SYDNEY - A second case of a destructive disease affecting banana plants has been confirmed in Australia, dashing hopes that a recently confirmed outbreak would be isolated and threatening the country's A$550 million ($423 million) sector.

The so-called Tropical Race 4 strain of Panama disease was found at a farm in Mareeba in the far north of Queensland, the local government said on Thursday.

It comes a month after the discovery of the first case in Queensland at a farm in Tully. State biosecurity officials quarantined that farm and growers hoped the incident would prove to be isolated.

Now, with a second case some 200 km (124 miles) from the original outbreak, the banana industry is concerned the disease may spread to other parts of the country's largest banana-producing state.

"The Panama tropical race 4 (TR4) on a second North Queensland banana farm has further emphasised the need for every assistance to be provided to the banana industry to help contain the disease," the Australian Banana Growers' Council said.

Panama disease hits banana plant roots, with Race 4 considered particularly destructive.

The disease can spread through contaminated water. Banana plantations in Central and South America were destroyed by an outbreak in the 1950s.

Australia does not export bananas but lower domestic production could push local prices higher, as in 2011 when Cyclone Yasi destroyed more than 20 percent of Australia's crop, driving prices up more than 400 percent.

Australian production is expected to hit 321,000 tonnes in the 2014/15 season, the official commodity forecaster said on March 3. Queensland is expected to account for more than 90 percent of that.