What was it all about?

Banana bunchy top virus (BBTV) is the most serious viral disease of bananas. Badly affected plants will not produce fruit and, if left unchecked, a plantation will become completely infected through the movement of infected banana aphids, which carry the virus.

In Australia, the disease is confined to South East Queensland and Northern New South Wales, meaning that more than 95 per cent of the industry (Far North Queensland, the Bundaberg district, Southern New South Wales zone, Western Australia and Northern Territory) is free of the disease.

This project was conducted from 2012 to 2015, as the second phase in a 10-year plan aimed at eradicating BBTV from Australia. Its aim was to preserve area and subzone freedom, eradicate the disease from other subzones and contain and suppress the disease in remaining subzones.

While there is no resistance to BBTV in any commercially acceptable cultivars, the life cycle of the disease is well understood and early detection and removal in commercial plantations is an effective means of control. But because early detection is difficult, trained professional inspectors were deployed under this project to detect and destroy infected plants properly

Project inspectors followed a planned surveillance strategy inspecting and categorising every plantation within the BBTV infection zone at a frequency determined by the level of infection within plantations.

During the life of the project, the data showed a trend towards plantations in New South Wales moving from the ‘infected’ categories to ‘free’ and ‘provisionally free’, however five plantations returned to the ‘high infection’ category.

The project also funded research to determine how long the virus can remain in the plant before symptoms develop (latency) and developed improved destruction methods for infected plants and the aphid vector during cooler slower growing conditions – this is subject to ongoing field investigations and glasshouse trials.