Agronomists have noted blight issues in a number of crops, such as oats, dry beans, and some concern in peas, according to provincial crop pathologist David Kaminski.

Why it matters: Producers misdiagnosing bacterial blight for something treatable by fungicide risk wasting time and money.

High winds in June did little to help mitigate bacterial blight risk. Parts of the province saw wind gusts over 100 kilometres an hour June 11, with several other days in June clocking wind gusts near or above 70 kilometres an hour.

“I don’t know if we can attribute everything to the wind,” Kaminski said, although he noted that high wind picking up soil and blasting plants results in wounds that pave the way for bacteria to infect a plant.

“Otherwise, bacteria have to get into the plant through natural openings like stomata,” he said.

Bacterial blight in oats is a problem year after year, he noted. They have not noted issues as widespread in peas, he said, but added that, given a general rise in pea acres this year, there is increased scrutiny on the crop in general.

Outside of wind damage, Kaminski said some issues might be seed-borne, particularly in non-certified, carried-over seed, while variety susceptibility or rotation issues may be other contributing factors. Nearby oat stubble, for instance, can be a vector for bacterial blight, he noted.

“With the pulses I don’t think it’s as common, but oats is quite common. There’s always a good chance that you’re on or near oat stubble as an early source of infection,” he said.

Producers might also have courted blight spread if dry beans were cultivated while leaves were wet, provincial pulse specialists told attendees of a provincial Crop Talk webinar June 23.

“Right now, the plants are still quite small, so the risk is quite low for spread that way, because you’re not really touching the plants, but if you’re cultivating later in the season and there’s some bacterial blight, you want to be careful not to cultivate when the leaves are wet,” pulse specialist Dennis Lange said during the webinar.

Hard to hone in on yield impact

It’s difficult to say how much those blight issues might come due at the bin, Kaminski noted.

In many cases, blight symptoms are noted early in the season, while the crop seems to grow out of the problem as the year goes on.

“That’s especially true in the cereals,” he said.

Eyes are typically drawn to damaged parts of the leaf, leading many to overestimate exactly how much of the flag leaf, so critical for head fill, is actually lost, Kaminski had told webinar attendees earlier.

Make the ID

Some producers may be wasting time and money spraying a problem that won’t be fixed with fungicide, Kaminski noted.

“Get it to a lab as soon as possible,” he said.

The Crop Diagnostic Centre in Winnipeg is “as good a place as any to start,” he added.

“They would be able to tell you in fairly quick time,” he said. “If it turns out to be a fungal disease and fungicides are an option, most of the timing for fungicides is at early flowering or later, because the pathogens, or the disease, can’t do too much in terms of yield until it gets onto the developing pods, and then it can be a real issue. So you want to have the fungicide there if you have disease developing before any of the pods are beginning to form.”

Kaminski says he is fielding pathogen identification questions from producers noting symptoms on the lower leaves of their pea plants.

In the most recent Bean Report, published by the Manitoba Pulse and Soybean Growers, the grower group noted that pea producers risk misdiagnosing bacterial blight with mycosphaerella (ascochyta) blight, which, unlike bacterial infections, can be treated with foliar fungicide.

Treatment

For fields that do come back with bacterial blight, producers have few in-season options.

Dry bean producers may turn to copper fungicides to slow halo blight, although the province warns that such products have to be applied repeatedly, early in the season, and are only moderately effective.

There are some peroxide-based products registered for dry beans, although Kaminski noted that those labels do not extend to crops like peas.

Likewise, he cautioned, those products are more protectant than treatment, and producers turning to them to prevent a problem will likely have to reapply multiple times.

“They may stop the disease where it is, but they won’t necessarily protect any new growth,” Kaminski said.

Studies on the efficacy of such products out of the University of Guelph showed little difference in leaf damage or yield between treated plots and an inoculated control, Crop Talk attendees heard June 23 and, while similar research out of North Dakota State University did see some benefit to foliage, that benefit similarly did not transfer to greater yield.

The post Spotlight on bacterial blight appeared first on Manitoba Co-operator.

Add bacterial blight to the problems Manitoba producers are fighting this year.

