Hail Damage – What is the Yield Loss in Cereals & Corn?

Submitted by Anne Kirk, Cereal Crop Specialist, Manitoba Agriculture

Hail has been reported in several areas of Manitoba, and due to the size of the hail and duration of the storm, crops were affected in some areas.  Assessments of damage will occur over the next few days.  The amount of loss expected from a hail event depends on the severity of hail, crop type, and the growth stage of the crop.

Spring Wheat – is least susceptible to hail damage prior to stem elongation since the growing point is below the soil surface and will likely not be damaged.  Hail damage during jointing or in the boot stage is difficult to assess.  Spikes can still pollinate and fill, and regrowth from new tillers can occur.  The more advanced the wheat is at the time of hail the greater the yield loss.  The greatest yield reduction from hail occurs in the milk stage.

Oats and Barley –  will tiller and recover better from hail than wheat, especially prior to the boot stage.  Grower experience has demonstrated that barley hailed severely in the boot stage has recovered to produce 70-80% of normal yield.  Crop hailed prior to the boot stage should be left if stems or green tissue remains.

Corn – early season hail occurring when the growing point is still below the soil surface will result in very little yield loss.  At the 6 leaf stage the growing point is above ground, but leaf loss without damage to the growing point has a small impact on yield.  Yield loss as a result of hail can be estimated by determining percent leaf defoliation (Table 2).   Leaf area removed and leaf necrosis need to be considered, while damaged green leaf tissue should not be included.  Assess leaves 7-10 days after a hail event, so that living and dead tissue can be easily distinguished.

Assessing Damage – New growth should be evident within a few days after a hail event.  Assess crop to evaluate new crop growth.    Yield potential of a damaged crop will depend on rainfall and temperatures in the next 30 days after hail damage.


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Copper Deficiency in Wheat – Symptoms and Cures

Submitted by John Heard, Soil Fertility Specialist, Manitoba Agriculture
Classic symtoms of copper deficiency on soils likely low in copper are:
·         twisted leaf tips 
·         sandy, low OM , high pH soil with known low copper levels 
Or could it just be environmental stress due to frost injury, lack of moisture and drying winds?
A tissue test is needed to confirm copper deficiency as the culprit. 
Studies in Manitoba compared three timings of foliar copper sprays on deficient spring wheat and showed that copper deficiencies and impact on yield can be severe or slight and can vary from year to year.
Timing and application method are important to regain yield! For more information and pictures on copper deficiency, see the full .pdf copy of Copper Deficiency in Wheat
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Post Anthesis Nitrogen for Wheat Protein

When wheat prices and protein premiums/discounts are high, there is renewed grower interest in late N applications to enhance wheat protein. Following is an old recipe we have recently evaluated in on-farm-tests and small plot studies.

  1. Apply 30 lb N/ac, which is 10 US gallons of UAN solution (28-0-0) diluted with 10 gallons water
  2. Apply with flat fan nozzles
  3. Apply 7-10 days following anthesis (so about 7-10 days after your fusarium head blight fungicide)
  4. Apply in morning or evening when temperatures are less than 20o C. Avoid heat of the day.

Under such treatments we have observed leaf burn of 8-15% of the leaf area without detrimental impact on yield. The one instance sprayed at mid day in high temperatures reduced yields by  6 bu/ac with 31% leaf damage . Protein increase ranged from 0-1.5% and averages are reported in Table 1.

Table 1. Effect of post anthesis N (PAN) on wheat class yield and protein (2015-16).

  CNHR (6 sites) CWRS (7 sites) CPS (2 sites)
Yield bu/ac
Base N 80 68 69
Base N & PAN 78 68 65
Protein %
Base N 13.0 14.2 13.8
Base N & PAN 13.6 14.6 14.1


In most cases, the farmer’s base rate of N was high at 150-200 lb N/ac (soil N plus fertilizer), so the extra N was not required for high protein.

The full on-farm-test report is available from the Manitoba Wheat and Barley Growers Association at: http://www.mbwheatandbarley.ca/wp-content/uploads/2014/11/OFT-summary-2017-FINAL.pdf

If attempting such a practice, leave a check strip – not so much for yield determination, but to gauge the success in protein increase.



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Will I be able to improve the grade of my grain by using gravity tables and colour sorters?

Gravity tables and colour sorters have been shown to be an effective way of sorting out fusarium-damaged kernels (FDK) if the grower has the time and money to spend on the method. Gravity tables remove kernels based on density and are effective at removing heavily infected seeds, but can also result in the loss of healthy seed. Optical sorters remove kernels based on visual differences, but the process can be time-consuming and is more suited to hard wheat than soft wheat. Additionally, fusarium-damaged barley and oat do not show significant shrivelling and are not likely to be removed by equipment sorting by density, weight or colour.

It is important to remember that removing FDK (i.e. visibly infected kernels) from a grain sample does not mean that the grain is free of DON, the toxin produced by Fusarium graminearum. The relationship between FDK and DON varies and in years where infection occurs late in anthesis (or even after anthesis), visual symptoms are not always apparent whereas DON levels can still be elevated. While the Canadian Grain Commission grades wheat based on percent FDK, some markets are interested in DON levels. It is important to discuss with grain buyers and/or elevators their guidelines regarding FDK and DON. It is also recommended that growers test their grain for DON to best determine how to market it.

