Australia
January 15, 2016
Source
Monsanto’s global team of scientists have discovered a new Downy Mildew isolate which does not match any of the registered Pfs:1-15 races.
The isolate, tested in Monsanto’s world-class laboratories in Holland, has been found on spinach in Australia and some European countries in the past year.
Monsanto Global Technology Development Crop Lead Kevin Walsh said it’s too early to declare a new strain of Downy Mildew, however scientists will be keeping a close eye on the isolate over the next six to twelve months.
“We find new isolates of Downy Mildew each year in lettuce and spinach. We monitor these isolates over time and location.
“Some isolates only appear in one season in one place; whereas other isolates will re-appear in the next seasons in multiple locations.
“In this case, we have seen the isolate appear in Europe and in Australia across a single season. It’s too early to declare a new race of Downy Mildew, but if the isolate is found again in subsequent seasons it may become a candidate for Pfs: 16 or 17”
Mr Walsh said Australian growers should be vigilant and apply Integrated Disease Management (IDM) techniques to ensure crops are protected against any new strains of the disease.
“When planting disease-resistant varieties, it’s unwise to rely on this as the only form of disease management. New pathotypes are developing all the time. This is a normal process that may be affected by an unpredictable climate and shifts in weather patterns.”
He said that while the use of IDM does not 100 per cent guarantee that crops will be free of disease, it provides growers with the best possible chance compared to using disease-resistance packages alone.
“Combining disease-resistance packages with other disease management strategies like weed control, crop rotation and responsible chemical use is best for two reasons: it slows the development of new strains of the disease and it provides growers with more choice.
“Rather than chasing a variety just for its resistance package, growers who use IDM can produce varieties they like that are popular in the market.”
“They have more choice when it comes to the leaf shape, the leaf quality and savoyness – these are all elements that matter to the consumer.”
Mr Walsh said Monsanto invested millions of dollars annually in breeding programs and IDM research to provide growers with peace-of-mind on disease protection.
“Monsanto breeders are already working on varieties resistant to the particular new pathotype we’ve found as it’s essential to stay ahead of the curve and provide the most resistant plants possible.”
IDM strategies for Downy Mildew in spinach and lettuce:
- Choose disease resistant packages: When it comes to protecting your crop against disease, Monsanto is thinking years ahead. Its dedicated team of scientists and breeders looks into all new isolates to ensure they can continue to provide products to growers that will perform well against future disease threats.
- Develop a responsible chemical management plan: Don’t wait until the disease is present. Start by using a protectant fungicide to stop fungal spores penetrating the plant. Only use stronger systemic fungicides when you see the disease appear. Rotate chemical classes and never over-apply chemical: that’s how chemical resistance starts.
- Control weeds: Fungal spores can be harbored in weed varieties – so don’t be lax when it comes to managing weeds on your property, even during the off season.
Rotate crops: This will prevent diseases from building up in soil.
How is a new race of Downy Mildew determined?
The International Working Group on Peronospora farinose (IWGP) is responsible for determining if new isolates of Downy Mildew classify as races. The IWGP looks at indicators including:
- If there has been economic impact
- If it has been found in multiple geographies
- If it has appeared across multiple seasons
- If it has been present on multiple varieties.
Species