Agronomists have noted blight issues in a number of crops, such as oats, dry beans, and some concern in peas, according to provincial crop pathologist David Kaminski.

Why it matters: Producers misdiagnosing bacterial blight for something treatable by fungicide risk wasting time and money.

High winds in June did little to help mitigate bacterial blight risk. Parts of the province saw wind gusts over 100 km/h June 11, with several other days in June clocking wind gusts near or above 70 km/h.

“I don’t know if we can attribute everything to the wind,” Kaminski said, though he noted high wind, by picking up soil and blasting plants, results in wounds that pave the way for bacteria to infect a plant.

“Otherwise, bacteria have to get into the plant through natural openings like stomata,” he said.

Bacterial blight in oats is a problem year-after-year, he noted. They have not noted issues as widespread in peas, he said, but added that, given a general rise in pea acres this year, there is increased scrutiny on the crop in general.

Outside of wind damage, Kaminski said some issues might be seed-borne, particularly in non-certified, carried-over seed, while variety susceptibility or rotation issues may be other contributing factors. Nearby oat stubble, for instance, can be a vector for bacterial blight, he noted.

“With the pulses I don’t think it’s as common, but oats is quite common. There’s always a good chance that you’re on or near oat stubble as an early source of infection,” he said.

Producers might also have courted blight spread if dry beans were cultivated while leaves were wet, provincial pulse specialists told attendees of a provincial Crop Talk webinar June 23.

“Right now, the plants are still quite small, so the risk is quite low for spread that way, because you’re not really touching the plants, but if you’re cultivating later in the season and there’s some bacterial blight, you want to be careful not to cultivate when the leaves are wet,” pulse specialist Dennis Lange said during the webinar.

Hard to hone in on yield impact

It’s difficult to say how much those blight issues might come due at the bin, Kaminski noted.

In many cases, blight symptoms are noted early in the season, while the crop seems to grow out of the problem as the year goes on.

“That’s especially true in the cereals,” he said.

Eyes are typically drawn to damaged parts of the leaf, leading many to overestimate exactly how much of the flag leaf, so critical for head-fill, is actually lost, Kaminski had told webinar attendees earlier.

Make the ID

Some producers may be wasting time and money spraying a problem that won’t be fixed with fungicide, Kaminski noted.

“Get it to a lab as soon as possible,” he said.

The Crop Diagnostic Centre in Winnipeg is “as good a place as any to start,” he added.

“They would be able to tell you in fairly quick time,” he said. “If it turns out to be a fungal disease and fungicides are an option, most of the timing for fungicides is at early flowering or later, because the pathogens, or the disease, can’t do too much in terms of yield until it gets onto the developing pods, and then it can be a real issue. So you want to have the fungicide there if you have disease developing before any of the pods are beginning to form.”

Kaminski says he is fielding pathogen identification questions from producers noting symptoms on the lower leaves of their pea plants.

In the most recent Bean Report published by Manitoba Pulse and Soybean Growers, the grower group noted that pea producers risk misdiagnosing bacterial blight with mycosphaerella (ascochyta) blight, which, unlike bacterial infections, can be treated with foliar fungicide.

Treatment

For fields that do come back with bacterial blight, producers have few in-season options.

Dry bean producers may turn to copper fungicides to slow halo blight, although the province warns that such products have to be applied repeatedly, early in the season, and are only moderately effective.

There are some peroxide-based products registered for dry beans, although Kaminksi noted that those labels do not extend to crops like peas.

Likewise, he cautioned, those products are more protectant than treatment, and producers turning to them to prevent a problem will likely have to reapply multiple times.

“They may stop the disease where it is, but they won’t necessarily protect any new growth,” Kaminski said.

Studies on the efficacy of such products out of the University of Guelph showed little difference in leaf damage or yield between treated plots and an inoculated control, Crop Talk attendees heard June 23 and, while similar research out of North Dakota State University did see some benefit to foliage, that benefit similarly did not transfer to greater yield.

The post June winds add to risk of bacterial blight appeared first on Manitoba Co-operator.

“There are products registered, but they’re registered for multiple applications, so if you’re just spraying something on a crop as a one-off, you probably won’t see that yield benefit,” Dennis Lange, provincial pulse specialist, said. “You may need to look at if you want to go down that route, doing multiple applications.”

