Thursday, December 22, 2011

Phosphorous Deficiency in Grapevines

Phosphorous deficiency is an occasional problem for grapevines. Under natural conditions, almost all vines have a beneficial fungus, mycorrhizae, associated with their roots, which helps them to acquire P, but sometimes the soil itself prevents P uptake.

The distinct symptom of phosphorus deficiency is the appearance of discoloured, redden leaves.

Ben South has found this patch of vineyard over 'ironstone'. In acid soils P forms very insoluble compounds with iron, and it binds strongly to the surface of iron oxides.

Most soils used for viticulture in McLaren Vale have low native concentrations of phosphorus and therefore phosphorus fertiliser inputs are normally required. In this case the 'ironstone' has bound up all of the soluble phosphorous in the soil.

Phosphorus is taken up by vines from the soil water in its soluble phosphate form which would also be quickly bound up to the 'ironstone'.

Contact James Hook for more information.

Thursday, December 8, 2011

EL 32 Bunch Closure

Light Brown Apple Moth damage to grapevines before bunch closure.

Bunch closure (EL 32) in tight bunched varieties is a critical time in the lifecycle of botrytis. The greater the amount of ‘trash’ or damaged berries from light brown apple moth (above) at bunch closure the greater the risk of botrytis.

Botrytis first infects berries as latent or ‘unseen’ infection, during flowering when the flower cap falls. A second type of infection begins to develop as berries press together. Botrytis fungal threads (mycelia) begin to grow from fungus on dead and dying plant tissues (such as ‘trash’ flower debris or damaged berries). This growth from dead material infects berries after berry softening and progressively increases in wet or humid weather.

Alternatively varieties grown with an open bunch configuration develop less rot in wet conditions. They have better airflow and lower canopy humidity after rain. A good canopy structure is a key part in botrytis control. High quality Shiraz that is picked in early March has a low risk of developing a significant level of botrytis before it is picked - without chemical application!

Monday, November 28, 2011

Downy Mildew Oilspots at Berries Peasize - UPDATE 28/11/2011

The reverse side of a downy mildew oilspot showing sporulation.
Above - A series of pictures of downy mildew oilspots on leaves.

FAQ on downy mildew post infection products.

These are the answers to some common questions we receive. 

What is the hectare rate of Ridomil Gold Plus?

Ridomil Gold Plus

Preflowering - 150g/225g per 100lts
Post Flowering - 225g per 100lts
Therefore we work on 2.25kg/ha at this time of the year.

Axiom Plus is 150g per 100lts
Therefore 1.5kg/ha with a 1000 lt Dilute Spray Volume canopy size.

What is the price per kg and ha?

Ridomil Gold Plus

$ per ha = $120
$ per kg = $53

Axiom Plus

$ per ha = $74
$ per kg = $49

Zeemil MZ

$ per ha = $120
$ per kg = $47

What is the shelf life of the product?

When tested the shelf life of Metalxyl is indefinite and it lasts for many years. Samples have been tested that are 10 years old and still 99% effective. As long as the product is well stored it has an excellent shelf life. You can contact the manufacturer of your Metaxyl for more information.

The shelf life on the protectant component of Ridomil Gold Plus, copper, is considered to be good also if stored correctly. Note that all downy mildew post infection fungicides have additional protectant added to them when applying to vineyards.

The shelf life on Mancozeb (in Zeemil MZ) is 2 years. Therefore it is recommended for in season use not storage unless there are no other options.

Tuesday, November 22, 2011

GWRDC's Trial Tasting.

Thursday the 15th of December at Jacobs Creek.

You are invited to a wine tasting workshop hosted by the South Australian Research and Development Institute (SARDI) to taste wines from a hotter and drier future.

The wines to be tasted were made from grapes grown in a GWRDC project investigating the effect of elevated temperature on grapevine physiology and wine attributes.

Through GWRDC’s project, SARDI has established a trial with:

• four varieties grown under current conditions versus a 2-4oC increase in daytime temperature, and
• a Shiraz trail grown under current versus elevated temperatures in combination with frequent irrigation versus water deficit.

Unlike comparisons between wines from hot versus cool regions or between hotter and cooler vintages in the same region, these trials allow for a direct, unequivocal assessment of temperature effects.

The tasting of wines from the 2011 vintage will be held on Thursday 15 December from 1–4pm at the Jacob's Creek Visitor Centre, Barossa Valley Way, Rowland Flat.

