Sunday, January 30, 2011

Vineyard Photos - What is looks like inside an abandoned vineyard.

Powdery mildew infection on leaves. The majority of green leaf surfaces are covered with powdery spores. Willunga, SA.
An increasing number of vineyard owners are abandoning their properties because they believe the vineyards are unsustainable. Abandoned and mothballed vineyards are becoming a serious issue for us in McLaren Vale and the Adelaide Hills.

It is an issue all around Australia.

Those who are unfortunate to be a neighbour of an abandoned vineyard, are suffering increased pest and weed management pressure due to the diseases that are being passed on from vine to vine.

Limiting this transmission of disease is greatly increasing the cost of grape growing, and in some cases 'good crops' have become too diseased to be harvested as premium fruit.

This season has seen a huge build up of powdery mildew (above & below) and downy mildew in abandoned vineyards; however these diseases are not quarantinable and council or our government has no authority to require the removal of diseased vines.

Victoria has some legislation - Plant Health & Plant Products Act 1995 (Section 12) - which talks of 'notifiable diseases' and 'control orders' being able to be issued in cases of disease.

A summary is listed here -
If a property is deemed infested, DPI has the power to order a property owner to destroy declared pests and diseases on their property if they pose a threat or are adversely affecting adjoining properties. If you have any concerns about a vineyard or orchard in your area being an actual source of pests and diseases and its potential to spread onto your property, the first step is to initiate a discussion with the owner and seek to resolve the issue.

In South Australia we urgently need some ability to control abandoned vineyards and stop the spread of disease. As a community we need legislation that removes abandoned vineyard blocks to reduce sources of pest infestations and disease load.

Powdery mildew on bunches. Willunga, SA.

Saturday, January 29, 2011

Downy Mildew - UPDATE 29/1/2011

In the Adelaide Hills - Downy Mildew oilspots continue to stay alive and in some cases are increasing in size and damaging berry stems causing fruit to dry out (below).

Donwy mildew has 'burnt' off part of this bunch as it has developed.
In all regions - We can see fresh oilspots from the Secondary Infection on the 13th and 14th of January. These new Downy Oilspots are of a small size and are beginning to turn red. Favourable weather including heavy dews in the Adelaide Hills have cause some advanced Downy Mildew infections to form a mosaic pattern on leaves (below).

Downy Mildew secondary infection spread. Note the mosaic pattern.
Secondary infection conditions are quite different to primary infections and can occur outside of a 10:10:24. For a secondary infection to occur there must be existing oilspots in the vineyard or located nearby. Unfortunately this season a high percentage of vineyards have been spreading Downy Mildew into those around them.

2010/2011 Downy Mildew Summary.

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.

4) One Downy Mildew Secondary Event (Warm, Wet Night) - 24th of November.

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

6) Two Downy Mildew Secondary Events (Warm, Wet Nights) - 13th and 14th of January.

Friday, January 21, 2011

Botrytis seen in 'green fruit' - UPDATE 21/1/2011

Chardonnay at 9o Baume ripeness.
Different varieties have a different of risk of bunch rots. It helps to consider botrytis risk in terms of rain events.

High risk varieties have tight bunches and thin berry skins. It is also possible to see botrytis in 'green fruit' which hasn't ripened yet.


Botrytis risk



High = Sav. Blanc, Riesling, Grenache, Semillon, Chenin Blanc

Medium = Viognier, Pinot Gris, Pinot Noir, Chardonnay, big bunched Shiraz,
Sangiovese, Mataro/Mouvedre, Petit Verdot, Verdelho

Low = Small bunched Shiraz, Merlot

Very Low = Cabernet Sauvignon

There are exceptions to these rules- different vineyard sites, croploads, canopy management and chemical strategy have an effect on the amount of rain a block can receive before showing signs of disease.

If heavy rain occurs and your grapes are riper than 9o Baume look inside the canopy for any evidence, especially in thin-skinned and tight bunched varieties. Semillon, Sauvignon Blanc, Chenin Blanc, Grenache, Chardonnay & Viognier are the first varieties that will show problems.

Botrytis needs significant rain or heavy dews to spread. If the weather remains fine any botrytis infections will hold to harvest and not significantly affect wine.

Be alert for rain in the next few weeks and assess your vineyard for any moulds. ALWAYS consult your grower liaison officer or winemaker before spraying for botrytis.

Saturday, January 15, 2011

Thursday, January 13, 2011

Downy Mildew - UPDATE 13/1/2011

Oilspots on a fresh leaf in the Adelaide Hills.
Adelaide Hills, Langhorne Creek and McLaren Vale vineyards have experienced a Downy Mildew Secondary Event, warm wet night on the 13th and 14th of January. This is the 6th Downy Event of the year. We have seen fresh spores and down on the backs of oilspots.


Growers will have to keep their vineyards covered with a Downy Mildew Protectant Fungicide as close as possible to harvest.

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.

4) One Downy Mildew Secondary Event (Warm, Wet Night) - 24th of November.

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

Wednesday, January 5, 2011

Downy Mildew Update - 5/1/2011

The damaging effect of Downy Mildew, from secondary events in November and early December, can be seen on bunches.

In McLaren Vale, where damage is very low, some early estimates put the crop loss at 2%. For fruit that is worth $1000 per tonne @ 4 tonne to the acre this is a reduction in gross profit of $100 per acre.


Above- Infection on flowers at Berry Set (EL 29) in the Adelaide Hills. This region has sporadic damage, some vineyards have very significant crop losses, while others have much less damage.