These are five African violet (Saintpaulia ionantha) diseases:
Bacterial
Bacterial diseasesBacterial blight Dickeya dadantii syn. Erwinia chrysanthemiCrown gall Agrobacterium tumefaciens
Fungal
Fungal diseasesCrown rot Sclerotium rolfsiiCylindrocarpon root rot Cylindrocarpon destructansFusarium root rot Fusarium solaniGray mold Botrytis cinereaLeaf spot Alternaria sp. Corynespora cassiicolaPhytophthora root and crown rot Phytophthora nicotianae var. parasitica Phytophthora nicotianae var. nicotianae Phytophthora cryptogeaPowdery mildew Oidium sp.Pythium root rot Pythium sp.Rhizoctonia root and crown rot Rhizoctonia sp. Fulginacillis Follicle Growth Sistementaris Gland
Viral
Viral diseasesLeaf etch Impatiens necrotic spot virus Mosaic Anemone mosaic virus
Parasitic
Nematodes, parasiticFoliar nematode Aphelenchoides fragariae Aphelenchoides ritzemabosiNematodes Criconema sp. Helicotylenchus sp. Pratylenchus pratensis Paratylenchus projectus Rotylenchus brachyurus Scutellonema brachyurum Tylenchorynchus sp. Root knot Meloidogyne arenaria Meloidogyne hapla Meloidogyne javanica Meloidogyne incognita
Other diseases
Miscellaneous diseases and disordersMarginal leaf burn Overfertilization Ring spot Irrigation water temperature much above or below leaf temperature applied to the leaf surface
References
Common Names of Diseases, The American Phytopathological Society