Wheat School: Should you spray for rust?

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Both stripe rust and leaf rust have been identified in the Ontario wheat crop. Will it affect your crop? What steps should you take to keep your crop safe from these leaf diseases?

In this episode of RealAgriculture Wheat School, resident agronomist Peter Johnson explains that stripe rust should be a concern for all growers while leaf rust is more of an isolated challenge that should only concern a few.

Last week, leaf rust was confirmed in a wheat field in Bruce County, Ontario. “We had a ton of leaf rust in the crop last year, but this is a case of us having the right conditions for it to overwinter,” says Johnson. “We should spray that field but it doesn’t put a huge spore load into the environment.” He adds that all growers should scout for leaf rust, and spray should they find it, “but it’s not a big deal for everybody.”

Johnson is more concerned about the potential impact of stripe rust, which had a tremendous impact on the 2016 Ontario crop. He notes that stripe rust blows in from south of the border so “the chances your wheat crop got exposed to stripe rust are really, really high.”

Do you need to spray a fungicide for stripe rust? That all depends on the variety, says Johnson. He recommends all growers go to www.gocereals.ca and check out the stripe rust tolerance rating for their variety.

He advises growers to keep a close eye on Venture and 25R46 – two of the hardest hit varieties last year. “If you have those in the field, you need to scout close and if you see even one pustule of leaf rust, you need to go out immediately and put on a fungicide.”

If growers see stripe rust in varieties with intermediate tolerance – a 4 rating – a fungicide is also required. “But if you have a variety with a 1 rating for stripe rust I think the genetic tolerace is good enough that the fungicide is not critical at this time,” adds Johnson. “You have to scout, but you may be able to wait and only have to spray your fusarium fungicide.”

Related: Wheat School: Identifying and Managing Stripe Rust

Click here for more Wheat School episodes.

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