Diseases
New seeding rate and plant stand calculators from the Canola Council of Canada (CCC) will help canola growers set an accurate seeding rate that balances the good start canola needs with their profitability goals and appetite for risk.

Why build them? Growers often default to seeding rates of 5 lb./ac. or lower, regardless of seed size or field conditions. These tools will help growers as well as agronomists and seed retailers make more refined decisions.

What do they do? With the target density calculator, users position sliding scales to determine the level of risk for various factors that influence plant stand targets. If weed competition is expected to be very low, for example, the calculator will set a lower target stand. But if spring frost risk is high, the calculator sets a higher target stand to compensate.

The seeding rate calculator has three modes. In seeding rate mode, users input thousand seed weight (TSW), target plant density and estimated seed survival, and the calculator computes the required seeding rate. In plant survival mode, users enter the number of plants per square foot that emerged along with known TSW and seeding rate, and the calculator gives the seed survival rate. In plant density mode, the calculator takes TSW, seeding rate and estimated seed survival to give the number of plants that should emerge.

Because yield potential is known to drop off with stands of around four plants per square foot, the CCC recommends at least six plants per square foot to provide a buffer against season-long plant loss.

Canada’s canola industry has a goal to reach average yields of 52 bu./ac. by 2025. The CCC estimates that improvements in seeding and plant establishment alone can contribute three bu./ac. The tools at canolacalculator.ca can help.
Published in Canola
Growers in Western Canada now have new options for controlling the most damaging diseases with the registration of Hornet fungicide and label updates for INTEGO Solo seed treatment from Nufarm Agriculture Inc.
Published in Fungicides
Stephanie Kowalski, an independent agronomist for Agronomy Advantage, says that because of the drought this past growing season, many agronomists had to help their customers mitigate further stress in soybeans, whether that was from pests, fungus-related diseases or building base fertility. Kowalski recently spoke at the 2017 Southwest Ag Conference in Ridgetown, Ont., where she was asked to share her three key lessons from 2016.

Besides the lack of rain in Ontario, one of the major players for soybean stress was the presence of spider mites. The most important factor to keep in mind for mites is to scout for them, since drought-stress holes can look very similar to spider mite damage. Once farmers notice stippling and discoloured patches, it’s important to take care of them as soon as possible.

“Spider mites are not an aphid pest, where you would wait for the threshold to build and then you take action,” Kowalski says. “You have to continually assess it and make an action decision because they won’t go away.”

She also says many agronomists thought aphids would be the big problem for growers due to the hot and dry year, which just goes to show that it can be difficult to predict pest problems from year to year.

With spider mites, Kowalski says it’s important to spray a dimethoate like Cygon or Lagon, and avoid a pyrethroid (like Matador) since it will also take out the predatory mites, increasing the spider mite pressure.

The second factor that came into soybean management this year had to do with fungicides. “Weather is only one factor of the fungicide decision,” Kowalski says. “Just because it’s a dry year, I wouldn’t write out a fungicide [prescription].”

Growers and agronomists should be looking at history (of white mould for example), row spacing and emergent population. Again, getting out and seeing what’s already in the field is important, since every year brings a different challenge.

“Proactively scouting and managing the crop throughout the growing season is never a bad idea,” Kowalski says. “Even if the growing conditions are ideal, scouting can be a very useful tool to identify ways to maximize yields economically.”

Don’t forget about the disease history of your fields either: If a field had soybeans or even canola previously, there is a likelihood that sclerotinia (the hard black bodies created by the white mould fungi) will be present following a diseased year and cause infection in that subsequent soybean crop.

Base fertility and soil health also play a role in mitigating stress in soybeans, especially in a drought year. The more soil organic matter available, the better the water retention, which helps limit drought stress due to the availability of moisture to those crops. Good fertility also means strong early season root growth and adequate nutrient levels in the root zones, resulting in more efficient water use, better nutrient uptake and less of a chance of deficiencies and stress. Early data shows managing phosphorous (P) and potassium (K) levels in soil at higher background levels has led to a good response in crops versus the current recommendations (sufficiency approach) that were established more than 30 years ago, when yields were lower.

