Tuesday, December 29, 2009

Powdery Mildew Late Season - UPDATE 29/12/2009

Look out for these signs deep in the canopy. Powdery Mildew in bunches (above).

Some Powdery Mildew is beginning to show in vineyards not sprayed effectively earlier this season.

Powdery Mildew is called a dry weather disease because it does not need rain to spread. In fact, large rainfalls can wash the disease from leaves and berries. Organic growers use this principle by using mild anti-fungal agents applied with high water rates.

Powdery does however like warm (21-28OC), humid (RH<70 br="br" comes="comes" conditions="conditions" from="from" like="like" north.="north." that="that" the="the" those="those" tropical="tropical" weather="weather">
Monitor now for the disease. Pay close attention to areas like low-hanging shoots or freshly growing laterals. Take time to check inside your canopy to assess your program.

Any sprays now may help reduce the amount of disease on outer leaves but at this late stage, they will not help in reducing levels of powdery on the bunches.

Avoid spraying sulphur at high temperatures (>350C) when the humidity is >70% within 24 hours of spraying.

Before spraying crops designated for sparkling wine, check your winery’s withholding periods. White varieties for table wine are likely to begin harvest in mid February.

Early Verasion

Early colour change in McLaren Vale Shiraz has been seen. Vineyards that normally begin to change colour (begin veraison) around the 2nd - 5th of January have started colour change on the 25th of December.

Chardonnay and Verdelho are also softening and beginning to produce sugar.

Based on this he season is likely to be an early harvest this vintage.

Following fruit set, the grape berries are green and hard to the touch. They have very little sugar and are high in organic acids. They begin to grow to about half their final size when they enter the stage of veraison. This stage signals the beginning of the ripening process and normally takes places around 40-50 days after fruit set.

During this stage the colours of the grape take from - red/black or yellow/green depending on the grape varieties. This color changing is due to the chlorophyll in the berry skin being replaced by anthocyanins (red wine grapes) and carotenoids (white wine grapes). In a process known as engustment, the berries start to soften as they build up sugars.

Within six days of the start of veraison, grape berries begin to grow dramatically as they accumulate glucose and fructose and acids begin to fall.

Thursday, December 24, 2009

Blister Mite

Blister mite (above) is one of the most obvious pest problems seen in the vineyard. Luckily it causes no real economic damage. Leaves covered with blister mite still produce energy to ripen your fruit.

Wednesday, December 23, 2009

Downy Mildew Oilspots - Secondary Spread in the Adelaide Hills



There is some Downy Mildew in the Adams Rd, Schuller Rd area of Blewitt Springs in the McLaren Vale GI. Some higher levels have been found in the Adelaide Hills, including vineyards on Range Rd and in Kuitpo.

Where growers have taken action Downy Mildew levels have largely remained steady with little secondary spread. Generally the warnings have been heard and acted upon in an adequate period.

The main disease issues have been seen in vineyards that have not been adequately protected, or have been mothballed. Abandoned Vineyards are looking like becoming a real headache for neighbours over the coming month!

Unfortunately in vineyards that are on minimum spray programmes or have not been protected against Downy Mildew, disease levels are increasing.

Wednesday, December 16, 2009

Berries Peasize EL31.

Berries Peasize EL 31 is a critical time to asses the level of light brown apple moth (LBAM) in your vineyard.

LBAM insecticides Avatar®, Entrust®, Proclaim® & Success® all have a with-holding period of peasize (EL 31). In most vineyards berries have grown past Peasize 7mm (EL 31). For Chardonnay, Shiraz, Merlot and Sangiovese in the warmer parts of McLaren Vale, only the biological insecticide BT’s can be used now.

Vineyards in the Adelaide Hills are 2 weeks away from the Berries Peasize cut off.

Predatory Shield Bug.
Above: A good guy- predatory shield bugs feed on caterpillars. Click here for more beneficial insect pictures. Beneficial insects can be your most effective tool in controlling LBAM in the lead up to harvest. A ‘hungry’ predator population will eat apple moth and keep them from eating berries.

Tuesday, December 15, 2009

Powdery Mildew - last chance for good control.



Powdery mildew has been spreading this week. Flag-shoots have been found. Cleistothecia infections have developed further with heavy, shaded, humid canopies aiding the development and spread of the disease.

Weeds have also enjoyed the weather recently, with levels increasing rapidly Wireweed and Fathen have been the main types seen.

Downy Mildew Secondary Spread - ID Photos

Downy mildew secondary spread on bunches and leaves.


