“Forecasting head blight is really quite challenging,” said Mike Harding, a research scientist and plant pathologist with Alberta Agriculture and Forestry.

• Read more: Provincial legislation isn’t helping fusarium battle, say seed growers

The province saw record levels of fusarium graminearum in 2016 because it was a wet year. The extremely dry conditions last summer reduced the incidence but the pathogen continues to spread to new areas, and there is more of it in areas that have already been infested.

“We can’t say that it is necessarily established everywhere, but it certainly is spreading,” said Harding.

Fusarium species are very adept at colonizing cereals and corn at the ground level, particularly in the first node of the plant, where the largest number of pathogens are found. Some of the pathogens that cause head blight produce asexual spores that can splash higher up on the plant when it rains. These spores then infect the anthers, grow down into developing kernels, and cause shrunken, bleached kernels.

“In years where we don’t see a lot of head blight, it doesn’t mean that the fusarium has gone away,” said Harding. “It just means that the fusarium may be present low down in the canopy or even on the roots.”

The pathogen could simply have been completing its life cycle down in the crop in 2017. As a result, producers should be on the lookout in any area where fusarium graminearum is common.

In 2017, there were dry conditions in south and central Alberta during the flowering period, and a survey by the Canadian Grain Commission showed that numbers were down.

“The weather influences this disease to a great extent,” said Harding, noting the highest risk is when there are wet conditions during the flowering period.

Even if the disease wasn’t seen in 2017, it could still have colonized crop residues.

“Just because we had low levels in 2017 doesn’t mean we couldn’t have another record-breaking year in 2018,” said Harding.

Fusarium graminearum head blight has been most common and damaging in southern Alberta, but a 2016 survey by Alberta Agriculture found 20 per cent of all the fields on the eastern side of the province had some signs of the pathogen. There are also a few pockets in other areas of the province and researchers found their first positive sample in the Peace in 2016.

“There are some areas where it is more severe and we expect to see a significant number with more than 20 per cent of fields with it in a wetter year,” said Harding. “But every field in the province needs to be on alert for this. It’s probably not going to stop moving.”

By the time symptoms of head blight have been found, there are no management options left. But it’s still good to scout during the late-milk to early-dough stage to look for signs of prematurely ripening florettes.

“Sometimes, even when you peel back or look around the edge of the bloom, you can see a pink or salmony-coloured growth of the fungus,” said Harding.

At harvest, producers will see shrivelled and bleached kernels.

In order to prevent the spread of the pathogens, producers should test their seed, and avoid bringing contaminated or infected seed onto their farm.

“Because fusarium is surviving on crop residue, crop rotation is a good management tool,” said Harding.

Other tips include using high-quality seed, seed treatment, purchasing good genetics, applying fungicide, and increased seeding rates.

This year, Alberta Agriculture has also developed an app that can be used on a computer or mobile phone. The app, which can be found at weatherdata.ca/m calculates hourly risk, and also offers weather alerts and historical fusarium data.

Producers should check it daily because the situation can change from day to day, said Harding. The site is only active during the growing season.

The post Don’t let your guard down — fusarium still a risk appeared first on Alberta Farmer Express.

“For disease to develop, we need certain weather, certain hosts, and certain pathogens, so it can really be like looking into a crystal ball,” said Stephen Strelkov, a professor and researcher at the University of Alberta.

“As a result, there are multiple issues that may be vying for attention.”

But when asked to give their best educated guess, three Alberta plant pathologists all targeted one disease that producers should watch out for this summer — fusarium head blight.

“If I were to name one disease that producers should be thinking about and preparing for, it would be fusarium head blight,” said Kelly Turkington, research scientist with Agriculture and Agri-Food Canada.

“It caused some real problems last year, and what that means is you have lots of infested residue in many areas of the Prairies that carries the fusarium pathogen.”

• Read more: Three more crop diseases to watch for in 2017

In 2016, fusarium shot up significantly in both incidence and severity, with almost one-quarter of all crop samples in Alberta testing positive for the disease — up from about six per cent in 2015. But the disease is also expanding its reach into other regions of the province from its typical epicentre of southern Alberta, said Michael Harding, research scientist with Alberta Agriculture and Forestry.

“Fusarium head blight is the one that’s probably experiencing the biggest change across the province and moving into areas where it previously hadn’t really been an issue,” said Harding.

“It is expanding into new areas regardless of the season, and the seasons where we have the really conducive environmental conditions, it’s becoming more and more severe.”

