Yet fusarium isn’t the only concern among growers and their cereal crops. Leaf rust, septoria, powdery mildew and tan spot can be problems in any year in winter and spring wheat as well as in oats and barley, which explains Corteva Agriscience’s decision to launch Cerefit, a new fungicide co-pack recently registered for use across Canada.

Cerefit is a dual mode-of-action, with a Group 11 (picoxystrobin) and a Group 3 (propiconazole) that provide preventive and curative activity. Neither active is new but the combination offers growers a new option in managing leaf diseases at critical times.

In the West, Cerefit will protect oat and barley crops at the early flag-leaf stage against leaf diseases, which can reduce yields by as much as 20 per cent. In the East, winter wheat will be the target crop, with Cerefit applied at the three- to six-leaf stage and a similar estimate of 20 per cent yield protection potential (according to research from Agriculture and Agri-Food Canada [AAFC]).

In Eastern Canada, Cerefit can be applied with Pixxaro herbicide to help combat Canada fleabane, which is now resistant to three different herbicide groups (Groups 2, 9 and 22).

Know the numbers

Corteva Agriscience product manager Lorne Thoen says growers generally have a dollar threshold they’re willing to invest in order to manage risk on certain diseases, depending on their potential severity and impact on yield or quality. On their own, leaf diseases might cost a grower up to 20 per cent of their yield. But with a disease like fusarium, losing 20 per cent of yield is only part of the problem: the remaining 80 per cent will be a challenge to market because of the presence of the pathogen. With that cost in mind, it’s an easier choice to invest money to manage fusarium and count on a lesser impact from leaf diseases.

“It’s all about managing risk from that winter wheat standpoint,” says Thoen, who’s based in Saskatoon. “You can have a grower with a good catch coming out of winter and a few broadleaf weeds. But they’re thinking, ‘It’s moist out, I have some warm afternoons and days that are going to create a good environment for that disease to stand in there. So I want to spray something for weeds and I’m going to throw in a fungicide to take care of that (disease environment).’”

Another tool in the toolbox

As with many innovations coming to market for growers, Cerefit represents a newer option, while maintaining the list of options in other fungicides. Thoen likens it to purchasing a new socket wrench: it may be easier to use and more effective in many cases but it doesn’t make an old half-inch wrench obsolete.

“Not only do we get a nice dual mode of action from the two fungicide modes but picoxystrobin is more preventative,” Thoen says. “Propiconazole is also a preventative but it also has curative qualities. To have another tool that’s a dual mode of action that’s both preventive and curative is always good but it doesn’t mean you’re not going to use the other tools that you have.”

As for the need for dual mode of action products in disease management, Thoen concedes that diseases are unique compared to weeds: the latter are a perennial challenge for growers whereas the former requires the pathogen, a host and a favourable environment in order to flourish. Yet in his time in the industry, Thoen has learned to never say “Never!” when it comes to taking a wait-and-see approach with diseases.

“Weeds are living plants that evolve and diseases are living organisms that evolve and change,” says Thoen, adding that resistance to disease might not be as critical as it’s become with weeds, yet it’s only a matter of time with diseases. “If you look at what’s coming out on the market from the industry, there are new modes of action fungicides and pre-mixes, and I don’t think there’ll be many single modes of action that come out.”

In addition to offering growers another option in the fight against Canada fleabane, using Pixxaro (halauxifen + fluroxypyr) in concert with Cerefit enables growers to accomplish two tasks with a single pass. As competitive as winter wheat can be on most species, it’s good to provide growers with another effective active ingredient against the troublesome species. As Thoen indicates, combining the fungicide and herbicide application also opens a window of opportunity for custom applications. By the time a fungicide application becomes necessary at the three- to six-leaf stage in winter wheat, many growers are fully engaged in planting corn or soybeans. Combining Cerefit and Pixxaro alleviates some of that timing concern.

The post New cereal fungicide seeks to carve out its own niche appeared first on Country Guide.

To be clear, only 10 per cent of the seed on those acres was susceptible to midge, and that’s been the reason for the continued success of the other 90 per cent in keeping the critters at bay. If 100 per cent of the varieties were tolerant, the small percentage of midge that could avoid the resistant trait would survive and reproduce, eventually becoming the dominant population, similar to how weeds become resistant to herbicides.

This approach is important because there’s only one gene — Sm1 — with the resistant trait. Its continued success depends on growers signing agreements that limit the use of farm-saved seed to one generation past certified.

Todd Hyra, western business manager for SeCan, says the program has been a success because 98 per cent of producers in the system have complied with the agreement. “They see the value, and we want to encourage that continued spirit of co-operation that’s kept this valuable trait in play.”

These agreements recently went digital and are logged in an electronic database, says Mike Espeseth, Western Grains Research Foundation communications manager and co-chair of the Midge Tolerant Wheat Stewardship Committee. The program ensures the products’ built-in portion of “refuge” seed stays at 10 per cent in order to maintain Sm1’s longevity.

Two years ago, when it was discovered that older varieties of soft white spring wheat also contained the Sm1 gene, producers were asked to voluntarily remediate products with a 10 per cent refuge while seed suppliers caught up. These days, all new midge-tolerant wheat (MTW) varieties contain refuge in the bag.

Adding tolerance to more varieties

The proportion of CWRS seeded to MTW has dropped over the last few years due to relatively dry weather which in turn meant lower midge pressure. Last year about eight per cent of total Prairie CWRS acreage was midge tolerant. Hyra says the “real home” of MTW is Saskatchewan, while acres have been lower in Alberta and Manitoba. “Seed customers are getting by on midge and have migrated to other varieties that provide shorter, stronger straw or better fusarium suppression.”

That might change if wet conditions continue this year, and breeders have been working on introducing the Sm1 gene into varieties which also offer higher yield and fusarium resistance.

“We expect the total percentage of MTW acres to increase again as varieties with short strong straw and improved fusarium tolerance hit the market in 2020 and 2021,” Hyra says.

For example, AAC Alida VB has short straw, low DON accumulation and is midge tolerant, he says.

AAC Warman and AAC LeRoy are two more CWRS varieties that combine midge tolerance with fusarium and lodging resistance, says Santosh Kumar, a wheat breeder at AAFC in Brandon. His program focuses almost entirely on CWRS wheat for Western Canada.

Another new variety, AAC Magnet, is rated moderately resistant to fusarium but is lacking on the midge-tolerance side, but not all producers want both.

Harpinder Randhawa is an AAFC Lethbridge spring wheat and triticale breeder responsible for soft white and Canada Prairie spring classes. He says in recent years his program has focused on providing options that tick as many boxes as possible for producers.

In the CPS class, Randhawa recently registered AC Crossfield and AAC Entice. Both are susceptible to midge but have an intermediate level of fusarium resistance. A third, AAC Castle, has midge tolerance as well as intermediate fusarium resistance and good straw strength.

