Wednesday, November 18, 2009

Berry Shatter in Grenache

Grenache have shed flowers which were not fertilised to form berries. This ‘shatter’ of bunches has been seen across all vineyard areas. This 'shatter' can look like the vines have been burned.

Shatter can be due to a number of factors including wind, high temperatures, water stress & nutrition. In many vineyards it may be a combination of several of these factors.

Tuesday, November 17, 2009

Early harvest expected - UPDATE 17/11/2009

Above: Berries 2-4mm and full flowering in the same bunch of Chardonnay Willunga. Will this turn into 'hen and chicken' set? The vines development is approximately a week ahead of last season, 2008/09, which was itself was an early vintage!

Saturday, November 14, 2009

7 seasons of CropWatch

Just realised today that we have been producing CropWatch's for 7 seasons. Each season has been different, always difficult in some way.

This is the current issue for the Adelaide Hills.

Adelaide Hills Crop Watch 131109

Thursday, November 12, 2009

Downy Mildew Risk = Very Low - UPDATE 12/11/2009

The hot and dry weather is not suitable for the disease. With each dry week the risk of Downy Mildew affecting your crop decreases. Grape Berries are immune to Downy Mildew infection once they reach 2-6mm (Berries Peppercorn EL 30-31).

The risk in McLaren Vale on a Downy Mildew outbreak affecting grapegrowers yields is effectively zero.

The risk for the Adelaide Hills is higher, but still low as these vineyards are further away from developing immunity, however levels in the hills region are also low.

Thursday, November 5, 2009

Botrytis - Q&A

Hi,

A question for DJ's. Should I spray for botrytis over flowering? We have Shiraz west of McLaren Vale, South Australia - crops up to 12 tonne/ha.

Kym




Dear Kym,
Flowering is an important time in determining your risk of botrytis rot at harvest. In South Australia Shiraz has a low to moderate risk compared to other varieties.

If you protect your vines over flowering it is a case of risk vs. cost of control. Given the predicted prices of grapes this season only use ‘big’ botryticides if you have had issues in the past.

Botrytis cost per hectare (1000lt dilute spray volume)


Filan* = $187
Scala* = $95
Chlorothanonil = $39
Teldor* = $109
Switch* = $129
Captan = $17
Rovral* = $40

*Tradenames in Australian market.

Rain during flowering can lead to botrytis infecting the developing berries through tiny wounds left by the flower caps falling off. This infection is known as ‘latent botrytis’ because the disease waits dormant in the berries as they develop. It will then appear as an infection if weather conditions suit when the fruit ripens.

The best defense against botrytis balanced yields, an early harvest, with an open canopy with loose bunches. A crop of 12 tonne/ha is a moderate tonnage and should not cause over cropping on your vines.

Botrytis in Pinot Noir.
This season canopies will grow larger than last season and with high soil moisture levels berries could be bigger and bunches tighter. This increases botrytis risk.

If your vineyard has a history of botrytis or your variety has tight bunches consider limiting the chances of latent infection with registered botrytis fungicides.

For vineyards operating organically or Bio-Dynamically the best defense against botrytis are techniques that lead to healthy vines with strong berry skins at harvest.

Monday, November 2, 2009

Apple Moth and Vine Moth - UPDATE 2/11/2009

While out checking vineyards this week Light Brown Apple Moth (LBAM) have been recorded. It is worthwhile assessing our vineyard now for signs of LBAM. Look for any flower parts that are stuck together. Apple moth damage is usually found in ‘hotspots’. If you find one damaged bunch like this check other bunches and in nearby leaves for more LBAM activity.

Light Brown Apple Moth.

How many LBAM grubs are a problem? 


LBAM caterpillars, or grubs cause damage to bunches which later leaves them much more susceptible to botrytis infection and spread. Also in high numbers apple moth reduce the yield of your block – which for high value fruit may become an issue. For low value fruit this may be less of an issue. The damage is terms of dollars of grapes at harvest is not as significant because the fruit eaten by the LBAM caterpillars is not as valuable.

We have also seen this week some large Vine Moth caterpillars (below).

Vine Moth caterpillar.

Are Vine moth a problem? 


Vine moth caterpillars generally only eat leaves and unless they are found in very high numbers they are not a significant pest. Be careful in young vineyards.

Seek advice- inform your winery and if necessary, apply a biological insecticide such as BT®, Prodigy®, Avatar®, Entrust®, Proclaim® or Success 2® and check labels for details.

Cost of control per hectare varies from $30-$50 per hectare for BT's, Proclaim, Prodigy, Avatar and Success 2. The BFA organically registered product Entrust is the most costly per hectare at approximately $80 per hectare.

Broad-spectrum insecticides are no longer registered for apple moth control.

Remember Prodigy can only be used up to 80% capfall and only BT’s can be used after berries reach peasize (EL 31). For some vineyards 80% Capfall will occur within 14 days.