An expensive disease

Years where producers saw high fusarium levels — such as last year — produce inoculum that stays in the soil for the following growing season, triggering another outbreak if conditions are warm and wet.

“It becomes a bit of a cycle,” said Strelkov. “There’s more severe disease, so there’s more infected residue, and then that’s available again to cause further infections. It can start to increase more rapidly as time goes by as you have more and more disease present.

“Fusarium head blight was a pretty big issue last year, so it definitely might be an issue again this year.”

And in wet seasons, the losses can be devastating for farmers. Since the early 1990s, when the disease caused its first severe outbreak in the Canadian Prairies, estimated losses have ranged between $50 million to $300 million annually in Canada.

“It will cause a reduction in yield as little as five per cent upwards of 30 per cent, depending on the level of disease,” said Turkington.

Fusarium also produces mycotoxins that limit the end-use markets for the grains, added Harding.

“In cases where you get a lot of mycotoxin in the grain, it can be difficult to find a market for it.”

But the thing that “really hits producers’ pocketbooks” is the downgrading that comes with fusarium-damaged kernels, said Turkington.

“You can quickly go from a No. 1 to a No. 2 to a No. 3 depending on the type of wheat.”

Last year, conditions were “very conducive” to fusarium, and producers saw a lot of downgrading, said Harding.

“When we get a wet season, we can have quite a bit of damage and financial loss,” he said.

“In cases where graminearum becomes common or well established, we start to see more fusarium-damaged kernels and more downgrading and, therefore, more financial loss.”

And when high levels of mycotoxins are combined with downgrading, “the grain almost becomes unmarketable,” added Turkington.

Management tools

Managing fusarium head blight can be a “tough nut to crack” too, said Harding.

“It’s really difficult to throw one single management tool at it and see any effect,” he said.

“There isn’t one thing you can do — like spray a fungicide or use a crop rotation or grow a resistant variety — to manage the disease. It’s challenging to manage it. You have to pile on as many management tools as necessary to try and get ahead of the disease.”

Extending your crop rotation, treating your seed, choosing fields with low levels of disease, and using a resistant variety will all help, but once the seed is in the ground, options are limited.

“At that point, you’ll want to look at spraying a fungicide and ensure that you get the most out of that fungicide as possible,” said Turkington.

“The key thing with fusarium is waiting until you have full head emergence. You get that product on all of the plant tissue ideally that you want to protect.

“It will certainly help to improve the level of control, which can be a challenge with fusarium head blight.”

But at best, fungicides will offer about 50 per cent control of the disease, and “once you see disease in your field, it’s too late to spray with a fungicide,” said Turkington.

So producers need to be on the lookout for it.

“You need to scout for it and you need to be aware of how much fusarium graminearum you have in your region or on your farm,” said Harding.

“If you’re in an area where it’s already common, you know to expect it. But fusarium graminearum is moving. If you’re a producer who hasn’t had to deal with fusarium graminearum before, that situation could change.”

The post What’s your biggest disease threat this year? appeared first on Alberta Farmer Express.

“When we did our survey in 2016, we found blackleg in almost 90 per cent of the fields we looked at,” said Mike Harding, research scientist in plant pathology with Alberta Agriculture and Forestry. “If we looked harder, we probably could have found it in just about all of them.”

But the good news from last year’s survey of almost 500 fields is that the severity of the disease was low — the highest infestation that was found rated only 0.4 on a scale of zero to five.

“There are some fields that have high levels of blackleg that would have had an economic impact but they are relatively few,” said Harding. “Currently, the majority of canola fields we visited did not have economic levels of blackleg because resistant cultivars were being used and they were effective.”

But producers still need to be vigilant — high levels of the pathogen and short rotations are a recipe for trouble.

“We need to be watching for it, scouting for it and taking precautions to manage it,” said Harding. “We could see the emergence of new virulent pathotypes that can overcome the resistance and that’s a big concern.”

The fungus infects canola in the early vegetative stages, when the plant is in cotyledon or early leaf stages. It invades the leaf, travelling down the stem to the base of the plant, where a canker will develop in the most severe cases.

“All of a sudden, you get a canker in the stem and it’s cutting off water and nutrients and then the seed doesn’t fill properly and you see these plants that are ripening prematurely and there’s a yield loss,” said Murray Hartman, an oilseed specialist with the province.

If stems are examined at harvest time, producers will often see blackening right at the soil surface, where the fungus is growing inside the stem. If the canker is not present, the yield loss is slight to moderate.