In the SWS class, he’s currently looking for midge-susceptible varieties to use as refuge for new varieties.

Finding promising candidates for MTW refuge is a key breeding challenge in every wheat class. Kumar says there’s a lot of complexity around finding a refuge variety because it has to look very similar to the MTW variety in maturity, height, yield and test weight.

Both breeding programs try to provide choice to farmers.

“If the farmers want fusarium and midge tolerance combined, there are good varieties to choose from. As public breeders, we want to provide better and appropriate choice to farmers so they don’t have to compromise,” Kumar says.

Randhawa says producers look at the whole agronomic package when making seeding decisions, and midge is just one variable. “In some areas with a lot of midge pressure where there are yield losses you don’t really have a choice (but to plant MTW), but in other areas without much pressure, you can decide.”

How midge tolerance works

Santosh Kumar, a wheat breeder for AAFC’s Brandon Research and Development Centre, says there are two mechanisms for midge tolerance in wheat. The first is Sm1-based resistance, which kills the larvae once they start feeding on the developing wheat kernels. This Sm1-based resistance mechanism is called antibiosis.

The second mechanism involves chemical compounds in wheat that inhibit the female midge from laying eggs on wheat heads. This mechanism is called “oviposition deterrence,” and isn’t as common in wheat breeding. Most programs rely on Sm1-based resistance.

But along with other AAFC, University of Manitoba and CDC Saskatoon scientists, Kumar’s program is working on alternatives and screening germplasm for additional sources of midge tolerance. Recently, a team of scientists discovered a promising gene in germplasm from southern Asia, although it’s too early to confirm its efficacy.

Once an alternative to Sm1 is discovered, Kumar says the plan is to bring additional sources of resistance together in new varieties to make midge tolerance more durable.

The post A decade of midge-tolerant wheat appeared first on Country Guide.

“It was a really major, widespread issue,” says Art Schaafsma, a professor in field crop pest management for the University of Guelph’s Ridgetown Campus. He says the last time the industry saw widespread issues with DON was in 2006 when producers were shocked to find contamination levels up to 10 parts per million (ppm). But in 2018, some producers saw levels of over 50 ppm. “The whole industry was up in arms about what to do with all this corn.”

Except for the DON contamination it was a high-quality crop, and most went to ethanol plants, with some byproducts reaching western Canadian feedlots.

Mycotoxin contamination poses challenges for the industry because the toxin doesn’t break down, but accumulates in byproducts.

Across Canada, DON is still the most economically significant mycotoxin. It can occur across all grain types and is associated with infection by Fusarium graminearum, the pathogen that causes fusarium head blight (FHB) in wheat and gibberella or fusarium ear rot in corn.

Higher-yielding corn hybrids tend to be more susceptible to DON contamination, and conditions that are ideal for corn are also ideal for toxin development, Schaafsma says.

“Years ago we’d have sporadic problems with DON. Every once in a while we’d have a larger outbreak. But yield is king, and the outbreaks are becoming more frequent and they’re hitting harder all the time.”

Oats and barley research

In Western Canada, fusarium is less of an issue, but there’s little room for complacency.

Sheryl Tittlemier, a research scientist at the Canadian Grain Commission’s Grain Research Laboratory, says the CGC annually analyzes samples of wheat, oats and barley for its cargo-monitoring program, as well as samples from the harvest sample program. The latter are used for research in grading factors such as fusarium damage.

Two mycotoxin groups are economically relevant in Canada: fusarium mycotoxins and ergot alkaloids, which can cause issues in feed grain. Both types depend on weather during the growing season, Tittlemier says.

A third mycotoxin, ochratoxin A (OTA), doesn’t occur in the field but can become a problem in stored grain.

The CGC just wrapped up a surveillance study in milling oats in collaboration with the Prairie Oat Growers Association (POGA), comparing mycotoxin concentrations year to year.

“When we looked at the harvest samples there was a wider range of DON concentrations than in the samples we obtained from processing facilities or shipments provided by grain handlers,” Tittlemier says. “We’re not seeing high levels of DON.

“This indicates that the industry is aware of the DON and is managing what ends up in the oats that they’re using. This data is proof that management is having an effect.”

In barley, DON presents more of a problem, says Marta Izydorczyk, a research scientist and program manager for barley at CGC.

“FHB is spreading in Western Canada — initially it was just in Manitoba but we’ve started to see it in the other western provinces,” she says. “For farmers, FHB on malting barley means lower yield and the likelihood that their barley won’t be selected for malting.”

The maximum limit for DON in barley is one ppm, says Izydorczyk; malting barley with levels above this is rejected.

Fusarium has a secondary impact in malting barley: if barley with low levels of DON is selected, fusarium and other fungi can grow and proliferate during malting, producing even more DON.

In collaboration with the Brewing and Malting Barley Research Institute, the CGC is currently testing an innovative post-harvest treatment developed by a Scandinavian company called ThermoSeed. It has the potential to eliminate the pathogen during malting and brewing. The ThermoSeed process can treat up to 1,500 kg of grain per hour, and is already used commercially in Sweden, Izydorczyk says.

“The project’s objective is to determine whether the ThermoSeed process can be applied to malting barley with low pathogens and low DON levels without any negative impact on seed germination and malting quality,” she says.

A sample of last year’s crop was shipped to Sweden and has already been treated and returned, she adds. “The results are looking promising — there are definitely no negative effects on barley germination.”

Sampling protocol

Mycotoxin contamination doesn’t currently affect grade, although it affects price — Schaafsma points to discounts in Ontario corn of up to $60 per tonne for DON contamination last year. The CGC has initiated a consultation on whether DON should become an official grading factor, but Canadian elevators do test for DON if fusarium is an issue or if buyers request it.

Last year, irregular readings from corn samples at elevators left many Ontario farmers disgruntled, Schaafsma says.

In some cases a farmer would deliver a load of corn, which would be sampled and tested and given a high mycotoxin reading, and then wouldn’t be allowed to dump the load, he says. “He’d bring the same load back, it would be retested and it would be fine. There was no confidence in the testing, either for the buyer or for the seller.”

The Grain Farmers of Ontario asked Schaafsma’s team to evaluate sampling protocols to assess whether probe samples were part of the problem. Schaafsma’s team found no issues with probe sampling. Nor did they find problems with the ELISA test kits used to evaluate DON levels, but they did find problems with sub-sampling in the grading house, he says.

There, grain would be tested for grading factors, and then a small random quantity of the grain would be siphoned off and run through a mycotoxin test.

There were issues with the ways samples were being selected and ground for the test, says Schaafsma.

“Within a two-kg sample we could get numbers ranging from five to 15 depending on the quantity of grain you took from the sample. We took a number of tests to see how much variability there was and the variability was high,” he says.

