Tuesday, April 24, 2012

Dead Arm - Q&A

Dead Arm question.


Not the wine, the Eutypa version! What causes it, and how best to deal with it? I could of course look it up but who needs to be resourceful when you have the DJ's?!


Thanks in advance.

Kristoff


Hi Kris,

Eutypa is present in many vineyards- of all ages.

All wine grape varieties are susceptible to Eutypa Dieback along with many other plants including Almonds, pome fruit trees and willows. All can be a source of disease.

Eutypa dieback of grapevine caused by Eutypa lata. Courtesy G. Munkvold
Eutypa is caused by the fungus Eutypa lata. The fungus produces ascospores on old infected wood and is spread by rain splash traveling on the wind.

The spores are able to travel large distances and can infect fresh, unprotected wounds, such as those left by pruning cuts. Spores are produced all year but can only infect fresh cuts during wet weather.

Treating exposed trunk wounds with particular fungicides or physical paint based barriers will prevent Eutypa dieback infection and is a recommended practice where cuts greater than 20 mm are needed. Click here for information on wound protection - http://www.sardi.sa.gov.au/pdfserve/hort/hort_crops/grapes/eutypa_trunk_disease/eu_pruningwound_fung.pdf

Once a vine is infected with Eutypa the only method currently available to growers to eradicate the fungus, is to remove infected tissue using remedial surgery. There are two main approaches to remedial surgery.

i) Cutting off the trunk at least 10 cm below any signs of obvious infection and training up a watershoot or grafting.

Remedial surgery - (c) SARDI
ii) Training a healthy shoot from the base of the trunk and removing the infected trunk once the new shoot begins cropping. Click here for more tips on remedial surgery.

Once inside the vine the fungus slowly grows spreading over a period of years along cordons and down to the trunk. Eutypa moves along the vines water-plumbing (the xylem).

Eutypa dieback causes characteristic stunted shoots, most obvious in spring, small bunches and in cross-section, a wedge of discoloured dead wood. It contributes to the decline of vineyards by reducing growth and yield. Bunches are smaller from a Eutypa infected vine, compared to healthy vines. Eventually Eutypa will kill vines.

Eutypa infection can be prevented by avoiding pruning cuts during wet weather. Pruning cuts made in early winter remain susceptible to the disease for some weeks, while those made in early spring heal much quicker.

If possible delay pruning until August for high risk blocks or those already showing signs of the disease - http://www.sardi.sa.gov.au/pages/hort/hort_crops/grapes/eutypa_trunk_disease/eutypapage1.htm

Thursday, April 19, 2012

2012 Olive Harvest

The 2012 Olive Harvest is beginning. Unfortunately for many olive groves the return per hectare will be one of the lowest experienced because of a combination of low yields and tough market conditions. Industry predictions are for the national yield to be down 70% from last season. 

The smaller olive crop could see prices slightly rise from the level of $2.70-$4.50Lt on the bulk market, however this is not expected to offset the reduction in income from low tonnages.

There is also a limit to how high local oil prices can go. Like many industries the Olive industry is suffering from the high Australian dollar making imported oil products.
 
Sam Freeman has been monitoring groves across the South East and McLaren Vale and he agrees that yields are down, but that it is not all doom and gloom. 

"After good yields during the 2011 harvest a majority of groves this season are seeing very low crop loads," Sam says. "The better maintained groves are not down by as much (as the 70% reported)."

"After the heavy crop last season, pruning has been a major focus for groves this year - Heavy crop followed by heavy pruning.”

"Biennial bearing of olive trees is common and so most groves are expected to recover for the 2013 harvest."

Experience with the wine industry shows that a lightly cropped years could help stabilise the industry. Unsold oil from the 2011 harvest can be blended with 2012 oil to meet market demands (this is an allowable practice under Australian standards). This helps clean out any left over stock, generate cash flow for processors and free up space for the 2013 harvest.
_____________

In other olive industry news the copper based fungicide, Tri Base Blue is now registered for use.

Tri-Base Blue is a liquid copper compound formulation that provides a useful alternative to traditional copper products. The active ingredients in Tri-Base Blue, tri-basic copper sulphate and metallic copper equivalent, protect olive trees against various fungal leaf spots, including peacock spot and anthracnose.

Tri-Base Blue is available for use by Australian olive growers under the provisions of the APVMA Permit Number – PER11360. This permit is in force until 31 March 2017 and copies must be obtained before use from the Australian Pesticides and Veterinary Medicines Authority website http://www.apvma.gov.au.

Thursday, April 12, 2012

McLaren Vale Sustainable Wine Growing Australia - Q&A

Hi,

A question for DJ's about the new McLaren Vale Sustainable Winegrowing Australia program.

What are the costs, including the testing involved of the program, to get a pass mark?

Bob 


Good question, Bob.

There is not a pass or fail mark to become a member. Your vineyard will, however, be placed into a category ranging from 0 (Not sustainable) to 4 (Extremely sustainable). 

