This is the third Scoping of Trunk disease incidence. 

Eutypa dieback survey
Limestone Coast 2019

Mark Sosnowski & Matthew Ayres (SARDI)

James Freckleton, Catherine Wotton & Brian Nitschinsk (LCGWC)

Summary
 A survey was undertaken in the Limestone Coast vineyards of Coonawarra, Wrattonbully and Mt
Benson/Robe to determine the incidence of grapevine trunk disease in November 2019.
 The overall mean incidence of dieback and eutypa foliar symptoms was 52 and 11%, respectively.
 The incidence of dieback was greatest in Wrattonbully (64%), followed by Coonawarra (57%) and Mt
Benson/Robe (34%). In terms of foliar symptoms of eutypa dieback, Coonawarra had the greatest
incidence (16%), compared with Wrattonbully (7.5%) and Mt Benson/Robe (1.2%).
 Over the past 7 years, the annual increase in incidence of dieback was 1% in Coonawarra and 7.5% in
Wrattonbully, this difference most likely due to the greater amount of vineyard rejuvenation and pruning
wound protection being undertaken in Coonawarra compared with Wrattonbully.
 Dieback and eutypa foliar symptoms were observed in vines as young as 4 years, the youngest
recorded with foliar symptoms in Australia. It is likely these vines were infected in the first year of
production, highlighting the importance of early intervention with wound protection.
 The incidence of blocks in Limestone Coast with 100% dieback was 5% in 2012 and has increased to
20% in 2019.
 Cabernet Sauvignon and Shiraz had the highest incidence of disease symptoms and Merlot and
Chardonnay were recorded with the lowest incidence.
 Rootstocks and clones varied in disease incidence, but due to limited representative sample sizes,
results were inconclusive, and further investigation is required.
 There were no differences in disease symptoms evident between spur-pruning management styles:
detailed, semi-detailed and hedged, highlighting the importance of applying other disease management
strategies.
 Overall, blocks with wound protection had only slightly lower disease symptoms than those with no
wound protection. Results showed that commencing wound protection on infected, mature vines is
unlikely to have any impact, and blocks exposed to infection for as little as the first 2 years of production
are still vulnerable to developing disease. Wound protection programs commencing from planting led
to considerably less symptoms than when protection was delayed.
 There was only a small reduction in disease incidence for blocks that had been remediated. The height
of cuts or incidence of trunks remaining with visible infection were not available, but may have
influenced the effect of remedial surgery on disease incidence.
 There was little difference in between blocks with and without frost protection.

Full Report – pdf download (29 pages) available in library checkout.