News On the alert

On the alert

ADVANCING DISEASE SUPPORT FOR GRAPE GROWERS

Plant pathologist Peter Magarey’s disease alerts over the past three decades have saved hundreds of Australian growers time, money and possible heartache.

Peter is the brains behind GrowCare, an online tool and service that alerts growers to the risk of downy mildew and provides disease management advice.

Dried grape growers have benefitted from the alert system for the past three years, and particularly over the last growing season where several warnings were issued due to the high number of rain events.

Based in Loxton, South Australia, Peter has been offering the service to Riverland growers for 27 years. But the story starts long before then.

“I grew up on a pear orchard in the Adelaide Hills, so I saw how information was provided to my parents and I think that’s what’s motivated me over the years – to create something that works for growers,” Peter said. “I knew I had a calling to the Riverland and Australian grape growers, and I’ve really been undeterred from that calling.

“What I’ve wanted to do all the way through is deliver information to growers in a timely manner so they can make decisions with precision, decisions that are correct.”

The GrowCare service, working in collaboration with peak industry bodies like Dried Fruits Australia, is now “unparalleled” in its capacity to provide detailed information and advice on downy mildew and other diseases and pests.

“With the development of weather stations and computer technology, our knowledge of disease, and a functional simulator of disease, we are now able to advise if a rain event is going to be conducive to downy mildew or not,” Peter said.

“Using data collected from a number of weather stations within dried and wine grape vineyards, I evaluate the weather conditions through our various simulation models to determine the likelihood of disease risk, which might be high, medium, low or none.

“Then we’re able to do two things. We can say to growers that the weather event just passed was not conducive to downy mildew – save your sprays, save your worries, save your money. Equally, we can say the conditions that just occurred were conducive to downy mildew and provide a series of options for disease management based on what and when you’ve sprayed.”

Making history

Downy mildew was first seen in Australia in the wet season of 1917, and it spread gradually during the subsequent wet years of the 1950s and ‘60s until the mid-1970s when it wreaked havoc in most vineyards across south-eastern Australia.

“Downy mildew only develops really badly when conditions are consecutively favourable for infection over the early parts of a growing season, and if they stay bad for the mid part of the season, then bang – you can lose your leaves, you can lose your crop,” Peter said.

“The seasons of 1973/74 and 1974/75 were consecutively the two wettest years in Australian history at that point.

“Many growers suffered near total crop loss and their vineyards were severely defoliated. Some didn’t know what downy mildew was, but they soon found out.”

The devastating losses triggered research by the South Australian Department of Agriculture at the Loxton Research Centre, now known as the South Australian Research and Development Institute (SARDI).

Around the same time, Peter was finishing his degree in ag science at the University of Adelaide followed by an honours year in plant pathology. He was planning on going back to work on the family orchard, but instead took on the role of senior plant pathologist at the research centre and “got straight into the thick of it with downy mildew”.

“It was 1976 and growers really wanted some solutions,” Peter said.

“I was tasked to continue investigations, started by then plant pathologist Peter Dry, into the epidemiology of downy mildew. Over the next few years, I did more work to determine under what conditions downy mildew infection occurred and how the disease spread.” Following Peter’s marriage in 1981 to Carla, an American woman, the couple travelled to the USA and met downy mildew expert Dr Bob Seem, who became his friend and colleague researcher for the rest of Bob’s working life.

Bob visited Loxton many times to offer specialised help to Peter and his colleague Malcolm Wachtel. Together they built a disease simulator – the first in Australian viticulture and one of the first globally to be used commercially to predict downy mildew infection events for grape growers.

It was put to the test in 1983/84 – the next “really wet” season after the 1970s events. While growers lost a lot of crop, the early prediction system helped to save some of it. Then during the “bad” years of 1992/93 and 2010/11, the team was able to offer much more help to growers.

Things that endure

Peter is now working on his next challenge – developing a GrowCare mobile phone application to make it even quicker and easier for growers to access the information they need. The first version of the app is expected to be available in the next year.

“At the moment we push out newsletters, but we want growers to be able to pull in information related to their vineyard,” he said. “At a glance, they want to know the outcome from their nearest weather station and what to do in their vineyard – whether to spray – so they can be on their way.”

Peter said the new project was aiming to transfer all their data, as well as the decades of knowledge stored in his head, into an application that will live on after he’s gone.

“I’ve been wonderfully blessed in the years I’ve been able to work because of my colleagues nationally and internationally. It’s been so satisfying and just wonderful being able to build things together – things that count, things that endure,” he said.

“That’s what I’m trying to do now. I’m going to be gone one day, and I’ve got Parkinson’s, so when I’m not here anymore, I’d like people to still be able to readily access that information with ease.

“If I can do that before I’m gone, I think I’ve achieved something that may be helpful. Until such time, it’s still head to the grindstone.” v

This page and far left: GrowCare directing founder Peter Magarey presenting at a workshop for dried grape growers in Sunraysia.

Middle: Peter Magarey and Bob Seem looking for downy mildew in a vineyard with overhead misting during studies to determine the conditions in which the disease spreads.