Final diagnosis


Potato virus Y (PVY)

Several chlorotic and necrotic spots cover the mature leaves of this young Burley tobacco plant; some of the lesions are gradually becoming necrotic. Potato virus Y (PVY)
The apex of this tobacco is virtually deformed and many leaves are more or less well developed. Leaves are smaller, deformed and show a green bronze colour. Potato Virus Y (PVY) / American strain
Clearing of a large proportion of secondary veins, some of which turn brown and become necrotic (vein clearing, vein necrosis). Potato virus Y (PVY)
A chlorotic Burley tobacco leaf; narrow and irregular tissue bands next to the veins remain green (vein mottling). Potato virus Y (PVY)
Chlorotic, and sometimes confluent rings on a Burley tobacco leaf. Potato virus Y (PVY)
Yellowing and necrosing of the midrib and of some veins of a Virginia tobacco leaf. Potato virus Y (PVY)
Many irregular brown spots cover the leaf. Some of them start from the veins. Potato virus Y (PVY).
Many small brown irregular and inter-veinal spots, with a narrow yellow halo. Potato virus Y (PVY)
This Virginia tobacco leaf is covered with a large number of chlorotic spots, some of which become gradually necrotic. Potato virus Y (PVY)
Brown, irregular, longitudinal streaks cover one side of the stem. Potato virus Y (PVY)
Flexuous viral particles of potato virus Y (PVY) are of 705 to 759 nm long and 12 nm in diameter.