Some New Zealand growers are seeing decreased crop yields from fungal diseases affecting wheat and barley.
Andy Bailey, a UK scientist and fungicide specialist, has seen the damage caused by the same diseases in the UK and Ireland.
Mr Bailey has been in New Zealand recently to share his expertise in a series of industry meetings.
According to the researcher, resistance developed by fungal disease Septoria was almost an inescapable outcome.
Farmers using single-site acting fungicides will develop resistant diseases over time, he warns.
Mr Bailey recommends an early season application of Phoenix with DMI's such as Bolide, which will launch in New Zealand this season.
Bolide provides broader spectrum control of key cereal diseases and exceptional performance against Septoria.
Watch the full interview with Andrew Bailey above.