The all-clear has been given to four Carnarvon banana growers whose properties were quarantined late last year after an outbreak of Panama disease.
Agriculture Minister Ernie Bridge said DNA fingerprinting by scientists at the Queensland University of Technology had shown that the strain of wilt disease found in the banana crops was not a major threat to the region's industry.
It had been feared the disease was a virulent strain so far found only in Queensland and New South Wales, which could attack all known commercial banana varieties.
However, the strain has been identified as one previously found in susceptible non-commercial banana varieties, which are grown for purposes such as windbreaks.
Carnarvon's commercial banana plants are usually resistent to that strain, but the scientists believe the outbreak may have been due to nutritional deficiencies in the affected plants.
Panama disease survives in soil, and when it infects the banana plant, it blocks the plant's vascular system so water cannot reach its leaves.
Properties found to be affected were immediately quarantined by the Department of Agriculture and growers advised to avoid transferring infected soil to other parts of their property.
Mr Bridge said quarantine restrictions would now be lifted, but he urged growers to select planting material carefully and clean borrowed machinery before using it on their property.
Surveying for the disease would continue, and a meeting of growers would be held soon to discuss eradication issues. Research by the Department would also be stepped up to identify the exact cause of the outbreak.
