AdelaideHillsCropWatchVintageReportP2

8/9/2019 AdelaideHillsCropWatchVintageReportP2

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CropWatch SA Adelaide Hills is a service provided by service provided by the Adelaide Hills Wine Region Inc. DJs Grower Services provide vineyard monitoring data,interpret weather data & compile the messages. Information is general in nature. Always seek professional advice specific to your vineyard. All photos (c) James Hook,Richard McGeachy & Peter Magarey unless noted. CropWatch acknowledges the support of James Hook & Matthew Wilson in preparing this message.

Flowering occurred during the

middle of November during aperiod of warm weather.

Flowering to capfall occurredquickly. For the majority ofvineyards, monitored as part ofthe CropWatch programme,flowering occurred over a twoweek period.

Vine canopy growth slowedduring this period, which is

considered to suit high qualityred wine production whereexcess shoot growth andshading can be a negativeissue.

Berry set was generally verygood. The notable exceptionbeing some berry shatter inPinot Noir, Pinot Gris andChardonnay, where this shatteroccurred vine yields were

reduced.There were severalChardonnay vineyards that hadbelow average crops due toreduced berry set which limitedharvest yields in these blocks.

Stuck flower caps were seen inShiraz and Merlot throughoutdistrict.

Undervine weed levels

increased dramatically afterspring rains and increasinglywarm soils.

Predatory insects

Beneficial wasp cocoons werefound in good numbers inbunches. Other beneficialinsects such as junkbugs(Lacewing juveniles), spiders,hoverflies and earwigs were

present in pleasing numbersthroughout most sites.

Flowering

Light Brown Apple MothFlowering is the critical time for assessing vineyards for signs of Light BrownApple Moth (LBAM). Look for any flower parts that are stuck together. LBAMdamage is usually found in hotspots. If you find one damaged flower checkother flowers nearby for caterpillar activity.

How many Light Brown Apple Moth caterpillars (above) present a problem inyour vineyard?

LBAM caterpillars cause bunch damage which leaves them more susceptibleto botrytis infection. Also, in high numbers Apple Moth reduce the vineyardsyield. For high value fruit, preventing yield loss may be worthwhile. For lowervalue fruit, yield loss is a lesser consideration. The yield loss, in terms ofdollars of grapes at harvest is not significant because the fruit eaten by the

Apple Moth caterpillars is outweighed by the cost of control.

The control option insecticides Proclaim, Prodigy, Avatar and Success2

allcost in the $30-45 per hectare range. The BFA organically registered productEntrust is $80 per hectare. The cost of applying BTs is $5 to $30 per hectare.


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Fruit development

Figure 1: Average Air Temperatures through November & December 2009 recorded at Balhannah.

Powdery Mildew - doesnt need rain to spread. It is favoured by mild temperatures (20 29oC) &cloudy conditions. During these conditions, Powdery rapidly produces spores and spreads on to unprotectedleaves and bunches.

Analysis of the average air temperatures during flowering (Figure 1) shows conditions from the 8th ofNovember to the 15th of November 2009 were ideal for Powdery Mildew spore production. Additionally, 62%of 24 hour periods in November rose above the 15oC threshold for Powdery Mildew development. Thiscoincided with the start of grapevine capfall.

CropWatch Bulletins first recorded significant finds of Powdery Mildew in Chardonnay around November 30thwhich correlates well with the powdery favourable weather two weeks prior to this.

Average air temperatures were also near the ideal range for Powdery during December which coincided withgrapevine canopies closing over which makes protective spray coverage becomes more difficult.

November and December are the critical times for Powdery Mildew control in the Adelaide Hills because;

1. The temperature range is conducive to Powdery Mildews lifecycle.

2. Vine canopies rapidly grow during this period making coverage more difficult.

3. After flowering grapevine berries rapidly expand in size which makes keeping them covered witheffective fungicide protection more difficult.

In any vineyards that developed significant levels of Powdery Mildew before harvest look closely at thespray coverage and practices during this high pressure period.


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Above - Powdery Mildew infection of abunch in December 2009. This infectionbegan during flowering in Novemberand developed under the favourableweather conditions in December. Signsof infection can be seen on the leavesand stem also (Left & Below).

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AdelaideHillsCropWatchVintageReportP2