Advisers and growers attribute the drop to effective use of rotations, backing up Grains Research and Development Corporation (GRDC)-funded research recommendations.

Richard Daniel, NGA chief executive officer, says about 35pc of respondents believe crown rot risk has increased and nearly all cited reasons of increased stubble retention or an increase in wheat on wheat.

"The results reinforce our belief that we have growers and advisers at different points of a crown rot ‘management curve’," Mr Daniel says.

"Many early adopters of minimum till realised that despite the soil moisture and other benefits of stubble retention, crown rot became a bigger threat.

"They responded by designing rotations to capture the benefits of stubble retention but minimise the disease impact."

The survey showed that where risk had decreased, less cropping area was affected and yield losses were both less frequent and at a lower level.

Respondents who indicated increased risk still had more than 80pc of cropping area affected with expected yield losses in average years of 250-500 kilograms per hectare and greater than 1000kg/ha in worst case seasons.

"The results further reinforce the view that developing and maintaining a sound rotation is still the key strategy to minimise the impact of this disease," Mr Daniel says.