Agronomy
Hard to identify and distinguish from one another, the annual grasses compete with winter wheat and fall rye because their growth habits are similar. Downy brome (Bromus tectorum) densities of 50 to 100 plants per square metre that emerge within three weeks of the crop can reduce winter wheat yields by 30 to 40 per cent. Both downy brome and Japanese brome (Bromus japonicas) are classified as noxious weeds in Alberta.  
Published in Weeds
Most soybean and canola acres have been planted across the province, the majority of corn acres are in the V3 to V5 range, and much of the winter wheat crop has progressed beyond the post-flowering stage, according to the latest field report from the Ontario Ministry of Agriculture, Food and Rural Affairs. Here's the breakdown by crop, below. 

Cereals

A large majority of the winter wheat crop has progressed beyond the post-flowering stage, and spraying for Fusarium head blight protection has been completed in many regions. Stripe rust is reported to be advancing in some areas in fields that did not receive a fungicide application. Significant yield loss can occur in cases where disease pressure is very high. Fields that received a T1 or T2 herbicide application are reported to be still holding disease pressure back well. True armyworm has been observed in some fields, but not at levels that have required control. Growers are encouraged to watch for head clipping feeding. Clover stands in winter wheat look excellent.

Corn
A large majority of the crop ranges from the V3-V5 stages. In general, growers and agronomists in many areas report that plant stands and crops look great. The exception is some localized, heavier textured soil regions where planting conditions of earlier planted corn may have been pushed, and replanting is occurring. Sidedressing has started or is well underway in many areas. OMAFRA recently completed it’s annual PSNT measurement survey from June 5-6. Average soil nitrate concentrations were 8.0 ppm which is lower than the 11-12 ppm range that has been observed over the past 5 years, suggesting N mineralization may be delayed from the cooler spring. The last year when PSNT survey values were in this range was 2011. With the recent warm weather, growers and applicators are reminded to check corn herbicide labels for maximum temperature restrictions. Of particular note, spraying of hormonal herbicides (ie. dicamba) should be avoided when temperatures are expected to be above 25 C during or after application.

Soybeans
With the exception of a few localized pockets where wet conditions have prevailed and planting continues, the majority of the soybean crop has been planted. The majority of the crop is in the 1-2 trifoliate stage. While stands look reasonable in many cases, some replanting continues in areas which received heavy rainfalls after planting where crusting was evident (particularly on fine textured soils), as well as areas where seedcorn maggot pressure was high and reduced populations. A uniform population as low as 100,000 plants per acre is still considered to provide good yield potential. Planting conditions have been reported to be good for late planted or replanted soybeans. Bean leaf beetles and soybean aphids have been observed in some fields, but at very low populations where control is not warranted. If soybeans are to be rolled after planting, rolling should occur at the 1st to 2nd trifoliate stage where plants are no longer brittle and susceptible to snapping, and ideally in the heat of the day when plants are flaccid. High stand losses can occur when plants are crisp and susceptible to snapping between the emergence and the 1st trifoliate stage. When in doubt, check plants after starting to roll and evaluate the stand for snapped plants which will no longer be viable.

Forages
Growers are reporting excellent yields for first cut hay. First cut hay timed for higher quality has neared completion in many regions. In general, there has been a good weather window for first cut in most parts of the province for both haylage/silage and dry hay, and harvest progressed quickly as a result.

Canola
While a small amount of canola planting was still being reported in some areas up until the end of last week, most planting is complete and the majority of crop across most growing regions is in the 3-4 leaf stage. Swede midge emergence was being reported as early as late May, and was occurring prior to Canola emergence in some fields. Growers are encouraged to place and monitor Swede Midge traps. The control threshold is 20 adults across all traps in a field, and has been met in some fields this spring. Flea beetle pressure has been apparent in some fields, with some control being warranted. As the crop progresses beyond the 3-4 leaf stage, Canola is generally able to keep ahead of feeding. While Cabbage Seed Pod weevil has been observed in some fields, it is not typically an issue until pod set starts.

Edible Beans
Edible bean planting is reported to be nearly complete with an estimated 95 per cent of intended acres planted. Planting progressed very quickly once started, with a large amount of crop planted in a relatively narrow window. Planting conditions have been reported to be good.
Published in Corporate News
Imagine yourself as a winter wheat kernel. You’re planted in the fall, germinate and grow a bit, then hibernate until spring when you start growing again. Meanwhile, fungus and insects are attacking your roots and shoots throughout the fall and spring. No wonder poor stand establishment is a major constraint for high-yielding winter wheat crops.  
Published in Cereals
The 2016 harvest season was one some growers would like to forget. Unfortunately, the reminder was still there when the snow melted this spring uncovering thousands of unharvested acres that producers had to combine plus get a 2017 crop in the ground. But adversity leads to opportunity and the Western Winter Wheat Initiative (WWWI) encourages producers to seed winter wheat this fall as a way of dealing with unseeded acres that didn’t get planted this spring.