DJ's Agronomist Matthew Wilson has observed that Downy Mildew has spread in the Adelaide Hills.

He says, "The Secondary Downy Mildew Event recorded on the morning of the 8th of December 2009, has caused spread of primary Oilspots within unprotected, infected blocks.

Interestingly, the majority of this secondary spread is located below the cordon or on fresh growth either up high on VSP systems or out on tips with sprawled canopies. This new growth is difficult to protect, but growers should be reminded to adjust spray coverage as the canopies develop. This season’s growth rates (relative to previous seasons), require some level of adjustment."

Matthew will be keeping a close eye on the weather in the Adelaide Hills as part of the CropWatch Programme.

Tuesday, December 8, 2009

Downy Mildew Secondary Event in the Adelaide Hills.




Above: Downy Mildew Oilspots as found in Woodside, yesterday the 7th of December.

CropWatch Adelaide Hills reports a Downy Mildew Secondary Event (warm, wet night) on the 8th of December. Balhannah received 8mm of rain last night in the four hours before dawn. This will cause Downy Mildew to spore and spread in unprotected vineyards.

What does this mean for Adelaide Hills vineyards?

Your fruit is immune to Downy infection once berries are appx. 2-5mm in size but leaves (and berry stems) remain at risk until harvest.

There is a low risk of Adelaide Hills grape growers losing bunches to Downy Mildew. CropWatch is more concerned about of further warm wet nights through December and January causing a build up of Downy Mildew Oilspots on vine leaves causing defoliation.

Thursday, December 3, 2009

Berry splitting from rain and sunburn - UPDATE 3/12/2009

Above - Developing berries that have been split by heavy rain last week.

Above - Sunburn / sulphur burnt fruit.

Light Brown Apple Moth - UPDATE 3/12/2009


This season has seen high levels of Light Brown Apple Moth caterpillars. Look for any flower parts that are stuck together - above.

How many Apple moth grubs are a problem? Apple Moth caterpillars, cause damage to bunches which makes 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.

Glyphosate Herbicide Drift - Identification Photos

Glyphosate Herbicide drift on a grapevine shoot tip.
Physical drift is a risk with Glyphosate based herbicides as this photo shows - above. This vineyard was sprayed 6 weeks ago and unfortunately a small amount of drift has affected some shoots. Glyphosate can drift in windy conditions and, because it is systemic, can translocate within grapevines.

Tuesday, December 1, 2009

Powdery Mildew - UPDATE 1/12/2009


Above - Powdery Mildew has been seen on bunches for the first time this week. Defuse Powdery mildew is almost impossible to see it looks like a faint web pattern on berry skin. It is caused by an infection just before the berries become naturally immune approximately 4 weeks after the end of flowering.

We have also been finding leaf spots of fine white growth like the one shown below.

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.

Wednesday, October 28, 2009

Powdery mildew has been found - UPDATE 28/10/2009

The first signs of Powdery Mildew for Vintage 2010.
The first signs of Powdery mildew have been seen in the last 10 days.So far these have been minor, however small Powdery mildew infections before flowering can turning into large problems at harvest.

Powdery mildew doesn’t need rain to spread - mild temperatures (20 – 29oC) & cloudy conditions favour the disease. In these conditions powdery rapidly produces spores and spreads on to unprotected leaves and bunches.

Be careful this season as weather conditions this spring have been favourable to the disease. Based on what we have seen in vineyards we feel Powdery mildew pressure is higher than last season.

Powdery has been found in two commercially monitored blocks, one block has a history of the disease, the other has been very clean up until now. The good news in most vineyards no Powdery has been found. On blocks with a bad history of disease, where growers have been running good protective spray plans for a few season vineyards the vineyards seem clean.

Powdery mildew prevention has effects over many seasons. Good control last season makes control easier this season. Good control this season makes future control easier by reducing the amount of disease that survives winter in the vineyard.

No Downy mildew - UPDATE 28/10/2009

Downy mildew needs rain to start its lifecycle.

No rain = no downy.

Weather conditions for the next week are not predicted to be favourable to Downy Mildew.

Monday, October 26, 2009

Junk Bugs - Predators in your vineyard.


Richard McGeachy has photographed these Junk Bugs. Junk Bugs are predatory insects found in your vineyard. They are the larval stage of Lacewings.

