author(s)
Altaf Hussain, Muhammad Arif, Aqleem Abbas, Babar Hussain, Murtaza Ali, Saleem Jaffar

abstract
Potato virus Y (PVY) is distributed worldwide and is most important plant virus affecting solanaceous crops in particular potato and tomato. PVY cause 10-100% yield loss on potato and 39-75% on tobacco crops worldwide. PVY has different strains which cause variety of symptoms on different parts of the host plant species. Initially three chief strains of PVY viz. PVYC, PVYN and PVYO were recognized. In recent years, new strains of PVY (Technically necrotic strains) such as PVYN and recombinants PVYN-Wi, PVYNTN, and PVYN: O have emerged in potato crop. PVY have a host range of 495 species in 72 genera of 31 families. The strains of PVY have different stability under dilution end point (DEP), thermal inactivation point (TIP) and longevity in vitro (LIV). PVY belongs to the potyvirus genus and currently thought to be largest genus of plant viruses. The genome of PVY is single strand of positive sense RNA (+ssRNA) which is in the order of approximately 9700 kb in length excluding the poly (A) tail. PVY is spread from plant to plant either by aphids in non-persistent, non-circulative manner and mechanical means. Among the aphids (family Aphidinae) Myzus persicae is the most important vector which is transmitting PVY efficiently. Breeding of resistant cultivars is considered best strategy to manage viral diseases in potatoes. PVY is also managed indirectly by controlling its vectors (aphids) with insecticides and mineral oils. Therefore to understand biology of PVY and to develop an efficient management strategy is very important.