Seeding winter wheat into chemfallow requires different planning than seeding into other stubble. Here are some tips that Janine Paly, WWWI agronomist for Alberta, has for producers to seed winter wheat successfully.

Minimize stubble disturbance/maintain stubble: Standing stubble is a key practice to establish winter wheat as the trapped snow insulates the crop from winter elements. Year-old stubble will break apart easier than stubble from a freshly harvested crop; however, any stubble is better than summerfallow. Minimize traffic over the field to maintain stubble integrity by using the same tracks in spraying operations and avoid harrowing and cultivating if possible.

Line up seed early: Before spring crops are harvested, take advantage of the less busy time and source seed. Plan to have the seed on farm and treated with a seed treatment before planting. Research conducted by Agriculture and Agri-Food Canada indicates a seed treatment minimizes seedling disease and can help with winter survival.

Fertility management: Selecting the right source and amount will help ensure your soil has a balanced supply of plant nutrients. It is important to perform a soil test to determine nutrient levels within the field. Winter wheat nitrogen management is different than spring wheat and determining the right timing of nitrogen application will vary depending on your operation. There are a few options: fall-applied, spring-applied or split application, but the method will vary depending on weather, soil moisture, and seeding equipment. Winter wheat has the ability to yield up to 40 per cent more than CWRS with adequate rates of nitrogen.

Seed early: Seeding early is a key factor in establishing a successful winter wheat crop. Plants that enter the winter with three to four leaves have a well-develop crown tissue and a better chance of winter survival. The optimal seeding window across the Prairies is between September 1 and 15. The question that may arise is, “How early can I seed?” It is better to seed earlier than later as producers can get busy with harvest operations and forget to seed within the optimal window. Extra consideration when seeding too early is the risk of disease transfer of stripe rust or wheat streak mosaic virus. If these diseases are of concern, growers can seed a resistant variety, delay seeding (depending on region), or should avoid seeding into conditions with volunteer cereals, or adjacent to a green wheat crop.
Published in Seeding/Planting
Choosing a successor is no easy task. While various family members may have ideas about who’s entitled to inherit the farm, the current owners may have very different ideas about who has the skills to keep the farm going in the long run. 

Throw blended families and in-laws into the mix and the question of succession may not have any clear-cut answers. And, in some instances, the best successor may come from outside the family. How does one decide? | READ MORE

Published in Corporate News
Local Liberal MP Francis Scarpaleggia and Jean-Claude Poissant, Parliamentary Secretary for the Minister of Agriculture, announced $2.9 million in funding at a press conference for two McGill projects aimed at mitigating greenhouse gas emissions caused by water and fertilizer use in agriculture.
Published in Emerging Trends
When it comes to the economics of growing winter cereals such as winter wheat and hybrid fall rye, the numbers don’t tell the full story. Looking at the three provincial government crop planning guides published for Prairie producers in 2017, winter wheat and hybrid fall rye land somewhere between the fifth and 16th most profitable crops to be grown in Manitoba, Saskatchewan and Alberta. But set aside the most profitable crops like pulses, canola, sunflower, corn and beans, and winter wheat profitability looks pretty good compared to spring wheat.
Published in Seeding/Planting
Many winter wheat growers in Western Canada are wondering if the seeding window can be extended. A multi-year, multi-site Prairie study is working towards a tool that will help growers answer that question for their own conditions.
Published in Seeding/Planting
A statement issued by the company On Tuesday, June 13th:

