Thursday, March 27, 2014

CropWatch End of Season Notes #V14.

KEY NOTES FOR THE FUTURE


This issue completes the tenth season of CropWatch McLaren Vale. As the CropWatch editor James Hook poses the following questions to of what could become more important over the next ten seasons.

INCREASED NEED FOR BIO-SECURITY


Ten years ago the weed species growing in vineyards were different. Undervine weed management has changed. Glyphosate herbicide resistant Wild Radish (Raphanus raphanistrum) has developed in Western Australia agricultural scientists believe that it will become established in South Australia either by the transfer of seed or by resistance developing independently here. Wild Radish has the potential to become a major weed in McLaren Vale if this occurs. In another ten years will herbicide resistant weeds be commonplace? Currently in the district the summer weeds Caltrop (Tribulus terrestris), Three Corner Jack (Emex australis) and Lincoln Weed (Diplotaxis tenuifolia) are spreading. Each season fresh infestations are occurring in new sites. Will they have spread across the entire region? The Mediterranean Fruit Fly outbreak in Sellicks Beach this year has highlighted how the introduction of exotic pests will complicate the logistics involved in contractor operations and the grape harvest. What would happen if Mediterranean Fruit Fly or worse Phylloxera lead to the introduction of permanent quarantine?

CLIMATE INSTABILITY


The 2014 growing season presented significant challenges to successfully ripening a crop at yields that are economically sustainable. Can you adapt your business to extreme weather events if they become more common? The season had started out wet with average winter rainfall, 300-350mm, but this soon turned into a dry season with effectively no rainfall after November.

There were positive impacts on vineyards (the dry spring kept disease levels low and the spread of Powdery Mildew and Downy Mildew from neglected vineyards was limited) but also negative impacts (increased reliance on irrigation and  possibly links to this seasons long flowering capfall period). Summer conditions were significantly warmer than average with two heatwaves through January which tested the limits of grapevine tolerance to extreme heat. Equally damaging were extremely high speed winds which reduced berry set, stripped leaves and reduced the size of canopies and increased the level of fruit exposure. Can you reduce the damage that heat and wind did to your vines if and when these conditions become more common?

ROW ORIENTATION


Will we need to change or trellis configuration and row orientation to best weather climate extremes?Tropical rain is more likely under current climate monitoring. Will McLaren Vale experience longer, hot, dry summers broken up by intense rain? How do we limit resulting berry splitting and the risks of Botrytis?

LOW INPUT SPRAY PROGRAMMES


With an unstable climate and more tropical rain can we continue to refine our organic, biodynamic and low input conventional farming?

Many growers are successfully using reduced sprays inputs, in terms of both number of applications and the rate of agrochemicals applied, compared to a decade ago. Spray unit technology has greatly improved. Downy Mildew outbreaks are an infrequent occurrence with only one vintage since CropWatch began where it has had any significant effect on the regions fruit (2011). Using weather stations and using CropWatch as a regional information service has enabled a targeted approach to preventing Downy Mildew from building up to outbreak levels.    

While reduced input sprays are generally working well but may have some unforeseen consequences. Why is Rust Mite bronzing to leaves increasing? Do we need to keep spraying after Christmas to keep mite levels lower during March? If we are protecting our own vines less how do we deal with neglected vineyards if we have wet, high pressure seasons? The 2011 vintage did have disease spreading between vineyards.

ROOTSTOCKS AND VARIETY


What rootstock and variety configurations do we need to deal with climate instability? Can we grow white varieties of wine grapes to be financially sustainable? Or is McLaren Vale going to be a 100% red wine region in ten years time?

Friday, March 14, 2014

Rust Mite leaf bronzing - Is it just from agrochemical usage?

Rust mite bronzing on leaves in a biodynamic vineyard in February 2013.
Agrochemical use is often seen as a cause of rust mites. For the record Rust Mite can be found in vines grown under minimal input regimes too (above & below).


A Shiraz leaf in March 2014.
Note that in McLaren Vale this year, vines grown by different techniques including biodynamic, organic and conventional management show signs of bronzing. In biodynamic or organic vineyards (which don’t use Mancozeb or insecticides) this is likely due to high rates of wettable sulphur which we use for powdery mildew control.

