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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

 

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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

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Cereal Crops Recovering from Frost Injury

The May 30th frost impacted spring cereal crops across Manitoba. Fortunately, majority of spring wheat, oats and barley were at the tillering stages of development where the growing point is still below ground and therefore protected from the cool air temperatures (the growing point moves above ground at jointing or stem elongation).

However, this doesn’t mean cereal crops escaped without some symptoms of injury.  In MAFRD’s June 3 webinar (available on YouTube at http://youtu.be/UDa3uWMmZzg), I covered some of the basics of frost injury symptoms in cereal crops and what to look for in terms of recovery. (And for those interested in canola and flax, my colleague Anastasia Kubinec of MAFRD covered some excellent material for those crop types in the same webinar).

For cereals, you want to look for new leaf growth (normal green color) from the growing point that should follow within 2 to 3 days after the frost event. It can go upwards of 5 days if growing conditions are cool.  Below is a great photo by Lionel Kaskiw with MAFRD which shows barley impacted by frost recovering.  You’ll also notice the water-soaked appearance of some of the older leaves, a classic symptom of frost injury.

Frost Damaged Barley

Frost-Damaged Barley Recovering; Note New Leaf Growth Emerging from the Growing Point – Photo by Lionel Kaskiw, MAFRD (2015)

Fortunately, the loss of leaf tissue at this early stage should have little impact on yield.  But be cautious when applying herbicides in the coming days.  Generally, you want to wait for at least 48 hours after the frost event, as well as seeing the crop resuming growth.  However, please check with your local chemical representative in terms of when it should be safe to apply herbicides after a frost event as it can be product-specific.

More additional information on frost damage, refer to MAFRD’s Spring Frost Damage Bulletin.

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

 

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Thinking about Reseeding Cereals? Read this First.

I have been receiving a few calls on producers considering reseeding poor barley stands, or concerned about their cereal crops in general. So I thought I would take this chance to review some key points producers and agronomists should think about if considering reseeding their cereal acres. A lot of the information is derived from a great article by North Dakota State University staff titled “Replanting or Late Planting Crops” (Publication A-934; Revised). I have included some of that information and added Manitoba-specific data and comments.

Why are some cereal fields impacted? Many producers were able to start seeding their cereal crops early in 2015. However, slow and/or uneven emergence was noted in many fields due to cool soil temperatures, dry soil conditions (in some areas of the province) and below normal temperatures following emergence. The slow growth was further complicated by excessive rainfall, wind, snow and frost over May Long weekend, and then another frost event on May 30. Not only do these conditions bring with it concern for erratic crop emergence and poor plant stand establishment, it can also promote a number of seeding diseases and root rots.

The Main Question to Answer. At the end of the day, producers must try and answer the question “Will which result in greater net return – keeping the original stand or replanting to the same/different crop?”.

The final decision should be backed by sound agronomic and economic information as well as taking into consideration AgriInsurance coverage and contracts. Agronomic information to consider should include: level of injury, crop uniformity and overall plant health of the original stand, alternate crop choices if reseeding, and management practices related to crop growth and development for either the original stand or the replanted crop. Producers and their agronomists should accurately assess all these factors in order to make an informed decision. I realize that is a lot of information to gather. Perhaps it is easy to think of it in a few steps.

Step 1: Evaluate original crop stand and yield potential. The best possible evaluation of the surviving stand is needed because the critical yield comparison ultimately will be between the original stand versus the replanted stand with a later than optimum planting date.  Remember, you need to allow time for crop to recover from injury prior to assessing plant stands!

To accurately evaluate the existing stand, stand counts should be taken at random from several areas of the field. For more information read the article “Doing Plant Stand Counts in Your Cereals”: http://cropchatter.com/doing-plant-counts-in-your-cereals/.  Typically for cereals, minimum stand levels that should be considered acceptable before reseeding is done ranges from 8 to 14 plants per square foot (NDSU). During early growth stages, most cereal crops can sustain some stand loss without experiencing significant yield reduction due to increased tillering. Keep in mind barley and oats typically tiller more than spring wheat.

However, the minimum stands stated is assuming plant stands are relatively uniform in distribution; what can complicate this assessment is the damage in fields can be distributed randomly throughout the field.

In addition to the direct effect of stand reduction, indirect effects of crop injury, such as increased weed competition and increased disease potential, should be considered. Damaged crops usually grow slowly until they have recovered, which provides the potential for greater weed competition.

Step 2: Evaluate yield potential & agronomics of replanted crop options. Crops replanted later in the season almost always will yield less than those planted at an optimum time. Figure 1 shows the yield potential of various crop types as seeding moves into June in Manitoba.

Figure 1: Percent Average Yield from 2005-2013 for Manitoba Crops Planted in Week/Month as Reported to MASC

Picture1

Not only yield potential should be considered however. A short growing season increases risk of damage by fall frost affecting both yield and quality of the replanted crop. Increased risk of high daytime temperatures can also affect crop development. For example, there is increased risk of the crop flowering when daytime temperatures are high which can increase probability of floret abortion.

