Tomato growers in South Australia are facing lengthier lockdowns than initially expected, as biosecurity officers work to eradicate a crop virus.

Tomato Brown Rugose Fruit Virus was detected at three locations in August. Workers belived the sites would only be shutdown a few weeks.

Rural editor Emily Minney caught up with Department of Primary Industries and Regions biosecurity director Nick Secomb to hear more about the complex process of eradicating the disease.