The ban on planting stone fruits—peaches, nectarines, plums, and apricots—has been lifted in two New York State counties that have been under quarantine because of plum pox, leaving only part of Niagara County where growers can’t grow these fruits.

Orleans and Wayne counties were released from the regulation after three years in a row of negative tests for the disease. The “no plant” zones covered 10,000 acres in Orleans County and 14,000 acres in Wayne County.

For the first time since plum pox was detected in 2006, no positive tests resulted in 2012. New York State inspectors tested 155,927 samples from more than 1,250 acres this year.

Niagara County last had a positive test in 2011, so an area there will remain under planting restrictions until at least 2014. It is the last place in the United States under regulation for plum pox.

“This is great news for New York’s stone fruit industry in Wayne and Orleans counties,” state agriculture commissioner Darrel Aubertine said.  “I’m cautiously optimistic that this progress will soon lead to a total eradication of the plum pox virus here in New York State and in turn, the continental United States.”

Certain quarantine provisions remain in effect. Propagation—collecting budwood and making nursery plantings—is still not allowed in the northern portions of Niagara, Orleans, and Wayne counties bordering Lake Ontario. The no-plant provisions apply in Niagara County near the towns of Appleton, West Somerset, and Burt.

Plum pox first appeared in the United States in Pennsylvania in 1999 and was declared eradicated ten years later. In 2006, it was discovered in Berrien County, Michigan, and in Niagara County, New York, and was later found in Orleans and Wayne counties.

The work of monitoring, locating, and eradicating virus-infected trees is a cooperative effort between states and the USDA’s Animal and Plant Health Inspection Service. The disease, which is controlled in the United States by quarantine and eradication, is transmitted in infected budwood and spread from tree to tree by aphids. The disease is widespread in Europe and infects some trees in Ontario, Canada, just across the Niagara River from New York, where efforts are also under way to eradicate it.

The disease is extremely damaging, reducing yields, causing premature drop, and disfiguring fruit.