Adelaide Hills Crop Watch 271109

8/14/2019 Adelaide Hills Crop Watch 271109

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CropWatch SA Adelaide Hills is a 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 and should not be relied upon. Always seek professional advice specific to your vineyard. All photos (c) JamesHook & Richard McGeachy unless noted. CropWatch acknowledges the support of James Hook & Matthew Wilson in preparing this message.

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All seven CropWatch vineyards still have active shoottip growth, however shoot growth has slowed down inthe last week as vines put more energy into developingtheir fruit.

Stuck flower caps have been seen in Shiraz and Merlotblocks (left). This might be due to thrips, water stress orthe timing of Capfall relative to the weather conditionswe experienced. Stuck caps can cause scaring damageto skins in red varieties (especially Shiraz, CabernetSauvignon and Merlot).

In general, berry set in Sauvignon Blanc, Shiraz andCabernet Sauvignon looks good, however low levels ofberry shatter have been seen in Pinot Noir, Pinot Gris,Merlot and Chardonnay blocks.

Light Brown Apple Moth

Check your developing bunches for signs of caterpillardamage. Look for any flower parts that are stucktogether. Apple moth damage is usually found inhotspots. If you find one damaged bunch like thischeck other bunches and in nearby leaves for moreapple moth activity.

Powdery Mildew

Do not sit back and think that hot weather in the last twoweeks means you are totally safe. Assess yourvineyards risk. Vineyards with a large canopy and ahistory of poor disease control are likely to have somedisease - in spite of hot weather.

Do not get caught out warm, overcast weather andlarger canopies due to winter rain have suited thedisease.

Monitor your vineyard before the Christmas break.Check 50-100 bunches and leaves for any signs like thephotos shown on the CropWatch Blog.

Active shoot tip growth and early berry set.

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Withholding Periods

Most vineyards are now past 80% Capfall. Many common vineyard products are now past theirwithholding periods.

Please always read the AWRI Dogbook for grapevine withholdings. Do not rely on product drums andlabels, as what is listed on the label is the domestic withholding period! For example SCALA 400SCtmhasa 7 day withholding for domestic grapes but an AWRI exporting withholding of 80% Capfall!

GRAPEVINE PRODUCTS THAT CANNOT BE USED AFTER FULLFLOWERING (80% CAPFALL).

Name AWRI Withholding Period Disease

Acrobat 80% Capfall Downy Mildew- postinfection

Polyram 80% Capfall Downy Mildew-protectant

Prosper 80% Capfall Powdery Mildew

Chlorothalonil (Bravo,Barrack, Unite etc)

80% Capfall Botrytis & Downy Mildew-protectant

Filan 10% Capfall Botrytis

Scala/Pyrus 80% Capfall*

*Some wineries have a 10%Capfall restriction.

Teldor 80% Capfall

Mimic, Prodigy 80% Capfall LBAM


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Downy Mildew

The weather in the last week was not suitable for awidespread Downy Mildew 10:10:24. All of the weather

data we collected showed vineyards drying out Saturdayand Sunday afternoons which broke the 24 hour diseasecycle.

However, in a shock find, we have found Downy MildewOilspots in Echunga (right). These were found only in asmall area of one vineyard and do not represent a majorconcern to the rest of the region.

How did this happen? Weather conditions in Octoberwere close to a Downy 10:10:24 primary infection but ourweather stations did not record these conditions. Also

most vineyards had shoots that were only 5-10cm andvine canopies were too small to host the disease.

At our Downy find at Echunga 10-10-24 conditions musthave occurred creating a primary infection event.Microclimate conditions such as longer heavier falls ofrain, heavy dews, or external issues such as irrigationleaks can all be contributing factors. Whatever thereason, it was enough to push the Downy Mildew acrossthe line.

What does this mean? This patch of Downy does not

pose a significant risk of causing an outbreak of thedisease. However it is likely there are more isolatedpatches in the region so be aware.

A low risk strategy is to continue to protect your vineyardagainst Downy Mildew and use a protectant fungicidewith your regular Powdery Mildew sprays.

If fine, dry weather prevails any Downy oilspots will dryout and eventually become inactive.

How do we know there is only a small amount ofDowny in the Adelaide Hills? Each week seven

different vineyards are monitored as part of theCropWatch services. The weather data is also checkedfor weather conditions and additionally many morevineyards are checked commercially. CropWatch alsocommunicates with winery and vineyard staff each weekto see what they have found.

Look for large yellow spots, sometimes with a darkerchocolate ring around the outside. Downy spores areeasy to see compared to Powdery Mildew and can evenbe seen from a tractor or a motorbike. It is worthwhilegiving all vineyard staff training in monitoring for and

recognising Downy.

If you have suspected Downy Mildew please use theBag Test to confirm and let us know where you found it.

Above Downy Mildew oilspots.

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Adelaide Hills Crop Watch 271109