Wednesday, December 31, 2008

Basal Leaf Yellowing

The yellowing of the oldest leaves of the shoot which are closest to the cordon is a natural process. Leaves only have a certain lifespan and the oldest leaves are now reaching this point.

Leaf yellowing may be increased by excess shading in the canopy or dry soil causing water stress.

Tuesday, December 30, 2008

Summer Weed Control

Basta vs Sprayseed vs Revolver.

Recent rain and high humidity have seen an increase in Fat Hen and Wireweed. Many vineyard will opt to control these before they set seed and add to the weed seed bank for future seasons.

All of the summer herbicides are classed as contact herbicides which means they only effect what they touch. They struggle if you do not get good coverage of your target weed, this can also apply to dusty weeds, or weeds that are water stressed where we see herbicides sometimes having poor results.

Basta has the advantage of being a Schedule 6 controlled poison, while Sprayseed/Revolver are Schedule 7 - Dangerous poisons. This has effects on your safety and who is able to buy and use the herbicide.

With Basta to get best results it needs to be applied below 33oC and with a relative humidity over 50%. During summer this limits the time of spraying generally to the mornings and evening although in some cases Basta may not be able to be used for many days at a time.

Basta is also sensitive to hard water (water high in dissolved calcium). If you are using mains or bore water, or water from a concrete tank add 1-2% of the water conditioning agent Ammend/Liase.

Revolver is a 'generic' version of sprayseed which has a price advantage in the current market.

Price per hectare at maximum lable rate:

Sprayseed = $13.75
Revolver = $13.15
Basta = $30.00

Saturday, December 27, 2008

Early cane hardening - Lignification

Over the last 10 days many vineyards have shown signs of shoot lignification (also called browning or hardening off).

A rough rule of thumb is for balanced Shiraz and Cabernet you should see 50% shoot lignification at veraison. This season most vines are showing lignification before veraison as a result of a dry spring and some water stress due to low soil moisture.

Wednesday, December 24, 2008

Leaf Roll Virus - More Identification Photos.

Leaf roll is not the only thing that can cause red leaves, but if you are seeing single vines or patches of vines with red leaves amongst other normal vines, it is the likely cause.

The Moon and Powdery - UPDATE 24/12/2008

The levels of Powdery Mildew have greatly increased in the last two weeks. In most vineyards this is not going to affect harvest as good protection earlier in the season have kept bunches clean.

While the scientist may explain the spread of Powdery by noting recent high humidity and overcast weather which suits the disease, there is another factor that could explain it.

December the 13th was a unique day in the astro calender that Bio-Dynamic farmers follow. It is called a "supermoon" because proxigee (the Moon's closest point to the Earth this year) and full moon occur at the same time.

This combination of a close and full moon causes king tides and other events on Earth. In Papua New Guinea the supermoon produced very high tides that caused dangerous flooding. Closer to home the supermoon's affect is also linked to increasing sap flow in plants. It is also a time for high disease, just as we have seen in the vineyards this week.

Could the gravity effect of a supermoon really cause disease to increase? The next supermoon is January 2010, so lets wait and see if that causes the spread of Powdery!

Wednesday, December 17, 2008

Blister Mite - Identification Photos

Blister Mite - front side of leaf.
Blister mite 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 enough to ripen your fruit.

Blister Mite - back side of leaf.

Rhone Valley Viticulture

By Richard McGeachy

Of the places I visited in Europe the Northern Rhone Valley had the most similarities with McLaren Vale – well the varieties anyway! The only red variety grown is Shiraz (50% of MV) and the white varieties were Viognier, Marsanne and Roussanne (all grown in relatively small amounts in MV).

Most of the vineyards are on the slopes above the Rhone river with the various appellations spread along the either side. The vine/row spacing 1 metre x 1 metre, like Burgundy. As is the case throughout France – the vines are dry grown as irrigation is illegal.

The majority of the terrain in the Rhone is bordering on insane to grow grapes on by Australia standards. The slopes in Côte-Rôtie particularly are extremely steep and most cannot be worked a conventional tractor.

A lot of the work is carried out by hand or with equipment being towed up the slope on a cable and guided by the grower – particularly soil work.

The simple act of applying sulphur is carried out using backpack sprayers or by small tracked vehicles being walked by the grower.
Above - A caterpillar tracked fungicide unit.

Small tracked vehicles were also used extensively, due to the grip, low centre of gravity and compact size.

