AgSolutions AdvisorNovember 2016

Blackleg and R-rated Canola Varieties. Understand the genetics for better crop management. Written by: Collen Redlick

Canola varieties developed in the 1990’s with genetic resistance to blackleg have been successful in reducing the loss of yield and quality associated with the disease. However growing R-rated resistant varieties alone is no longer sufficient to ensure protection against blackleg. What can cause this reduction in effectiveness and what can you do as a grower to help make sure you get the best performance out of the R-rated variety you have planned for your rotation?

Blackleg has two ways to infect

Left unmanaged, blackleg has the potential to reduce yield potential in a canola crop by up to 50%. In addition, Canada exports 90% of its canola, and countries with no measurable blackleg are highly sensitive to any level of blackleg residues in their imports. It’s a significant issue with economic consequences for growers in Western Canada.

Leptospheria maculans is the virulent species of blackleg and the one responsible for most of the damage. The fungus overwinters on canola stubble and can last in fields for up to 4 years. There are two sources of spores, each occurring at different stages of its life cycle.

Pycnidiospores are produced by pycnidia found on infected lower leaf lesions early in the season or on fresh stubble from the previous season. During moist conditions the spores are exuded and can travel by splash onto nearby leaves. Later in the season, ascospores are produced and released by pseudothecia on older stubble. These spores can be wind dispersed up to a couple of hundred meters. Both types of spores infect leaves in susceptible plants and progress to stems where they cause blackleg cankers, lodging, and premature death of the plant, which can lead to significant yield loss.

Life Cycle of L. maculans.

Source: Gavin Ash, Charles Sturt Univ. Wagga Wagga, New South Wales Australia

Lower leaf lesions and pycnidia are usually seen earlier in the season.

Stem cankers and pseudothicia result from an infected plant and are seen later in the season.

Source: AgSolutions® Performance Trials, Western Canada

Resistant canola has two ways to defend itself

Canola varieties that are rated for resistance against blackleg have genes that defend the plant against infection in two ways:

Qualitative resistance or major gene resistance (also known as seedling resistance) occurs at the site of initial infection on the cotyledons or leaves to limit the spread of the disease. The canola genes involved recognize specific genes in the fungal pathogen to initiate the defense response.

Quantitative resistance or minor gene resistance (also known as adult plant resistance) occurs later during the formation of cankers to slow down the disease. There are likely multiple plant genes involved, each having a relatively small effect on the fungal pathogen.

Qualitative disease resistance results… …only if both the gene in the pathogen and the R gene in the host are present, otherwise a susceptible reaction results and disease symptoms are observed.

Source: www.canolacouncil.org/canola-encyclopedia/diseases/blackleg/

The key to understanding how R-rated canola varieties can become more susceptible to blackleg over time is to understand that there is variation in the genetic makeup of L. maculans. In other words there are different virulent races of blackleg pathogen and these can coexist in the same field at the same time. Seeding the same R-rated canola variety with the same genes for resistance repeatedly can select for a blackleg race that does not have the corresponding fungal gene. If there are no matching genes then the resistance response doesn’t happen in the plant. Resistance breaks down and the disease spreads.

Source: Canola ouncil of Canada, video, Blackleg Disease and Resistance Management https://youtu.be/nkaHFrE_1D4?list=UUpROV-G7e-MnkPQHLcjcTBA

There can be different races of blackleg (represented here by different coloured patches) present in a field at any one time.

Some blackleg races can overcome the resistance genes that are present in canola.

Blackleg races that can overcome the resistance gene can become predominant.

Growing canola with the same resistance genetics in a field in a tight rotation can lead to the failure of that particular resistance gene in canola and the spread of blackleg.

C

How can you help preserve resistance?

Understanding that the fungus L. maculans can exist in a variety of races and that some may not match up to the resistance genes of a specific canola variety is important. Luckily not all R-rated canola varieties use the same qualitative and quantitative genes for resistance and this provides growers with an opportunity for optimizing blackleg disease management.

To preserve resistance genetics and manage blackleg in tighter canola rotations it is recommended that you seed R-rated canola varieties that are different, from different seed sources. Although information on the source of genetic resistance in a given variety is not currently available to growers, rotating varieties and using newer hybrids are best practices to bring a mix of resistance genes into the canola rotation. Using different genes for qualitative (and quantitative) resistance helps to ensure that you’re not selecting a race of blackleg that can proliferate.