Darrall Marshall, operations manager at G3 Glenlea, says there is no standard practice for mycotoxin tests at elevators in Western Canada. He says elevators follow standard formulas to sample grain. Samples go into the grading room and are tested according to CGC grading standards. Grain is ground for DON tests, but neither the tests nor the grinders are regulated for this — instead, elevators follow protocols set by grinder manufacturers.

“If it’s not done absolutely precisely, you’ll get different numbers because it’s parts per million you’re dealing with. And human error can be a factor,” Marshall says, adding. “Inconsistency in the process will lead to different results.”

Schaafsma presented his findings to an industry meeting in late August, and says some elevators have already made changes to what they’re doing.

“We’re trying to set up a standard practice so we can have more confidence in the sampling. We hope for the new crop to have something in place for corn so people don’t need to be upset,” he says.

“Sampling is so key to understanding what you have, so you can’t be too careful to get the right result,” he says. “It’s way beyond just taking a cup of grain and testing it.”

Schaafsma’s team is currently developing a sampling system farmers can use to test their grain before it leaves the farm. “It’s easy to sample dust with a vacuum while grain is being transferred, so we did some work with wheat and we’re now doing it with corn where we’re looking for a relationship between what’s in the dust and the grain,” he says.

“This would give farmers results right away, so they know if they should unload a given load or blend it off and try again.”

The post Careful grain sampling key when looking for mycotoxins appeared first on Country Guide.

Yet other, more immediate concerns are also coming to the fore, including disease. Twitter has been flooded with photos, videos and warnings about disease, and in the cool, wet start to the 2017 growing season, farmers needed to step up their monitoring for leaf rust and fusarium head blight (FHB).

It’s with that overall perspective in mind that Country Guide brings you this update on cereal varieties for 2017. Although it’s been a relatively slow year for the development and registration of new varieties, there’s little doubt about wheat’s continued value for field crop production.

As always, we recommend you do your research and talk to trusted seed dealers about these new varieties for more information and greater detail.

C&M Seeds

JDC78 is a small-seeded hard red winter wheat that has excellent yields for southern Ontario. In previous testing south of London, it has proved one of the top-yielding options out of all classes of wheat — not just the hard red class. JDC78 is named after the “C” in C&M Seeds — J. D. Cameron — who fought tirelessly to get the hard red class of wheat started in Ontario. Among its top features, JDC78 is a short variety with upright leaf structure and excellent protein levels. It also performs well in high-management scenarios.

Arnold is a hard red winter wheat with average yields that really stands out in today’s pricing structure. It is uniquely priced compared to other hard red wheat varieties and will only be grown under contract as an identity preserved WheatPRO variety for a milling partner. In 2016, some growers received more than $300 per tonne for their production. Arnold is pending registration with a limited number of contracts available. For more information, call C&M Seeds at 1-888-733-9432.

DOW Seeds

DS572SRW is a medium-tall awned soft red winter wheat that delivered an average of 110 per cent yield index during a two-year period, and 111 per cent in 2016 (under intense management). The trials are a summary in Areas 1 and 2 in Ontario. This variety offers good overall disease tolerance with above average yields, as well as excellent winter survival and exceptional test weight. More details on DS572SRW are available at GoCereals.ca.

Pioneer

Pioneer brand 25R61 is an awned, medium maturity soft red variety with outstanding yield potential. It has very good test weight, very good resistance to fusarium head blight (FHB) and excellent resistance to leaf rust. It also has improved strip rust resistance compared to 25R46. This product is available pending registration and will be sold in limited volumes for 2017.

Pioneer brand 25R74 is an early harvest maturity soft red with short plant height. It has excellent yield potential and a good test weight. It is an awned variety. This product has above average fusarium head blight resistance, excellent resistance to stripe rust and excellent resistance to powdery mildew. This product is available pending registration and will also be sold in limited volumes for 2017.

The post New cereal varieties for Eastern Canada appeared first on Country Guide.

Nor can it be denied that oat acres are volatile in Ontario. Although 90,000 acres were harvested in 2001 and 50,000 acres in 2016, the 2015 crop was much larger in the wake of poor planting conditions for wheat in late 2014. But then there was the usual boomerang: the big 2015 crop caused a lower price offering for 2016 and subsequently fewer acres.

In Quebec, oats have been a long-standing leader among cereals, with 259,350 acres harvested in 2010. Although that number dropped to 185,250 in 2016, this was the first year in the past six where oats didn’t outrank all other cereals (wheat eclipsed oats in 2016, with 214,890 acres harvested).

Yet something interesting is also happening with oats. It’s gaining popularity as a cover crop.

According to Dr. Weikai Yan, a research scientist with Agriculture and Agri-Food Canada’s (AAFC) Ottawa Research and Development Centre, oats may be a small cereal crop nationwide, but it’s one of the largest cereal crops in Quebec and New Brunswick. Part of that is attributed to its natural resistance to fusarium head blight (FHB) which can render wheat or barley grains unusable as feed. Yan adds that oats can also be a key rotational component in cropping systems.

“Its values are not only economic but also environmental,” he says, referring to oats’ emerging preference as a cover crop. “It’s becoming a mainstream practice. There are roughly one million acres of winter wheat in Ontario, and it’s estimated (by Peter Johnson, an independent agronomist) that 50 per cent of the land grown to winter wheat is planted with oats as a cover crop after wheat harvest. So the acreage of oats is much higher than we think.”

Yan considers crown rust to be one of the worst crop diseases given that its strains can change or mutate quickly to overcome resistant genes. And he’s not alone in that assessment. He explains that an oats cultivar is resistant to crown rust only if it has a resistance gene that has not been overcome by crown rust strains in a particular region. The problem is that a resistance gene in oats will be overcome by the disease; it’s only a matter of time.

What adds to the challenge, aside from the availability and performance of resistance genes, is the transmission of pathogens and the infrequent nature of disease occurrences. Yan points out that there is also no program to develop new resistance genes in oats. That work was carried out by Dr. James Chong at AAFC Winnipeg a few years ago, who used to work on introgression of resistance genes from wild oats to cultivated oats. Currently, there are nine resistance (Pc) genes that are still very effective against crown rust in Eastern Canada.

Pc91 is the most common of the nine and was derived (introgressed) from a wild oats cultivar found in the U.S. It’s effective at all stages of plant development and is the resistance source in AAC Bullet, AAC Oaklin, AAC Almonte and AAC Roskens. Leggett is a cultivar carrying Pc94. Some new cultivars carrying Pc94 are being developed in Eastern Canada. Pc45, Pc50, Pc51, Pc54, Pc58, Pc59, Pc91, Pc94 and Pc96 are still very effective, but Pc38, Pc48, Pc56 and Pc68, all of which were introduced in the 1970s, are no longer effective against crown rust.