Delayed seeding may also increase potential of yield loss due to disease and insects. MAFRD articles Crop Choices in a Late Planting Scenario and Mitigating Risks Associated with Delayed Seeding will provide additional information to producers.

Step 3: Determine Reseeding Costs. Comparison of the estimated yield of the original stand with expected yield of the replanted crop minus any costs associated with reseeding must be considered.

The decision to reseed ultimately must be made by comparing the economics of the original plant stand with that of a replanted crop. This can be subjective and each case must be considered individually in terms of time of year, alternate crop choices, previous herbicide use, crop economics, AgriInsurance coverage and contracts, and other related factors.  If a producer has AgriInsurance, it is recommended they contact their MASC agent prior to terminating a field and replanting.

Once again, I’d like to acknowledge information from NDSU’s article “Replanting or Late Planting Crops” (Publication A-934; Revised).

Submitted by: Pam de Rocquigny, Provincial Cereal Crops Specialist

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A History of the Recommendations Made by the PRCWRT

The Prairie Recommending Committee for Wheat, Rye and Triticale (PRCWRT) evaluates candidate cultivars (varieties) of wheat, rye and triticale and, upon the request of the owner or designate, makes recommendations to the Variety Registration Office, Canadian Food Inspection Agency regarding the suitability of the candidate for registration.

The attached file shows a history of their recommendations made from 1959 to March 4, 2014:   PRCWRT Recommendations 1959-PresentNote: some varieties recommended have been registered by CFIA since the file was last updated.

As you look through the list, you’ll see the number of varieties that were supported by the PRCWRT have increased over the years.  You will also note that even though a variety was supported by the PRCWRT, not all lines were registered (see comments column).

For more information on the PRCWRT, visit their website at http://www.pgdc.ca/committees_wrt.html

Submitted by: Pam de Rocquigny, Provincial Cereal Crops Specialist

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The Relationship between Yield & Protein in MCVET Spring Wheat

There are numerous factors that impact protein content in wheat.  While environmental factors such as moisture and temperature have large effects on protein content, production practices such as variety selection, seeding date and fertility management can also influence protein content.

Influence of Genetics.  Not all wheat varieties have the same potential for grain yield and differ slightly in their ability to convert soil nitrogen to grain protein.  We typically see higher yielding varieties with lower protein content, largely due to dilution as protein is diluted by the increased carbohydrate (i.e. kernel number) production seen with higher yields.

Manitoba Data. Jochum Wiersma of the University of Minnesota created the following scatter plot for me that I included in a recent Ag Days 2015 presentation. The figure includes the long term data of varieties belonging to the CWRS & the CWGP classes tested by MCVET.   Long term yield data is from 2000 to 2014 expressed as a % of the overall grand mean (66 bu/ac), while protein data is from 2002 to 2014.

Picture1

As the figure illustrates, there is a grouping of varieties according to class based on the relationship between yield and protein content.  However, there is variation with each class and there are a few varieties with higher yield potential that still has protein content appropriate for the CWRS class.

Submitted by: Pam de Rocquigny, Provincial Cereal Crops Specialist

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Yields Respectable in 2014 Despite a Challenging Year

Manitoba Agricultural Services Corporation (MASC) has released an early version of the 2014 yield report with 99.8% of the Harvest Production Reports (HPRs) keyed in.  The table below summarizes the 2014 average yield by crop type based on the harvested acres, as well as comparisons to 2013 and a 5-year average (2009 to 2013).

2014 yields

In February 2015, MASC will release their annual Yield Manitoba publication and update their Manitoba Management Plus Program (MMPP) website (http://www.mmpp.com/mmpp.nsf/mmpp_index.html) where further information on yields and acres by variety will be released.  Additionally, the data will be more complete in February as all HPR’s will be keyed in.

Submitted by:  Pam de Rocquigny, Anastasia Kubinec & Dennis Lange, Crop Specialist with MAFRD

Special Thanks to Doug Wilcox, MASC, for providing the 2014 data!

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Results of the 2014 FHB Spring Wheat Field Survey

Forty-seven spring wheat fields in Manitoba were surveyed by MAFRD staff to visually assess the incidence and severity of fusarium head blight (FHB).  Fusarium head blight in each field was assessed by sampling 100 plants when most crops were at the growth stage of ZGS 73 – 85. In each field, the percentage of infected spikes (disease incidence) and the mean spike proportion infected (SPI) were determined. The FHB Index (overall severity) was calculated as (% incidence x % SPI / 100).

RESULTS:

Symptoms of FHB were observed in 35 out of the 47 fields. The average % disease incidence was 5.9% (range 0 – 28.0%), SPI was 16.8% (range 0 – 55.0%) and the resulting average FHB Index was 1.0% (range 0 – 7.4%). Table 1 further illustrates the average FHB Index in the four regions of Central, Eastern/Interlake, Southwest and Northwest, and the number of fields surveyed per region.

2014 FHB Index in Spring Wheat by Agricultural Region

The 2014 FHB Index of 1.0% was lower than the 10-year (2003-2012) average of 2.9% (see Table 2) and similar to the previous few years. No survey was conducted in 2013 but levels were considered low.