We regularly evaluate all aspects of our business. As part of these activities, we have recently taken the decision to exit the canola seed business. We are no longer selling or promoting our canola hybrids. We will, however, continue to support our existing canola seed portfolio through 2017 seeding and our programs and in-field product support, as per their terms and conditions. This decision is a business decision and we will work with all relevant parties to facilitate an orderly transition.
Published in Corporate News
Canola stubble has traditionally been the preferred stubble for winter wheat plantings because it can capture snow to insulate the overwintering wheat crop, improving winter survivability. However, some high-yielding canola hybrids have later maturities, presenting a challenge for seeding winter wheat at the optimum time.  
Published in Seeding/Planting
There are both environmental and agronomic concerns surrounding the management of livestock manure. The major environmental concerns are: potential risk of nutrient accumulation in soil – particularly nitrogen (N) and phosphorus (P) – and risk of nutrient movement into surface or groundwater. Poor manure management can also cause accumulation of salts in soil, surface water or groundwater and pathogenic micro-organisms in surface water.
Published in Fertilizer
Japanese brome (Bromus japonicas) exists as a winter annual or summer annual grass weed in the Canadian Prairies.
Published in Weeds
Cereals
Current weather conditions are ideal for fusarium head blight development in winter wheat. Many wheat fields in Southwestern Ontario have applied a T3 fungicide to reduce their risk particularly if they are growing a FHB susceptible variety. T3 fungicide applications further east will begin this week and continuing into next week for Eastern Ontario. A number of fields saw increased stripe rust pressure over the weekend. Growers with fields that were a few days away from a T3 application opted to wait and spray for both stripe rust and fusarium at the T3 timing. Some fields received an early heading fungicide application if they were a week or more away from a T3 fungicide application and growing a stripe rust susceptible variety to reduce the impact from stripe rust. Those fields will then receive a second fungicide application at pollination for protection against fusarium if needed. There have been reports of leaf tip necrosis starting on the flag leaf and moving down in fields. This leaf tip necrosis is likely associated with a specific or group of disease resistant genes and is the plant’s response to the presence of disease such as stripe rust. The yield impact from this is minimal.

Early spring cereal fields are at tillering and continue to look good. All weed control applications should be wrapping up shortly.

Corn
Corn planting is essentially now complete. With the exception of corn silage or some growers in long season regions, most unplanted fields will now likely be switched to soybeans. If corn herbicides have been applied but corn could not be planted, work with your herbicide provider to determine next best cropping steps. Overall corn is progressing well with a large amount of crop at the 2-3 leaf growth stage, with early planted corn beyond that. Minimal corn replants have been reported to date. Some sidedressing is now underway. There have been reports of black cutworm and slug feeding in a number of fields as a result of delayed crop planting and emergence and cool, wet weather conditions. There have also been reports of corn turning purple or white as a result of stress but those fields are expected to grow out of this.

OMAFRA Field Crop staff began tracking soil nitrate levels at a number of sites across the province the first week of May. Initial results suggest that soil nitrate levels are lower this year compared to previous years. Conventional PSNT timing sampling is being completed this week. Results will be posted at Weathercentral.ca under “Corn – GFO Nitrogen Research” as they are made available.

Soybeans
Soybean planting is 80 per cent completed across the province with some areas further behind compared to previous years due to significant rainfall this spring. The crop ranges from the hook stage to unifoliate growth stage. There continues to be weed challenges in a number of fields that did not receive a pre-plant burndown. Weed control during the early stages of soybean growth is critical. When making herbicide spray decisions pay attention to the growth stage of the weed as well as the growth stage of the soybeans.

There have been damage reports and replants particularly in Lambton, Essex, Niagara and Haldimand counties where they have received large amounts of rainfall and crusting became an issue. When doing plant population assessments a stand with 100,000 uniform plants per acre should not be considered for replanting. Research has shown that 100,000 plants per acre has a 98 per cent yield potential on most soil types.

On heavy clay soils 110,000-120,000 plants per acre are necessary for maximum yield potential. Rolling fields after the soybeans have fully emerged compared to rolling immediately after seeding helps alleviate stand losses due to crusting. Rolling can be up done up to the 1st trifoliate stage. There have been reports of seed corn maggot feeding in a number of regions due to the cool, wet weather. Fields planted without Class 12 insecticides that have sufficient stand loss due to certain soil insects including seedcorn maggot may warrant the completion of Inspection of Crop Pest Assessment by a professional pest advisor. If stand loss thresholds for the Class 12 regulations are reached, Class 12 insecticides can be purchased for that farm property. Contact a Professional Pest Advisor and refer here for more information. Bean leaf beetle feeding has also been reported in Essex County. Fields planted with fungicide-only seed should be scouted during the early seedling stages. Spray is warranted if 16 adult beetles per 30 cm of row are found on VC to V2 stage soybeans. If plants are clipped off at the stem, control is warranted if adults are still present and actively feeding.

Forages
First-cut alfalfa has begun in many areas with excellent yields being reported to date. Growers who applied some early season N to forage stands are reporting significant yield boosts. Alfalfa weevil and potato leafhoppers have been present in some areas. 