References

1. Canola Council of Canada (video) https://youtu.be/nkaHFrE_1D4?list=UUpROV-G7e-MnkPQHLcjcTBA

2. AAF Blackleg of Canola (online) http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex147

3. Canola Council of Canada (online) http://www.canolacouncil.org/canola-encyclopedia/diseases/blackleg/

4. Management strategies for durable blackleg resistance in canola in Australia S.J. Marcroft1, H. Li2, S.J. Sprague3, B.J. Howlett3, M.J. Barbetti4, K. Sivasithamparam2, T.D. Potter5, P.A. Salisbury6

5. Introgression of blackleg (Leptosphaeria maculans) resistance into Brassica napus from B. carinata and identification of microsatellite (SSR) markers M. H. Rahman1, G. Hawkins1, M. Avery1, M. R. Thiagarajah1, A. G. Sharpe2, R. M. Lange3, V. Bansal1*, G. R. Stringam1

6. Breeding for Blackleg Disease Resistance in Canola: The Impact of New Strains on the Industry W.G. D. FERNANDO and Yu CHEN Dept. of Plant Science, University of Manitoba, Winnipeg, MB, Canada R3T 2N2

AgSolutions AdvisorNovember 2016

Fusarium Seedling Blight, Head Blight and DON. Know infection timing to help preserve cereal quality. Written by: Andrew Reid

Managing the risk of fusarium infection is an important issue for cereal growers in Western Canada. Maintaining or increasing yield and grain quality requires a good understanding of how fusarium infects a crop and the steps that can be taken to reduce the potential for damage.

Fusarium can infect cereal in two ways and both have negative, but slightly different consequences for the crop. Fusarium that is soil-borne and seed-borne is the source for seedling blight, affecting the plant during emergence, resulting in reduced germination, poor crop establishment and an early hit on yield potential. Fusarium that infects the crop later, during flowering and heading can cause fusarium head blight (FHB) with a subsequent reduction in quality and grade. FHB and the resulting fusarium damaged kernels (FDK) are a source of the vomitoxin, deoxynivalenol (DON). DON has well-documented negative effects in grain for milling and animal consumption where even small increases in levels can significantly reduce grades.

FHB can be caused by a range of pathogens including Fusarium graminearum, F. avenceum, F. poae, F. sporotrichioides, F. equiseti and F. culmorum. F. graminearium is the most common and aggressive fusarium pathogen in cereals and is responsible for both fusarium seedling blight and fusarium head blight. So how does this one pathogen cause two different diseases? And what do you need to know from a disease management perspective?

Source: www.grainscanada.gc.ca/guides-guides/identification/fusarium/iwbfm-mibof-eng.htm

FDK also known as ‘tombstone kernels’ appear chalky white to pink in colour and have a shriveled, thin appearance.

Red Spring Wheat samples comparing healthy to FDK

A. Healthy Kernel

B. Immature Kernel without Fusarium Infection

C. Lightly Infected with Fusarium

D. Severely Infected with Fusarium

A B C D

Fusarium’s life cycle and FHB infection

To understand the relationship between seedling blight, head blight and fusarium let’s take a closer look at the life cycle of the pathogen. In a fusarium-infected field the fungus overwinters on crop residues and in the soil as well as on seed that has come from previously infected plants. Emerging seedlings can be infected at this stage resulting in seedling blight. So for fusarium seedling blight and other related diseases, the inoculum is more localized.

Fusarium head blight on the other hand results from infection that occurs at a specific, later stage in fusarium’s life cycle. During this stage, fusarium perithecia develop on older, infested residue and release ascospores that can be spread by wind and rain. If these spores land on the cereal head during flowering, infection can result in head blight. The inoculum in this case can travel a distance. Seeding into a clean field with absolutely clean seed can still result in infection if there are previously infected fields nearby and the environmental conditions are right.

Fusarium head blight disease cycle

Perithecia on older infected residue release ascospores that can travel to infect heads during flowering and cause FHB.

Source: http://ohioline.osu.edu/factsheet/plpath-cer-06

Does fusarium-infected seed cause FHB infection?