“Pc91 is still effective in Eastern Canada but it has already been overcome in the U.S. and some parts of Western Canada,” says Yan, emphasizing the importance of searching for new sources of resistance. “Another strategy we use is to pyramid resistance genes in a single cultivar to slow down the appearance of new virulence genes in crown rust. Pc59, Pc61, Pc91 and Pc94 are effective resistance genes in Eastern Canada, and we’re trying to put these and some others into a single cultivar to achieve lasting resistance.”

Path of pathogens

As for the transmission of crown rust, Dr. Allen Xue, a research scientist in plant pathology with AAFC’s Ottawa Research and Development Centre, says the severity of the disease from year to year depends on environmental and weather conditions. Planting resistant cultivars is the most effective and feasible strategy for reducing the disease’s impact.

“It’s different (in Eastern Canada) than on the Prairies,” says Xue. Here, spores can blow up from the southern U.S., or the primary inoculum can come from the over-wintering sexual cycle on buckthorn. Together this results in a more diverse race population in Ontario and Quebec than in the West.

Xue and Yan have worked together on crown rust since 2013 under the federal government’s Growing Forward 2 initiative, with Xue monitoring the predominant races in Eastern Canada and identifying effective resistance genes for breeding efforts. Crown rust is documented as having the ability to cause yield losses of up to 40 per cent due to damage to the leaves, although Xue believes that number to be closer to 10 per cent on average, based on annual disease surveys in Ontario in the past 10 years.

“In a disease epidemic year, we still see little or no disease in fields with resistant cultivars or those sprayed with fungicides, and severely affected fields with yield losses up to 60 per cent with susceptible cultivars without spraying,” Xue says.

Oats as a cover

Where oats are making a surprising resurgence is as a cover crop. Red clover remains a traditional source, and there are more growers testing cover blends, some with 10 or more species. Quentin Martin, who operates Cribit Seeds, near Winterbourne, Ont., is a big believer in oats’ potential, acknowledging that as a spring cereal crop it will occasionally surpass 100,000 acres. But it’s as a cover crop that can be planted after every wheat, barley or oats acre that misses a red clover seeding where it shows its true upside, which can reach a million acres in the province some years.

Martin agrees that crown rust is still the key disease and notes that AAC Bullet is the best variety as a spring-planted grain. In 2016, he sampled numerous fields and submitted samples to the University of Guelph’s diagnostics lab.

“You’ll see varied results in the fall, and we’ve promoted the use of certified AAC Bullet to improve those odds,” Martin says.

Martin has also noticed a difference between spring and summer environments as they relate to an oats cover crop becoming a new host, similar to buckthorn. He’s had discussions with participants of an Ontario Cereal Crop Committee meeting, and the consensus was that the summer environment is different enough that growers using oats as a cover aren’t “overexposing” it and creating that new host.

The use of oats as a cover crop is an added concern for Yan as well. He believes it makes the disease more frequent, yet in his experience, it’s the wind-blown spores that are the more important source. Rainfall in May and June are key to creating the conditions for disease spores to germinate and develop on oats.

Like Martin, Yan along with Xue and Dr. Baoluo Ma, an agronomist with AAFC Ottawa, performed cover crop variety tests in the fall of 2016. He found cultivars that yielded the most biomass have two things in common: early development (where they’re photoperiod insensitive) and resistance to crown rust. In addition, some cultivars that are normally susceptible to crown rust can be resistant in the fall, which means the crown rust strains can be different from those in the spring.

The post Crown rust comes after oats appeared first on Country Guide.

But new research from Agriculture and Agri-Food Canada’s Swift Current Research and Development Centre is contributing a few pieces to the puzzle.

Research scientist Myriam Fernandez says breeding for resistance to the leaf spot (LS) complex hasn’t made the strides seen in fusarium or other wheat disease breeding programs. But LS is the most frequently encountered disease of bread and durum wheat on the Prairies, and can sharply reduce yield and quality under the right conditions.

Fernandez is the author of a new long-term study assessing the impacts of climate change as well as regional and agronomic practices on leaf spotting in bread and durum wheat.

“It is expected that seasonal fluctuations in the severity of diseases and prevalent pathogens will continue in Western Canada, with the potential for high levels of diseases such as LS and a corresponding decrease in crop productivity,” she writes in the study.

The study looks at data from long-term surveys of wheat and durum acres across Saskatchewan from 2001 to 2012, when the province saw variable weather conditions, including dry years and years with above-average moisture, mostly between 2010 and 2012.

Durum more susceptible

“Disease severity increased going northward and eastward, so it was favoured in wetter areas. This was mostly associated to the septoria leaf complex, which is favoured by wet conditions,” says Fernandez.

The study found that durum is more susceptible to LS than common wheat.

Spot blotch, caused by the pathogen Cochliobolus sativus, showed a marked increase in wetter years, and was most prevalent in durum.

“If wet and warm weather continues, this pathogen could become an important leaf spotting pathogen in Saskatchewan, especially in durum wheat,” says Fernandez. The same trends, she notes, have been described in other parts of the world during similar weather conditions. “It’s very important to also consider that C. sativus also causes root rot and black point/smudge in cereals.”

Linking climate and leaf diseases

Herb Cutforth, an agricultural meteorologist at Swift Current, says climate data in southwest Saskatchewan shows warming over the past 50 years or so, especially between January and April. From May through August minimum temperatures have warmed slightly.

“Yearly precipitation totals haven’t changed much, but the number of events with little precipitation have increased,” he says.

Brian Amiro, a University of Manitoba soil scientist specializing in agricultural meteorology, says that although descriptions of climate trends tend to be very regional, some general western Canadian trends over the last 60 years have shown an uptick in winter temperatures and less snow; this means some pathogens could more successfully overwinter across the region.

Climate studies, as distinct from weather, look at longer-term patterns, and it is difficult to pick out specific climate-related signals influencing diseases, says Amiro.

Nevertheless, it seems clear climate change will have an impact on Canadian crop production into the future, says Amiro, who was an editor on a 2014 Alberta Institute of Agrologists green paper into the need to adapt production practices in response to likely climate scenarios over the next few decades.

The green paper cites International Panel on Climate Change (IPCC) projections that suggest the prairie region will see a one degree Celsius increase in summer temperatures and a two degree Celsius increase by 2050, as well as the potential for a 10 to 20 per cent increase in precipitation.

Best management practices

The Saskatchewan study showed that for bread wheat, leaf spot severity was greater after a year of summerfallow under reduced tillage than when wheat had been preceded by an oilseed crop under reduced tillage. For durum wheat, LS severity was greatest for reduced tillage systems where there was no previous crop information followed by summerfallow systems. In contrast, durum wheat with a previous oilseed crop had the lowest mean disease severity.

Fernandez says her recommendations for curbing disease pressure have remained the same since the 1990s, and will become even more important if disease pressure increases.