Canola
Canola emergence has been good to date; however, crop advancement has been slow particularly in northern Ontario. The earliest planted fields are at the 4 leaf stage. Growers in the Timiskaming area are already catching swede midge at this time and are likely going to have to spray sooner than anticipated. Swede midge has also been caught in the Shelburne area but has not yet reached thresholds. Due to the later planted crop and swede midge emergence this year it is anticipated that swede midge feeding will be a significant challenge. There have also been reports of high flea beetle pressure in some fields. 

Edible Beans
Due to the excessive moisture in many areas, edible bean planting is approximately 15 per cent complete. It is expected that the remaining acres will be planted later this week once conditions dry up.
Published in Corporate News
What I’d like to give you is a view from my previous careers working in Europe, New Zealand, and now Australia with regards to disease management. I’d like to give you a flavour of some of my impressions of disease management over the last 35 years with reference to getting the balance right with regard to the disease triangle and integrated disease management. 

Where are we in terms of integrated disease management (IDM)? What is IDM all about? Principally it’s about trying to make sure we use all the tools in the toolbox, integrating genetic resistance with chemical fungicides, cultural control and overall crop agronomy. When we sow the crop and how we look after it with nitrogen can profoundly affect how much disease pressure we’re under.

Getting it just right is never going to be easy. What’s happened in Australia? Before 2002, there wasn’t a huge amount of fungicide usage because it’s a much less responsive environment. Then we had an “exotic incursion.” Stripe rust came in from North America, probably on a grower’s boots. That changed the pendulum, from a dependence on genetic resistance to a reliance on fungicides, because, overnight, a huge proportion of all of the germplasm in Australia became susceptible to stripe rust.

Meanwhile in Europe, there was a totally different swing of the pendulum. It was inspired by a new set of varieties, in this case semi-dwarf varieties. With the new cultivars and more nitrogen, crops stayed greener for longer. Suddenly yields increased enormously in the ’70s. Higher yields and longer growing seasons in Europe drove growers to apply more and more fungicide. If you go to Europe now, it’s all about T1, T2 and T3 – Timing 1, Timing 2, Timing 3 with fungicides as a fixed part of crop agronomy. Up until 2005 in Europe, the pendulum had swung very much to the fungicide side of the IDM pendulum.

Slide 6
However, that’s all changed. In Europe, the profound driver for change has been fungicide resistance. Fungicide resistance influences everything that a European grower now does with fungicides. If there’s one thing that I think is really important to take on, it is that fungicide resistance – if it’s not affecting you now, it will be shortly unless you can moderate your use of fungicides.

What’s gradually happened over time is that we’ve got better products with greater activity, but at the same time fewer products based on limited modes of action. There are fewer products that are more and more environmentally benign, but at the same time at greater risk of resistance development. In other words, we’ve moved from multi-site fungicides that killed the fungus in many different ways to single-site fungicides that do less damage in the environment but actually are much more vulnerable to resistance.

Fungicide insensitivity and resistance
Fungicide insensitivity and resistance has occurred principally in two ways. In Europe in the late 1990s and early 2000s, strobilurins, such as pyraclostrobin and azoxystrobin, came along with the biggest media hype since glyphosate. However, after only three to four years, the pathogen causing powdery mildew and then Septoria tritici (now Zymoseptoria tritici) in wheat developed resistance to stobilurins, and that’s been a real challenge ever since. In two to three years, the strobilurins went from being the best products to control foliar diseases in broad acre cereals to products that wouldn’t work against Septoria, a disease that is widespread in northwest Europe. I think that’s when attitudes really changed and people started asking the question, “Is there a different way to control disease?”

Slide 16
We’re in our infancy with fungicide resistance issues in Australia. We can see it in the field with powdery mildew in barley. Our triazole fungicides such as Tilt (propiconazole), Folicur (tebuconazole), Proline (prothioconazole), Prosaro (prothioconazole and tebuconazole co-formulated) don’t work as effectively to control powdery mildew. With Septoria, we’re not yet seeing reduced activity in the field, but the samples are showing insensitivity in the laboratory, so there is increasing threat that we will see resistance to fungicides in the field. 

Europe and triazole use
What has happened in Europe with the triazoles over the last 20 years is that triazole fungicides have gradually become less effective against key diseases, firstly not working as effectively in the lab and then gradually being noted to be less effective in the field. That’s why with triazoles I think it’s important to talk about “fungicide insensitivity” and not “fungicide resistance.”

For example, it’s taken 20 years of exposing the Septoria pathogen population to the triazoles for them to become less effective. They still have activity but are now only 60 to 70 per cent effective when it used to be 90 to 100 per cent. So in Europe the triazoles and the strobilurins become less effective and ineffective for key diseases in a similar time period, but the triazoles had been gradually degrading in their effectiveness over time. 

