,

Can Stripe Rust Overwinter in Manitoba?

Short Answer: Yes.

Long Answer: Normally in Manitoba, the majority of our inoculum blows in from the central US states by what is known as the “Puccinia Pathway”. However, according to Dr. Brent McCallum, a Research Scientist with AAFC in Morden, MB, there was evidence of both stripe and leaf rust overwintering on winter wheat in Manitoba a few years ago but at such low levels it wasn’t a concern. Dr. Kelly Turkington, a Research Scientist with AAFC in Lacombe, AB, also indicated overwintering of stripe rust occurred in Alberta and parts of Saskatchewan in 2010/11 where there were measurable losses. In that particular year, there was a breakdown of resistance in the 2010 planted winter wheat crop and that led to higher infections into 2011.

So yes, stripe rust can overwinter. However, the ability of stripe rust to overwinter in Manitoba, or elsewhere, would depend on factors such as the severity of the winter and snowfall amounts.

If stripe rust is seen in the fall, take note of the variety and its resistance rating. Although nothing can be done about variety selection at this point, in the future consider stripe rust resistance when evaluating and selecting winter wheat varieties. Genetics….it’s a fast and easy way to protect your crop from disease pressure!

If winter weather conditions allow for overwintering of stripe rust, it could provide a local source of inoculum early in the spring – as early as the crop starts actively growing. A cool, wet spring could also favor spread and infection of stripe rust, not only to winter wheat but to other crops such as spring wheat.

If you do see stripe rust this fall in your winter wheat crop, mark those fields as ones to watch as soon as the crop breaks dormancy next spring. If stripe rust does overwinter, a fungicide application may be necessary.

Should a fall fungicide application be considered?

There has been some recent research conducted looking at the yield response and economics of a fall fungicide application in winter wheat. From 2011 to 2013, researchers from AAFC conducted a study across Western Canada looking at a variety of management factors, including one looking at a fall fungicide application. Results were recently reported in Top Crop Manager at http://www.topcropmanager.com/business-management/improving-winter-wheat-19554. The following statements are from the article.

In regards to the fall fungicide treatment, “the study showed some benefit from the fall foliar fungicide treatment, however the increase was small and resulted in decreased net returns,” says Turkington (who was involved with the study). “In areas with confirmed stripe rust in the fall, the yields gains were a bit better. However the cost of application is prohibitive at this point compared to no application. ”

More research is currently underway by Turkington and Dr. Randy Kutcher (University of Saskatchewan) looking at a fall fungicide application, a spring fungicide application at flag leaf emergence, and a dual application (one in the fall and one in the spring).  “The preliminary results after the first two years aren’t showing much of a benefit from the fall foliar fungicide application, similar to our recent study,” Turkington says. “Some of the results suggest a dual fall and spring application does not provide any additional benefit over a spring application in Western Canada.”

So for this fall, don’t pull out the sprayer if you see stripe rust in your winter wheat.  But, be ready to scout in the spring! And look for more updates to current winter wheat research underway across Western Canada.

Submitted by: Pam de Rocquigny, Provincial Cereal Crops Specialist and Holly Derksen, Field Crops Pathologist, Manitoba Agriculture; with assistance from Dr. Brent McCallum, AAFC Morden and Dr. Kelly Turkington, AAFC Lacombe.

Manitoba Agriculture on Twitter: @MBGovAg
Manitoba Agriculture on YouTube: www.youtube.com/ManitobaAgriculture
Manitoba Agriculture website: www.manitoba.ca/agriculture

 

Respond
Have a follow-up question?

Stripe Rust Inching Closer to Manitoba – Reminder to Scout!

Stripe rust, also known as yellow rust, is caused by the fungus Puccinia striiformis and can affect wheat, barley and triticale.  Stripe rust is identified by small,  yellowish uredinia that appear in linear rows the length of the leaf blade (see figure).

Stripe Rust in Winter Wheat 2015 (P.de Rocquingy)

Stripe Rust in Winter Wheat (Photo by P.de Rocquigny, 2015)

In Manitoba, stripe rust does not overwinter. Instead, the majority of our stripe rust inoculum blows in from the central US states by what is known as the “Puccinia Pathway”. Normally the first inoculum starts arriving at the beginning of June. However, this can vary depending on how much inoculum is present in the United States and when the winds blow from the south.

Fortunately, the progress of stripe rust inoculum, as well as other cereal rusts, is documented on the USDA’s website (http://www.ars.usda.gov/News/docs.htm?docid=9757). To date, there have been a number of stripe rust detections in winter wheat, with the most recent located in North Dakota (in winter wheat research plots in two different counties – as reported by Andrew Friskop, Cereal Extension Pathologist with NDSU Department of Plant Pathology).

In Manitoba, majority of winter wheat is in the stem elongation stage of development. There have been no reports of stripe rust to date; however, inoculum can move quickly so growers should scout their winter wheat for early infections. The good news is stripe rust can be managed by timely fungicide applications.  If the disease pressure, weather conditions (stripe rust favours cool, damp conditions) and crop yield potential warrant application, foliar fungicides should be applied before the disease is well-established in the crop to provide maximum benefit. There are numerous products available for the control of stripe rust; please refer to the Guide to Field Crop Protection.

For more information on stripe rust, its symptoms and control measures, visit Manitoba Agriculture’s website at http://www.gov.mb.ca/agriculture/crops/plant-diseases/stripe-rust-puccina-pathway.html.