Lacewings go through complete metamorphosis (egg, larva, pupa, adult) and have at least two generations per year. The life cycle takes about 4 weeks depending on temperature. A female Lacewing can deposit over 200 eggs. In 4 to 5 days, the eggs will hatch into small junk bug larvae.

Lacewing larvae are brownish and can have dark reddish-brown stripes and spots (as shown).

They have large jaws for grasping prey and injecting a paralyzing venom. Lacewing larvae, sometimes called aphid lions, typically feed on soft-bodied insects such as aphids, mealy bugs, thrips, and Light Brown Apple Moth. The larvae develop three instars in to 3 weeks, and are 9.5 mm long when full grown. Larvae will spin a silken pale cocoon that is loosely attached to foliage. During the pupal stage they develop wings and reproductive organs.

After 5 to 7 days the adult will emerge from the cocoon and begin to mate. Adult lacewings have chewing mouthparts, are about 18-19 mm long, and feed mostly on nectar and pollen. They can survive for about 5 to 6 weeks.

Thursday, October 22, 2009

Vine Stress & Poor Nutrition.

Over the last three weeks many vineyards have not been growing through the wet weather. Also they have shown symptoms of nutrient deficiency including iron as shown by pale leaves (above).

The reason for this slow growth and poor nutrition is a lack of root growth.

Talking with Stoller USA agronomist - Guillermo de la Borda he offer the following advice.

As a rough rule of thumb if your vines shoots are not growing neither are your vine roots. Vine roots pick up the nutrients for growth at this time of the year.

Several stress events which limited vine growth have occurred in including;

- Hail damage
- Wind damage
- Salinity
- Cold soils.

All of these stresses upset the vines hormone production and normal growth. Waterlogging and cold soils slow down root growth. Physical damage including hail, wind and frost cause the plant hormone Ethylene to be produced. Ethylene interferes with the plants growth hormones Auxin, Cytokinin and Gibberellic Acid. With an imbalance of these growth hormones root growth is stunted, this in turn stunts shoot growth.

Many growers apply fertiliser to improve shoot growth, but without active root growth the vines will not pick up the fertiliser and growth will not improve.

The good news is, as vines experience good weather, they should grow out of this ‘stress damage’ and grow new roots on their own accord.

See Stoller's frost recovery programme here.

Friday, October 16, 2009

Leaf Botrytis - UPDATE 16/10/2009

Botrytis seen on leaves, shoots and inflorescences this week. Pictured bottom is severe hail damage in Blewitt Springs.




No Downy mildew 10:10:24 a near miss - UPDATE 16/10/2009

CropWatch McLaren Vale and CropWatch Adelaide Hills report the weather was not suitable for Downy mildew this week.

In McLaren Vale windy conditions assisted in drying vineyards out creating conditions that stopped the 24 hours of leaf wetness that Downy mildew needs to start its lifecycle. While Downy mildew can survive short gaps of leaf wetness, the computer disease models shows the canopy dried out enough to halt the Downy.

Analysis of the weather data shows that the Adelaide Hills has had a near miss for a 10:10:24 Downy Primary Event.

Fortunately overnight temperatures were less than 10oC on the wet nights of the 12th/13th, 13th/14th and 14th/15th. High wind speeds also aided drying out canopies and breaking the 24 hours of leaf wetness Downy mildew needs.

Wednesday, October 14, 2009

Grapevine Nutritional Deficiencies

Due to a cold and wet start many vineyards have been slow to grow. Vineyards on black cracking clays (Biscay Soils) have a naturally high fertility. In most seasons vines are healthy and yields are good. Sometimes, due to the alkaline limestone rock underneath, grapevines can have some nutritional problems but these are generally fixed once the weather warms up.

Look out for these symptoms particularly if your vineyard is on heavy black clay.
Currently in the vineyard nutritional disorders are easily seen on this soil type including Magnesium as shown (upper and lower left).



Above and Below: Iron Deficiency shows up as pale leaves.

Thursday, October 8, 2009

CropWatch Adelaide Hills

Adelaide Hills Crop Watch 091009

Rust Mite - UPDATE 8/10/2009

Rust mite are slowing down some vineyards and restricting early shoot growth. This damage seems to be the most severe in blocks that were pruned late this season.

This is seen as shoots with slow and perhaps stunted shoot growth with distorted leaves. It is too late for spraying to be effective this season. The stunting effects of Rust Mite are limited by the application of Sulfur at bud-burst.

With warm weather and good growing conditions, these any distorted shoots will begin to grow normally and the damage becomes difficult to detect by flowering.