“Use the most resistant cultivar available,” she says. “Do not practise summerfallow, and diversify crop rotations with non-cereals, such as pulses, as much as possible, particularly when using zero-till.”

“Only use an aerial fungicide if spotting on the upper leaves is significant, and don’t apply a fungicide at early crop growth,” she adds. “All wheat crops develop leaf spot lesions on the lower leaves which, depending on the environment later on, and the susceptibility of the cultivar, might not progress much further.”

The post Is climate change making leaf diseases worse? appeared first on Country Guide.

The cause was the now-familiar fusarium head blight (FHB), which has now spread across the Prairies. The early panic has subsided, and the industry has learned that the problem can be managed by rotation, fungicides and cleaning. But is there a simpler solution, namely planting varieties that don’t get the disease in the first place?

Simple for the farmers, but not so simple for plant breeders. Yet they say progress has been made, and is continuing.

Last February, the Western Grains Research Foundation (WGRF) announced $21.4 million in checkoff funding for Agriculture and Agri-Food Canada wheat and barley breeding projects to be delivered over the next five years.

WGRF executive director Garth Patterson says fusarium resistance breeding and research is a key priority for the programs and projects funded by the organization.

Across the country, several researchers are studying fusarium from every angle, from pathology to agronomy. This November, many will gather in Ottawa to discuss their findings at the eighth Canadian Workshop on Fusarium Head Blight. On the agenda are resistance breeding, cereal genomics, pathogen genomics and disease management.

Not a single disease

Fusarium is a tough nut to crack, partly because there are multiple species in Canada.

“In the eastern Prairies, Manitoba and Saskatchwan, Fusarium graminearum is the main pathogen,” explains Anita Brûlé-Babel, a wheat breeder at the University of Manitoba. “As you move west you see more fusarium pathogens, more prevalent in some years than others. For instance, Fusarium culmorum tends to be more adapted to cooler conditions.” Southwestern Saskatchewan sometimes hosts yet another pathogen, Fusarium avenaceum.

But Brûlé-Babel says that the genes selected for resistance tend to respond across species, which is good news for breeders.

Every wheat breeding project in Canada screens for new sources of fusarium resistance. Brûlé-Babel is leading the University of Manitoba’s WGRF-funded work in fusarium resistance in winter wheat.

She is currently working with graduate students to map new resistance genes in winter wheat and using marker-assisted selection to screen breeding materials. She oversees Western Canada’s largest FHB nursery, to which wheat breeders can send genetic materials to be evaluated for fusarium response.

“In that nursery we provide data for variety registration trials for spring wheat and winter wheat,” she says.

This year, Brûlé-Babel is also overseeing studies on whether varieties respond differently to different isolates of the pathogen and how effective fungicides are with different levels of resistant genotypes.

We’ve also started another project looking at fall rye, because there’s no data on fusarium in fall rye in Western Canada, she says.

Cross-prairie collaboration

Brûlé-Babel’s is not the only lab in Western Canada focused on fusarium, and collaboration happens at all levels when it comes to resistance breeding.

This means new fusarium-resistant varieties are reaching the market sooner. Brûlé-Babel says there’s been a big improvement in the availability of resistant varieties over the last five years. Red spring has more resistant types because it has the most breeders working on the problem.

“Proportion wise we’ve made quite a shift — the majority of lines proposed are in the intermediate to moderately resistant categories. Right now we’re looking at 56 per cent of the newer varieties being intermediate to moderately resistant,” Brulé-Babel says.

Durum resistance is the least developed, because good natural sources of resistance don’t exist in the gene pool. But University of Saskatchewan Crop Development Centre (CDC) wheat breeder Curtis Pozniak, who was recently involved with assembling the durum wheat genome, is engaged in a SaskWheat/SeCan project at CDC developing new varieties with improved disease resistance.

“We’re still making progress, and we’ve seen a shift to improved resistance, but we’re not at a level where farmers can say ‘My crop is safe from fusarium,’” says Brûlé-Babel.

Challenges

Brûlé-Babel says breeding for resistance is complex because resistance itself is complex: five types of fusarium resistance have been identified. Type 1, for example, resists infection to start with, Type 2 is resistant to disease spread in the spike, and Type 3 is resistant to toxin accumulation.

“With all of these types of resistance, evaluating where it comes from and how the mechanisms operate is complicated,” Brûlé-Babel says.

“The final thing people have to understand with this pathogen is that even the resistance we have is not complete. Leaf and stem rust resistance can be quite complete, but with fusarium that’s not the case,” she explains. “We’re trying to reduce the level of disease to the point where we can increase the grade and market the crop.”

Gina Feist, research program manager for WGRF, says Canada’s research and breeding efforts are on par with those of the U.S. (whose efforts are concerted by the U.S. Wheat and Barley Scab Initiative). Though cross-border collaboration is limited, as Canadian and U.S. wheat and barley varieties are different, it does happen.

“It’s a worldwide, multi-crop issue, and Canadian scientists are linked in with international efforts. That’s probably the best way to beat this long term,” Patterson says.

“My hope is that we can sustain the progress, and through these technologies and genomics be able to make greater gains,” says Feist.

So it looks as if genetic solutions are on the way. But meanwhile, producers are advised to stay on their guard against fusarium — to choose resistant varieties, practice crop rotation, monitor environmental conditions, stay abreast of FHB forecasts, and use fungicides, paying careful attention to timing of application.

The post A genetic solution to fusarium? appeared first on Country Guide.

After changing into hospital scrubs in a locker room, Fetch and his team deactivate an alarm system and go through four doors to enter the laboratory. The Level 3 containment lab, certified by the Canadian Food Inspection Agency, operates under negative pressure so air cannot leave the room. The scientists work carefully with isolates from Africa obtained through CFIA import permits. Their work starts in November and lasts only during winter so cold will kill the agent should it accidentally escape from the lab. Before leaving, Fetch and his crew shower to wash away any spores that might be clinging to their bodies and hair.

Watching these extreme biosecurity measures, you’d think the scientists are dealing with a dangerous pandemic agent that, if it ever got out, could cause widespread devastation. And you’d be right.

Fetch leads a team of Agriculture and Agri-Food Canada research scientists racing against time to find genes with resistance to Ug99, a new race of wheat stem rust spreading through eastern Africa and central Asia.

Although Ug99 is currently confined to a distant corner of the globe, it has the potential to cross borders, even oceans, and infect wheat crops worldwide.

The stakes to develop resistant lines are high because, so far, over 80 per cent of the world’s wheat varieties have little or no resistance to Ug99.

The fungal disease is so virulent that crops, once infected, have been known to collapse completely in a few weeks.

Which means that Ug99, if it continues to spread, is a potential threat to wheat everywhere, including Western Canada.

“It’s almost like a forest fire,” said Fetch. “If it gets out of control, it just spreads so fast that, at that point, even with chemicals, it would be difficult to control if you had enough acres infected.”