Submitted by:  Pam de Rocquigny, Provincial Cereal Crops Specialist, Manitoba Agriculture

Respond
Have a follow-up question?
,

Stripe Rust Reported in Manitoba

As reported in the June 16th Insect & Disease Report issued by MAFRD (http://www.gov.mb.ca/agriculture/crops/seasonal-reports/insect-report-archive/insect-update-2015-06-16.html), stripe rust has been found in Manitoba.  The first report came from a winter wheat field southwest of Killarney, followed by symptoms being found in MCVET winter wheat plots in Carman (see Figure 1). And on June 18th, stripe rust was reported in spring wheat west of Altona.

Stripe Rust in Winter Wheat 2015 (P.de Rocquingy)

Figure 1: Stripe Rust on Winter Wheat. Photo by Pam de Rocquigny, 2015

Producers are encouraged to continue scouting their winter wheat and spring wheat fields as early detection is important. The good news is wheat stripe rust can be managed by timely fungicide applications.  If the disease pressure, weather conditions and crop yield potential warrant application, foliar fungicides should be applied before the disease is well-established in the crop to provide maximum benefit. There are numerous products available for the control of stripe rust; please refer to the Guide to Field Crop Protection.

If rust infections are only noticed later, especially past the flowering stage, a fungicide is likely unwarranted as the yield effect will be minimal.

For more information on stripe rust, its symptoms and control measures, visit MAFRD’s website at http://www.gov.mb.ca/agriculture/crops/plant-diseases/stripe-rust-puccina-pathway.html.

Submitted by:  Pam de Rocquigny, Provincial Cereal Crops Specialist, MAFRD with information from Holly Derksen

 

Respond
Have a follow-up question?
,

Qn: What are Stripe Rust Resistance Ratings for Wheat Varieties Grown in Manitoba?

In the most recent Insect & Disease Update (http://www.gov.mb.ca/agriculture/crops/seasonal-reports/insect-report-archive/insect-update-2015-06-02.html), Holly Derksen, MAFRD Pathologist, included a Rust Update where “stripe rust has been reported in North Dakota all the way up to the Canadian border” (source: Cereal Rust Bulletins, USDA).

stripe rust

Stripe Rust Symptoms. Photo Credit: Dr. Brent McCallum, Agriculture & Agri-Food Canada

What are the stripe rust resistance ratings for wheat varieties grown in Manitoba?  The most current stripe rust disease resistance ratings for spring wheat varieties can be found in Seed Manitoba 2015 (http://www.seedmb.ca/). There is variability of resistance levels in many of the CWRS varieties, but many of the current varieties do have improved levels of resistance.

However, resistance ratings for winter wheat varieties were not included in Seed Manitoba 2015, but will be in future issues.  Therefore, find below a table showing the stripe rust ratings for winter wheat varieties.  Disease data was collected during (and in some cases after) the varieties went through the variety registration process.

resistance level to stripe rust

Resistance level disease ratings:  R = Resistant; MR = Moderately Resistant; I = Intermediate; MS = Moderately Susceptible; S = Susceptible; ‘-‘ = not available.

 

Producers are encouraged to continue scouting their wheat fields!  To learn about stripe rust, its disease cycle and symptoms, and control measures, visit MAFRD’s website at http://www.gov.mb.ca/agriculture/crops/plant-diseases/stripe-rust-puccina-pathway.html.

Since winter wheat is advancing quickly, it is hopeful winter wheat will not be impacted if stripe rust does arrive here in Manitoba.  However, as mentioned earlier producers should continue scouting their spring and winter wheat fields.

Submitted by: Pam de Rocquigny, Provincial Cereal Crops Specialist, MAFRD

Respond
Have a follow-up question?

Should Manitoba growers be worried about the early reports of stripe rust in Alberta?

Submitted by Holly Derksen, MAFRD Field Crop Pathologist

Probably not.

Stripe rust has been reported in winter wheat fields in Alberta this spring (http://www.producer.com/2015/04/stripe-rust-in-alberta-winter-wheat/). This could indicate that the fungus overwintered on the crop. Overwintering of stripe rust in Canada also occurred in 2011, a year where there were measurable losses from stripe rust in both winter and spring wheat in Alberta and parts of Saskatchewan. That year a breakdown in resistance in the 2010 planted winter wheat crop led to higher infections leading into 2011. Persistent snow cover allowed for good overwintering conditions and a cool, wet spring favoured spread and infection of the stripe rust fungus. Growers in Alberta are being encouraged to vigilantly scout for the spread and proliferation of this disease this spring, especially in varieties that do not carry any resistance. Reports from Montana and Oregon have also indicated an early outbreak of stripe rust with fungicide applications being recommended in many cases.

In Manitoba, the majority of our inoculum blows in from the central US states by what is known as the “Puccinia Pathway”. Progress of this inoculum, as well as other cereal rusts, is documented on the USDA’s website (http://www.ars.usda.gov/News/docs.htm?docid=9757). To date, there have been a number of stripe rust detections with the furthest north located near Omaha, Nebraska. There have been no reports of stripe rust in Manitoba, however, inoculum can move quickly so growers should continue to scout their winter wheat and newly emerging spring wheat for early infections. The ideal timing for a fungicide application for protection against stripe rust in wheat is at the flag leaf stage. If rust infections are only noticed later in the year, especially past the flowering stage, a fungicide is likely unwarranted as the yield effect will be minimal.

Respond
Have a follow-up question?