Terracing is used extensively to overcome the slopes, this photo (below) is looking northward towards Côte-Rôtie from Condrieu.

This photo is above Tain-l’Hermitage below the Chapel on a west facing slope. Also note the iron deficiency showing in the tips. It was common in this soils – I doubt it was corrected when they were applying fungicides and fertigation is obviously not an option.

An organic vineyard I visited used a small excavator to perform the weeding. The grower would drive along each terrace and reach between the vines with a hooked blade on the head.

The maintenance of the terrace walls can growers 2-3 months over the winter months. Given that most growers don’t have much more than 6 hectares it gives you some idea of the labor involved.

Interestingly the flats beside the river were used for an array of vegetables and green houses (below).

Powdery Pressure increases - UPDATE 17/12/2008

Vineyard checks this week have seen a big increase in the amount of Powdery in the district. In most cases this is limited to leaf spots in fresh shoot tips or active lateral growth (top).

If there are signs of powdery on bunches, like the one shown above, in your vineyard, apply two sprays of a suitable registered fungicide at 10-day intervals in attempt to stop the disease increasing.

When protecting for Powdery avoid spraying wettable sulfur at high temperatures (>350C) when the humidity is >70% within 24 hours of spraying. Growers can opt to use Legendtm in hot weather to avoid sulfur burning. This allows them to keep up the protection on their vineyard.

Tuesday, December 16, 2008

Hen and Chicken Set - UPDATE 16/12/2008

Chardonnay set in Mendosa Clone.
Last weeks welcome rainfall has 'pumped up' fruit. If your vineyard has uneven berry development like 'hen and chicken' this will be obvious now. The picture show Mendosa clone Chardonnay which is known to have issues with berry set.

Leaf Roll Virus - Identification Photos.

Suspected Leafroll Virus in Cabernet Sauvignon.
Looking vineyards this week some vines are showing red leaf symptoms - generally Cabernet Sauvignon and Shiraz.

We suspect this is Leaf Roll Virus expressing itself in early Summer. These Shiraz vines pictured are showing reddening and some early signs of the leaf curling.

Vine symptoms are not a reliable indicator of the presence of leafroll virus because other factors may lead to similar symptoms. Laboratory analytical techniques can be used to positively identify the virus in grapevines. Waite Diagnostics use the PCR method to test for leafroll and other grapevine viruses.

Ground truthing - Data is only what you make of it.

The ability to record the processes involved grape growing has increased greatly in the last 20 years. The widespread use of computers has given growers and wineries the ability to keep records of anything that concerns viticulture and winemaking. If it can be measured, it can be made available by the power of the internet.

For the grapegrower, using a computer with a web connection, you can access spectral images of your vine vigour, see how much rain has fallen, how much is expected and, if you are set up look at your soil moisture level. The technology is even available to turn on your water by remote control.

In this way you can run a vineyard from an office.
Vigorous grape vine before pruning c.1920
I am sitting in a vineyard as I upload this to the internet. Web based information is powerful, but there is one big drawback... What does the data really mean if you can't see the block?

Spectral imaging.
Spectral imaging, moisture monitoring loggers and automatic weather stations are key technologies that allow predictions to be made about your vineyard. All are extremely useful, but all need to be 'ground truth-ed' to get the best out of the data.

I once saw a vineyard that was watered from an office in Adelaide, when soil moisture reached a certain level, Summer Refill Point, a notification would be produced, the manager would then have the irrigation scheduled by solenoids connected by a radio link. The next time soil moisture reached the refill point it would be irrigated again.

This was an incredibly efficient system, but in reality it was failing. A quick inspection of the vineyard showed the vines had growing tips, the fruit swelled up and the vines had all the traits of being over watered. The refill lines on the computer graph were set too high.

What the vines looked like, what crop load they were carrying, and all the other the visual cues they giving out were going unnoticed. The computer said water, so they were.

Above: The Visitors Centre MEA Automatic Weather Station. This is a highly accurate device for recording weather data like relative humidity, wind speed, direction and temperature. However its data still needs to be ground truth-ed to get the best meaning from it.

It is possible to get the same miscues from automatic weather stations. For example where a station is placed will affect how it reads. If it placed inside a grapevine canopy it will record different data than if it is in open air. A weather station outside of the canopy will record a hotter temperature than one with its sensors shielded from the sun by a layer of leaves. A leaf wetness sensor placed inside the canopy will dry out slower than one placed in the open. So on and so forth. Most of the time this is academic except for when those differences are vital in making vineyard decisions.

