Re-record and Spore Ultrastructure of Nosema melasomae Sidor & Jodal 1986, a Microsporidian Pathogen of Crysomela populi (Coleoptera: Chrysomelidae)

Background: Chrysomela (=Melasoma) populi is one of the most serious pests on poplar plantations. In the present study, a microsporidian pathogen, Nosema melasomae infecting Crysomela populi is re-recorded from a new geographical locality and its spore ultrastructure is given for the first time. Methods: Larvae and adults of C. populi were dissected in Ringer’s solution and prepared wet smears were examined under a microscope. Detected fresh and stained spores were measured and photographed using an Olympus BX51 microscope with a DP-25 digital camera and a DP2-BSW Soft Imaging System. The ultrastructure of the pathogen was studied with a Philips EM 208 transmission electron microscope using standard preparation techniques as previously described Results: Fresh spores of the microsporidian pathogen are elongate, 4.86 ± 0.71 μm in length and 1.64 ± 0.19 μm in width. The spore wall is considerable thin, measured 60 to 100 nm and consists of a clear endospore (40 to 80 nm) and an electron-dense, uniform exospore (15 to 30 nm). The polar filament is isofilar and has only 6-8 coils. Nuclei in the cell are 400-560 nm in diameter. The polaroplast has a thin lamellated structure. Conclusion: The pathogen from C. populi is N. melasomae Sidor & Jodal, 1986 and its systematic position given by Sidor and Jodal. The spore ultrastructure of N. melasomae differs from those of other microsporidia infecting chrysomelids.