The main message here is that fusarium-infected seed can be a source of seedling blight but does not directly cause head blight within the same year. The following quote from Alberta Agriculture sums it up well.

Although (fusarium) infected seed can cause seedling blight, it typically does not directly give rise to head blight symptoms in one growing season. The fungus will move from the infected seed to the root, crown and stem base tissues of the plant that develops from the infested seed, thus creating potential sources of infested residue that can impact subsequent crops.

Source: http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/faq12513

Using clean seed is always recommended as it helps to reduce the amount of potential inoculum in a field and increases the potential for healthier crop establishment. However clean seed alone does not prevent the potential for disease. The source of inoculum can still be in nearby soil or on previously infested residues that are local or at a distance.

Healthy wheat on left, compared to FHB blighted head. Source: Fusarium Head Blight of Wheat, Univ. of Nebraska, EC1896.

Recommendations for reducing the risk.

Reducing your risk of diseases caused by fusarium requires a plan that includes vigilance in the field (scouting), knowing where other sources of fusarium may be in nearby fields (cereal and corn residues) and a proactive approach that includes:

• Using clean, disease-free seed to help prevent the introduction and build up of inoculum in the field. Testing your seed to ensure good germination, vigour and low disease levels.

• Performing a full pathogen screen of bin-run seed to determine what level of infection may be present. You can then make the best seed treatment choice for those diseases.

• Rotating to other, less susceptible crops. Seeding cereal one in three or four years will allow local sources of inoculum to reduce somewhat.

• Seeding cereal varieties that are moderately resistant to fusarium. While true resistance has not yet been bred, there are still some moderately resistant varieties available.

• Using of a foliar fungicide that targets fusarium at flowering to help reduce the risk associated with FHB under conditions where the disease may develop.

• The use of an appropriate seed treatment that is effective against seed and soil-borne fusarium.

Understanding fusarium’s life cycle along with where, when and how it can cause damage is essential when implementing an integrated plan for reducing the risk to your crop. It’s also a good idea to keep up to date on current and future developments for managing the disease. Consider BASF your partner for sound agronomic advice. We invite you to get in touch with any questions you have about fusarium and ways to protect the quality and yield of your cereal crop.

AgSolutions AdvisorNovember 2016

Preventing the build up of resistance. Strategies for managing herbicide-resistant weeds in cereals. Written by: Bryce Geisel

Herbicide resistance continues to rise all over the world. With over 60 unique cases, Canada has the third highest number of herbicide-resistant weeds, falling just behind Australia and the US.1 Of the resistant cases reported in Canada, a major issue is herbicide-resistant wild oats – one of the ten worst annual weeds in cereals.2 Group 1-resistant and multiple-resistant wild oats are widespread with almost 20% of Western Canadian fields containing herbicide-resistant wild oats.2

For Canada, surveys conducted from 2007 to 2009 showed that 24.4 million acres were affected by herbicide resistance.3 The cost to the industry was estimated at around $1.1 to $1.5 billion per year due to reduced yields and greater herbicide use.3 With a consistent increase of 1.5 new cases of herbicide resistance each year,3 the results of this current round of surveys conducted by Agriculture and Agri-Food Canada will likely show an even greater impact on the industry.

Source: Heap, I. 2016. WeedScience.org. Adapted from Top Crop Manager.3

Increase in unique resistant weed cases in CanadaIncrease in unique resistant weed cases in Canada

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How resistance develops

Herbicide resistance is a result of natural variations in a weed’s DNA. A good analogy is how five people may take the same pain medication, but it only cures headaches for four of them. The fifth individual is somehow resistant to the medication, and you only find out after they’ve taken the pill and nothing happens.

The same holds true for weeds. Prior to treatment, you can’t distinguish between the susceptible and resistant individuals. Utilizing the same herbicidal mode of action over and over, you’re more likely to encounter a naturally resistant individual that survives and reproduces. As the susceptible individuals are killed off by that same mode of action, the resistant ones continue to set seed and spread typically until they can no longer be written off as spray misses.

