Wednesday, October 29, 2008

LBAM have moved into Chardonnay bunches - UPDATE 29/10/2008

Stuck flower material is a sign of light brown apple moth activity.
Monitoring tip: Look for brown caps stuck together in the bunches during capfall.

Levels of more than 4 per vine panel would be considered high at this time of the year. Less than 1 per panel is low.

Tuesday, October 28, 2008

Irrigation Notes - UPDATE 28/10/2008


Consider the effects of this seasons lack of Spring rain on your soil moisture levels. As soil moisture dries out, or is used up by the plant, the shoot tendrils first shorten then are not present. As the plant further slows and the soil dries the shoot tips shortens until the leaves overlap the growing tip. The final sign of dry soil is the shoot tip becomes burnt as shown above.

Too much soil moisture can also be a problem. It is well known that over irrigation of grapevines grown in McLaren Vale can lead to the development of large vines that carry heavy crops of low quality grapes.

Initial irrigation experiments involving the application of Regulated Deficit Irrigation (RDI) to grapevines began in the late 1980s and involve reducing the water inputs to vines during the early stages of bunch development after both flowering and fruit set are complete.
RDI can reduce both bunch and berry size, and increase grape flavor, colour and aroma. When applied properly RDI improves fruit quality but has the potential to significantly decrease yield.

Shiraz and Grenache respond well to RDI irrigation. Cabernet Sauvignon does not seem to benefit from deficit irrigation. White grape varieties also are best kept ‘happy’ through flowering as stress can reduce quality.

RDI is effective when we have limited spring rain where soil moisture tensions measured by gypsum blocks in the vine root zone reach and can be maintained with careful irrigation in the range 200-400 kPa for heavy (clay) soils and 50-80 kPa for sands.

New soil moisture monitoring equipment measures soil moisture levels as a volume, mm per metre, of percentage of water. With these readings levels for RDI vary from site to site.

RDI may contribute to salinity problems where soils and irrigation waters are high in salt. It pays to be careful if your bore water quality is above 1500ppm.

Grafted Vines - Union failure


In order for the graft to take, contact must occur between the cambium layer of the scion and the cambium layer of the rootstock. If this doesn't occur it leads to graft union failure.

The contrast between a failed graft (top shoot) and a successful graft (bottom shoot).


This photo series shows fail of the graft to make a union with between the cambium layer of the graft (scion) and the host vine (rootstock). Symptoms of this are sudden wilting of the grafted bud and also shifting of the union under the grafting tape. Prior to the the graft bud developed normally and was 7-10cm long.

Callus is the white tissue that forms on cut surfaces.
Note that there is only a very thin line of callus tissue linking the graft to the rootstock. When the graft is unwrapped it easily slips out.


Unfortunately, the graft union has ceased to take. When this happens, the flow of nutrients from the rootstock to the top growth (scion)  stops completely and the top growth will deteriorate.

For more information about graft failure or other viticultural queries contact us at - djs@djsgrowers.com.au.

Grafted Vines - Pest Alert - UPDATE 28/10/2008


Check your grafted vines for signs of Heliothis Caterpillars. These can affect the growth of your developing buds if found in high numbers. High levels have been seen in two vineyards in the McLaren Flat district of McLaren Vale.



Monday, October 27, 2008

Vineyard Predators - Lacewing Identifcation Photos


Top predators in the vineyard. Adult Ladybug - above and juvenile Brown Lacewing 'Junkbug' - below.


Thursday, October 23, 2008

Grand Period of Growth



This is the time of the year that you can literally watch grape vines grow.  I went out first thing on Friday morning and checked out some vines and marked their progress.  I came back at the end of the day to that same vine and it had grown 3.0 centimeters.  

The tips had progressed towards their never ending goal of touching the sun (or at least trying to do so) and a few other shoots had done their best at getting “caught-up” with the neighboring vines.  This growth (as well as being totally impressive) is critical towards the vines goal of ripening a seed.  The vine needs enough leaf surface area to effectively and efficiently participate in photosynthesis.  Without this grand period of growth, the vine may be short leafed, which is the equivalent of not having enough energy to evenly ripen the fruit. 