“Even if it doesn’t look like you have blackleg, you should be snipping your plants and just seeing how many of them do have blackening and how much of the core has blackened,” said Hartman. “It gives you a heads-up on whether the blackleg is starting to build in the field.”

If there’s a significant amount of blackening at the bottom of the stem, it will have an impact on yield.

Using resistant varieties, fungicides, and seed treatments — along with proper rotations — should keep blackleg at low levels. But the latter is a challenge given the profitability of canola.

“Blackleg is one of those diseases that will do much better in a short rotation — a one-in-two-year rotation versus a one in three or a one in four,” said Hartman.

But because of the economics, Hartman said he doesn’t think that growers will lengthen their rotations any time soon.

“So we have to do a better job with the scouting, and using variety resistance. In those cases where we have a problem field, those are the cases where a rotation has to be extended.”

But the wild card in this situation is China, which buys about 40 per cent of Canada’s canola annually.

It has been saying for years that it fears Canadian canola seed could introduce blackleg to the country (even though the seed goes straight to crushing plants and not to farms). Last year, China threatened to slash dockage levels to one per cent from the current 2.5 per cent — a potential crisis for Canadian canola exports that took the involvement of the prime minister to avert.

But the deal only secures market access at current dockage levels until 2020, so the issue should remain on the radar of producers, said Hartman.

“Their (Chinese) varieties already have blackleg resistance — it’s not like they have nothing for resistance if it does get there. But it is one of the trade concerns,” he said. “As an industry, we have to be cognizant of this, and as a grower, you also have to be because of your yield and the profit, too.”

The post You’ve got blackleg in your fields — whether you know it or not appeared first on Alberta Farmer Express.

“We’re hearing and seeing evidence of pretty extreme root rot in pulses, especially peas,” said Mike Harding, research scientist and plant pathologist with Alberta Agriculture and Forestry.

“It doesn’t look like it’s going to be a great year for anyone who has peas in a field that is prone to getting root rot.”

Root rot was first detected two years ago.

“While it has been here for a significantly longer period than that, it has flown under the radar,” said Harding. “It seems like it’s a new pathogen for us but in reality, it has been here for a while. As a result, we haven’t been breeding for resistance, or looked for products that are effective against it.”

The impact on peas depends on how long peas have been in the rotation, compaction, drainage issues, and rainfall amounts. The organisms that cause the disease are soil-borne and can infect the plant at any stage.

“There are all kinds of things that line up and in some situations, it is severe; in some it is moderate; and there are some pea fields out there that look wonderful,” said Harding.

When infected, a plant begins to yellow, as the roots lose the ability to move nutrients up from the soil. Plants can look wilted and sick, and in some cases, might die off.

“For some reason, some varieties seem to stay greener above ground longer than some others,” he said. “The damage is done to the root and the yield loss is still there, but the plants don’t show symptoms as bad as some others. Some varieties look really, really bad when they get root rot and others look not quite so bad.”

Producers should scout periodically for root rot.

“Even in the absence of above-ground symptoms, you can still look for root rot by digging up the plant and just having a look at the root,” said Harding.

In a normal pea crop, there should be a cluster of pink, healthy, nodules on the roots to fix nitrogen. The roots should have lateral root growth and look like a big ball. But root rot pathogens cause small lateral and feeder roots to die out, so the ball becomes a stick, instead of a nice, robust root system.

The root system can have a honey brown colour with aphanomyces root rot, and black in the case of fusarium root rot.

Drainage and rotation

Good drainage can make a huge difference as fields with poor drainage are susceptible to root rot, as are compacted ones. Crop rotation is also key.

“If a farmer has only been growing peas for 10 years and has a four-year rotation, we see fewer issues, because those pathogens haven’t had time to accumulate in the soil,” said Harding. “With farms that have been growing peas for 30 to 35 years, the pathogens may have accumulated above that threshold where we start to see severe problems.”

There is no current treatment for the disease, save for seed treatment before planting.

Producers should avoid planting peas in fields that are waterlogged or have low spots with poor drainage.

“Try to avoid fields that have compaction issues; choose lighter loamier soils rather than hard clay that gets packed and compressed.”

Producers in the irrigation areas should take care not to waterlog their soils.

“Use high-quality, certified seed with a seed treatment. If you have both fusarium or aphanomyces in your field, then you need two seed treatments,” said Harding.

Alberta Pulse Growers recommends producers who see root rot should avoid seeding peas or lentils on that field again for five years. It also has a root rot guide at pulse.ab.ca.

The post Root rot rears its ugly head — and there’s no treatment appeared first on Alberta Farmer Express.