Thursday, March 13, 2014

Bunch Stem Necrosis - ID Photos 13/3/2014

Bunch Stem Necrosis and late season Powdery Mildew infection (Feb 2014). Contact James Hook for more information.
Bunch Stem Necrosis in Langhorne Creek (March 2014).

Wednesday, March 12, 2014

Manganese in export wine - Q&A - Does this affect what we do in the vineyard?

On 27 February, Wine Australia released a warning to wine exporters regarding the increased scrutiny of manganese, iron and copper levels in wine by Chinese authorities. 

Maximum regulatory levels now being imposed by Chinese authorities are 2 mg/lt for manganese, 1 mg/lt for copper and 8 mg/lt for iron. Wine Australia have recommended that all wine intended for export to China should undergo analysis to confirm that it complies with these limits. 

Chinese law controls the amount of manganese that can be added to wine, however Australians don't add any manganese to their wine, neither do winemakers in other traditional wine producing countries. Manganese is a natural element present in soil. We do common apply manganese to grapevines as a trace nutrient. The rates of application per hectare are extremely low compared to the regulatory limits. For context a level of 2mg/lt in wine is equal to 2 ppm. 

One application of a 10% strength manganese foilar fertilizer @ 2.5lt/ha applies 0.25kg/Mn/ha. If 100% of this manganese is taken in to the vine and then into the fruit (this is unlikely as fertiliser would also be converted into plant tissue, and/or lost to the soil etc. but for hypothetical reasons lets run with it) and each hectare of vines grew 10,000kg (10 tonne), then turned into 7,000 lts, this would give us the following equation.

0.25mg Mn in 7,000lts = 0.035mg Mn in 1,000lts. 
0.035mg in 1,000lts equals 0.00035mg/L of Mn or 0.00035ppm. 

With this rough equation we would have to apply our foliar fertiliser 2,800 times per season and have 100% efficiency into the fruit  to increase the resulting wine 1.0mg/lt.

Make sense? Trace element applications are exactly that, only a trace.

Manganese in export wine - Does this affect what we do in the vineyard? 

 

The short answer is no, DJ's recommend continuing to apply manganese to your vines if you have a demonstrable need. If you have any doubts over the level of manganese  in your grape juice or the resultant wine consider contacting the AWRI which can test for manganese levels.

Thursday, March 6, 2014

McLaren Vale Recycling now takes used Drummuster containers.



drumMUSTER sets up on wine region’s doorstep



The state’s top wine and grape growers will have more options to recycle their agvet chemical container waste thanks to a brand new drumMUSTER site in McLaren Vale.


The site will provide a new, flexible option for farmers looking to dispose of their chemical drums


South Australia drumMUSTER Consultant David Jesse said farmers, grape growers and other chemical users in the McLaren Vale area have a site that’s convenient for them.

“The new site is located on the doorstep of many wine grape growers,” he said.


“It’s an alternative location to City Of Onkaparinga Council site and will alleviate the need to travel. It’s a great complement to the existing council site.”

David said the McLaren site will be operating five days a week between 8.30am -  4.30pm offering growers more regular opportunity to dispose of drums.


“Many growers already use this facility to dispose of cans and bottles,” David said. “Local resellers and growers are keen to see this facility established.”


James Hook from DJ’s Growers said the McLaren Vale’s Sustainable Farming Programme highlighted that local recycling was an industry weakness.  

“This means growers have approximately 250 days per year when they can deliver drums, compared to approximately four days per year in the past. We are going to see a dramatic improvement in local recycling,” he said.

Almost 50,000 drums have been collected and recycled in the region since 2000. That’s nearly 80 tonnes of waste avoiding landfill. 

The new site is located at 6/229 Main Road, McLaren. Those with more than 50 drums will need to book by calling 8323 9441.

Remember to rinse all drums. Pierce metal drums to allow for better air-flow after rinsing. All drums need to have lids off before delivering.

Since 1999, drumMUSTER has collected more than 23 million drums nation-wide. That represents more than 28,000 tonnes of waste avoiding landfill and being recycled into new and useful things again like plastic cable covers, wheelie bins and pipes.

For more information contact David Jesse on 0409 834 113. For further information on the drumMUSTER program, call 1800 008 707 or log on to www.drummuster.com.au.