There is newer technology available that sorts grain based on chemical composition using near infrared transmission (NIR). This method is more effective at reducing DON levels because it is not only dependent on visual symptoms on the kernel. The machinery required to sort grain using NIR can be quite expensive to purchase, but is relatively inexpensive to run. For more information on this technology please refer to http://bomill.com/products/.


Submitted by

Holly Derksen, Field Crop Pathologist, Manitoba Agriculture

Barbara Ziesman, Provincial Specialist, Plant Disease, Saskatchewan Ministry of Agriculture

Michael Harding, Research Scientist, Plant Pathology, Alberta Agriculture & Forestry

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Getting the Facts on Fusarium Head Blight

Fusarium head blight, or FHB, is a major disease that wheat and other cereal producers deal with each year to varying levels. The conditions in 2016 were conducive for infection in both winter and spring wheat as well as other cereal crops (symptoms were observed in both barley and oats). While 2016 was not the worse year on record for FHB in Manitoba (see post on FHB survey results), levels across the prairies were amongst the highest they have been in recent years.

Manitoba Agriculture has partnered with Alberta Agriculture and Forestry and the Saskatchewan Ministry of Agriculture to develop a Q & A series “Getting the Facts on Fusarium Head Blight”. This series will address FHB issues producers faced in the 2016 season as well as issues they are facing regarding infected seed. The answers provided will be a combined effort of the provincial disease specialists with input from researchers at Agriculture and Agri-Food Canada, the University of Saskatchewan, and the University of Manitoba.

If you have a question you would like to see addressed please submit via Crop Chatter or contact your provincial disease specialist.

Submitted by

Holly Derksen, Field Crop Pathologist, Manitoba Agriculture

Barbara Ziesman, Provincial Specialist, Plant Disease, Saskatchewan Ministry of Agriculture

Michael Harding, Research Scientist, Plant Pathology, Alberta Agriculture & Forestry

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Wheat Class Modernization – Changes Coming August 1, 2016

Over the past few weeks, I have spoken at a couple of crop tours.  When presenting in front of the MCVET spring wheat trials, one of the questions I asked attendees was “Who knows what is occurring on August 1, 2016?”.

The answer is the first steps of the Wheat Class Modernization by the Canadian Grain Commission. On August 1, 2016 there are 2 new classes being created: Canadian Northern Hard Red (CNHR) and Canada Western Special Purpose (CWSP).  There are many varieties moving to these 2 new classes.  Primary grade determinant tables will also come into effect August 1, 2016 and are available here:

There are also three wheat classes being eliminated on August 1, 2016:

  • Canada Western Interim Wheat (CWIW);
  • Canada Western General Purpose (CWGP); and
  • Canada Western Feed classes.

My colleague in Saskatchewan, Provincial Cereal Crops Specialist Mitchell Japp, wrote an article Wheat Class Modernizing Starts August 1, 2016.  It is a must read and covers the changes coming August 1, 2016, and includes important links to additional information.

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

Manitoba Agriculture website: www.manitoba.ca/agriculture
Manitoba Agriculture on Twitter: @MBGovAg
Manitoba Agriculture on YouTube: www.youtube.com/ManitobaAgriculture
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Seeing Tall Plants in Your Semi-Dwarf Wheat?

Originally published July 24, 2015

If the differences in height are sporadic throughout the field, i.e. the odd plant here and there, it is probably one of three things causing these ‘tall-types’:

  1. a result if seed of another variety was inadvertently comingled with the variety you think you have (through cleaning of equipment, bins, harvest, etc.).
  2. a variety that is segregating for plant height – is less common but in extreme growing conditions can bring differences in plant height that previously had gone unnoticed.
  3. with introduction of semi-dwarf genes (Rht1), it’s been noticed that in certain lines and genetic backgrounds a number of tall plants would appear at a low frequency from one generation to the next generation.  Fancy terms is some plants become aneuploids, meaning individual progeny has one or more chromosome missing or extra.  Monosomic deletions, i.e. plants missing one chromosome, are most commonly encountered. Because Rht1 act as a suppressor of height, their reduced dosage as in monosomics, produces plants taller than in the euploid condition.If seed is saved, half the plants derived from these tall-types should revert back to the original variety, while the other half of the plants will be the taller-types again.

There is a very good article in the 2015 Saskatchewan Seed Guide (page 20) further explaining these ‘tall types’ in semi-dwarf wheat: http://www.saskseed.ca/images/seed_guide2015.pdf.

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


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

Information provided is from the Manitoba Insect and Disease Update for the week of July 13th at: http://www.gov.mb.ca/agriculture/crops/seasonal-reports/insect-report-archive/insect-report-2016-07-13.html

You will often find aphids clustered on some plants; adults with the young nymphs nearby. Aphids develop through their stages very rapidly, so when monitoring all aphids are counted, not just larger ones. Parasitized aphids (Fig. 2), known as aphid mummies will look swollen and discoloured and are not counted.