LBAM - UPDATE 23/10/2008



LBAM larvae have been seen hiding in shoot tips, or folded up in leaves this week. These are the first generation of larvae that live on grapevines.

Light brown apple moth stick leaves together to protect themselves from natural predators like Earwigs, Lacewing junkbugs and spiders.



A tip for monitoring for apple moth is to look closely at the watershoots, or buttshoots growing from low down on the trunk. The first generations of apple moth are commonly found in these watershoots because they are close to the weeds or broadleaf plants that they live on.

Wednesday, October 22, 2008

Rolled Cover Crop


Tall Ryecorn that has been rolled into a weed suppressing mat in a Blewitt Springs vineyard. This is to provide summer weed control (note the resistant ryegrass in the background which will be spot sprayed later in the season).
For more information about rolling covercrops see: http://www.pridhamviticulture.com.au/

Monday, October 20, 2008

Organic Herbicide Trial

This season we have been working on a system to replace Glyphosate with an organic method of weed control.

Here are the results of our trial system.


Step 1: Undervine slash the vineyard.



Step 2: 7 days later - Slasher Organic product registered for pH adjustment. 400Lt/ha. 4lt per 100lt strength.




Step 3: 7 days later -Second application of Slasher @ 600lt/ha of spray volume. 4lt per 100lt strength.

Friday, October 17, 2008

Apple Moth and Heliothis - UPDATE 17/10/2008

Apple Moth (right) and Heliothis caterpillars (below) are both active in the vineyard.


Good monitoring now will establish the levels in your vineyard allowing you to carefully consider your options in the lead up to flowering (EL 19-25) the critical timing for Apple Moth damage.


Heliothis are a pest of young vines because they can eat shoot tips and slow growth.

Predators can now be found in the vineyard. These are attracted to the ‘free feed’ from small apple moth larvae.

Thrip Damage - UPDATE 17/10/2008


Bright yellow leaf spotting can be seen in many vineyards - above.

This is caused by thrips, small sap sucking insects. This is not a concern, although the spots can be confused with Powdery Mildew spots or occasionally other faults like herbicide spray drift. Powdery has grey growth on the underside of the leaf. Thrip damage is a bright yellow spot only.

Powdery Mildew - UPDATE 17/10/2008


The first signs of Powdery Mildew have been detected.

Small finds of Powdery spots have been seen. This season appears to have low to moderate pressure but this could change with humid overcast weather.

Growers need to keep the developing bunches remain well-protected from infection for at least four to five weeks after flowering.

If you have maintained good spray coverage by then, you are well on your way to harvesting a powdery-free crop.

For conventional farming: If you are in doubt, apply a thorough coverage with either sulphur, or DMI – a Group C fungicide - or a Stroby – a Group K fungicide - or another registered product immediately before and after flowering. If you have been using the same Group C or Group K fungicides for a few seasons in a row consider AVCARE resistance management guidelines. See Resistance guidelines for help.

For organic farming: Increase the frequency of your protection as the vines flower.

Tuesday, October 14, 2008

Predators in the vineyard - UPDATE 14/10/2008

The importance of predatory insects in McLaren Vale vineyards is often talked about. Are they a real help? Where high numbers of pests like Mealy bug are present it is unlikely that any beneficial bugs will be able to decrease their amount.

However if the vineyard has a balanced insect ecosystem then predators do the hard work for you.

A Lace Wing ‘junk bug’. Use of many products like Mancozeb decimates the natural predator population in a vineyard.


Predator numbers in your canopy will increase at the start of spring as insects move onto the vines from outside host plants. The weather conditions and what you spray in the vineyard will then change the rate at which the population breeds. Even sulfur at high rates has been shown to have an effect on the lifecycle of lacewings and other beneficial bugs. Predators have trouble surviving summer if certain chemicals are overused.