Drop in any time between 1 and 4 pm to taste the wines and discuss the research behind the wines with Dr Victor Sadras and the team.

Please contact Martin Moran (martin.moran@sa.gov.au or 0448 928 513) to register your interest in the free workshop.

Monday, November 21, 2011

Latest Downy Mildew photos - UPDATE 21/11/2011

Our message –

“Take downy mildew seriously in the Adelaide Hills and those sites in on the Fleurieu that are like the Adelaide Hills. Use eradicants if uncovered as spread now will affect grape yield because flowers are highly susceptible to downy mildew.

For McLaren Vale prevent downy mildew building up to high levels like it did in some vineyards last season.”



 

What does this mean for my vineyard?


You 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, November 3, 2011

Downy Mildew Oilspots at 80% Capfall - UPDATE 3/11/2011

A Downy Mildew Oilspot

Sodium Toxicity - What to look for

Sodium Chloride on older leaves.
Salt (sodium) toxicity blackens and scorches leaf margins. Look for older leaves with darkened edges which later scorch tan and curl upwards (sodium) and scorching extending inward to form patches between main veins (chloride).

Salt affected vines will show poor growth of vines and will have early leaf drop beginning with the older leaves first.

Wednesday, November 2, 2011

Powdery Mildew Flagshoot - UPDATE 2/11/2011

Powdery Mildew Flagshoot.

Dormant buds can be infected with Powdery Mildew and survive over winter. When these buds shoot they are deformed and covered with the Powdery Mildew spores. Note the stunted growth and ash-grey growth with distorted or upward curled leaves.

Tuesday, November 1, 2011

Wind Damage Vine Shoot Tips - UPDATE 1/11/2011



These are a pictures of wind damaged shoot tips taken in the Sellicks Foothills sub-district of McLaren Vale. The vineyard has just begun flowering (EL-19 Early Flowering) and is still rapidly growing. The main growing tip has been rubbed away by high winds and lateral shoots are beginning to push to compensate for this.

Fast growing vines and certain cultivars are more prone to wind damage. Damage to shoots is most common in spring and early summer when new shoots are fast growing and weak (green). Later in the season, after shoots have lignified (turned brown), leaf damage is more common. This late season wind damage is very common in the Sellicks Foothills sub-district of McLaren Vale.

Heavy leaf wind damage, late in the season, can cause a reduction in photosynthesis that may impact fruit quality.

Tuesday, October 25, 2011

Downy Mildew Oilspots - UPDATE 25/10/2011


Above- A downy mildew primary oilspot.


Above - A secondary fresh downy mildew oilspot on a Grenache leaf.

Wednesday, October 12, 2011

Powdery Mildew - Identification photos.



Sam Freeman shows the underside (below) and top side (right) of powdery mildew found in Cabernet Sauvignon. Powdery mildew increases during spring from a small amount and spreads.

Fresh powdery has the appearance of a whitish film on the backs of leaves. New leaf growth is distorted and older leaves become blackened.

Powdery mildew spores are carried by air and, once active, will continue to spread in dry conditions.

Monday, October 10, 2011

Eutypa Dieback - Spring Identification Pictures.

Eutypa and other trunk diseases have been identified as causing significant problems in South Australian vineyards. This season appears to be a 'big' year for Eutypa symptoms.

Eutypa is present in many vineyards- of all ages. The fungus grows slowly in the wood and produces foliar symptoms several years after the initial infection. Pictured below is a 10 year old vineyard in the Sellicks Foothills demonstrating that Eutypa can be found in 'young' vines.

Eutypa dieback foliar symptoms are are most obvious in spring when shoots are 30-70 cm long.


Eutypa infection reduces bunch numbers and reduces vine yield.

Thursday, October 6, 2011

Shoot thinning in Shiraz

Before thinning.
Note the before (above) and after (below) photos of shoot thinning in Shiraz.

Post thinning.
Being more attentive about vine balance and aggressive shoot thinning, in pinot and shiraz, aims to reduce crop loads and shoot numbers. It is an interesting technique for increase light exposure inside vine canopies.

The following shoots are thinned:

- absolutely all water shoots.

- any other infertile shoots without visible inflorescences, which emerge from the pruned spur. However, at least one near-stem new shoot must remain at each shoot position for the following winter pruning.