Fig. 1. Aphids on wheat

Fig. 2. Aphid mummy

The economic threshold on cereals is 10-15 aphids /stem prior to the soft dough stage. Research has found that after the early-dough stage insecticide treatments were not cost-effective.
Scouting tips: It is quite normal to find some plants with 10-15 or more per stem, but if there are a lot of plants around these with none or very few per stem, than the field would be below the economic threshold. If you can randomly pick plants (not looking specifically for plant with aphids to do counts on), and on average be above 10-15 per stem, and not yet at the soft dough stage, that is the point when insecticides become economical. Aim to sample at least 20 stems for aphids; selecting 5 stems from each of at least 4 areas of the field is a good sampling plan.
Factors regulating aphid populations: Sometimes aphid populations will increase, but other times populations will stabilize or decrease due to predators and parasites, diseases, or heavy rains which can reduce a population. So if a heavy rain goes through, sometimes it is good to reassess a population. And if natural enemy levels are high, it is good to assess whether levels of aphids are possibly declining.
Soil moisture levels and aphids in cereals: As another consideration, research on English grain aphid in winter wheat found that there was a greater yield reduction for a given aphid density when plants were grown under water stress versus nonstress conditions. They concluded that “therefore, the water status of the plant should be considered to determine an economic injury level for S. avenae infesting winter wheat” (Environmental Entomology. 1988. Pp. 596-602). This may be difficult to do, but does show that a given level of aphid feeding on cereals is likely to reduce yields more when plants are growing under water deficits, which is generally not the case this year.
Submitted by: John Gavloski, Entomologist, Manitoba Agriculture


Visit the Insect Pages of Manitoba Agriculture’s website at:http://www.gov.mb.ca/agriculture/crops/insects/index.html


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Assessing Hail Damage in Cereal Crops

Over the last few days, hail has been reported in several areas of Manitoba, potentially impacting cereal crops. Assessing damage will take a few days, and impact will largely depend on stage of the crop and how severe the hail event was, i.e duration of storm, size of hail.

Generally, cereal crops prior to stem elongation can recover from hail, even if there is substantial leaf damage as the growing point is below the soil surface and will likely not be damaged.

Hail damage occurring during stem elongation or the boot stage can be difficult to assess. Spikes can still pollinate and fill, and regrowth from new tillers can occur. Generally speaking, hail causes the greatest damage to small grains from the boot stage through later stages.

In a study by R.H. Busch in North Dakota in wheat, the greatest yield reduction resulted when stems were broken in the milk stage, followed by anthesis, soft dough, boot, and hard dough stages – see Table below (Busch, 1975).

Grain yield reduction in spring wheat with 100 percent of stems bent.
Growth stage Yield reduction (%)
Boot (Zadoks 45) 28 to 39%
Anthesis (Zadoks 65) 15 to 60%
Milk (Zadoks 75) 30 to 70%
Soft dough (Zadoks 83) 16 to 55%
Hard dough (Zadoks 87) 3 to 47%
Table derived from Busch, 1975


Remember to contact your hail insurance provider for their procedures in assessing hail damage as they may be different than what has been provided here.

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

Source:  Busch, R. H. 1975.  The effect of simulated hail injury on spring wheat. North Dakota AES Bulletin 497. 18 pp.
Manitoba Agriculture website: www.manitoba.ca/agriculture
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Have you thought about your seedling mortality?

You’ve chosen the variety or varieties you want to grow in 2016. You’ve decided on your target plant stand. And from your seed test results, you have the percent germination and thousand kernel weight (TKW). But have you given any thought to your seedling mortality?

When calculating the seeding rate needed to achieve your target plant stand, you often hear about TKW and percent germination. But remember when calculating seeding rates, you need to take into account the seedling mortality rate, i.e. what percent of viable seed will germinate but not produce a plant.

Seedling mortality can vary greatly from year to year, and field to field. For cereals, seedling mortality rates can range from 5 to 20%.  Many farmers and agronomists have found a 5 to 10% mortality rate can be assumed. However, farmers may need to make adjustments to their seedling mortality based on factors such as available moisture, soil temperature, residue cover, seed quality, amount of seed-placed fertilizer, seeding depth, seeding date, and disease and insect pressure.

One additional factor you maybe should consider is the impact of seeding rate itself on seedling mortality or stand loss. Grant Mehring from North Dakota State University shared some recent work at the 2015 Manitoba Agronomists Conference looking at optimum seeding rates for hard red spring wheat. Across 23 environments from 2013 to 2015, his research showed increased stand loss as seeding rate increased (from a percent stand loss of 3% at the lowest seeding rate up to 21% at the highest seeding rate). His research suggests using a seedling mortality of 10 to 20%, even under good seed bed conditions.

Determining seedling mortality is not easy. Since mortality depends on the combination of conditions and management practices of individual farms, producers should keep records of emergence (and thus mortality) in their fields each year. The data collected will help in the future when calculating seeding rates.

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

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