Elephant Weevil - UPDATE 14/10/2008

Orthorhinus cylindrirostris, is commonly known as the Elephant Weevil. Elephant Weevils and associated damage have been seen. These are rare in McLaren Vale, but in other regions like the Hunter Valley in NSW, they are a major pest.
Elephant Weevil.
A hollowed out vine trunk.
Look out for any weak vine arms with hollowed out wood. The female elephant weevil bores a hole into the trunk or arm of the vine. Into this hole she lays an egg. On hatching the young weevil larva begins to feed on the wood, boring downwards eating as it goes. When fully grown, the larvae makes its way back up the tunnel it has made until it reaches the point close to where it hatched, and here it pupates.

Thursday, October 9, 2008

Powdery Mildew - UPDATE 9/10/2008

Early signs of Powdery spores on Grenache have been seen in one vineyard. This was in a previous hotspot where we have found disease beginning in previous years. The powdery looks semi-active (dark brown growth). Fresh active growth appears grey as shown below.

Vine Scale - UPDATE 9/10/2008

Vine Scale.
Look for signs of vine scale sucking sap from shoots and stunting growth. Tag any finds and consider control next winter. There is a valley (Ingleburn Creek catchment) that seems to have the highest levels in the McLaren Vale Region.

Which Mite is that? Q&A


Hi,

I am curious about how to tell the difference between grapevine mites?I have a uni project to do on pest and disease and this would be of assistance.

Many thanks,


Andrew


A= There are three common types of mite pest in South Australian vineyards. Grapevine Rust Mite, Grapevine Blister Mite and Grapevine Bud Mite.

Rust Mite affected shoots are common. The photo below is from the Blewitt Springs district of McLaren Vale this season.

Slow and distorted growth caused by Rust Mite.
Rust mite 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. Rust mite levels can be reduced by a sulphur (and Canola Oil) spray at Chardonnay 10% budburst.

Bud Mite are found in most vineyards.

Grapevine Bud Mite.

Bud mite damage causes shoot to have no growing tip and only produce one or two crinkled leaves. Bud mites generally don't cause economic damage and levels under 1 per 100 shoots are considered minor. Bud mite cannot be easily controlled by fungicide spraying.

Blister Mite can look severe, but rarely causes mature vines any trouble. Blister mite can be an issue in nurseries though.


Grapevine Blister Mite.

Tuesday, October 7, 2008

Iron Deficiency

Iron Deficiency.
On heavy clay soils, or vineyards over limestone chalk, Iron deficiency can show up as pale leaves. These symptoms can generally be lessened by applying Iron chelate by fertigation.

DJ's has information on what are the best options for correcting this deficiency. Contact us for more details.

Cuculio weevil - UPDATE 7/10/2008


This week high levels of Cuculio weevil have been seen damaging vines (and olives). They emerge for the soil and at night and chew leaves and even whole buds.
In some vineyards in the areas west of Willunga severe damage has occurred. In the vineyard pictured whole panels have been stripped of all shoots and the buds have been chewed out.

Thursday, October 2, 2008

Covercrop of the year?

Ryecorn in Blewitt Springs.




This Ryecorn is flowering. The grower plans to roll the cover crop to create a weed suppressing mat.


Unfortunately, there are some human side effects. Shortly after taking this photograph and walking through the crop, I was temporarily blinded by an allergic reaction. Ironic.

A Grade Shiraz? - Q&A

Hi,

I am curious about how you can tell the grade of Shiraz so early in the season? What sets A-Grade vineyards apart?

Many thanks,

Andrew



Vineyards need to be set up to grow A-Grade Shiraz. Canopy shoot density is one of the critical factors to look at and this can be seen now in spring. Getting light onto your developing flowers and then fruit is vital to growing a shiraz fruit with ripe tannins and a dense colour.


A Shiraz vineyard targeted for A-Grade with very even shoot spacing in spring.

The pictured vineyard is a good example of even Shiraz with good shoot positioning to give an open canopy at harvest. 

The trick for this grower now is to control growth using nutrition and irrigation through the season to obtain the desired berry size. If they accomplish this, they are well on the way to growing high quality Shiraz.