Why it matters: Bacterial blight often adds insult to injury after hail, but hail recovery products have yet to prove their yield benefit with a single application, and multiple applications are largely lacking data so far.

There are two types of post-hail recovery products, hydrogen peroxide or copper based, currently on the market. Both are typically used in the organic industry, although conventional farmers have since tagged the products as a potential bane for blight after leaves have suffered hail damage or other wounds, making them vulnerable to infection.

Lange pointed to North Dakota trials testing single application of four copper-based products (Kocide 3000, MasterCop, Badge SC and ET-F 2017) and two peroxide-based fungicides (Oxidate 2.0 and Sanidate 12.0, both offered in Canada through chemical company Plant Products in Eastern Canada).

Not all of those copper-based products are registered in Canada.

Treated plots did, in fact, appear more vibrant after application, those trials found. Trial data showed an immediate decrease in blight symptoms, dropping over 10 per cent in the worst per- forming product, and over 20 per cent for ET-F.

Seventeen days later, however, both hydrogen peroxide-based products showed little difference from the untreated plot.

That visual improvement did not translate to yield however, and Lange pointed to other trials in Ontario that did not even find visual difference after treatment.

Lange is now looking for Manitoba-based results from trials in Carman.

How many passes?

That answer will be highly reliant on the weather, Lange said. A dry season will have little risk of bacterial blight, and producers may want to consider that low risk before investing in a multiple application product. Even the recent combination of rain and hail may not spell bad blight if weather turns hot and dry, he said. Future wet weather, however, will raise disease risk.

Oxidate 2.0 is registered for up to eight applications although other products, such as copper-based Coppercide WP through Loveland Products, have no maximum application limit.

“Both trials that they’ve done so far have been single application of some of these products, whether it’s a copper-based product or whether it’s a hydrogen peroxide-based product,” Lange said.

Beans can recover from blight if damage happens early in the season and growing conditions are good, he said, although damage after flowering is a different story.

Lange urged anyone testing these products to leave a test strip to confirm the treatment’s actual impact.

Hail recovery products have sparked interest with growers, according to the Manitoba Pulse and Soybean Growers.

Production specialist Cassandra Tkachuk says she has yet to work with any growers using the products, but the commodity group’s on-farm network has got inquiries on future trials. Oxidate, in particular, has garnered interest, she added.

“Bacterial blight in dry beans is definitely an is- sue at the top of dry bean growers’ minds because there’s nothing you could really do about it until these products came along, but from what I have learned, we can’t definitively say that these products will control bacterial blight,” she said.

Tkachuk argued that more testing is needed to confirm efficacy, particularly in Manitoba conditions and with multiple applications.

Dry beans are a high-value crop, something that might entice farmers to invest more on inputs, she noted, but also noted that there is little data supporting the economic or productive viability of multiple applications of these products.

“It’s definitely worth testing on farm,” she said.

She urged interested producers to contact the commodity group’s on-farm network to set up their own trials.

Another option?

Nitrogen management may fill a similar function by boosting growth after hail, Lange also suggested. Experts have typically recommended 100 pounds per acre of available nitrogen for a 2,000-pound-per-acre crop, recommendations based on North Dakota.

Local research by the University of Manitoba’s Kristen MacMillan, however, suggests that major yield jumps don’t occur until there is 140 pounds per acre of available nitrogen in the soil.

That work has been done recently in some of Manitoba’s driest weather in recent history, and Lange said he would be interested to see if that high nitrogen guideline holds up in wetter conditions.

“I guess the moral of the story is you need to know what your fertility is like… maybe bumping that up a bit might keep your plants greener longer and healthier and able to withstand issues that you might have with bacterial blight in the season,” he said.

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This summer the university, in partnership with Manitoba Pulse and Soybean Growers (MPSG) and Manitoba Agriculture, will begin a three-year study to gain more knowledge of soybean diseases, in particular foliar diseases that invade the leaves of the infected plants, such as downy mildew and bacterial blight.

“Prevention is always the first and foremost measure for disease control,” said Bryan Cassone, project lead and assistant professor in the biology department at BU. “However, this is only possible if we know what is infecting our fields and can develop early diagnostic tools and control strategies, which vary dramatically based on the type of pathogen. The reason why many disease outbreaks occur is a lack of this knowledge.”

