Wine producer cuts off vines damaged by major fungal disease
A fungal disease has forced a vigneron in northern New South Wales to pull out 25 per cent of his Chambourcin vines.
Bago Vineyards' Jim Mobbs says Botryosphaeria dieback is more significant as the vines age.
"It's a disease of the trunks and the cordons, which are the main arms that run along the wires," he said.
"When vines get older you have larger pruning cuts, so you have bigger areas for the fungus spores to sit and start off."
The disease starts at those pruning cuts and then spreads backwards towards the roots.
"It starts off as a 'v' or wedge and then gradually goes around the whole stem, or whole trunk, and cuts off all the cambian layers, all the growth layers," he said.
Mr Mobbs says that Botryosphaeria is a problem for wine grape producers worldwide.
"It could be a lot to do with the techniques of our pruning, so there may be cultural ways of helping it," he said.
"There are some chemical methods but it's still not controlling the problem completely."
"I've just knocked out 25 per cent, just chainsawed them off at the roots," he said.
"The disease doesn't go into the roots so if a sucker comes up I can actually train that back to the wire.
"If that doesn't work, and they die on me, I'll just put a bulldozer at the end and replant them."
He says it also affects some of his other grape vines but not to same degree as it does the Chambourcin.
"It could be because I've got a different pruning system or a different trellising system, I'm not sure yet," he said.
"Some grape vines grow quite different to others and Chambourcins have got long internodes between the buds, so you tend to have bigger spurs and when you go to cut back on the spur for the pruning you're going to have a bigger cut."
Australia will host the International Workshop on Grapevine Trunk Diseases for the first time in November this year in Adelaide.