Every year brings a different challenge for soybeans and other crops: 2014 was a terrible white mould year, 2015 had significant spring frost events and aphids and 2016 was a droughty year, so proactively scouting and managing the crop throughout the growing season is never a bad idea, Kowalski says. “Even if the growing conditions are ideal, scouting can be a very useful tool to identify ways to maximize yields economically.”
Published in Soybeans
Stripe rust could show up with a vengence in Ontario again this year, but that doesn’t mean we’re lacking the tools to control the problem.

Last year was one of the worst stripe rust years that Albert Tenuta, field crop extension plant pathologist with the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA), has seen. Tenuta addressed the latest on where, when, and how often to apply fungicides to a room of farmers and agronomists at the Southwest Agriculture Conference, which took place Jan. 4 and 5 in Ridgetown, Ont. One of the diseases of focus was stripe rust and whether we can expect to see the same levels of the disease as last year.

Stripe rust typically thrives when temperatures sit around 16 C. But last year rust was exploding and multiplying in elevated nighttime temperatures sitting around 21 to 23 C. This may mean that the pathogen is changing in stripe rust.

“We’re seeing more and more races developing, becoming more heat tolerant,” Tenuta says. “They are living organisms that adapt and change, so nothing stays static over time.”

Since stripe rust is an obligate parasite (the disease needs a host to survive), the rust retreats back to the south in the U.S. in the winter, where there is greenery. With the milder winter last year, it’s likely spores are overwintering closer to Ontario, meaning the spores don’t need to travel as far and making it easier for them to reproduce. As millions and millions of spores are created, there are mutants that can develop and bypass resistance (from temperatures, for example) leading to an increase in cases of the disease.

If stripe rust had overwintered in the province, farmers would have seen it much earlier than the first reports in early May. This year, if conditions are right, we could potentially see the disease back in the province; it depends on the direction of wind as well as temperatures.

If the disease shows up again this year, there are two main ways for farmers to protect their crops. The first is well-timed application of fungicide. According to Martin Chilvers, assistant professor at Michigan State University and co-speaker at the session, in 2016 the most successful applications were the T2, or prior to flowering, applications. With applications at this stage, researchers were able to protect 20 bushels. Strobilurins and triazole compounds are best if applied as a preventative measure for stripe rust, although triazole also shows some post-infection functions as well.

Choosing a stripe-resistant variety is also important – even if it’s a moderately resistant variety. “Although you still see some disease developing, those lesions are often smaller, so they don’t produce as many spores,” Tenuta says. Therefore, spore production is reduced and successive generations decrease substantially.

But, Tenuta cautions, it’s still important to choose a variety that protects against Fusarium first and foremost. “Remember, Fusarium head blight is a risk you have every year. Stripe rust may occur – it may not.” Keep a lookout for stripe rust in your crops starting in May.
Published in Diseases
In a year like 2016, when sclerotinia stem rot was widespread in canola, the expectation might be that the disease (called white mould in soybean) could have been problematic in soybean as well. Not so, says Dennis Lange, industry development specialist for pulses with Manitoba Agriculture in Altona, Man.
Published in Soybeans
A team of U.S. Department of Agriculture (USDA) and university scientists has developed a sensitive new assay method for detecting the fungus that causes wheat blast, a disease of wheat in South America and, most recently, Bangladesh.
Published in Diseases
"Ug99” might not mean much to the world outside agriculture, but few wheat diseases have so much potential to devastate production – and ultimately, consumer access to a basic staple – around the world.
Published in Diseases
Manitoba Pulse and Soybean Growers has revealed the most prevalent races of Phytophthora sojae found in Manitoba. | READ MORE
Published in Diseases
Nine high school students will study the effects of potassium supplementation on canola plants infected with blackleg fungal disease at the Canadian Light Source (CLS) in Saskatoon. The students will use the CLS beamlines to conduct elemental and molecular analysis on the infected plants. | READ MORE
Published in Diseases
Root rot was rampant in pulse crops this year, due to the wet conditions. Dr. Bruce Gossen, research scientist with Agriculture and Agri-Food Canada, says root rot has become more prevalent on the prairies as the popularity of pulse crops continues to increase. | READ MORE
Published in Diseases
The Canadian Grain Commission has announced grading changes to Canadian fababeans, chickpeas and wheat. 

