Wine & Viticulture Journal, Spring 2021 Preview

Spring 2021 · Volume 36 Number 4

SPRING

• Weighing up the effects of oak products and micro-oxygenation • Fungicide resistance to Botrytis cinerea • A machine learning-based system for early and accurate yield forecasting • Bumper 2021 harvest: what does it mean for growers?

• Varietal report: Durif - an AUS vs US comparison

US US OR OR

CONTENTS

MER MER

INDUSTRY ASSOCIATION COLUMNS 8

ha ha

never been as unbelievably challenging as the last two years

00L 00L

M M

nits

U

AGW (Tony Battaglene): Planning for the unexpected has

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WINE AUSTRLIA (Liz Waters): Harvesting the benefits of agtech

10 ASVO (Brooke Howell): ASVO 2021 oenology seminar — navigating new winemaking trends and finding solutions to existing problems

WINEMAKING

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14 ERIKA SZYMANSKI: Oak products and micro-oxygenation: a surprising lack of surprises 18 Use of alternative vessels to oak barrels during fermentation of Sauvignon Blanc: a comparison of stainless-steel, concrete and polyethylene tanks and clay jars 24 Fresher wines, fewer sulfites: a new yeast for today’s challenges 30 AWRI REPORT: Vintage 2021 – observations from the AWRI helpdesk

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VITICULTURE 32 Frequency and distribution of fungicide resistance in Botrytis cinerea collected from Australian vineyards 40 Dogs sniffing phylloxera – an industry perspective 46 A machine learning-based system for early and accurate vineyard yield forecasting 52 Can carbon sequestration in vineyard soils provide an internationally valid offset for greenhouse gas emissions?

60 Vine times for breeding

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64 ALTERNATIVE VARIETIES: Aligoté

BUSINESS & MARKETING 66 Making the most of a cellar door in a COVID-19 world 70 Show me the money! Better understanding winery costs and efficiencies 73 Bumper harvest in 2021: what does it mean for growers?

75 Accelerated wine cooling before opening a wine bottle: is it good practice or better to avoid?

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VARIETAL REPORT 79 Durif/Petite Sirah - an Aus vs US comparison

W I N E M A K I N G W I N E M AT U R AT I O N

Oak products and micro-oxygenation: a surprising lack of surprises

By Erika Szymanski

Despite an ever-growing number of oak adjuncts and micro-oxygenation technologies available to winemakers that enable the effects of barrel-ageing to be mimicked in less time than the real thing, there is limited publicly-available research into the combined effect of the use of the two. Erika takes a look at what can be drawn from those few studies.

other spoilage microbes, among other things.

but when I went searching for studies that

Sometimes, understandably, winemakers

combined the two, I could count the results

are interested in availing themselves of

on my fingers. Odd, though maybe less odd

some of these functions without having to

in light of how many variations are involved,

of barrel-ageing generally means

take up all of them. An ever-growing bevy

and the likelihood that suppliers and the large

combining oak products with

of products serve those interests, notably

wineries who most stand to benefit will run

micro-oxygenation.

including oak adjuncts — staves and chips,

private trials with the specific combinations

but also other creative oak derivatives — and

they need.

IN BRIEF ■ Recreating the desirable effects

■ There is limited publicly available research on the combined effects of these.

■ This limited research has confirmed that more wood leads to more wood-derived sensory characteristics; more oxygen leads to faster phenolic evolution.

B

arrels have multiple functions in

micro-oxygenation, or micro-ox, technologies

Among those who are conducting

that mimic the gradual dose of outside air

controlled trials of oak and micro-ox

that a barrel will deliver to its contents over

treatments layered on top of each other is

time. Perhaps unsurprisingly, companies do

a group based in the analytical chemistry

not yet seem to be offering a replacement

department at the Universidad de Valladolid

for the thrill of finding Brett where it was not

in Spain. Its interests have recently

wanted — though plenty of yeast purveyors

centered on the properties of Quercus

will provide mixed microbial products to

pyrenaica, Rebollo or Pyrenean oak, a

encourage a wider range of sensory-active

species common in northwest Spain and

metabolic byproducts in more controlled

Portugal. Q. pyrenaica is of little use for

ways.