The McLaren Vale Sustainable Winegrowing Australia is based on a self assessment workbook. This document will take your time to fill it out and gather the information, but in most cases these are records that grapegrowers are should already be keeping, for example fertiliser and irrigation application records.

There is a cost for the self-assessment workbook when you register. This costs is $50.

It is a very comprehensive document that covers all aspects of sustainably producing winegrapes. It consists of six chapters.

In two of these chapters to gain an extremely sustainable rating growers need to be basing their soil management and irrigation on scientific testing.

Chapter 1 -  Soil Health, Nutrition & Fertiliser Management assigns a best practice rating for growers who base their fertiliser strategies on annual tissue testing, commonly called 'petiole testing', backed up with soil testing on a three year cycle. Using the current costs of these tests a grower would need to annually assign a budget of $90 for petiole tests. A soil test every three years would costing around the $200 mark, therefore a budget of $67.

Total $157 annually.

In theory these tests will pay for themselves many times over. Soil testing and tissue testing are excellent tools for identifying limits to your production. In particular high salinity or excess sodium will cause vines to grow poorly and produce poor yields with low fruit quality. Diagnosis of salinity problems should be a routine practice.

Chapter 4 - Water Management recommends testing your water source, or getting an assessment of it annually. In many cases this test can be supplied at not cost to the grapegrower via governmental agencies, or at a low cost from private source.

Estimated cost $70.

As mentioned above, salinity and sodicity are major issues that have to be addressed by grapegrowers in order to be economically and environmentally sustainable.

The Sustainable Winegrowing Australia launch, held at the Bocce Club, was a huge success with more than 100 people in attendance. The presentation gave an overview of the MVSWGA program and provided MVGWTA with an opportunity to thank the many contributors to the program. Pic Hailey Brown.
Chester Osborne, Stephen Strachan and Peter Hayes. Pic Hailey Brown. 

In reviewing the rest of the self-assessment workbook chapters there are no other direct costs associated with moving your grapegrowing business towards sustainability. 

The final cost should be assigned to becoming certified after completing your self-assessment score. The certification of the program will be undertaken by a third party which is likely to have a cost. 

As with any certification, it can - and should - add extra credibility to your product and brand. In the future you may also need to have membership of an environmental certification scheme, such as ENTWINE Australia, which your local sustainability programme can count for.

Hope this answers your question. For more information please see - www.mclarenvale.info

Regards,

James

Near Map has updated to show 8th of March overflight


View the latest images of McLaren Vale here.

Monday, April 9, 2012

Crop Thinning - Q&A

Guys,
I've enjoyed reading your thoughts and comments on various viticulture issues. I have a question (actually, quite a few), the first relates to crop thinning and the most appropriate time to do so to enhance quality. I've read various articles that suggest doing so at veraison gives you the opportunity to eliminate bunches that are a bit tardy to set, whilst others suggest that it must be done well in advance of veraison. Any ideas on this?
Cheers
Grant
Hi Grant,

At the risk of sounding heavy handed- crop thinning is not really a very good habit to get into. It is expensive and is best avoided by trying to 'balance' a vineyard so it is not necessary.

It does have some uses in young vineyards that are overcropped (pictured upper left), or varieties that have a large variation in their flowering and ripening (Grenache ; Zinfandel).

In these cases taking off any green fruit at verasion helps reduce the amount of unripe, or less than ripe fruit that goes into making wine. With Zinfandel they can leave unripe fruit and hand pick it later as a second crop. As a rough rule of thumb the earlier unripe crop is removed the better it is for wine quality, as the energy produced from the vines leaves goes to remaining crop longer, therefore the fruit has 'ripening power' to produce flavour colour etc.

The trouble is how do you explain the concept of removing just the right crop to someone who hasn't spent a lot of time in a vineyard and doesn't understand the concept of vine balance. We use simple rules of thumb to make it easier to accomplish. At verasion you instruct 'If it is green cut it off, if it is red leave it there.'

The obvious point here is at verasion if the fruit hasn't coloured up if will be less ripe compared to bunch that has fully coloured up. Another way of giving instruction is to cut off fruit from shoots that are less than 30cm long. Short shoots with fruit on them is a sign the vineyard vigour and crop load are not balanced. Experienced labour can also remove clumps of fruit (lower left).

Pruning is the time to do your 'crop thinning' by getting the bud number right for your vines vigour. The vineyard should produce 5 kg of Fruit of 1 kg of Canes. 5:1. The Fruit weight/cane weight is called the Ravaz index. You should leave 30 buds per kg of canes removed. Much better explanation in 'Sunlight into Wine' for more info.

I know it is from the text book but it simple but very effective, especially after a few years of balance.

Regards James

Thursday, April 5, 2012

Congratulations to Chris Herriman.