MPSG is the primary funder for the project, providing $112,509 over three years and, along with Manitoba Agriculture, will be involved in collection of field data.

“This is quite a significant project for us and we are excited at the potential it has to reap some benefits for growers,” said Kristen Podolsky, production specialist with MPSG. “The information from this study will be invaluable in terms of us being able to be proactive. It can be difficult to develop a management strategy for farmers when a disease is already set into a crop. So, this way we are being proactive in trying to identify diseases that are present right now at very low levels, which will give us some time to develop a strategy on how we can manage it and then get that message out to growers.”

Podolsky says MPSG is excited for its first collaboration with BU and especially the partnership with Cassone.

“This is a first for us in terms of collaboration on a research project, we haven’t worked with BU too extensively in the past so we are happy to open that relationship and Dr. Cassone has previous experience studying soybeans and coming from Ohio, he has experience with diseases that we haven’t encountered yet in Manitoba.”

Cassone joined the BU’s biology department last year and comes from Ohio State University where he conducted his post-doctoral research on soybeans.

“Before I moved to Manitoba last September, I spent four years working on soybean. I know growers place an emphasis on preventive research, and I also know that soybean production has exploded in the province over the last few years,” Cassone said.

Baseline data

The goal of this research project is to build the data ‘foundation’ that can be used in the future to determine which diseases pose the greatest risk to future Manitoba soybean yields.

“Once a thorough ‘disease library’ has been generated, the data can be used to develop more cost-effective tools that are suitable for mainstream use,” Cassone said.

Researchers will genetically analyze whole fields of soybean plants in search of distinctive DNA markers of disease.

“We are in a fairly good position so far in Manitoba in terms of soybean diseases, in that we don’t have any diseases that really stand out or are yield limiting yet,” Podolsky said. “White mould would probably be the No. 1 disease in soybeans right now but fortunately soybeans are a lot more tolerant than a lot of our other broadleaf crops. And, white mould is a disease that growers are fairly familiar with because they are already managing it in their canola, sunflowers and other broadleaf crops.”

Two full surveys of at least 50 Manitoba soybean fields will be carried out.

“This will be a two-stage survey, so we are doing 50 fields in June and 50 fields in August. In June it is an early detection of diseases and in June we will also be able to quantify the occurrence of root rot, which is also the primary disease that is impacting soybeans. Later in August we will be looking at the foliar disease,” Podolsky said.

In each field, researchers will pluck a single leaf from every plant, preserve it and return to the lab where it will be fully sequenced.

DNA mapping

Cassone says this process will tease out DNA from any kind of disease that the plant could be harbouring.

“We go through multiple stages of ‘DNA work’ before we generate the data – literally hundreds of millions of pieces of DNA from the plant and the pathogens. These are pieced together for each plant like a giant DNA puzzle,” Cassone said. “The whole process will take three months or so. However, the silver lining for future disease surveillance is with these giant DNA puzzles now solved, we can easily develop sensitive diagnostic tools.”

Cassone says that not only does this research have the potential to better outline known soybean diseases but may also shed some light on diseases that have never been detected in Manitoba.

“I think that what is unique about this survey is that it is going to take our knowledge to the next level and help us identify diseases that could be misdiagnosed currently or aren’t being identified because we don’t have any visual symptoms at the time that we would normally be looking,” Podolsky said.

Research findings will also help in developing models to predict when and where diseases could strike, leading to reduced spraying requirements for producers.

“Typically the pathogen will invade the plant before symptoms develop. Certainly if the disease is caught early enough it can influence the spraying regimes used by growers,” Cassone said.

In the future, researchers will look to combine information about the number and type of pathogens with information on environmental factors, like temperature and humidity, to create computer models that can zero in on regions in Manitoba that are more susceptible to a given disease in a given year.

“We are trying to be proactive so that we can sustain in our industry and continue to grow it in a way that we can understand the diseases, how they impact yield and then deliver the message to growers on how we can manage that and prevent yield loss, so we can continue to see soybean acres grow and continue to be profitable,” Podolsky said.

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