To understand how this happens, let’s look at two different ways where weeds can develop resistance: target-site resistance and metabolic resistance. Herbicides normally attach to an important enzyme or protein that is critical to a weed’s survival, and prevent it from carrying out its function. This could be an enzyme involved in photosynthesis, detoxification or protein synthesis, to name a few. In target-site resistance, the mutation in this individual’s DNA changes the target enzyme, preventing the herbicide from binding. In a different type of resistance, the herbicide doesn’t even reach the target enzyme before it’s broken down by the plant’s hyperactive detox pathways – that’s metabolic resistance.

Target-site resistance visualized

Source: Adapted from Beckie, H. 2009. Herbicide resistance update.4

Just because a weed is resistant to one mode of action, doesn’t prevent it from being resistant to another. For instance, because Group 2 herbicides have been consistently used to target Group 1-resistant wild oats, biotypes with multiple resistance to both Groups 1 and 2 are now a rising concern.

Cross-resistance happens when the plant has mutations in more than one enzyme. Or in some cases, such as the wild oat resistant to Groups 1, 2, 8 and 25 found in Manitoba, it could be metabolic resistance.3 Resistant genes won’t simply disappear either. As long as the same chemistries are being used, resistant weeds will continue to survive, set seed and spread.

Target-site resistance visulaized

NON-RESISTANT WEED

Substrate

Enzyme

Substrate

Enzyme

Herbicide

Substrate cannot bind

Plant Lives

RESISTANT WEED

Substrate

Enzyme EnzymePlant Lives

Plant Dies

Herbicide

Herbicide cannot bind

How chemistries are grouped

Herbicides are assigned group numbers based on the plant process or enzyme they target – this is their mode of action (MOA). This helps you determine if a certain product is suitable for the weeds in your field and in planning your herbicide rotations. Even though different products within the same group may target different weeds, the underlying chemistry is similar. Simply rotating into a different product or brand that belongs to the same herbicide group will not help prevent herbicide resistance.

Group Function Outcome

1AcetylCoA carboxylase

(ACCase) inhibitorsInterferes with fatty acid creation so the plant cannot build new cell membranes needed for growth. Only effective on grasses.

2Acetolactate synthase (ALS) and

actohydroxyacid synthase (AHAS) inhibitors

Interferes with production of branched-chain amino acids, taking away building blocks needed for protein synthesis and plant growth.

3 Root growth inhibitorsBinds the tubulin protein, inhibiting cell division and stunting root growth.

4, 19 Growth regulatorsMimics the plant’s natural growth hormones or inhibits their transport, causing uncontrolled growth and eventual plant death.

5, 6, 7 Photosystem II inhibitorsBinds a specific protein in photosystem II, interfering with photosynthesis and plant growth.

8, 15, 16 Shoot growth inhibitors

Chemistries affect more than one plant process, including the synthesis of fatty acids and lipids, proteins, plant pigments and growth regulators (gibberellins). This prevents cell growth and division.

95-enolpyruvylshikimate-

3-phosphate (EPSP) synthase inhibitor

Glyphosate is the only one in this group. It inhibits the production of aromatic amino acids needed for protein synthesis and growth.

10 Glutamine synthase inhibitorsInhibits an enzyme that converts ammonia to glutamine. Ammonia builds up to toxic levels, destroying the plant cell.

12, 13, 27 Pigment synthesis inhibitorsInhibits the production of carotenoids needed to mop up reactive chemical compounds, leading to a bleached appearance and cell death.

14, 22 Cell membrane disruptersDirectly or indirectly causes a build-up of reactive compounds that destroy cell membranes, leading to cell leakage and plant death.

The Weed Science Society of America classification system is used in Canada. Sources: Adapted using information from multiple sources.5,6,7

Best practices

Wild mustard, green foxtail and kochia have all shown resistance to multiple chemistries – and they’re becoming increasingly difficult to manage. It’s crucial that we manage resistant weeds while preventing the onset of resistance to other chemistries.

Use multiple modes of action (MMOA) with overlapping weed spectrums

For instance, 2,4-D does not effectively control cleavers. Even if it’s used in a tank mix with a Group 2 herbicide, the application ultimately relies on Group 2 action and selects for Group 2-resistant cleavers. For MMOA to be an effective strategy, active ingredients must have overlapping weed spectrums so resistant weeds aren’t given an opportunity to set seed. Know your weeds and what chemistries are effective on them.

