Two strains of potato virus Y "potyvirus" (PVY) were isolated from naturally infected potato Solanum tuberosum CV. Spunta plants from Al Dakahliya and Dammietta governorates showing rougosity, mosaic, and veinal necrosis on the leaves; stunting; stem canker; and palm sheep. The identification was based on the symptomatology, indicator plants, physical properties, serological tests "ELISA and immuno electron microscopy", molecular wieght, and negative staining with electron microscopy. The virus

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... induced systemic and non systemic symptoms which appears on the indicator plants. Datura stramonium was resistant to both strains (PVY N -W and PVY O ). On the other hand Nicotiana tabacum CV. Turkish, White Burley, Xanth, and Samsun., S. tuberosum CV. King Edward, Spunta., and D. metel showed various systemic symptoms. The thermal inactivation point (TIP) was between 53 o C and 56 o C, dilution end point (DEP) for the tested virus was between 10 -3 and 10 -4 , while longevity in vitro (LIV) was between 48 and 60 hr at room temperature (RT). Indirect -Enzyme Linked Immuno Sorbent Assay (I-ELISA) showed that there are nine positive samples from twenty fife samples. Electron microscopy showed separated particles of PVY with length of 600 nm , while using immuno electron microscopy showed PVY particles in aggregates. The molecular weight of purified PVY coat protein was 34 KDa through polyacrylamide gel electrophoresis test