Over 508,000 grapevines and seedlings suspected of carrying a virus were burned in two vineyards on Tuesday to?ensure the quality of products from the well-known Chinese wine-region, the East Valley of Helan Mountain in the Ningxia Hui autonomous region.

This is the first time Ningxia has destroyed massive amounts of virus-tainted vines, Xinhua News Agency reported.

A survey in April by the local authority found 15 of 468 samples of six types of vines carried leafroll virus, one of the most widespread viruses affecting grapevines worldwide.

Grape leafroll virus was once an increasing concern across wine-regions including California's grape producing areas in the United States.

Deborah Golino, plant?pathologist and director of the University of California, was quoted by Western Farm Press as saying: "What you get (with leafroll virus) is delayed fruit maturity, poor color and reduced yields. A vine with leafroll may be around in your field for many, many years, but you're getting a constant effect year after year. Your costs of managing that vineyard are going to be the same. However, your product is going to be affected and there's going to be less of it."

The local authority said the virus was only found in a small percentage of wineries and the scale of contagion is controllable.