive Plant Disease Control under Uncertainty: Modeling and Communication Strategies

The European Union (EU) has established a risk-based regulatory framework to prevent the introduction and spread of harmful plant pests and diseases. This strategy is supported by risk assessment, surveillance for early detection, contingency planning, and stakeholder engagement. Here, we illustrate how modeling can support all these phases using several priority quarantine pathogens for the EU. To identify pest introduction hotspots, a Bayesian hierarchical spatial model was applied using regional data. Results showed that higher annual temperature, precipitation, and human population density increased the risk of pest introduction. Some risk assessments on Phyllosticta citricarpa, the causal agent of citrus black spot (CBS), have underpinned EU regulations. However, subsequent research on climate suitability and a recent outbreak in Tunisia indicated that CBS epidemics can occur under Mediterranean conditions in the EU. In terms of outbreak management, an individual-based epidemiological model was used to assess response programs for Xylella fastidiosa in almond orchards in Alicante, Spain. While all outbreak management strategies reduced disease progression, surveillance intensity was key to control effectiveness and efficiency. For huanglongbing of citrus, models indicated that early detection and aggressive vector control could contain disease progression for a certain period. EU Member States have developed contingency plans for priority quarantine pathogens, tested through simulation exercises with positive stakeholder feedback. However, social science studies have highlighted limited awareness of these contingency plans among growers, underlining the importance of early stakeholder involvement.