Rotate crop types along with herbicide groups

Research has shown that the risk of resistance is higher in fields with cereal-based rotations. At least three or more different crop types should be rotated (e.g. cereals oilseed pulse). This risk is further reduced if perennial forage crops or fallow are worked into the rotation.8

Note that wild oat seeds can last up to 10 years in the soil.2 Even if you rotate into canola one year and control resistant weeds using your canola herbicide, those dormant weed seeds in the soil will germinate once you plant cereals again in the next year and use your regular cereal herbicide.

Apply full label rates

Using less than the label rate is a common pitfall. Similar to taking cough medicine, a lower dose may not have an effect at all. It’ll allow weeds to survive, increasing the risk of resistance.

Use certified seed and clean equipment

This will help prevent the transfer of resistant weeds from one field to the next. Avoid using seed from fields with a history of resistant weeds.

Start with clean fields

Seed your crop early in a weed-free field to give it a competitive advantage over weeds. An effective burndown will help control early emerging weeds.

Rotate MOAs from pre-seed to post-emergence

Rotate into different MOAs for post-emergent control. This helps control weeds that escaped burndown, managing them before they set seed.

Cultural practices

Seed at an optimal rate, decrease row spacing and seed early to outcompete weeds.

Scout after application and get tested

If you see weed patches that are not affected by a herbicide you’ve used in the past, get them tested for herbicide resistance. Previously, weeds have been tested by screening for known mutations in targeted enzymes, but this only works on target-site resistance. To test for metabolic resistance, a new method of screening is now in development. It involves applying the herbicide to a section of the weed’s leaf tissue. The more quickly the herbicide disappears, the more resistant the plant is.9

Because of the large number of herbicides using Group 1 and Group 2 chemistries, these two groups are the most prone to resistance. And we can’t simply wait for the development of new modes of action. It took 20 years to develop Group 27 chemistry and that was in 2008.10 Left unchecked, herbicide resistance limits our crop choices and herbicide options, affecting yield and quality. Prevention is key.

Weed Herbicide group resistance (“+” indicates multiple resistance)Alberta Manitoba Saskatchewan

Ball mustard 2 - -Common chickweed 2 2 2Common hempnettle 2, 4 2 -

Weed Herbicide group resistance (“+” indicates multiple resistance)Alberta Manitoba Saskatchewan

Common lambs-quarters - - 2Cowcockle 2 - -False cleavers 2+4, 2 2Field pennycress 2 2 2Green foxtail 1, 3 1, 2, 3, 1+3 1, 3, 1+3Kochia 2, 2+9 2, 2+9 2, 2+4, 2+9Narrowleaf hawksbeard 2 - -Pale smartweed 2 2 -Persian darnel 1 - 1Powell amaranth - 2 -Redroot pigweed - 2 2Russian thistle 2 - 2Shepherd’s purse 2 - 2Spiny sowthistle 2 - -Wild buckwheat 2 - -Wild mustard 2 2, 4, 5 2

Wild oats 1, 2, 8, 1+2+81, 2, 8, 1+2+25,

1+2+8+25, 1+2+8+14+151, 2, 8, 1+2+8

An overview of resistant weeds in Western Canada. Source: Created using data from Heap, I. 2016, weedscience.org.5

References

1. Booker, R. 2016. Herbicide resistance major problem in Canada. The Western Producer. Retrieved from http://www.producer.com/2016/03/herbicide-resistance-major-problem-in-canada/

2. Raine, M. 2015. Weed of the week: wild oats. The Western Producer.

3. Beckie, H. 2016. State of weed resistance in Western Canada. Top Crop Manager.

4. Beckie, H. 2009. Herbicide resistance update. Manitoba Agronomy Conference, Winnipeg, MB, Canada. (Presentation)

5. Heap, I. The International Survey of Herbicide Resistant Weeds. Online. Internet. Thursday, September 29, 2016. Available www.weedscience.org

6. Alberta Agriculture and Forestry. 2016. Herbicide group classification by mode of action. Retrieved from http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/prm6487

7. United Soybean Board and Taken Action partners. 2014. Herbicide Classification Guide. Retrieved from http://reader.mediawiremobile.com/USB/issues/106905/viewer?page=1

8. Beckie, H. 2009. Herbicide resistance in weeds: influence of farm practices. Weeds, Herbicides and Management (2) 17-23.