barrel manufacture, largely because it has

Recreating the desirable effects of

not been cultivated for that purpose, so

a winery: contributing flavour and

barrel-ageing without its undesirable risks

trees with the necessary grain structure for

texture, stabilising colour, assisting

and costs generally means combining oak

high-quality cooperage are in short supply.

oxidative stability, storing wine, soaking

products with micro-ox. It is therefore a bit

However, its sensory characteristics make it

up wine, soaking up money, giving cellar

odd that more publicly available research has

a sound choice for chips, staves and other

hands something heavy and awkward to

not been conducted on that combination. A

oak products where flavour can be the most

move, taking up space, decorating spaces

fairly wide range of oak products and micro-

important priority. Some producers in Galicia

for entertaining visitors, and providing a

ox strategies see endemic attention in the

are also interested in cultivating local oak

convenient home for Brettanomyces and

literature — and have for a decade or two—

options to preserve the ‘local’ aromas of their

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V I T I C U LT U R E P E S T S & D I S E A S E S

Frequency and distribution of fungicide resistance in Botrytis cinerea collected from Australian vineyards

By Lincoln Harper1, Fran Lopez-Ruiz1, Suzanne McKay2, Ismail Ismail2, Barbara Hall2 and Mark Sosnowski2

Screening of Botrytis cinerea cultures collected from Australian winegrape vineyards for fungicide resistance is currently underway in a Wine Australia funded project. More than 800 B. cinerea cultures collected between 2013 and 2019 were screened against three commercially-critical fungicides: fenhexamid, fludioxonil and pyrimethanil. The authors report on the resistance frequencies for these fungicides.

INTRODUCTION

B

spectrum multi-site fungicides (Australian

otrytis bunch rot (BBR), caused by

Pesticides and Veterinary Medicines

the fungus Botrytis cinerea (Figure

Authority).

1), is one of the most economically

B. cinerea is considered a ‘high-

important diseases of grapevines in Australia,

risk’ pathogen for fungicide resistance

second only to powdery mildew (Scholefield

development due to its high reproductive

and Morison 2010). BBR and other bunch rots

rate and short life cycle (Brent and Hollomon

impact all Australian grapegrowing regions,

1998). Monitoring the frequency of fungicide

with an average cost of $50 million per annum

resistance in B. cinerea is necessary to ensure

to the grape and wine industry (Emmett et al.

that management practices can be adjusted in

1992, Scholefield and Morison 2010).

a timely manner.

Besides cultural practices, the primary

B. cinerea cultures resistant to

approach to control BBR in vineyards is

anilinopyrimidines (APs, group 9) have been

through the routine application of fungicides

previously described in grapevines in Australia

(Elad et al. 2016). In Australia, chemical

(Sergeeva et al. 2002). Mutations associated

applications can include single-site and broad-

with resistance to fungicide groups 9, 12 and

IN BRIEF ■ Since 2013, Wine Australia has funded research into fungicide resistance in Botrytis cinerea.

■ Fungicide sensitivity screening

and the identification of resistance-associated genetic mutations against seven chemical groups was carried out between 2013 and 2016.

■ Samples were collected from vineyards in Western Australia, South Australia, Tasmania, Victoria, New South Wales and Queensland.

■ Resistance frequencies for

fenhexamid (TELDOR®), fludioxinil (one of the active constituents in Switch®) and pyrimethanil (SCALA®, fludioxinil and pyrimethanil) were tested.

Figure 1. Botrytis bunch rot caused by the fungus Botrytis cinerea on grapes. (Photo credit: Kejal Dodhia, Curtin University)

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School of Molecular and Life Sciences, Centre for Crop and Disease Management, Curtin University, Bentley 6102, Western Australia 2 South Australian Research and Development Institute, Plant Research Centre, Urrbrae 5064, South Australia

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