Modelling airborne inoculum dynamics and disease progression of the red leaf blotch of almond in Catalonia, NE Spain

Red leaf blotch (RLB) of almond, caused by the fungus Polystigma amygdalinum P.F. Cannon, is one of the most important leaf diseases affecting almond trees (Prunus dulcis (Mill.) D.A. Webb) in the Mediterranean basin and Middle East regions. From 2019 to 2021, airborne ascospores were monitored on a daily scale through Hirst-type air samplers in two almond orchards located in Lleida (NE Spain) and quantified through qPCR methods. In the same locations, red leaf blotch incidence and severity were evaluated weekly in 2021. Weather data (direct and derived variables) is also provided, from two automatic weather stations located near the almond orchards, for potential epidemiologic studies.