Occurrence of Aulacorthum Solani on Potato: A Vector of Potato Virus Yo and Potato Leafroll Virus in India

Foxglove aphid Aulacorthum solani (Kaltenbach) is a polyphagous pest causing direct and indirect losses to crops, and potato is its important host. Its incidence and distribution have extended manifolds in potato growing regions of India especially in seed production areas. In the recent past, it has been occurring on potato in the four agroecosystems of Shimla, Jalandhar, Modipuram and Gwalior. This study determines species distribution and its viruliferous nature with respect to most predominant viruses viz., Potato virus Y° (PVY°) and Potato leafroll virus (PLRV). Adults of A. solani (prestarved) were given an acquisition feeding of 24 hr on pure culture of PVY° and PLRV, and then released on to tissue culture raised healthy potato seedlings for inoculation. These plants were allowed for expression of external visual symptoms and were PCR tested at weekly intervals for 35 days. PCR results revealed that PVY° and PLRV were first detected in plants at 2^nd week after inoculation but with no visible symptoms. However, clear visual symptoms of PVY° and PLRV were witnessed during 4^th week after inoculation confirming viruliferous nature of A. solani. It was further confirmed by sequencing coat protein gene of two viruses and comparing with reported sequences in the database.