The rate at which leaves dry out after rain has a big impact on predicting weather influenced diseases like Downy Mildew. It is possible that a sensor placed inside the canopy will record different data than one in the open. Leaves inside a fully grown canopy will stay wet longer after rain than the sensor may record. Without checking the vineyard you could trust the data alone.

Technology needs to be used in conjunction with visually inspecting vineyards to get the best out of data. The more technology you have, the more important a persons eyes and ears are.

Wednesday, December 10, 2008

Burgundy Machina

By Richard McGeachy

Vine and row spacing in Burgundy is set by law and is totally different to what we see in Australia. The rows are just 1m wide and the vines are spaced 1m apart or less – equating to 10-11,000 vines per hectare. This photo shows how tightly packed the vineyards are!

As a result any tractor operations are carried out with equipment you are unlikely to see cruising the rows of Australia vineyards.

This first tractor is a combined trimmer and spray unit. Rather than use an oscillating cutter bar they have hydraulically driven spinning heads. The 3 wheels run down the center of 3 different rows. It’s fair to assume this reduces compaction given that 2 operations can be carried out simultaneously whilst spreading the load across 3 rows.

This photo shows an old spray unit, the tractor only straddles one row of vines.

These were the most common that I saw driving around the vineyards. Most of them had some sort of attachment for turning the soil/weeding as well as shown below.

No prizes for guessing what ‘L’OCCASION’ means…

Trimming is a major past time in the vineyards of Burgundy. Despite being just 2 weeks from harvest fresh growing tips were evident in many blocks. I suspect the higher quality (Grand cru, 1st cru) vineyards that were typically on the slopes were better able to control this growth – likely due to the greater to distance the roots had to travel to the water table, as different to the lesser quality (‘villages’, ‘regionals’) vineyards on the flats.

Judging by the maturity of the second crop (it’s a Pinot vine pictured above) the trimming had started quite some time ago and was continuing right up until vintage. I barely saw a shoot out of place for the whole time I was there.

Tuesday, December 9, 2008

When do you stop spraying for disease? Q&A

Hi DJ's,

At what time of the season should you stop spraying for powdery mildew? What about Apple Moth?


Ryan J

At the time of writing this answer vineyards are at EL-30-31, nearing Berries Peasize.

In vineyards targeted at "A Grade," that have shoots that have stopped, open bunches and sunlight in the bunch zone, Powdery Mildew has not been seen and the risks of it developing are slight. Open canopies and small berries also cause conditions that limit botrytis.

In can be difficult to talk in general terms, but having a good clean block now, means you are looking at a clean harvest and can consider stopping your protective sprays.

Powdery Mildew on green berries.
For those with actively growing blocks don’t sit back and think dry weather means you are totally safe.  

 Assess your vineyards risk. Vineyards with a large canopy and a history of poor disease control are likely to have some disease- in spite of dry weather.

Levels of powdery mildew are lower than in the last few years but don’t get caught out – warm, overcast weather does suit the disease.

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

Powdery Mildew- is a dry disease. It doesn’t need any rain to spread. While hot summer day time temperatures (plus 32-34oC) don’t suit the disease night time temperatures in the mid 20’soC do. While the heat of the day may last 5-6 hours temperatures in the morning, evening and night suit the disease. While a quarter of the day doesn’t suit the disease the remaining three quarters of the time it does well.

There is Powdery in sheltered canopies around the district. Be particularly careful where you have seen Powdery in previous seasons. Look at your 50 bunches around this area.

Downy Mildew- all fruit is now immune, although vines can defoliate if levels build up enough, however the risk of this is almost nil.

Downy is totally reliant on rain to affect vines (and other crops). No rain = no downy.

Some rain is forecast this but at this stage it is likely to only be 10 -20mm over three days and not conducive to either a 10:10:24 Primary Event.

Botrytis- Needs rain or moisture to spread. Any botrytis present in your vineyard now is ‘dormant’ inside your berries or present in small amounts on any flower caps or dead plant material trapped inside bunches as they close. No rain before harvest = no botrytis.

LBAM- Some fresh LBAM egg masses have been seen. Levels vary from vineyard to vineyard. Now that berries have grown past peasize (EL 31), only the biological insecticide BT’s- Delfin, Dipel etc can be used.

Lightning strike - Identification Photos

Occasionally a vineyard get struck by lightning. The lightning often strikes foilage or cordon wires and a strong electric discharge travels down the row. The heat of this causes vines to wilt and any plastic filtings to melt. The vines almost look burnt and often have hollowed out shoots which have been 'cooked' from the inside out.

