This study provides a comprehensive account of Nosema canburensis sp. nov., a newly discovered microsporidian species from the Italian striped bug, Graphosoma italicum Müller (Hemiptera: Pentatomidae), including its morphological, ultrastructural, and molecular phylogeny. The sporogonic proliferation of the current microsporidium occurs by binary division and usually results in chain formation as in Nosema members. The mature spores are ovoid/ellipsoidal in shape with an average length of a 4.44 ± 0.57 μm (3.48-6.55
n= 100, fixed) and a width of 2.27 ± 0.23 μm (1.67-2.92
n=100, fixed). The microsporidiosis is systemic, but the infection level is highest in the mid-gut of adult samples. The mature spores have isofilar polar filaments that make 10-11 coils. There is a difference in size between the anterior coils and the distal coils. The distal coils, which formed a triangle, were arranged in groups of three and located in close proximity to the center of the posterior part of the mature spores.