Therefore with the terminology we use, I think it’s important to recognize we really have three basic modes of action that we use in broad acre cereal disease control – triazoles, strobilurins, and the new SDHIs [succinate dehydrogenase inhibitors].

With the triazoles I think it is probably more appropriate to call it “insensitivity” rather than resistance, since if you say to a grower, “It’s resistant,” the tendency is to think that it won’t work when in reality it is still partially effective.

With regard to the SDHIs, they’re not actually that new since the family of chemistry has been around for 40 years. But a new branch of SDHI chemistry is now taking Europe by storm, as the strobilurins now have less application because of resistance in key pathogens. But after only three years of commercial use with these new SDHIs, resistance is developing quickly in the net blotch and Septoria pathogens.

It’s really important to recognize that fungicide resistance is changing the way in which growers and advisors elsewhere in the world manage their cereal crops. In Australia, growers and advisors are just beginning on that resistance journey. You’ve already had some exposure in Canada to the fact that the strobilurins are at high risk of resistance development in the pathogen.  It begs the question, “What can you do about it?”

Click here for part two: The importance of multiple modes of action and linking pathology with crop physiology.
Published in Diseases
Montana has seen a spike in pulse crop acres in the last 10 to 20 years. When I started 10 years ago, my crop responsibilities included spring wheat, winter wheat, durum, and maybe a little barley. Now wheat is becoming a rotational crop for pulse production.
Published in Diseases
With many of the intended acres of various crops now in the ground throughout the province, producers should be on the lookout for pests such as cereal leaf beetle, black cutworm, armyworm and flea beetle, according to the latest crop report from the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA).
Published in Corporate News
Benson Hill Biosystems, an agricultural technology company unlocking the genetic potential of plants through cloud biology, has announced a partnership with the University of Guelph to develop traits that increase canola yield as part of the Genome Canada Genomic Applications Partnership Program (GAPP). The GAPP, along with provincial co-funding from the Ontario Ministry of Research, Innovation and Science, will provide $2 million towards the $3.4 million project.

The GAPP funds research and development projects that address industry opportunities in order to accelerate the application of genomics-derived solutions and sustainable innovations that are beneficial to Canadians. Canola is a major driver of the Canadian economy representing $7.4 billion in farm cash receipts and over $9 billion in exports, primarily to China, Japan, Mexico and the United States. Canola also serves a critical role in our global food system. Seeds are crushed into a cooking oil that is one of the lowest in saturated fats, making it a popular choice for food services seeking to lower trans fats in their products. The remaining canola meal provides a high protein livestock feed.

Benson Hill, using its proprietary CropOS cognitive computational platform, has identified a portfolio of trait candidates demonstrated to improve photosynthesis, one of the most complex systems in plants that is responsible for all agriculture production. In collaboration with the University of Guelph, researchers will validate these and other trait candidates in canola for further testing and development.

Benson Hill's platform combines vast datasets and biological knowledge with big data analytics and scalable cloud-based computing – an intersection of disciplines known as cloud biology – to predict biological outcomes for any target crop using any genomics tool, from breeding to gene editing to transgenics. The ability to more accurately predict gene targets that are linked to certain phenotypic outcomes with CropOS enables Benson Hill to accelerate identification of promising trait candidates, reducing product development costs and increasing speed to market.
Published in Genetics/Traits
[Miss part one? Click here]
Importance of multiple modes of action

I’m horrified to hear that you can apply straight strobilurin fungicide to your crops, since there’s no other mode of action in the application to protect you from pathogen mutants that might be strobilurin resistant. If you went back to when the strobilurins were breaking down to Ascochyta in some of your pulse crops, it’s worth asking yourself, wouldn’t it have been better to have been using them in combination with other older multi-site fungicides in order to give the strobilurins a degree of protection? 

What’s now happening in Europe is that there’s a lot of dependence on the triazole fungicides since there is widespread resistance amongst a number of pathogens to strobilurins and increasingly to SDHIs. However it’s not the same with all pathogens. For example, the rusts – stripe rust, leaf rust – seem particularly stable. But with the necrotrophic diseases such as Septoria, such as net blotch, such as scald, populations are shifting. That stated, the triazoles remain the backbone of disease management programs all over the world.

It’s actually becoming more complicated for advisors in Europe. What’s happening is that different regions in Europe have different pathogen populations that are differentially susceptible to triazoles. What researchers are finding is that the triazole that works best in one area of Europe might not be the triazole that works best in another.

