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Mildew history

This may seem a little ‘dry’ but read on. History is important when mapping futures.

In 1970, research on grapevine downy mildew in the Riverland began in Loxton. From 1970-75, the Department of Agriculture’s plant pathologist Peter Dry began investigating the conditions favouring disease. With others from 1976, began what turned into a 50-year investigation into improved management of downy mildew in Australian vineyards.

Downy was first discovered in Australia in the wet-season 1917. It then spread across the eastern-states. In the very-wet 1950s, downy spread further but spray-machinery remained primitive. Severe national outbreaks in 1973/74 and 1974/75 triggered investigation into the finer aspects of disease epidemiology. Previously, downy in Australia was known to spread during ‘warm-wet’ days and ‘in wetter-than-average’ seasons. Hydraulic-boom and air-mist sprayers if present, applied Bordeaux mixture or later, other forms of copper, or the new products like mancozeb. Ridomil didn’t exist. Despite calendar-based schedules of 4-6 protectant sprays/season, downy wreaked havoc in wet-seasons.

In this pre-electronic era, clockwork-driven weather instruments with ink-nibs drew wiggly lines across paper charts to monitor temperature, humidity, leaf-wetness or rainfall.

Research in Europe was still published in French or German. This limited Australian research and international science exchanges were few. In the 1980s-90s, long-term international collaboration with pathologists from Cornell University and elsewhere boosted progress. With this help, networks of electronic weather stations became widespread and D-Model, an innovative computer-based simulator of downy epidemiology, was built to process weather data. Phone, fax and later, email, provided growers with advice of disease risk. In the late-90s, national collaboration led to AusVit®, an advanced decision-support system that included downy and the other foliage diseases and pests. But, it became a little-used market-failure!

Since 1995 CropWatch®, and latterly the web-based GrowCare® services, combined with advanced spray technology, provide a disease-risk advisory service for growers to make ‘decisions with precision’. Disease-risk alerts are poised to be sent from the next growing season via SMS within minutes of vineyard infection events. Downy mildew is no-longer Australian viticulture’s major foliage disease. So what’s next?

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