- if there are two or several shoots growing from one bud, the strongest one (with inflorescences) is retained, all others are removed. Many varieties have a tendency to produce several shoots from each shoot position.

Shoot thinning is carried out when the new shoots have reached a length of approx. 10 to 30cm, ie at a time in spring when the whole vine is still easily manageable.

Tuesday, October 4, 2011

Leaf Botrytis - UPDATE 4/10/2011

Leaf botrytis.
In long periods of wet weather, botrytis can infect the dead and dying parts of young stems, and leaves damaged by wind and hail. The resulting leaf symptoms can have a brown colour.

The appearance of leaf and stem botrytis doesn't mean that we will get botrytis at harvest, but it does show that recent weather is conductive to it.

Thursday, September 29, 2011

Weather damage in McLaren Vale & Langhorne Creek - UPDATE 29/9/2011

This week has seen extremes in weather damage.

In South East frost damage in Shiraz and particularly chardonnay has been recorded. We are hearing it's very patchy but some vineyards have been affected badly.

The frost on Sunday morning also has burnt some vineyards in Langhorne Creek and, to a lesser extent, McLaren Vale (below).





On Wednesday night a large hail storm moved through McLaren Vale. Most of the damage is north of the township. This has broken vine shoots as shown below. Significant damage is mostly in the Seaview area, with damage reducing as the storm went into the Blewitt Springs area. Vineyards on the Range of McLaren Vale and in the southern Adelaide Hills have also been damaged.

No real fruit loss, but likely to be some quality affects from high lateral growth and shoot uniformity.

Monday, September 26, 2011

Earwig Damage - UPDATE 26/9/2011

This week some earwig damage has been seen. Check around posts and other 'hiding' places for earwigs.

Interestingly, in previous years observations, the variety Merlot seems to attract the most serious damage. We are not sure why this is the case but you will often see much more leaves eaten and significant damage in Merlot than other varieties.

Most of the time earwigs do not need to be actively controlled since healthy plants will outgrow small amounts of earwig damage. While the damage can look serious, unless the inflorescences (future bunches)are eaten away, the earwigs are not affecting your crop.

Later in the season earwigs are a predator for Light Brown Apple Moth caterpillars (LBAM).

Wednesday, September 21, 2011

Vine Scale: Severe Infestation - UPDATE 21/9/2011

Vine Scale on Cabernet Sauvignon.
Mature scale attach themselves to the vine and excrete honeydew that may lead to sooty mould. Vine scales produce a number of eggs over several days. The eggs are laid under the cover of the adult "scales" which offer protection.

In this case shown vine scale are aggressively sucking sap from this Cabernet Sauvignon vineyard. If left without treatment vine scale will likely kill this grapevine.

The high level of vine scale pictured has a severe affect on vine growth.

Monday, September 19, 2011

Glyphosate Resistant Ryegrass - What to look for.

Warning signs:

✗ Continual reliance on glyphosate for weed control under trees and vines.
✗ Use of few alternative herbicide modes of action used including residual herbicides.
✗ Lack of non herbicide weed control methods eg mowing, mulching, tillage or grazing.
✗ Allowing weed control escapes to set seed.
✗ Entering spring with high weed numbers.
✗ Poor vineyard hygiene (contaminated machinery, vehicles and stock coming onto farm)leading to movement of herbicide resistant weed seed.
✗ Lack of competition from inter-row cover-crops.
✗ Poor application technique leading to sub-lethal rates of herbicide at the ends of rows(poor control = more weeds)

If you suspect you have a resistance problem – get plants or seed tested to see which herbicides still work. The best strategy is to ensure that no further seed set is allowed to occur, and drive down the weed seed bank using a number of diverse weed management tactics.

For more information visit the website: www.glyphosateresistance.org.au

Monday, September 5, 2011

Bordeaux vintage begins

Bordeaux wine grower for Chateau Bauduc, Gavin Quinney reports on their vintage with these photographs.


Hail damaged vines at Cos d'Estournel. 45% of 64 hectares around Chai were hit 1/9.


Lafite harvest started 3/9 at their parcel in St-Estephe, near Lafon Rochet. This is about 14 days early. Unfortunately the region has received a significant hail storm and the race it on to pick the fruit in good condition.