Average FHB Index in Manitoba Spring Wheat (2003-2012)

Although favourable conditions for inoculum development and infection of the winter wheat crop existed in 2014, a transition to warmer, drier weather conditions when spring wheat was at anthesis, combined with foliar fungicide application in majority of fields surveyed (83%), likely contributed to the reduced FHB severity and little to no yield or quality loss in spring wheat.

Samples of infected heads were also collected and sent to AAFC Morden for further analysis of Fusarium species responsible for infection.

Submitted by:  Pam de Rocquigny, Provincial Cereal Crops Specialist

MAFRD Staff who conducted surveys: Ingrid Kristjanson, Dennis Lange, Earl Bargen, Derek Chomokovski, Rejean Picard, Amir Farooq, Lionel Kaskiw, Elmer Kaskiw, Marnie McCracken, Stephanie Jersak & Pam de Rocquigny.

A special THANK YOU to those producers who allow MAFRD to survey their winter wheat fields!

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Leaf Rust in Spring Wheat

Over the past several weeks, I have been touring the MCVET cereal sites.  Last week, I found leaf rust in one of the spring wheat trials in southern Manitoba.

Wheat leaf rust, caused by Puccinia triticina, is one of the most common diseases of wheat on worldwide.  The most characteristic signs of leaf rust infection are the rusty-red spores in round to oval pustules breaking through the leaf surface.

Leaf Rust in MCVET Spring Wheat Trial 2014

Leaf Rust in Spring Wheat. Photo by: Pam de Rocquigny, 2014

Yield loss and reduction of test weight are related to disease severity and time of infection. Yield losses of 30 percent to 40 percent have been recorded when severe infection occurred before flowering and damage on the flag leaf was high (> 60 percent to 100 percent).  However, if severe leaf rust does not occur until dough stages of kernel development or beyond, yield losses may be in the range of 5 percent to 15 percent.

Genetic resistance in varieties to leaf rust limits infection and retards fungus growth and spore formation. The population of the leaf rust fungus is genetically diverse and made up of many races. Different races have the ability to cause infection on varieties with different resistance genes. The leaf rust pathogen is dynamic, and races are constantly changing. Varieties formerly considered resistant can become susceptible if new rust races develop. Resistant levels are reviewed (and updated if necessary) each year for varieties and are provided in SEED MANITOBA (www.seedmb.ca).

Surveys & Monitoring is Important!  Field surveys conducted during the growing season by AAFC and MAFRD is critical as it allows the sampling of the natural populations of pathogens in the field to determine the virulence in the populations.  This in turn provides an indication of the effectiveness of current resistance sources for new crop cultivars. Growers should also monitor their crops throughout the season and be aware of disease developments in their local area. Monitoring, and early detection and reporting of rust will improve disease management outcomes.

Submitted by:  Pam de Rocquigny, Provincial Cereal Crops Specialist

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Finding Ergot?

MAFRD staff have been busy doing surveys in cereal fields and MCVET trials over the past several weeks.  I have come across ergot in a number of winter wheat and spring wheat fields, as well as the MCVET spring wheat trials.

What is Ergot?  Ergot infects many cereals and grasses, including, in order of decreasing susceptibility, rye, triticale, wheat and barley. Oats are rarely affected. Ergot symptoms become evident during kernel formation, when ergot bodies are formed in place of kernels. The ergot bodies, also called sclerotia, are formed from a hard mass of fungal mycelium. The ergot bodies have a hard protective rind on the outside, which is black to dark purple in colour. They are often elongated and protrude from the glumes of maturing heads (see photo below).

Yield reductions are usually slight. However, the ergot bodies contain toxic alkaloids that are poisonous to humans and livestock, which can result in rejection or downgrading of contaminated grain.

Ergot

Spring Wheat Infected with Ergot.  Photo by Pam de Rocquigny, 2014

Conditions that favour Ergot – Ergot is most prevalent in years when cool, damp weather in late spring and early summer favour ergot germination and prolong the flowering period of cereals and grasses increasing the opportunity for ergot infection.

What are some options for managing Ergot?  Unfortunately, there is not much to control ergot in the field once ergot is found. Prevention is the best management strategy.

  • Harvesting techniques: Ergot levels are typically higher around the edge of the field so scout fields to determine where ergot development is the worst, such as the headlands, and harvest those areas separately. In some cases, delaying harvest of a standing crop may allow more time for ergot bodies to fall out of the head.
  • Tillage: For farmers using conventional tillage, burying the crop residue and ergot bodies to a depth of approximately four centimetres can impede their germination the following spring.
  • Seed cleaning: Ergot bodies are relatively easy to clean from the seed lot, but can be expensive. However, it may be worth the cost to save a grade.
  • Plant clean seed: Planting seed infested with ergot bodies can spread disease to previously clean fields. There are no seed treatments effective against ergot.
  • Crop rotation: Ergot bodies survive in the soil for approximately one year, so crop rotation away from cereals for one to two years is recommended.
  • Sanitation: Mow around headlands or roadways to remove grasses before they flower so they do not serve as a host for the first stage of the disease cycle.

Submitted by: Pam de Rocquigny, MAFRD Cereal Crops Specialist

Sources:

 

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