On the move

First identified in Uganda in 1999 (hence the name), Ug99 is now present in 13 countries. Most are along Africa’s east coast from Egypt all the way down to South Africa. Ug99 has also been detected in Yemen and Iran.

Pathology experts worry Ug99, carried on the wind, could spread to Pakistan, India and China, where wheat is a staple crop. From there, spores could potentially ride trade winds over the Pacific Ocean to North America. This is not as far-fetched as it sounds. Dust particles have been known to blow across China to North America and a rust spore is no heavier than a speck of dust.

It’s also possible that spores could come over on the bodies of international travellers, which is how the SARS epidemic came to Canada from Hong Kong in 2003.

Even more worrying is the fact that new strains of Ug99 keep appearing, allowing the disease to stay one jump ahead of efforts to breed resistant varieties. Currently, there are 13 known strains of Ug99, including the original one. If a wheat variety contains only one resistant gene, a mutating Ug99 could pick it off and remain unchecked.

For that reason, Fetch and his colleagues are trying to use genes in combination to create multi-gene stacks of resistance. In that way, even if Ug99 overcomes one resistant gene, there are several others in the gene stack to counter it.

And there’s good news. Fetch said his group of roughly 15 scientists has found three new resistant genes and is currently identifying associated molecular markers to make sure those genes have actually been added to the lines they’re working with.

“The ideal system is to put multiple genes in a line so that, if Ug99 overcomes one gene, it still cannot attack the plant fully because there are other genes that are still effective,” says Fetch.

Resistant Canadian varieties

Currently, the two Canadian wheat varieties with the best resistance are AC Cadillac and AC Peace. Both are relatively old — Cadillac was registered in 1996 — so they may not be as good as the new high-yielding cultivars. But Cadillac is considered a gold standard for disease resistance and breeders have used it in crosses since 2005. In 2013, Agriculture and Agri-Food Canada released AAC Tenacious, a hard red spring wheat with Cadillac resistance to rust and fusarium head blight. Fetch says Tenacious contains two resistant genes — better than most wheat but still not quite enough to satisfy breeders.

There hasn’t been an epidemic of wheat stem rust on spring wheat in Canada for over 60 years. The last major one occurred in 1955 and caused hundreds of millions of dollars in losses. Since then, breeders have achieved durable resistance by stacking resistant genes into wheat varieties. Annual surveys in Canada and the U.S. monitor for changes in rust populations.

Most Canadian spring wheat varieties are resistant to current stem rust races in North America. But since Ug99 is not from North America, its arrival here could undo decades of progress in preventing rust outbreaks. Fetch says if Ug99 were to arrive in the southern U.S. in January, it could migrate northward along the so-called Puccinia pathway of spore movement into Western Canada within one growing season. Surveillance in the U.S. would give Canadian farmers advance warning. As a result, they could prepare for Ug99’s arrival by either planting the few available resistant wheat varieties or stocking up on fungicides.

Are fungicides an option?

But could chemical companies make enough fungicide available in such a short time to protect the millions of acres of wheat grown annually on the Prairies? It’s a big if.

“If you did not have fungicides available, it would cause some serious problems because (Ug99) is available on 80 per cent of our wheat,” Fetch says.

An added problem is that fungicides increase farmers’ input costs and their continued use could produce fungicide-resistant strains of stem rust.

Canada and the U.S. have one advantage over other countries in controlling the spread of Ug99. A common native shrub called the barberry, found throughout temperate and subtropical regions of Africa and Asia, acts as an alternate host plant, which allows rust spores to reproduce sexually. Normally, Ug99 reproduces asexually and releases spores that, for the most part, are genetically identical. However, when the barberry gets infected, sexual reproduction of spores can re-scramble the genes and produce new strains of the disease.

Widespread eradication programs throughout North America in the early 20th century largely eliminated barberry populations. But Fetch says eradicating the barberry in Africa and Asia is unrealistic, especially since its berries can be used for food or medicine.

Another concern is that the barberry is also present in South America, although it’s unclear if this shrub is the kind that gets stem rust. Fetch says a recently funded pro­ject in collaboration with scientists in Brazil, where barberry is native, will try to find out. If it turns out Latin America has rust strains which can infect barberry, that potentially brings Ug99 even closer to home.

Research into Ug99 is an international effort with scientific teams in various countries working co-operatively.

In 2011, the Bill & Melinda Gates Foundation and the U.K. Department for International Development announced a $40 million investment in a global project led by Cornell University to identify new rust-resistant genes in wheat and to distribute resistant seeds to farmers.

The post Heading off a stem rust pandemic appeared first on Country Guide.

Peter Johnson believes it’s time to adopt the same caution with fusarium as with soybean cyst nematodes in much of Ontario, or with white mould on beans in the east. You just can’t plan on winning that bet.

This coming season will mark 20 years since the 1996 disaster that decimated fields across Ontario, with 90 per cent of the province’s winter wheat downgraded due to fusarium.

It could happen again. In 2016, fusarium remains a risk. The days when farmers could say “not-this-year” are all but gone. So if you’ve got wheat, Johnson says, spray it and be done with it.

In the past five years, there has been a significant shift in disease thinking, particularly in wheat. Low commodity prices convinced more growers to take a chance on fusarium, a move which Johnson, an independent agronomist, believes to be unwise, pointing to 2015 as an example.

“It was a poor wheat crop, a tough winter, with late-planted wheat and 12 to 13 per cent taken out and replanted because it just wasn’t good enough to keep,” Johnson says. “And then with a really dry May, I had producers calling me up, saying, ‘Why would I waste money on a fusarium fungicide? My yield potential is low and my disease risk has to be low because we’ve had no rainfall.’”

Johnson could see their logic, yet he still advocated spraying for fusarium. He estimates as many as 80 per cent of growers in Essex County and a little less than half of producers in Kent opted to roll the dice and skip spraying for the year.

Then it started to rain.

Johnson recalls one grower who delivered his wheat, took a tremendous grade discount, paid for the crop to be dried, and was left with a net 80 cents per bushel on yields of 80 bu./ac. — just $64 per acre.

“We simply cannot predict the conditions,” Johnson says, adding that the same scenario played out in 2014, with a poor wheat crop and dry conditions in May (although not as dry as May 2015). “I wasn’t getting as many calls, but still had some, and the exact same thing happened.”

The difference in that 2014 crop was the large-scale planting of Pioneer 25R40 the previous fall. Unfortunately, there wasn’t a lot of fusarium data available for that variety, and a lot of producers liked what they saw of it, and accepted the risk. Then the right weather conditions developed, particularly in a region bounded by Grand Bend, Exeter and London — a swath that became known as “The Black Triangle.”

Indeed, Johnson says, the last two years have really driven home the damage that fusarium can do.