Blister Mite- UPDATE 8/10/2009


Some blister mite have been seen in monitored vineyards this week.

Friday, October 2, 2009

Light Brown Apple Moth - UPDATE 2/10/2009

The first signs of the second Light Brown Apple Moth generation have been seen this week. Lookout for their eggs. Egg Masses are not easy to see because they appear clear. These take a few weeks to hatch.

At first the grubs (caterpillars) are found only in leaves but will begin to move into bunches when flowering begins.

Pay close attention to you vineyard if you have had LBAM problems in the past. Where present, the grubs feed for a week or two before moving during flowering to feed on bunches. If you detect larvae on more than 10% of shoots, it may be necessary to apply an insecticide such as BT’s, Mimic®, Prodigy®,Avatar®, Proclaim®, Entrust® or Success2® during the flowering period.

Wednesday, September 30, 2009

Powdery Mildew – The creeping disease - Q&A

Question for James.

How do you assess whether disease pressure is high or low? Why do they call powdery mildew the creeping disease?

Open canopied Shiraz. Note the high level of uV light that can get into the vine canopy.

How do we assess disease pressure?

History – Powdery survives from year to year in your vineyard. Good control last season helps reduce risk for this season coming.

Susceptibility - Verdelho and Chardonnay are the most susceptible varieties to Powdery – while Shiraz is only moderately susceptible. The variety Merlot seems to have low natural susceptibility.

Vigour - High vigour blocks are more at risk than low vigour vineyards. In high vigour vineyards it is difficult to get good protective spray coverage and tend to have dense canopies. When the canopy is extremely dense protection is difficult. Dense canopies cause shade which favours Powdery.

During overcast weather conditions, with high humidity (both favouring Powdery Mildews lifecycle) we say pressure is high.

The best time to control this disease is in the early season by limit the spread of any Powdery mildew flagshoots and stopping any bunch infection during flowering. That is why we call powdery mildew the creeping disease because it creeps around as the canopy closes over.

A rough rule of thumb is start control when shoots are 20- 30cm long, or 2-3 weeks past budburst.

McLaren Vale growers have been having good success by treating each vineyard patch based on its disease risk. They have been using high pressure programmes for blocks with a history of Powdery and low pressure programmes on block where control has been good.

Monday, September 28, 2009

Hail Damage has increased - UPDATE 28/9/2009


A series of hailstorms on Friday night into Saturday morning has severely damaged some vineyards. Check your vineyard for damage. In the worst affected blocks shoots have been snapped in half and some inflorescence damage (as shown below).



There is a lack of definitive information on grapevine recovery responses to hail. It has been several years since McLaren Vale and the Adelaide Hills received damage of this level and growers experiences are limited.

However, you have to best consider how to best manage the vines to maintain yield, both in this season and next season and ensure good canopy structure. Consider the use of foliar fertilisers in your next spray round. Doses of kelp products are also considered beneficial after stress events including hail and frost.

Thursday, September 24, 2009

Low risk of Downy Mildew 10:10:24 - UPDATE 24/9/2009

The region has received heavy rain fall this week – which have been close to producing a 10:10:24 Downy Mildew event. Fortunately night-time minimum temperatures have been below 10oC which slows the disease from starting its life cycle.

We feel there is only a low chance of Downy Mildew because vines do not have a sufficient canopy to host the disease.

A no risk strategy would be to protect your vineyard with your next scheduled spray round using a registered Downy Mildew protectant fungicide. Applied before further rain this protected against the spread of Downy Mildew, which could occur if we have future;

1- (10:10:24) Primary Events or,
2- Secondary events (warm, wet nights - 98% Relative Humidity with some rain before dawn).

Downy Mildew needs unprotected foliage to infect vines. We are entering the high-risk period when shoots are 10-30 cm long in the lead up to flowering. Leaves of any size are susceptible to infection but the larger the amount of unprotected foliage, the higher the risk.

Hail Damage - UPDATE 24/9/2009


Some hail damage has been seen in McLaren Flat. Fortunately most of the district was spared from damage.

Leaf botrytis can develop in vines that have been damaged by earlier hail and wind – as shown above. This can be common in seasons where we have windy and wet weather in spring. Further rain increases leaf botrytis infections, while dry conditions help heal it up. Leaf botrytis is very easy to monitor for because it is easy to see. Many growers worry because of its obvious nature. The good news is unless the leaf botrytis spreads onto the vine stem or inflorescence no crop is lost. Monitor closely for spread.