9. Phys.org. 2016. New method developed for testing herbicide resistance in weeds. Retrieved from http://phys.org/news/2016-04-method-herbicide-resistance-weeds.html

10.FarmForum. 2013. Rotate herbicide Group numbers, not names, to help manage resistance. Retrieved from http://farmforum.ca/article/rotate-herbicide-group-numbers-not-names-to-help-manage-resistance/

AgSolutions AdvisorNovember 2016

The importance of testing cereal seed. Testing cereal seed prior to planting as part of an integrated management strategy. Written by: Russ Trischuk

Introduction

One of the first things to consider at the end or beginning of the season, is testing the quality of your seed. Understanding where the seed stands in terms of germination, vigour and disease allows you to make more informed management decisions to achieve higher yields. Growers often consider management practices related to the seed as optional, but starting with the best possible seed helps to ensure that you’ll be satisfied with the end results. It’s time for seed testing to be thought of as mandatory.

Another important consideration is, what do I need to do to achieve that optimal plant stand? To reach your target, there are two important tests that need to be done: a germination test and a kernel weight test. The germination test tells you how many seeds are actually going to produce viable plants and a kernel weight test is essential for calculating seeding rate. Once you have these two pieces of information you can accurately calculate your seeding rate to reach the desired plant stand count.

Regional considerations

Because of the cool, wet conditions we experienced this fall, growers saw decreased seed quality and increased disease levels at harvest. Growers should be aware that testing seed in the fall is a good practice, however seed being used for the following year should be re-tested in the spring to ensure that the germination and vigour observed in the fall has been maintained. It’s also a common misconception that as the weather warms up, it’s no longer necessary to rely on seed treatments. When in actuality, most diseases are most active and are more virulent at 15 to 20°C making them just as detrimental as they are at cooler temperatures. Fusarium head blight (FHB) levels were also particularly high this year which makes it critical for growers to use a seed treatment to manage this disease. Using a seed treatment under all conditions is an investment that should be made on every field, every year regardless of conditions.

Consequences

The decisions you make at seeding affect the potential of your crop for the rest of the season and you only get one chance to do it right. There’s no opportunity to go back in and re-spray like you can with herbicides or fungicides. Diseases like smuts and bunts in cereals can be avoided with the use of a seed treatment but without it, there is no other time to manage them. Similarly, fusarium-infected seedlings increase the levels of inoculum present in the soil and can reduce your plant stand. This increase in inoculum could also increase your risk of FHB in subsequent cereal crops in that field. Or alternatively, the seedling can die and become a food source to

cause FHB in future years. FHB can also result in fusarium damaged kernels (FDK) which can affect the quality of cereals and can lead to grade reduction, loss in revenue and contamination of the grain with mycotoxins (Figure 1) like deoxynivalenol (DON). Proactively conducting a disease test and using a seed treatment are all part of an integrated approach to managing fusarium and other potential diseases. Understanding your on-seed disease levels can help you identify potential problems and provides a valuable opportunity to avoid them. Testing your seed is a relatively inexpensive investment compared to the value of the information you gain, especially since you only get one chance at seeding.

Mycotoxins CommodityMaximum tolerance Canada

(mg/kg)

Deoxynivalenol (DON)

Uncleaned soft wheat for human consumption

2

Diets for cattle and poultry 5

Diets for swine, young calves and lactating dairy animals

1

Zearalenone (ZEN)

Gilt diets <1-3

Cow diets 10 (1.5 other toxins present)

Sheep and pig diets 0.25-5

Ergot

Cattle, sheep, horses 2-3

Swine 4-6

Chicks 6-9

Figure 1. Recommended tolerance levels (mg/kg) of several mycotoxins in Canada. Source: adapted from the Canadian Food Inspection Agency.

Best practices

So what should you be looking for in your seed? Choose seed with high germination rates (>90%), high seedling vigour (don’t use seed below 90% if possible) and low seed-borne disease levels. Remember not to focus solely on your disease results because vigour rate is also very important. It’s better to use seed with slightly higher disease levels and a high vigour rate than seed with lower disease and a low vigour rate.

