Thursday, December 9, 2010

Downy Mildew Update - OUTBREAK in the Adelaide Hills. Langhorne Creek flood plain and Currency Creek.

The Adelaide Hills Wine Region, Langhorne Creek & Currency Creek and parts of the Southern Fleurieu are at risk of crop loss due to Downy Mildew;

Weather conditions, as outlined below have caused a build up of the disease to levels that pose a significant danger. This build up has occur in spite of growers keeping up protection as best they could. The weather this season has made keeping a 100% coverage very difficult.

1) 10:10:24 Primary Event – 30th October - This was confirmed by the finding of Oilspots from this 10:10:24 Event in mid-November.



2) & 3) Two Downy Mildew Secondary Events (Warm, Wet Nights) 12th and 14th of November.
- This was confirmed by secondary oilspot spread onto fresh leaf surfaces (pictured below).



4) One Downy Mildew Secondary Event (Warm, Wet Night) - 24th of November.
- This was confirmed by further secondary oilspot spread including some onto flowering bunches (pictured below).




5) One Downy Mildew Seconday Event (Warm, Wet Night)- 7th of December.

What does this mean?


More Downy Mildew Oilspots and bunch damage will occur when the spread of Downy Mildew from event 5) on the 7th of December incubates and becomes visible.

The Adelaide Hills is having a Downy Mildew outbreak – and because vineyards are flowering - if left uncontrolled this will affect vineyard yields. Other regions that are later have a reduced risk of crop loss - but if more Downy Mildew Secondary Events occur oilspot levels could build up to a level that defoliates vineyards.

Get specific advice for your situation.

Gwr 074downymildewqa PDF r3

The Grape and Wine Research and Development Corporation (GWRDC) have put together the attached document on Downy Mildew answering Frequently Asked Questions. This has been assembled by Dr Peter Magarey (of Magarey Plant Pathology).

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