In most cases vines recover in the next year.

Friday, December 5, 2008

Powdery in December - Monitoring bunches.

Images by Richard McGeachy of the most serious Powdery infections he has seen in McLaren Vale this year.

Wednesday, December 3, 2008

BioDynamic Burgundy

Richard McGeachy continues to relate his travels through France...

Unknown spray drift - what is it?

As I was leaving the town of Beaune in Burgundy I noticed this dense white cloud emanating from a vineyard. I pulled over in a headland and walked back down the road to find out what was happening. There didn’t appear to be anything wrong with the equipment and nothing was burning – so I waited for the driver to get to the end of the row.

Burgundian engineering.
After a brief conversation with the driver (his English was vastly better than my French!) it turned out this block was being run biodynamically and he was spraying bentonite for botrytis protection. It had been raining fairly consistently for about a week up to this point (September 10th) and the fruit was just becoming edible (9-10 Baume). The rain had been falling in the equivalent of the first week of March for McLaren Vale. I didn’t walk through his vineyard to check how much, if any, botrytis was present.

Botrytis infection in Pinot Noir.

However I was able to walk through another biodynamic block early that week and it took very little effort to discover bunches with levels of infection as shown – at least one like this per panel. The grower was not concerned (outwardly anyway) as the block was being handpicked; given that vintage was at least 2 weeks away I would have been more than a little worried!

Powdery mildew.

It was also reasonably easy to find severe powdery mildew infections on bunches in this same block. The powdery appeared to be predominantly isolated to second crop and the upper leaf. Second crop was widespread in Burgundy due to the amount of trimming carried out during the season.

Tuesday, December 2, 2008

Shiraz Bunch Sizes

Most vineyards have good fruitfulness - good number of bunches per shoot - but it would be safe to assume they will weight less than last year.

Many of the Shiraz bunches we have seen this year look open, with gaps in the bunches and look to be a lower than average size. From this 35 year old vineyard in McLaren Vale we found bunches that typically ranged between 100mm and 200mm as shown. We are interested in your comments. What do you think?

Vine Weevil - Identification Photo.

Grapevine weevil.
Look for signs of berry damage from vine weevil pictured above. Levels of weevil seem to be higher than normal in some vineyards and in these cases they are causing damage to the developing fruit. Damage seems to be heaviest where there is no ground cover around the vineyard. All insects are attracted to vines at this time of the year because the surrounding vegetation had dried out.

Bunch damage. Berries 2-4mm approximately EL-30.

Thursday, November 27, 2008

Berry Shatter

Berry shatter has been seen in some vineyards. Some shatter can be the vines natural way to regulate its crop, however water stress during flowering can also wither fruit as shown top.

Wednesday, November 26, 2008

Lime Induced Chlorosis - Burgundy, France

In Winter 2008 Richard McGeachy traveled to Europe to investigate their viticulture and bring techniques back to McLaren Vale. Some of the issues faced in Burgundy are experienced here also. Iron (Fe) deficiency is a plant disorder known as "lime-induced chlorosis".

Limestone from the subsoil mixed into the topsoil by tillage.
This photo above was taken in the hills just to the west of the town of Gevrey Chambertin – showing the amount of limestone present in the freshly tilled paddock.
Severe lime induced chlorosis.Symptoms include leaves turning yellow or brown in the margins between the veins which may remain green, while young leaves may appear to be bleached.
This second photo shows severe lime induced chlorosis in a Pinot Noir vineyard near the town of Gevrey Chambertin.

A low level of lime induced chlorosis (yellow leaves).

This final photo above shows that some vineyards were more severely affected than others depending on the depth of top soil – and likely whether the grower was applying iron or not!

Growers in South Australia have had good success using EDDHA chelated iron to correct their iron deficiency induced chlorosis. Ironically most of these chelated iron products are imported from Europe.

Thursday, November 20, 2008

Heat Stress / Sulphur Burn - Identification Pictures

Sulphur Burn on young leaves.

Apple Moth - Predator and Prey - Identification Pictures

Light brown apple moth levels (LBAM) are high this season compared to the last few years.

Where apple moth are present they have moved into bunches. Look for ‘strings’ of brown flower caps stuck in bunches. You can also find at this time of the year LBAM pupae (grubs turning into moths in a cocoon) and egg masses.

Pictured is an egg mass, top and damage to the bunches, bottom.