Germination testing

• Measure of the percentage of seeds in a seed lot capable of germination under the best possible conditions

Vigour testing

• Determines the proportion of seeds that will be vigorous enough to germinate and survive the stresses associated with emergence under more realistic conditions

Disease testing

• Certified seed only has to meet standards for germination and doesn’t have to meet minimum disease standards, but planting clean seed avoids introduction of disease

• Correct diagnosis is key because diseases often occur as a complex so it’s impossible to identify the diseases without proper testing

• FDK are not always pink and are often confused with heat stress, so it’s essential to have an expert analyze your seed

Seed cleaning

• Removes disease or damaged seed for improved quality

Seed treatment

• Protects against early season seed- and soil-borne diseases, increases germination and emergence consistency, enhances vigour, maintains root health and helps the crop withstand minor stresses (BASF AgCelence® Seed Treatments)

• Choose a seed treatment that offers multiple modes of action and effective control of all major seed and seedling diseases of economic importance

Expert opinion

With the wet weather and cool temperatures we saw at harvest, Holly Gelech from BioVision Seed Labs says the pathology lab was very busy. The high levels of moisture created conditions extremely conducive for infection, which is why growers saw high levels of disease. This is why it’s imperative for growers to test their seed in the fall to understand what their baseline seed quality is. Holly recommends a test package that includes germination, the cool stress test (vigour test) and a fungal scan. Germination has been a benchmark test for decades but the full fungal scan has only been in the marketplace for approximately 5 years. Traditionally, growers would test seed for a specific disease that may be a problem in their field but now with a full fungal scan, growers can really pin-point the potential for seed-borne disease development in their seed lot. Holly stressed that while we can’t control the weather, we can gain insight into seed-borne diseases with accurate testing and start the growing season off right with effective seed treatments.

Future innovations

We’re continuously conducting research to improve our seed solutions to help you achieve successful crop establishment. Fusarium management in cereals can be daunting, as the pathogen is prevalent across all of Western Canada, but there are tools available that growers can utilize. The ultimate goal is to incorporate fusarium resistance into cereal varieties but it’s a very difficult disease to breed resistance for. It is an ongoing process however and in the meantime, there are varieties currently available with some levels of resistance which can help you manage the disease. BASF is also conducting research on the best application timing for FHB control in-crop and we’re also working on new seed treatment innovations to manage fusarium from seeding until harvest.

Always read and follow label directions.

AgCelence is a registered trade-mark of BASF SE; used with permission by BASF Canada Inc. © 2016 BASF Inc.

AgSolutions AdvisorNovember 2016

Give your cereal crops an early advantage. Incorporating a seed treatment as part of a best management strategy for successful establishment in cereals. Written by: Andrew Reid

Introduction

Using a seed treatment gives cereals the early advantage they need to grow successfully throughout the season. Planting untreated seed when there is evidence of fusarium (especially Fusarium graminearum) or other seed-borne diseases, will reduce germination and emergence levels significantly. Using untreated seed can increase pathogen levels present in the soil, leading to increased disease pressure later in the season and in future years. Planting clean cereal seed is the primary way to limit the introduction of pathogens into the field. Additionally, using an effective seed treatment helps to manage diseases that may be present on the seed and it can reduce the impact of diseases in the soil as well.

In Western Canada, the 2015 growing season ended dry and the beginning of the 2016 season started out the same way. Because of this, it was tempting to assume that disease pressure in cereal fields would be low this year. However, wet weather persisted for most of the summer and into the fall which added to the disease pressure across most of the prairie regions (Figure 1). All these factors make it extremely essential to use a highly effective seed treatment that can protect the entire seedling during the critical growth stages to ensure that your crop gets off to a good start.

Regional considerations

Because of the cool, wet conditions this fall, growers have been seeing decreased seed quality due to sprouting and increased disease levels. Growers should be aware that conducting a germination test in the fall is a good practice, however seed being used for the following year should be re-tested in the spring to ensure that germination and vigour observed in the fall has been maintained. It’s also a common misconception that as the weather warms up it’s no longer necessary to rely on seed treatments. In actuality, most diseases are most active and are more virulent at 15 to 20°C making them just as detrimental as they are at cooler temperatures. Using a seed treatment under all conditions is an investment that should be made on every field, every year regardless of conditions. Wireworm populations have also been identified in isolated pockets throughout Western Canada, creating an issue for cereal growers. Accurate identification is essential to determine if wireworms are responsible for damage and to decide whether to use an insecticide in combination with your seed treatment.