Now I know what you’re thinking: aren’t triazoles all from the same family of chemistry with the same mode of action? That’s where the resistance to these molecules is more complicated. For example, in one region, Folicur might not work very well on the Septoria pathogen, but a Tilt still does a reasonable job, depending on the history of fungicide use. Somewhere else in Europe, the exact reverse might be happening.

In Europe, they’ve set up a project called EuroWheat with 26 trials all across Europe examining triazole fungicides and their activity against key diseases, looking at not only what’s happening in the field in terms of foliar control, but then taking samples for lab analysis. It’s revealing that the pathogen is adapting in different regions differently, depending on what fungicides have been used, particularly the Septoria population. 

We are now beginning to see the same thing with Septoria in Australia. Some products that are effective on the mainland of Australia don’t work well in Tasmania. 

What can we do to protect fungicides going forward? We can minimize our use of them. Pick the best adapted, highest yielding, and most resistant varieties we can use. Such a choice might enable you to use just one fungicide application instead of two applications. In some parts of the world, there are guidelines advising using that active ingredient just once in a growing season. But probably the strongest message that comes out around the different regions of the world is the one about mixing different modes of action in cereal crops. 

So think about fungicides as part of that integrated disease management package – use them, but don’t overuse them. 

Across Europe at the moment, the new SDHIs are entering the market already mixed and formulated with a triazole in order to ensure the use of two modes of action in a fungicide application. “Make sure that you’re mixing different modes of action” is the strongest message that comes out of the scientific studies on fungicide resistance and it’s the one key take-home that I can give you. If you’re not mixing, ask why not.

There is one area that is important to clarify and that is with regard to fungicide rate and resistance. I don’t believe that there’s a lot of scientific evidence in the literature that suggests keeping fungicide rates high is a good anti-resistance strategy. Generally it is with herbicides, but I’m not sure that evidence exists for fungicides. Frank van den Bosch from Rothamsted in the U.K. did a literature search on 46 different fungicide studies and found there were more studies showing that increasing fungicide rate increased resistance selection pressure than the reverse. I think it’s more appropriate that we consider fungicide rate as an efficacy message, not a resistance message: i.e. what rate of fungicide is appropriate to obtain the best economic outcome. There are other things, like mixing our active ingredients with different modes of action, which are far more important in resistance management than considering fungicide rates.

Linking pathology with crop physiology
The other factor that is really important is linking our knowledge of pathology with crop physiology. Fungicides don’t only kill a disease, they keep plant leaves greener for longer, providing soil water is available to express the benefit of the disease free leaves. The upper leaves of the cereal crop canopy, particularly the top four, affect the ability of a plant to produce yield. In Australia, disease management strategies based on fungicides are particularly dependent on the presence of soil water to express the benefit of a fungicide both in terms of yield response and economic return. 

One of the things from Europe that I think they have right is that they talk all the time about “What are the key parts of the plant to protect from disease?” If you’re growing a cereal crop, what do the individual leaves on that cereal crop contribute to yield? That’s an incredibly important part of any strategy using a fungicide. We use fungicides to make money, not just control disease, and what’s been really good in Europe is actually characterizing which parts of the plant are best to protect from disease.

When it comes to thinking about fungicides, don’t only think about the disease. The time of disease onset in the crop will determine to which leaves fungicides are applied. In Europe, set development timings trigger the questions. “Do we have the disease? Are the conditions conducive for the disease? What’s this crop going to yield?” These are key questions that link the effect of the disease with the physiology of the crop.

Slide 29
slide 30
I think the key message when it comes to thinking about using fungicides as part of an integrated disease management package is to recognize that they’re not very effective at protecting tissue that’s not emerged at the time of application. Other than reducing overall inoculum in the crop, fungicides only directly protect the leaves and plant structures that are emerged at the time of application, so you need to target the most important leaves that contribute to yield.

The interaction of crop disease development and crop physiology is now a target for an Australian modelling team. In summary, it’s important to look at disease development and crop development together. 

I’d like to finish off with a reference to future developments. The Magnetic Induction Cycler (MIC) is about the size of a four-litre pail. From leaf samples using MIC, you can determine the genetic makeup of the pathogen population, determining not only the presence of genetic mutations that might affect fungicide performance but also the frequency of the population with that mutation. In the future this technology will assist the advisor in making the right product choice for individual paddocks. That technology moving forward could be linked with automated spore traps informing us when pathogen spores are moving into the paddock, their genetic makeup and how that’s going to affect product choice.

