''Taphrina bullata'' is an

ascomycete Ascomycota is a phylum of the kingdom Fungi that, together with the Basidiomycota, forms the subkingdom Dikarya. Its members are commonly known as the sac fungi or ascomycetes. It is the largest phylum of Fungi, with over 64,000 species. The defi ...

fungus that is a

plant pathogen Plant pathology (also phytopathology) is the scientific study of diseases in plants caused by pathogens (infectious organisms) and environmental conditions (physiological factors). Organisms that cause infectious disease include fungi, oomyc ...

. It causes leaf blisters on pear trees.

References

Fungal tree pathogens and diseases Pear tree diseases Taphrinomycetes Fungi described in 1866 Taxa named by Miles Joseph Berkeley Taxa named by Christopher Edmund Broome {{fungus-tree-disease-stub