Source: merredinmercury 2009-6-19 10:36:48
Herbicide resistance has been a problem in the Wheat belt, but a new threat of fungicide resistance is emerging.
Australian Centre for Necrotrophic Fungal Pathogens at Murdoch University Professor Richard Oliver said fungicides cost Australian growers about $150 million a year.
¡°Many are using three or more treatments on a crop,¡± he said.
¡°Nearly all the fungicides used in WA are from the same mode-of-action group ¨C the triazoles, otherwise known as group 3 or DMI¡¯s.¡±
Professor Oliver, who is also the Grains Research and Development Corporation deputy chairperson, said experience in Europe suggests some fungal diseases are developing dangerous resistance to this group of fungicides, so he¡¯s asking WA grain growers to be vigilant and contribute to a nationally coordinated project to address the risk of fungicide resistance.
¡°We want to know if there are any cases of fungicide escape by fungal pathogens of grain and we¡¯re looking for fungal disease that occurs soon after fullrate treatment with fungicides such as Alto, Garrison, Opus, Jockey, Tilt or Folicur,¡± he said.
Fungicide escape is most likely to occur for powdery mildew of barley and wheat, wheat yellow spot and barley net blotch.
Cereal rusts have no known history of fungicide resistance anywhere in the world.
Fungi from lesions or pustules on efficiently sprayed leaves are sought.
Professor Oliver said fungicide resistance was a potentially significant problem.
He suggested growers alternate available mode-of-action groups and strongly recommended they use full label rates and genetically resistant cultivars when available.