Science comes to the rescue
Australian researchers have developed a new method which gives much better control of fungal diseases. The initial research focussed on the disease black rot, which isn't found in Australia yet but is a devastating disease in American grapevines. Our scientists set out to create a control method to protect our wine industry if or when black rot reaches our shores.
In the meantime, this successful technique will reduce the prevalence of this disease overseas, meaning it's actually less likely to infect our crops in future. I say 'crops' because the treatment isn't specific to grapevines only, but has the potential to revolutionise fungal disease control in apples, citrus, bananas, mangos, avocados etc.
For the home gardener wrestling with black spot on their roses or wondering if they can save their Agonis flexuosa 'After Dark' from myrtle rust, this is excellent news. So what is this new technique?
Stage one involves cutting the plant (whatever it is) back hard, removing all foliage. If it has loose bark I'd rub that off too. Remove all the debris and the mulch from beneath the plant, bag it and dispose of it in the rubbish, not your green bin. Burning it is also an option if you won't be annoying neighbours. Spray the plant all over with a fungicide. If there are low-growing shoots cut them off and bin them.
Next, replace the mulch with clean new material to prevent spores being splashed up onto the plant. Feed and water as usual, and when the new leaves emerge spray them with a foliar fungicide in accordance with the directions on the packet. If it rains heavily, spray again if you are using a non-systemic fungicide. You should be able to achieve total control if you are willing to put in the effort.