As of July 1, 2017, all grades of fababeans will have an ergot tolerance of 0.05 per cent in Eastern Canada. In Western Canada, all grades of fababeans and chickpeas will have an ergot tolerance of 0.05 per cent as of August 1, 2017. Ergot is a cereal disease that is toxic to people and animals. Ergot does not occur in these crops, but cross-contamination can occur during handling. Adding a tolerance for ergot in fababeans and chickpeas will help guarantee the safety of Canadian grain. A tolerance of 0.05 per cent is consistent with the other pulses in the Official Grain Grading Guide.


The tolerance for grasshopper and army worm damage in No. 3 Canada Western Red Spring, No. 3 Canada Western Hard White Spring and No. 3 Canada Northern Hard Red wheat will be tightened from eight per cent to six per cent, effective August 1, 2017. The tolerance for grasshopper and army worm damage was tightened after research showed that eight per cent grasshopper and army worm damage can impact end-use functionality.

These changes are based on recommendations made to the Canadian Grain Commission by the Eastern Standards Committee and the Western Standards Committee at their meetings in November. The Canadian Grain Commission also reiterated its commitment to continuing to evaluate new technologies for objectively assessing grain for factors such as deoxynivalenol (DON).
Published in Pulses
The warning bells rang loud and clear in 2013 when a shift in clubroot pathotypes overcame clubroot-resistant canola varieties on the market. Tests found the pathotypes present were capable of overcoming most of the clubroot-resistant canola hybrids. Because this breakdown in resistance wasn’t unexpected, plant breeders have continued to look for alternate sources of resistance that can be bred into new varieties to help manage the multiple pathotypes that have been identified in Alberta.
Published in Diseases
What doesn’t kill a bug sometimes makes it stronger…or bigger, or longer lived, or able to lay lots and lots of eggs. This biological phenomenon is called “hormesis.” It is an area of growing interest for entomologists, including those who study the effects of insecticides on insects. And it has important implications for agriculture.

Hormesis refers to an organism’s response to a stressor, where a low dose of the stressor causes a stimulating effect, like increased reproduction, and a high dose is very damaging or lethal. In the case of an insect, stressors could include things like insecticides, temperatures outside of the insect’s comfort range, insufficient food, and insufficient oxygen. But hormetic responses are not limited to insects. They have been observed in many, many organisms, ranging from microbes and plants to humans.

How hormesis actually works isn’t completely understood. “Probably the most commonly cited general theory is the idea of overcompensation. Systems that affect growth and reproduction [in insects and other organisms] are self-regulating and work on feedback mechanisms. So any sort of disturbance to those processes can result in the system trying to correct and overcompensate for it,” explains Chris Cutler, an associate professor with the department of environmental sciences in Dalhousie University’s faculty of agriculture. 

For instance, let’s say an insect is exposed to a low dose of a poison that causes its reproductive system to go slightly out of whack. According to the overcompensation theory, its reproductive system will attempt to counteract the problem but will temporarily overshoot its response, leading to higher reproduction. “In a general sense, I think that is kind of how hormesis operates, but we still have a lot of the nuts and bolts to figure out,” Cutler says. 

He explains that hormetic responses have evolved over millions of years as mechanisms for organisms to deal with low amounts of stress. So hormesis has always been around. However, it’s only recently that scientists have been identifying such responses as an actual phenomenon. “I think in the past, researchers would often look at [a hormetic] result and say ‘that’s weird’ or ‘that’s an outlier,’ and not really have a word to describe it. Those types of papers have gotten lost in the literature decades ago, but you can find them if you look hard enough,” he notes.