Consequences

The decisions you make at seeding affect the potential of your crop for the rest of the season and you only get one chance to do it right. There’s no opportunity to go back in and re-spray like you can with herbicides or fungicides. Diseases like smuts and bunts in cereals can be avoided with the use of a seed treatment but without it, there is no other time to manage them. Similarly, fusarium-infected seedlings increase the levels of inoculum present in the soil and can reduce your plant stand. This increase in inoculum could also increase your risk of FHB in subsequent cereal crops in that field. Or alternatively, the seedling can die and become a food source to cause FHB in future years. FHB can also result in fusarium damaged kernels which can affect the quality of cereals and can lead to grade reduction, loss in revenue and contamination of the grain with mycotoxins.

Figure 1: 7-day precipitation map for the Prairie region, July 13-19 – Environment Canada 2016

Proactively conducting a disease test and using a seed treatment are all part of an integrated approach to managing fusarium and other potential diseases. Overall, understanding the quality of your seed lot can help you identify potential problems and provides a valuable opportunity to avoid them. Testing your seed is a relatively inexpensive investment compared to the value of the information you gain, especially since you only get one chance at seeding.

Best practices

So what should you be looking for in your seed? Choose seed with high germination rates (>90%), high seedling vigour (don’t use seed below 90% if possible) and low seed-borne disease levels. Remember not to focus solely on your disease results because vigour rate is also very important. It’s better to use seed with slightly higher disease levels and a high vigour rate than seed with lower disease and a low vigour rate.

Germination testing

• Measure of the percentage of seeds in a seed lot capable of germination under the best possible conditions

Vigour testing

• Determines the proportion of seeds that will be vigorous enough to germinate and survive the stresses associated with emergence under more realistic conditions

Disease testing

• Certified seed only has to meet standards for germination and doesn’t have to meet minimum disease standards, but planting clean seed avoids introduction of disease

• Correct diagnosis is key because diseases often occur as a complex so it’s impossible to identify the diseases without proper testing

• Fusarium damaged kernels are not always pink and are often confused with heat stress, so it’s essential to have an expert analyze your seed

Seed cleaning

• Removes disease or damaged seed for improved quality

Seed treatment

• Protects against early season seed- and soil-borne diseases, increases germination and emergence consistency, enhances vigour, maintains root health and helps the crop withstand minor stresses (BASF AgCelence® Seed Treatments)

• Choose a seed treatment that offers multiple modes of action and effective control of all major seed and seedling diseases of economic importance

Expert opinion

With the wet weather and cool temperatures we saw at harvest, Holly Gelech from BioVision Seed Labs says the pathology lab was very busy. The high levels of moisture created conditions extremely conducive for infection, which is why growers saw high levels of disease. This is why it’s imperative for growers to test their seed in the fall to understand what their baseline seed quality is. Holly recommends a test package that includes germination, the cool stress test (vigour test) and a fungal scan. Germination has been a benchmark test for decades but the full fungal scan has only been in the marketplace for approximately 5 years. Traditionally, growers would test seed for a specific disease that may be a problem in their field but now with a full fungal scan, growers can really pin-point the potential for seed-borne disease development in their seed lot. Holly stressed that while we can’t control the weather, we can gain insight into seed-borne diseases with accurate testing and start the growing season off right with effective seed treatments.

Future innovations

We’re continuously conducting research to improve our seed solutions to help you achieve successful crop establishment. Fusarium management in cereals can be daunting, as the pathogen is prevalent across all of Western Canada, but there are tools available that growers can utilize. The ultimate goal is to incorporate fusarium resistance into cereal varieties but it’s a very difficult disease to breed resistance for. It is an ongoing process however and in the meantime, there are varieties currently available with some levels of resistance which can help you manage the disease. BASF is also conducting research on the best application timing for FHB in-crop and we’re also working on better solutions for seed treatment innovations to manage fusarium from seeding until harvest.

Always read and follow label directions.

AgCelence is a registered trade-mark of BASF SE; used with permission by BASF Canada Inc. © 2016 BASF Inc.