“We’ve seen how the use of fungicides changes the nitrogen response curve,” he says, pointing to work he has done with Shane McClure. “It’s very clear that in order to make wheat profitable, you need to use higher rates of nitrogen, and if you don’t spray the fungicide, you don’t get a response to the added nitrogen.”

Besides, even with DONcast, no technology can predict the weather perfectly. That’s why Johnson says it makes sense to remove the uncertainty, by spraying your wheat every year.

“If every farmer in Ontario quit growing corn for five years, maybe — and it’s a big maybe — we would reduce the inoculum loads,” Johnson says.

“But we’re not going to stop growing corn, nor should we… so we are going to have enough inoculum potential regardless of what we do.”

In other words, if the weather conditions are right for the disease to develop, then everyone is going to get hit.

Aren’t things challenging enough?

Full-maturity soybean varieties are also affecting fusarium rates. In the past five years, farmers have been told to extend the maturities on their soybean crops, even if it means delaying planting winter wheat.

Johnson doesn’t favour this at all.

“We grow close to three million acres of soybeans in this province, and we struggle on a perfect fall like last year, where I was sure we’d break a million acres of wheat,” he says.

“I can grow long-season soybeans on two-thirds of my soybean acres and max-out on yield. Yet how is it that I can’t spread out my soybean harvest well enough that on the third of the acres that are going to wheat, I plant them earlier and I go with a little shorter-season variety of soybeans so that I get my wheat in in decent time?”

Besides, long-term research shows a good wheat crop in the rotation leads to a proven five bushels more in rotational soybean yield. The boost in corn isn’t as quantifiable, but the field studies conducted at University of Guelph’s Elora Research Station and at the university’s Ridgetown Campus are undeniable: wheat in the rotation means more bushels of soybeans.

Asked if the genetics used in wheat are contributing to higher fusarium rates or if the disease is becoming more resistant to fungicides, Johnson points to two factors affecting the genetics: no GMO wheat technologies are available to growers, and there is a big disparity between the level of investment in cereal breeding compared to corn and soybeans. And that’s not just in Ontario, but globally as well.

“There’s about one-tenth the amount of dollars invested in wheat breeding,” says Johnson.

The role of genetics

“As an agronomist, all I can do is support the increased yield potential that the breeder is giving me in a new variety, so they’re doing a tremendous job, but if we multiplied that effort times 10 would we make much faster progress? Would we have higher levels of success? I have to believe the answer is yes.”

Still, there has been some genetic progress in winter wheat, particularly in Ontario. The varieties are all rated on gocereals.ca, and as of the latest ratings, none was listed as “highly susceptible” to fusarium. That’s a first in the province’s history. There were highly susceptible varieties in the test, but sponsors know those are almost unmarketable, so they weren’t made available.

“We have had significant improvement over time on average in our wheat varieties’ resistance,” agrees Johnson.

“But even with that, the pressure is such that genetics alone can’t do the job — they just aren’t good enough. So even though we’ve done amazingly in terms of moving the bar forward, it’s not enough.”

It’s one thing to make the application of a fusarium fungicide an annual management practice, but it’s also important to rotate chemistries, something that agronomists, chemical company representatives, weed scientists and extension personnel have been advocating for years.

Yet Johnson finds farmers tend to be creatures of habit. If they used Carumba (metconazole) three years ago on their last winter wheat crop, they’re likely to stay the course with Carumba in 2016.

The problem with that approach is that New York had its first case of a strain of fusarium that is resistant to Folicur (tebuconazole), one of the actives (with Proline or prothioconazole) in Prosaro.

Thus far, there is no resistance to prothioconazole or metconazole.

“From a resistance management strategy, farmers should go back to their records and say, ‘If that field was in wheat three years ago, and it got Prosaro, this year I’m going to use Carumba’,” says Johnson. “Most growers aren’t doing that, and from a resistance management perspective, that’s a mistake.”

The post If it’s wheat, spray for fusarium appeared first on Country Guide.

Country Guide recently spoke to provincial plant pathologists about what they saw this past summer, and what it might mean for the future.

Manitoba

In the Keystone province, provincial plant pathologists Vikram Bisht and Pratisara Bajracharya report that growers enjoyed a bit of a break. It’s traditionally the wettest part of the Prairies, especially in the Red River Valley, sometimes referred to as “Death Valley” because of its heavy disease pressure

This summer, however, while rainfall was mainly adequate to support yields, weather was drier than usual. This translated into lower disease pressure across the board, Bisht said. “Diseases and insects just weren’t a major issue in a lot of cases.”

Bajracharya agreed, saying that in cereals there were some instances of fusarium head blight, leaf rust and stem rust, but nothing that rang the alarm bells.

“They were present, but at fairly low levels,” she said.

Winter wheat was an exception. “This year the timing was ‘good’ for fusarium in winter wheat,” Bisht said. “Flowering seemed to coincide with periods of very high risk, and we saw a few fields that did get caught.”

Bisht said Manitoba growers have come to view fungicide applications on cereals as essential due to the perennially wet and humid conditions, and a few growers even apply fungicides at herbicide timing, flag leaf and flowering stages, for a total of three applications.

“They really like to get good coverage and protection,” Bisht said. “Even when it might not always be the most economical thing to do.”

Bisht also noted that ergot infections in wheat crops had fallen this season, after a fairly serious problem last year.

Corn grower (primarily in the Red River Valley) saw similar results for similar reasons. Drier conditions prevented the usual crop diseases like corn smut, common rust and Goss’s wilt from running rampant. Bajracharya noted Goss’s wilt stayed in check, which was particularly good news for growers who have struggled with it in recent years.

“It’s a bacterial infection, not fungal, so of course fungicides simply don’t work on it,” she said.

Sclerotinia and blackleg were present at low levels in canola, but also not at crisis proportions. So far clubroot, though present, hasn’t become a major issue.

“It was nice to also see the two common diseases of canola were not a major issue for growers this year,” Bajracharya said.

Bisht added this doesn’t mean growers can afford to be less vigilant. Both are stubble-borne infections that can linger in fields from season to season, and robust rotation is a key to keeping both in check, as it is with clubroot, which remains a concern.

“Rotation is a major issue and if it is properly practised it can certainly bring down the risk level for growers for all these canola diseases,” Bisht said.

Soybean honeymoon ending?

Soybean growers didn’t have huge issues this year either — but Bisht said reality is beginning to settle in after a bit of a honeymoon period.

While growers did benefit from the general low disease pressure, they saw some cases of rhizoctonia and fusarium root rot, especially when conditions turned a bit wetter later in the season.

Brown spot, caused by a fungal pathogen, has also begun to show up, and it’s one of those diseases that are typical of soybean-growing areas. When it hits a field it can defoliate plants, but leaves the beans themselves alone, meaning its effect is purely on yield, not quality, Bisht said.

