Pest survey card on Sphaerulina musiva

This pest survey card was prepared in the context of the EFSA mandate on plant pest surveillance (M-2020-0114), at the request of the European Commission. Its purpose is to guide the Member States in preparing data and information for surveys for the causal agent of Septoria leaf spots and cankers disease of poplars (Populus spp.) and their hybrids, Sphaerulina musiva. These are required to design statistically sound and risk-based pest surveys, in line with current international standards. This pathogen is a well-defined and distinguishable fungal species of the family Mycosphaerellaceae. The fungus is a Union quarantine pest currently reported only in North and South America and China. Sphaerulina musiva infects both leaves and stems/branches causing two types of symptoms: leaf spots and perennial stem and branch cankers. In spring, leaf spots are caused by wind-borne ascospores (primary inoculum) released from pseudothecia from overwintered leaves. In summer, conidia (secondary inoculum) released by pycnidia developed on leaf spots are dispersed by water and infect both leaves and young stems. In winter, the pathogen overwinters in colonised fallen leaves. Sphaerulina musiva infects all native North American poplar and aspen species and their hybrids and Salix lucida. Among European native and introduced poplars, Populus nigra and the hybrid Populus x canadensis are the only known hosts of the pathogen. Detection surveys in the EU should focus on all poplar and aspen species and poplar hybrids, both native and those introduced into the EU. Delimiting surveys should also focus on Salix spp. Evidence on other EU native species not listed as known hosts of S. musiva is lacking. However, these should also be included in detection and delimiting surveys. Climatic conditions and host availability, which are widely distributed in EU territory (forests, plantations, cities, parks), are not considered to be limiting factors for the establishment of the pathogen in the EU territory, if introduced. Sphaerulina musiva can be detected in the field by visual examination of leaf spots and cankers on stems and branches. Following visual examination, samples must be collected for laboratory identification. The identity of the pathogen must be confirmed by classic and molecular diagnostic techniques (PCR and qPCR assays). An in situ identification method is also available.