Snail Bait Application


Late winter and early spring snail levels are high. How do you bait for them? Derek Cameron spied this home made solution to applying snail bait. The grower used PVC pipe to create a hopper and shute. This was had fed with mesurol bait and run out down the rows.

Friday, August 26, 2011

Junk Bugs - Lacewing Larvae - ID Photos

Junk Bug a larval insect known for carrying a heap of debris around as camouflage.
This week we photographed these Junk Bugs. Junk Bugs are predatory insects found in your vineyard. These predators 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).

A Junk bug (lacewing larvae) on the surface of a leaf.
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, August 25, 2011

Two Chardonnay vineyards - 14 days difference.

The most advanced Chardonnay vineyards (Left) are around the 1-2 leaf stage (EL 7-8), whilst late pruned vineyards (Right) are only at Bud-swell to Green-tip (EL 5).

It is worthwhile planning an early spray round for Powdery Mildew in vineyards that had the disease last season. This is likely to be due in 14 days for early Chardonnay vineyards.

Monday, August 1, 2011

New agrochemical container from Nufarm


Nufarm have begun to product agrochemcials in their QuikPour container.
Designed in Australia, QuikPour’s is an easy to handle 15 litre container with a large mouth and collapsible internal bladder which means it flows out at quick rate.

QuikPour’s is considered to be a good option by Nufarm because:
• No glug, no splash – safer for users.
• Lighter pack weight – 25% reduction in weight to carry compared with the current 20 litre container for OH&S benefits.
• Easy to open – designed to be opened with gloves on, no need to use a tool
• Environmental benefits –more than 80% reduction in plastic used per litre compared with rigid plastic containers.

Abandoned vineyards - time for peer pressure

As part of CropWatch McLaren Vale and commercial monitoring I study the spread of powdery mildew (and in certain years when we have outbreaks downy mildew) from abandoned vineyards. I use these vineyards to get photos of disease and make observation of spread etc.

My considered opinion is disease does spread from abandoned vineyards to neighboring properties and that this increases the cost of disease control in adjoining vineyards.

For the big three fungal disease, powdery mildew, downy mildew and botrytis, the pressure was very high last season (Vintage 2011). High pressure last season has both positive and negative consequences for this season. If you had good control last season, then you know that your spray programme was robust, and you have a low level of disease carrying over to this season.
Powdery mildew leaves - Dec 2010.
Powdery mildew on chardonnay bunches - Dec 2012

Unfortunately if you had a significant amount of disease last season you are likely to begin this season with a higher pressure than in a clean vineyard.

Powdery mildew is influenced by the amount of inoculum inherited from last season. Downy mildew survives in the soil for a great length of time, so it will be present for many years after widespread infections in the 2010/11 season.

The first ten weeks of the season will be critical to keeping your fruit clean from both powdery & downy mildew. Powdery mildew early season control is critical to win the battle control next season’s disease this season. Downy mildew protection will also be important if we have a wet grapevine growing season.

Unfortunately there is one factor that you have no control over. How clean are neighboring vineyards? Contrary to what is often reported we can identify many situations where unprotected vineyards are having a significant build up of disease, which in turn is spreading into surrounding tended vineyards.

Downy mildew on abandoned Grenache, Whites Valley 5172 - Dec 2010.
Your proximity unsprayed vineyards will also lead to a higher risk of powdery mildew and, if weather conditions lead to 10:10:24 events, downy mildew.

Abandoned vineyards are one of the main issue the industry faces, other than an over supply of fruit, the increased disease pressure from abandoned, or poorly tended vineyards.

Abandoned vineyards are a potential host of pests and diseases and can be a significant concern for neighboring properties. Unfortunately it would seem that there is not relevant legislation that makes a basic level of care a legal requirement in South Australia. In our opinion farm owners have a moral obligation to manage the risk of an abandoned vineyard.

During Vintage 2011 several abandoned vineyards in the McLaren Vale region greatly increased the levels of powdery mildew and downy mildew in adjoining vineyards.

Approximate spread of powdery mildew by January 2011*. The 150 meter radius of disease affects five separate vineyards and significantly increases the disease pressure in these vineyards.
*This vineyard was featured in our earlier post - Vineyard Photos - What is looks like inside an abandoned vineyard.

It is now time to put pressure on farm owners who did not tend their vineyards last season. They need to be tended or pulled out for the sake of their neighbors and the sake of the wider grape industry.