Lastly, I believe RNA interference technology has the potential to produce the next phase of environmentally-friendly fungicides. The technology is based on short segments of nucleotide that are absorbed into the plant and pathogen, and which can switch off the RNA messenger before it can synthesize the proteins for fungal development in that plant. It is very specific technology and offers some great potential for disease management in the future.
Published in Diseases
Blackleg is caused by two species of the pathogen. The major one is called Leptosphaeria maculans. The other one is a much less virulent species called Leptosphaeria biglobosa. For control of the disease, pathologists look at some of the weak links where we can apply most of the impact on the disease. The pathogen only survives on residues. If you don’t have a residue, it doesn’t survive well in the soil. That’s why rotation is important.

The pathogen produces a fruiting body in the spring called a pseudothecium or another type called a pycnidium. They produce spores that land on the cotyledons of canola. If you have insect damage from pests like flea beetles, the infection can be worse. With wounding, the pathogen can get into the cotyledon tissue even without moisture. From there the infection develops and you see the cankers at the base of the stem later on in the growing season.
Slide 4
Photo courtesy of Gary Peng.

There are three important things that can lead to an infection:
·      there’s residue to harbour the pathogen inoculum
·      you need to have early infection to get into the stem
·      insect damage may help the infection to occur more severely. 

The disease was very prevalent in the late ’80s, early ’90s. Then we introduced some resistant varieties in the early ’90s, which brought down the occurrence for many years. Partially that was resistance bred into varieties, but we also had three- or four-year rotations. That was a big part of the whole management effectiveness.

In the last five to six years, the disease incidence has been creeping back up to 20 to 25 per cent in Alberta and Manitoba, and about 10 per cent in Saskatchewan. However, the average severity remained below level 1 (light). Research by Sheau-Fang Hwang in Alberta indicates that in most years, this level of severity could result in a yield loss of about two to eight per cent on a susceptible variety. But from a trade perspective, our trading partners want to see the disease level trend going down.

Why the upward trend?
The first reason for an increase in blackleg incidence is likely the change of the pathogen population, which is adapting to the resistant varieties. The pathogen population may be becoming more virulent or with a greater proportion of virulent isolates in it. 

Plant breeders have used major gene resistance to control the disease. The resistant gene blocks the infection by the pathogen carrying the corresponding avirulence gene. For example, an Rlm3 resistant gene would block the pathogen with avirulence AvrLm3 gene (abbreviated to Av3). It might be like a lock-and-key, but for some reason, over time, the Av gene may change and the resistant gene may not be able to recognize it.

My colleague, Randy Kutcher, looked at the change in pathogen populations in 2007 when he looked at the avirulent gene prevalence on the Prairies. In his work looking at 800 isolates of L. maculans, the percentage of Av2 and Av6 genes were very high in the population, and the others at more moderate to low levels. Further work in 2010 and 2011 with Dilantha Fernando at the University of Manitoba found the picture had changed quite a bit. The presence of the Av3 and Av9 genes had decreased quite a bit, but at the same time Av7 seemed to be increasing quite a bit. That means the Rlm3 gene would be less likely to be effective across the Prairies because the Av3 gene had changed mostly to the virulent type. The Rlm3 gene was first introduced back in early 1990s and has been used for over 20 years.

Other research in Fernando’s lab also looked at what resistant genes are present in 206 varieties/breeding lines in Western Canada. The resistance gene that was predominantly found was Rlm3 in around 70 per cent of the varieties/breeding lines. There was also a bit of Rlm1 detected as well. Overall, the diversity of R genes is still quite limited in the germplasm tested. The important message is that Rlm3 is not going to remain effective on the Prairies because the corresponding Av3 gene is already fairly low in the pathogen population. 

However, when we looked at field data in Alberta and Manitoba, while the occurrence of other Av genes was high, disease levels ranged widely. This told us there was something else going on, which we called non-specific resistance in our varieties, although the effect was definitely less than the major gene resistance.

We further investigated this non-specific resistance in our varieties. We tested commercial varieties with a pathogen without a corresponding Av gene so any resistance observed would be due to non-specific gene resistance. Almost all the varieties had a slightly smaller amount of the disease on inoculated cotyledons than the susceptible Westar. At the same time, it’s a totally different kind of resistance reaction as opposed to the major gene resistance. It would not stop the infection completely – it just slowed it down a little bit, and on some varieties, substantially.

A further look at three of those varieties found the progress of plant mortality originated from cotyledon or petiole inoculation was somehow reduced, but varied between the varieties. Using a fluorescent protein gene labeled isolate, photography was able to show the reduced spread of the pathogen in the cotyledon compared to the susceptible Westar variety.

