Risk prediction of Lecanosticta acicola spore abundance in Atlantic climate regions

Abstract

Brown spot needle blight disease, caused by the fungus Lecanosticta acicola, affects pine trees across the northern hemisphere. In recent years, its incidence has expanded to new areas and host species. This is in association with climate change. Interest in understanding the basis of its epidemiology and proposing appropriate management measures has also increased. However, there is a lack of studies that characterise the relationship between spore abundance trends and climatic factors, which are essential to understand the spread of the disease. We collected spore abundance data for three years from 16 traps located in pine plantations over the Basque Country (north of Spain), the first European region where L. acicola was detected. A rapid change in pathogen behaviour led to serious financial losses in the forestry sector. We then modelled the relationship between spore abundance and weather variables in terms of generalised additive models. The resulting model was used to estimate the risk of disease spread over the whole area of Basque Country. We also generated a risk projection for the north of the Iberian Peninsula, an area influenced by the Atlantic climate, where the disease is currently causing severe damage. Cumulative rainfall acted as a reliable predictor of the spore abundance of the pathogen; thus, data from weather stations can be directly incorporated into early warning protocols to inform effective preventive actions.