“We’ve documented incidents of hormesis in all sorts of insects, dozens of species across many different families and orders of insects, exposed to many different types of stress, whether it’s an insecticide stress, nutritional stress, temperature stress, radiation stress. So hormesis occurs widely and the concept is now pretty well accepted by researchers, and people are really starting to catch on to the idea.” 

Cutler began his research on hormesis completely by accident. “I did my PhD research at the University of Guelph and was working with the Colorado potato beetle. In one of my experiments with an insect growth regulator, which is a more selective or more friendly type of insecticide, I was exposing eggs to the insecticide. I was expecting deleterious effects, like smaller eggs, eggs that wouldn’t hatch, and that type of thing. But in one experiment, I saw that at the low dose the survival and weight of the larvae were higher than in the control. At first I thought I’d got the concentrations mixed up or something. So I repeated the experiment a couple of times and got the same result. And I stumbled on this idea of hormesis, which at that time [about a decade ago] had not garnered much attention at all in insect circles.” 

At present, the hormesis research at Cutler’s lab focuses mainly on insecticide-induced responses of various insects to various insecticides. “We’ve been using green peach aphid as a model. It is a widespread insect pest occurring all over the world, attacking lots of different crops, and insecticide resistance is a big problem in that insect,” he notes.

For example, he and his lab have been looking at how this aphid responds to imidacloprid, a commonly used neonicotinoid sold under various trade names, such as Admire. Their research shows that when the aphid is exposed to low doses of imidacloprid, the aphid’s reproductive output goes way up. Cutler says, “We’ve shown this in laboratory and greenhouse experiments where, after a few weeks, the population of the aphids on a plant can double due to exposure to the insecticide that is supposed to kill them.” 

In a field situation, many different factors can lead to less-than-lethal doses of insecticide. “Insecticides break down over time. Sunlight will break them down. They are subject to microbial degradation. They are subject to wash-off by the rain. Also, drift can occur, so you may be trying to apply a high dose but the wind takes it so you get a low dose on the plant. And you have canopy effects when you spray so you don’t get as high a dose under the leaves or further down the plant,” Cutler explains. 

“So inevitably you’re going to get insects that are exposed to these sublethal doses. And some of these low doses could be hormetic.”

Cutler sees many possible implications of hormesis for agriculture. One obvious one is that insecticide-induced hormesis could make a pest problem even worse by causing pest resurgences and secondary pest outbreaks. Pest resurgence is when the population of an insecticide-treated pest increases rapidly to even higher numbers than before the insecticide was applied. A secondary pest outbreak refers to a rapid population increase in a pest species that had been less important than the target species until the insecticide was applied.

Pest resurgences and outbreaks are often assumed to be due to the harmful effects of the insecticide on the pest’s natural enemies (the predators and parasitoids that attack it). But that assumption isn’t necessarily correct in all cases. Cutler explains, “There have been experiments that have excluded that possibility and shown the outbreak in the field – whether it’s due to aphids or thrips or leafhoppers – is directly due to stimulation from the insecticide.” 

The degree to which insecticide-induced hormesis is contributing to pest resurgences and outbreaks in agricultural fields is not yet known. However, it has been documented in many field situations.

Insecticide-induced pest resurgences and outbreaks could clearly have serious impacts on susceptible crops, and could prompt farmers to apply more insecticides, raising their input costs and increasing the risks of insecticide resistance and negative impacts on the environment.

On the other hand, hormesis has positive implications for businesses that rear insects. “Insect rearing is a billion-dollar industry. Insects are reared for a lot of different purposes – for use in research, food for pets, food for people. Honeybees are reared for honey and pollination,” Cutler notes. “I think we can probably harness some of these hormetic principles for rearing these beneficial insects. It has been shown, for instance, that when you are rearing insects like Caribbean fruit flies for sterile insect release (SIR) programs, if you deprive them of oxygen for an hour, that mild stress can prime them to become better at finding mates, become better at emerging, have lower mortality and longer life spans. So this type of preconditioning hormesis can improve the performance of those insects later in life.”

