Mystery vine death prompts testing

When a South Australian grower noticed two vines dying in his four-acre vineyard, he was concerned but not alarmed.

Then the following year, another two vines died. Alarm bells started to ring. What was causing vine death?

All four dead vines were in a 10 metre radius and declined quickly from about mid-December and were dead by mid-January.

The grower contacted his local viticulture consultant, and they decided to watch the patch for another year. The next season, three vines in the same area died.

This time the grower decided to contact Vinehealth Australia. Within 24 hours, the Vinehealth team was at the site taking various vine and soil samples.

Soil samples were taken for phylloxera and nematode testing. The samples were negative for phylloxera, but 17 of 19 samples were positive for root-knot nematode complex.

Grapevine wood samples from the various dying vines were also sent to a pathologist for trunk disease and root rot analysis. No trunk disease or root rot was found, but the graft area was found to be completely dead.

Vinehealth Australia also sent shoots away to test for a range of viruses. Results were positive for Rupestris Stem Pitting virus (RSPV), a minor virus of grapevines carried without causing symptoms.

Vines were also positive for Grapevine Fleck virus (GFkV), which was determined to be a possible cause of vine death. “This virus is associated with graft incompatibility that Shiraz is sensitive to. The virus in Shiraz vines comes in from the 140 Ruggeri rootstock, as one of the clones of this rootstock in South Australia is a carrier of this virus,” Suzanne said.

The vineyard will continue to be monitored this coming season with further testing planned to rule out other causes.

While the grower is now working on management strategies for Grapevine Fleck virus, he is relieved the problem isn’t phylloxera.

“I didn’t think it was phylloxera, and the tests confirmed it, so it is really good to know what the actual problem is,” the grower said.

“What I’ve learnt from this is to be very careful about the planting material I buy. And to get testing done as soon as I notice a problem. If you see a problem, get onto it straight away and don’t stop looking for an answer until you find one.”

Suzanne said this was a timely reminder for growers to:

  • Monitor vines regularly, noting anything unusual or different.
  • Seek help to identify what the problem is.
  • Undertake testing to verify the problem.
  • Talk to Vinehealth Australia if you’re concerned you might have a notifiable pest or disease, such as phylloxera.