Other relatively minor issues were seen with bacterial blight, though the severity and number of incidents remained relatively low. There was also some minor pressure from pod blight and stem blight, which are caused by a complex of fungal pathogens.

“These are all issues we’re going to have to be on the lookout for in the coming years,” Bisht said. “I’m afraid soybean won’t be quite as much a Cinderella crop anymore.”

Late blight scare

Manitoba’s potato crop continued to fight its ongoing battle with diseases. This year late blight infections appeared in the first week of September, placing growers on high alert, Bisht said.

“It’s a very serious disease, and it can take down an entire crop over the course of just three or four days, under favourable conditions and without fungicide protection,” he said.

One factor in the industry’s favour was an early and relatively dry harvest, which meant much of the crop was already out of danger, Bisht said. This also meant fewer problems with storeability.

Bisht also noted the crop has seen a tricky new insect pest arise recently — the European corn borer. Its presence in potatoes is an unintended consequence of the widespread adoption of Bt corn varieties.

“Potato is its next favourite host,” Bisht said. “This has been seen in other potato production areas in the U.S.”

A Group 4 insecticide will control them, but timing is a real challenge. They can only be controlled while they’re on the plant, but not after they bore into the stem and gain the protection of the plant.

“Timing is going to be a real challenge,” Bisht said.

Saskatchewan

Moving west, Saskatchewan growers saw much the same pattern, with drier conditions hampering disease development, said provincial plant pathologist Faye Bouchard.

“This was a change after the past several years, where we saw some wetter-than-usual conditions promoting disease development,” Bouchard said.

Bouchard told Guide that plant pathologists typically talk about infections needing a “disease triangle” that consists of having inoculum present, a susceptible host crop and environmental conditions conducive to the development of disease.

“In this case it was the environmental conditions that were the missing piece of the triangle,” she said.

And while drying conditions did affect yields a bit, Bouchard added the emerging consensus is that growers in a lot of areas wound up with much better quality than in recent years, which helped to at least partially cushion the blow.

“There were definitely also a lot less quality issues related to disease showing up in samples during harvest,” Bouchard said. “For example, there were far fewer fusarium-damaged kernels in wheat.”

Growers did apply fungicides when conditions warranted it — i.e. during an elevated risk forecast at flowering. But generally, fungicide use was down in step with the generally drier weather.

“It’s taken longer for (fusarium) to get here, and while growers started using fungicides in the wet conditions, they appear to still be using a decision model that looks at risk levels before they use them,” Bouchard said.

That’s good news because careful stewardship means the products will remain effective longer and won’t fall prey to fungicide resistance.

“A plant pathologist will always say we should protect these products and maintain their effectiveness as long as possible,” Bouchard said. “That means using them only when necessary, and properly rotating between modes of action.”

Low canola disease pressure

The province’s major canola diseases — sclerotinia and blackleg — also seemed to be largely in remission this year, with only a few isolated cases appearing, although it appears there may have been more blackleg when crops were hit with damaging weather like hail, which opened it up to infections.

“That’s our suspicion, and we’re investigating it a bit further to understand exactly what happened there,” Bouchard said.

The perennial advice for growers on canola and diseases is robust rotation, Bouchard said, and it appears the message is getting through.

“We recommend a one-in-four-year canola rotation, and I think there are a lot of growers who are doing a good job of this now,” Bouchard said. “Unfortunately, there are still some areas where rotations are tighter, and when it comes to plant disease, your first and best tool is rotation.”

Yet while growers may have had  lower disease pressure this season, those diseases are still lurking in the background.

“Unfortunately they’re now endemic to the area, and they’ll reappear when we inevitably have more favourable conditions for them in the future,” she said.

Alberta

“Crop diseases just weren’t the top-of-mind story this season — that was the drought,” said Michael Harding, an Alberta Agriculture plant pathologist based in Brooks. “That was the issue limiting potential yield this year.”

Dry weather also hampered the development of most of the common diseases in the province, including sclerotinia and blackleg in canola and fusarium head blight in cereals.

“We still saw all the usual suspects,” Harding said. “It’s not like they went anywhere, they were just present at much lower levels.”

When moisture improves, all the common problems will reassert themselves when weather conditions line up, he said.

Unusual suspects

That’s not to say there weren’t a few unusual suspects, however, with a couple of oddities cropping up in Alberta fields that bear watching in future seasons — things Harding said aren’t “ordinary to see or something we’d see every year.”

Wheat streak mosaic, a viral infection commonly carried by the wheat curl mite, popped up on a few wheat fields, for example. There were also cases of aster yellows spread in the same way, this time by the tellingly named aster leafhopper in canola. Neither threatened large acreage, but Harding said growers should be aware that both insects could persist and continue spreading the diseases.

“For example, we’ll see wheat curl mites overwinter on winter wheat, then in the spring move into spring cereal crops when the insects arrive,” Harding said. “These host crops support the disease, but until conditions are just right, it’s not a disease we’re necessarily going to see a lot of.”

Harding also noted that there were more bacterial diseases beginning to crop up, saying he found their development a bit surprising. Two notable examples were bacterial leaf streak in wheat and Goss’s wilt in corn.

A break from stripe rust

Dry weather likely saved growers a tough foe to battle. Stripe rust showed up early in winter wheat fields, only to be greeted by less-than-ideal dry conditions.

“It overwintered on winter wheat and emerged early in the spring, poised to become a major problem — but it never really got rolling,” Harding said.

It’s a cooler-season disease, so the hot, dry conditions in 2015 didn’t support it, and a number of the commonly grown wheat cultivars in the area also have decent genetic resistance to the disease.

The elephant in the room when talking about crop diseases with an Albertan is, of course, clubroot, a soil-borne disease issue that’s rapidly blown up after being discovered in the Edmonton area just a few years ago. Harding confirmed the disease continues to spread, and that the available genetic resistance isn’t a silver bullet. He talks instead of the need for cultural practices centred around crop rotation and certain cultural practices such as avoiding spreading soil between fields.

With the issue just beginning to appear in the other two Prairie provinces, Harding hoped those jurisdictions can learn from Alberta’s experience and get on top of the situation early, while it’s still relatively easy to control — advice he says also applies on the farm level, due to the way the disease can lurk in the background developing, before appearing as a full-blown wreck.

“This is a disease that is much easier to control if you find it earlier,” he said. “You have a lot more options when you’re dealing with, say, a 30-square-metre patch, rather than 30 or 40 acres.”

Harding said the approach that works best for this disease is really one that’s transferable to any crop issue — an effective rotation, regular and timely scouting including taking the time to know what symptoms to look for, and using tools like economic models and extension information to support decisions.

“That’s the foundation of any good disease-management strategy,” Harding said.

The post Crop diseases take a bit of a break in 2015 appeared first on Country Guide.