Congratulations to Chris Herriman who was awarded the 'Most Outstanding Viticulture Student 2011' from the Marcellin Technical College. As part of his studies Chris works at DJ's with Andrew Tuck as his mentor. We are very pleased to have him as part of our team, and know that he has a bright future in agribusiness.

Climate Change in Viticulture - Q&A

Hi DJ's,
I am new to viticulture, and since I started my studies I have been hearing about the potential impact that global warming will have on grape growing; for most irrigation dependent regions, the news was all bad. So if this is the case has anyone been planning for the changes?
I get the feeling we just focus on each season and its issues.... no rain when we want it, rain when we don't, prices down, costs up, good labour scarce etc. No one I have come across seems to be planning for the potential contingencies that will/ may arise from global warming. What type of planning are you doing with respect to climate change and its impact on your capacity to grow grapes profitably?

Cheers,

Mat

Hi Mat,

An interesting post Mat the simple answer to your fundamental question is yes, we do think about the long term affect of climate change in vineyards.

There is some new research showing that for first time been able to attribute early ripening of wine grapes to climate warming and declines in soil water content. The study reveals that management factors has also influenced the shift, offering hope for growers to develop adaptation strategies.

Assumptions we make.


We assume that the weather will get warmer and there will be less rain, critically there will be less rain in Winter and Spring. There is debate about this and sometimes there are more questions than answers.
Changes in the weather are very complicated and beyond the scope of single businesses to comprehend. By way of illustration what do you do if you are someone like say Yalumba or Henschke? You have established vineyards - some well over 100 years. There is no imaginable replacement for these vineyards - they are the epitome of your brand and style. You can't simply change varieties or replace iconic vineyards.

What we do encourage.


Building up levels of soil organic matter to try and increase the capacity of our soils to hold moisture. Being more fussy about vine balance and shoot thinning, in Shiraz and Grenache, to try and reduce crop loads and shoot numbers to manage and heatwave, hot, dry and windy conditions. Managing soil moisture content through increasing irrigation or mulching, or vine rootstock choice.

Additional shelter belts and a more diverse permanent sward might also reduce some of the drying out and dust issues as if conditions get hotter. Cover crop consideration plays an important part.

Hope this helps.

Regards,

James

Key Reference

Earlier wine-grape ripening driven by climatic warming and drying and management practices (Webb et. al)

Tuesday, April 3, 2012

Organic Compost.

Compost contains organic carbon and nutrients whilst also adding soil moisture retention, structure and increasing root mass. It is added to vines after harvest to integrate into the soil over winter.

Above - Bulk Organic Compost is applied with a Marshall spreader.

Organic matter is vital for good soil health and adding quality compost with organic carbon to the soil helps to improve soil condition. McLaren Vale soils are generally low in organic carbon. We record levels in vineyards between 0.5% to 3.0%.

Remember that value is not just about how much compost costs. While chicken manure is cheap per cubic meter, per tonne of nutrient it is expensive and can have side effects.


As the Willunga based composters Petes Soil say on their website,
"Poorly or non-composted materials pose the risk of introducing pests and pathogens, weed seeds and may behave less predictably than material which has undergone the stabilising phase of the composting process. Non-composted manures may conceal a surprising amount of salt, contributing significant amounts to the soil with prolonged use."
Banded compost applied under the vine row as a soil amendment - Willunga, McLaren Vale Wine Region, SA.

Sunday, April 1, 2012

Post Harvest Disease - Does it matter in your vineyard?

Late season powdery mildew on a vine leaf.
There is much debate about whether vineyards should be sprayed after harvest Latest research would indicate that these sprays are often not needed.

Powdery mildew - Grape growers become concerned about high levels of Powdery mildew on their leaves (above).

1/ You might reduce the spread of powdery mildew in the canopy.

However, where disease has already developed, further increases in levels of powdery after–harvest generally make little difference to leaf and vine health.

2/ You might aim to reduce the amount of disease for next season.

Unfortunately spraying after picking has little effect on the chances of Powdery mildew next year.

Most buds that survive to next season are susceptible to powdery only in early growing season, so spraying now will not affect levels of winter-carryover in the buds. Also, the fruiting bodies of powdery, called cleistothecia, are somewhat like apples on a tree, they ripen in late summer and autumn. Since cleistothecia have already matured in most vineyards by now, post-harvest sprays are too late and do nothing to reduce their numbers.

Spraying for Rust Mite after harvest is also not recommended.


The Rust Mite bronzing to leaves you see are not doing any damage to your vine leaves and they function normally.


If you have bronzing on your leaves (above), record this as it is the threshold for rust mite spray next spring. Spraying in spring 2012 is recommended if uniform, moderate to high bronzing is obvious in your vineyard now (March 2012).

A spring spray aims to re-set the rust mite population down to a level where predatory mites can then maintain effective control. However, this approach does have some toxicity to predators therefore, using it when it is not needed can damage predators unnecessarily!