Wednesday, December 22, 2010

Downy Mildew Update - 22/12/2010

Oilspots are visible from the Downy Mildew Secondary Event on the 7/8th of December.

In McLaren Vale sites have been identified that have significant Downy Mildew. In some cases these are abandoned vineyards, or rouge vines around housing, shedding or old farms (shown below). These vines are acting like 'disease bombs' and are spreading Downy Mildew. Some of these sites have most of the vines leaf surface covered with Downy Mildew.

Unfortunately in the Adelaide Hills Downy Mildew has spread onto bunches, which remain open to infection until they are approximately 4-5mm in size (shown above).

The most obvious sign of Downy Mildew is leaf oilspots and leave surface infection (shown below).

Tuesday, December 14, 2010

Downy Mildew Update - 14/12/2010

Downy Mildew Oilspots have been seen spread from Downy Mildew secondary events in November.

We are expecting to see further spread from the Downy Mildew Secondary Event (Warm,Wet Night) that occurred on the 7th/8th of December. Oilspots from this event are predicted to become visible on or about the 16th of December.

Check vineyards now. If you find any oilspots tag them. We have found oilspots in the area roughly outlined below. Even if you are outside of this area - you still need to check for oilspots.

Above - Older oilspots have a burnt look but have white down on the underside of the leaf.

Left & Below - Oilspots can often look very plain when seen from the front, but once they are turned over the infection becomes obvious. Picture here is the same fresh Downy Mildew oilspot seen from the front and back.

The 'bag test' indicates active downy mildew.

Pour clean water into an empty, sealable plastic bag, shake the contents, then empty to leave the bag lightly moistened.

Collect fresh leaves or bunches suspected of having downy. Seal them in the bag and leave overnight in the dart at 20°C to 25°c.

Next morning, white down will have developed on the undersides of oilspots with active downy mildew or on young bunches (berries < 5 mm).

Monday, December 13, 2010

Near Maps has updated 19th of November

The Lazy Ballerina cellar door neat Kuitpo Forest -
View the latest images of McLaren Vale here.

Friday, December 10, 2010

Downy in McLaren Vale - UPDATE 12/10/2010

While McLaren Vale does not have the same risk of Downy Mildew as the surrounding regions - the levels of oilspots we have seen in the last 48 hours has increased dramatically (below).

Downy Mildew spreads very quickly. We are expecting to see more spread from the rain on the 7th and 8th of December. We haven't seen this yet - Downy Mildew takes some time to incubate before it is visible. We are predicting the spread from December 7/8th will be visible on or about the 16th of December.

Many growers will panic when they see these Downy Mildew oilspots - but remember fruit past Berries Peasize is considered immune from infection (although leaves and bunch racchi can get infected at any stage of the season).

A low risk option is to spray any unprotected vineyards with a registered post-infection Downy Mildew product - remember that this needs to occur before Saturday to stop the increase in the

For specific advise you can ring DJ's on - 8323 8339, or my mobile direct - 0400656350.

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).

Wednesday, December 8, 2010

The summer storms over McLaren Vale - 7th December

The build up.

The thunder storm wave. Photo by Peter Kennedy.

The wind did howl, and the wind did moan.

The hot road steams after the first storm passes.

The vine canopies drip wet.

The second thundercell passes over Paxton Vineyards Thomas block.

The third wave storm over the bones of the ol' Tatachilla winery.

Monday, December 6, 2010

Downy Mildew - where it is and what is looks like - UPDATE 6/12/2010.

Downy Mildew Map of McLaren Vale.

As of the 6/12/2010.

Red Circles have 1 to 5 Downy Mildew Oilspots per 50 meters of vineyard row and Secondary Spread. Black circle has a higher level.

Downy Mildew Oilspots- Back of leaf has characteristic white down (above) - front of the leaf looks like it is a burnt spot (below).

Thursday, December 2, 2010

Insects in the vineyard - ID Photos

Vine Moth

Light Brown Apple Moth

Wingless Grasshoppers & Locusts

Wingless Grasshoppers and locust have been seen in McLaren Vale and Adelaide Hills vineyards. In general levels are low and surrounding grassland and pastures have enough green feed to support the locusts limiting any significant damage to grapevines (below).

Late nymph and adult locust eat green feed during summer. They tend to move from nearby drying pastures and crops into vineyards during December to February where there is a source of green feed. They prefer to feed on tender young shoots and leaves and leave a smooth edge to their feeding area. The vine rows nearest the drying pastures and crops tend to be most damaged.

Wednesday, December 1, 2010

Powdery Mildew Pressure is very high - UPDATE 12/1/2009

Humid and warm weather conditions are causing vineyards to be at a high risk of developing Powdery mildew infections.

Powdery mildew has been spreading this week. Most monitored Chardonnay vineyards now have some signs of the disease.

Flag-shoots have been detected in blocks within the district. Cleistothecia infections have developed further with large, shaded, humid canopies aiding the development and spread of the disease (below).

If there is any sign of Powdery in your vineyard, apply two sprays of a suitable registered fungicide at 10-day intervals in attempt to stop the disease increasing. For Powdery protection avoid spraying wettable sulfur at high temperatures (>35oC) when the humidity is >70% within 24 hours of spraying. Growers can opt to use Legend in hot weather to avoid sulfur burning. This allows them to keep up the protection on your vineyard.