FUNGICIDE resistance may be a serious concern for vegetable growers but there are practices that can assist.
NSW Department of Primary Industries senior plant pathologist, Dr Len Tesoriero, spoke at Hort Connections 2017 in May about the ongoing battle that is fungicide resistance.
He said the problem can stem from a change in the fungal population that makes the fungicide less effective or ineffective, and that resistant strains of the fungus are selected by repeated use of a particular chemical or fungicides with the same mode of action.
Resistant strains can then reproduce and increase in the fungal population.
Resistance can also result from a genetic mutation or if a fungal strain can use an alternative biochemical pathway.
“In a few cases, fungicides can also stimulate plant chemical and physical defences to pathogens,” he said.
Fungicide resistance was a matter for the entire horticulture industry, according to Dr Tesoriero.
“It is incumbent of the industry as a whole to look at the whole picture there,” he said.
He detailed several methods that could work together to help manage the problem:
- Limit the total number of spray applications;
- Apply fungicide from different activity group;
- Alternate with fungicide from different activity group;
- Include fungicides with mult-site activity;
- Use microbial bio-controls;
- Apply as preventative treatments (before symptoms);
- Avoid extended spray intervals;
- And use preventative integrated crop management strategies such as resistant varieties; crop scheduling; crop rotation; crop hygiene.
Ashley Walmsley
Ashley Walmsley is the editor of ACM's only national, fresh produce magazine, Good Fruit & Vegetables, while also covering horticulture stories for the agricultural papers and websites. He also writes the weekly, The Ringer, column in the Qld Country Life.
Ashley Walmsley is the editor of ACM's only national, fresh produce magazine, Good Fruit & Vegetables, while also covering horticulture stories for the agricultural papers and websites. He also writes the weekly, The Ringer, column in the Qld Country Life.