If you can slow down the movement from the cotyledon via the petiole into the stem, there may not be enough of the pathogen getting into the stem before the cotyledons drop off. This is one of the reasons that non-race-specific resistance works in some of those varieties we have.
SLIDE 22
Photo courtesy of Gary Peng.
Click here for part two: management strategies

This article is a summary of the presentation “Managing blackleg of canola in Western Canada,” delivered by Dr. Gary Peng, Agriculture and Agri-Food Canada, Saskatoon, at the Field Crop Disease Summit, Feb. 21-22, 2017. Click here to download the full presentation.

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Published in Diseases
Management strategies
The Canola Council of Canada is proposing a risk assessment chart. If you have a four-year rotation, likely your risk of having blackleg is very low. We know it’s effective, but I realize it isn’t always easy to implement. [Miss part one? Click here]

Scouting is important because it gives you a sense of your risk situation. There is an easy procedure that can be used to assess risk. After swathing, pull 50 plants, cut the stems at the base of the plant where blackleg develops and assess the damage to the stem. Use the pictorial guide I developed to assess the level of disease. If you don’t have any disease or very light disease, your variety might still be holding fairly well as long as you continue with longer crop rotation. But if you have an R-rated variety with a much higher disease level than you expected, your variety may not be holding up.

If you do want to switch varieties, try to rotate to another major resistance gene. We currently don’t have enough public information from seed companies to know what their resistance sources are. The Canola Council of Canada has proposed a new resistance labelling system to show the resistance gene labelling. It is voluntary and may start in 2018.   
Slide 25
Photo courtesy of Gary Peng.

If you don’t have any issues or major blackleg damage, there’s no urgency for you to switch between resistance groups right away, but it’s always a good practice to rotate them if you know the R genes. We understand 90 per cent of growers would rotate among the different varieties today mostly for weed management options. There is a similar principle in rotating varieties for disease management.

I want to also stress that we have quite a diverse pathogen population on the Prairies. In reality, over 90 races have been detected. That means with every known resistance gene, there is a different virulent isolate out there that would be able to overcome the resistance right away. We really need to consider, if we have different R genes available, rotation of those R genes. And we also need to maintain the non-race-specific resistance, which has been serving us relatively well.

What about fungicides?
Research on various fungicide products and application timings has been conducted. One involved 17 station years across the Prairies. We used four fungicide products, mostly the strobilurins and a triazole, and a combination of both active ingredients. We looked at applications at the two- to four-leaf stage, the bolting stage, and an application at both stages.  We also compared a susceptible variety with a resistant and a moderately resistant variety.

When we put all the data from 17 station years together, the early application of a strobilurin fungicide reduced the disease severity and also increased yield quite significantly compared to the non-treated check. The average disease severity was around about 1.5. The later application did not work, which makes sense because the key stage of infection is the cotyledon. 

We further looked at the data and divided it into two scenarios: those fields with much lower disease levels of around a 0.5 severity rating, and those with a disease severity of about 2.5. In the fields with low disease severity, the fungicide application did not provide any yield benefit. Where disease severity was about 2.5, a fungicide application at the two- to four-leaf stage reduced the disease severity significantly and also increased yield by seven bushels per acre compared to the non-treated check. 

However, these results were on Westar – a susceptible variety that was used to show the worst case when an R/MR variety is losing resistance. We looked at R/MR canola varieties at the 17 site years and found none of the fungicide applications were effective in providing a yield advantage (also indicating that the R/MR varieties have stronger tolerance to blackleg impact). That means if you have a certain level of resistance in your variety, in most cases the fungicide application would not provide a substantial yield benefit.

Where a fungicide treatment might come in is if the varieties you have been using are starting to show signs of an increased amount of blackleg. You should scout crops and assess the level of disease development over time. Also consider the length of the crop rotation and other risk factors outlined by the Canola Council of Canada. If you feel you are at high risk, an early application at the two- to four-leaf stage may be warranted.
Risk chart


This article is a summary of the presentation “Managing blackleg of canola in Western Canada,” delivered by Dr. Gary Peng, Agriculture and Agri-Food Canada, Saskatoon, at the Field Crop Disease Summit, Feb. 21-22, 2017. Click here to download the full presentation.

Don't forget to subscribe to our email newsletters so you're the first to know about current research in crop management.

Top Crop Manager's Herbicide Resistance Summit has been announced! Sign up today for early-bird pricing: https://www.weedsummit.ca/event/registration
Published in Diseases
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