“Last year we had a dozen or so fields in southern Alberta that tested positive for or were assumed to be wheat streak mosaic, based on the symptoms,” said Mike Harding, research scientist and plant pathologist with Alberta Agriculture in Brooks. “We had been on the lookout for it in case it overwintered, and then we had a very mild winter.”

All positive fields have been south of the Trans-Canada Highway.

A number of factors need to come together for wheat streak mosaic virus to develop. The virus is carried by an insect known as the wheat curl mite, which can migrate from field to field via the wind.

“Wheat streak mosaic virus doesn’t overwinter here,” said Harding. “So if the mite doesn’t overwinter, or isn’t infectious, then we don’t see the disease.”

Symptoms present themselves differently depending on both the weather and the cultivars, and the disease can be difficult to diagnose. Infected plants will display light green, yellow or white streaks on the leaves, parallel to the veins. As the crop matures, some plants will be stunted.

“The most conspicuous symptoms are the ones that are present in younger plants with light green or pale green or whitish streaking along the leaf blade,” said Harding.

The disease can also look similar to stripe rust. When stripe rust occurs, it also manifests as yellow streaks, with orange spores eventually appearing on the leaf.

“If you go back the next day or two and you don’t see orange stripes, it’s probably not stripe rust,” said Harding. “You can protect against stripe rust infection with fungicides, but wheat streak mosaic can’t be managed with fungicides because it is a virus.”

The wheat curl mite can damage the wheat crop by feeding on the plants. But the virus itself reduces the plant’s ability to photosynthesize and reduces its ability to fill grain heads.

“In many cases, you’re losing the green tissue that you need to make plump kernels.”

Wheat streak mosaic virus hasn’t been an issue in Alberta for a long time.

“This is probably the most significant virus that we have had in the last 10 to 20 years,” said Harding. “It’s just a matter of all those planets aligning to get us to that spot. We have to have the mite, it has to be infectious, and it has to spread from field to field.”

‘Green bridge’

Alberta winters typically kill off the wheat streak mosaic virus. But the virus can survive when there is a “green bridge” — such as winter wheat that stays green through the winter.

“If you have a wheat streak mosaic virus in the area and it comes up at the same time that there are wheat curl mite issues in the spring cereals that haven’t been harvested yet, the vector moves into the cereals and survives in the green tissues through the winter and then green bridges through a season when it would normally die,” said Harding.

The disease is rare, so there are no treatments, and no resistant or tolerant varieties.

While there are lots of good reasons to seed winter wheat early, wheat streak mosaic virus is one reason to seed winter wheat at a later date.

“We don’t want to see this overwinter and be a problem again next year,” he said.

Community effort is what really will cut down the disease, and so everyone in the area needs to take action.

“If eight out of 10 avoid green bridging, but two don’t, everyone could have the disease,” said Harding.

Anyone who has a field with wheat streak mosaic in it will want to control their volunteers. Last year, when the disease showed up late in the season, some producers cut the crop and baled it for green feed. Other who found the virus early enough took off the infected crop, and seeded another, non-cereal crop.

The post Wheat streak mosaic virus returns to Alberta appeared first on Alberta Farmer Express.

To learn more, or to see more MSU alerts, visit the Montana AgAlert website.

If you find suspicious cereal fields and would like them tested for CCN, contact Dr. Michael Harding by email or by calling 403-362-1338.

Mike Harding is a plant pathologist with Alberta Agriculture and Rural Development

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It appears that the stripe rust fungus may have overwintered in both southern and central Alberta because all reports are on lower leaves and no striping yet on new leaves. Additionally, Eric Amundsen reported the ability to recover viable stripe rust spores from winter wheat in southern Alberta on March 30, 2015.

Two of the five positive fields in southern Alberta had symptoms on more than one plant per square meter indicating that scouting for stripe rust in winter wheat should remain a priority.

The post Stripe rust update for southern and central Alberta appeared first on Alberta Farmer Express.

A Jan. 19 Capital Press story says stripe rust has been discovered in Oregon’s Willamette Valley. Oregon State University plant pathologist Chris Mundt and three extension researchers issued an alert Jan. 19 informing growers that they have found stripe rust in early-planted experimental plots and commercial fields, beginning with sightings Jan. 7-12, three weeks earlier than ever previously recorded.

Harding said leaf rust on winter wheat in southern Alberta has also been reported. He said it would be wise to scout winter wheat crops regularly for rusts as the wind trajectories and weather conditions are now putting southern Alberta cereal producers at risk for these diseases.

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