In his current research, Cutler is delving into a number of different aspects of insecticide-induced hormesis, with the help of funding from the Natural Sciences and Engineering Research Council of Canada. 

“One of the things we’re doing is looking at this idea of priming, so can mild exposure to one stress condition the insect to deal [more effectively] with subsequent stresses later in life or in subsequent generations? We’re looking at that in aphids.” 

Cutler and his lab are also examining the possibility that hormesis may be contributing to insecticide resistance. “We’re looking at a couple of different angles there. We want to see if exposures to low doses of insecticide that may cause hormesis also induce the insect to produce more detoxification enzymes. When you and I or insects are exposed to poisons, we have enzymes that break down those poisons. So, if the insect is exposed to mild doses of insecticide, do we see more of those enzymes?” he says.  

“[Another insecticide resistance angle] we’re looking at is whether exposure to mild doses of insecticide can increase mutations in insects. One of the main causes for mutations in organisms is stress. So we want to see if, for instance, hormetic stress that can cause increases in reproduction can also cause increases in mutations in insects such as aphids, and can some of these mutations be for insecticide resistance?”

Cutler is also investigating insecticide-induced hormesis in bees. He does a lot of research on bees and pesticides, so he’s well aware that pesticides are an important risk factor for bees. But he wondered whether insecticide-induced hormesis might occur in bees since it has been found in so many other insects. He recently published a paper identifying evidence in the literature that low doses of insecticide stimulate longevity, learning and memory of bees. Now he’ll be pursuing that idea in his own experiments. 

What you can do
Although there is still much to learn about hormesis, especially under field conditions, Cutler offers a few suggestions for practices that could help reduce the risk of insecticide-induced hormesis on your farm. 

One practice is to keep an eye on the pest population after pesticide applications. “I suspect that rapidly reproducing pests like aphids, leafhoppers and mites are more prone to outbreaks and resurgences from hormesis, although this has yet to be tested. This might be particularly true for insecticides that degrade to sublethal concentrations more quickly or for systemic insecticides (seed treatments) that work against early season pests but will be at sublethal amounts for most insects after a few weeks.”

Second, minimize drift and ensure good plant coverage when spraying insecticides. “This will minimize exposure of the pests to sublethal concentrations that might induce hormetic responses to stimulate their population growth.”

And third, avoid cutting insecticide rates below those recommended on the label. “As many growers will know, cutting rates is usually problematic because it can ‘encourage’ development of insecticide resistance while increasing the chances of suboptimal pest control. At the same time, exposure to these lower sublethal concentrations could stimulate reproduction of certain pests, possibly creating a double-whammy for the grower.”
Published in Insecticides
In Western Canada, clubroot in canola is a serious problem. In Alberta alone, infestations have been identified in more than 2000 fields across several municipalities. Although clubroot represents a potentially serious threat to canola production in Saskatchewan, so far only a few isolated infestations have been identified. Industry approached researchers to see if there might be an option for controlling clubroot in these small areas and limiting the spread of this soilborne disease to other fields.
Published in Diseases
Spraying barley crops with RNA molecules that inhibit fungus growth could help protect the plants against disease, according to a new study published in PLOS Pathogens.
Published in Diseases
Soybean harvest is underway and some producers have been pleasantly surprised with yields despite the lack of precipitation, according to the latest field crop report from the Ontario Ministry of Agriculture, Food and Rural Affairs. 

Soybeans
Harvest began the previous week in parts of western and central Ontario. Yield reports have been variable ranging from single digit to upper 60 bushels per acre (bu/ac). Low yield reports, not surprisingly, appear to correspond closely with the precipitation received throughout the season. However, some producers have been pleasantly surprised with how well soybeans have yielded even with less than ideal amounts of precipitation. Seed size appears to be smaller than normal, although quality has been good to date. Although the presence of green stems is more prominent this year than others, it has not seemed to significantly reduce harvesting efficiency. It is estimated that between 40 and 45 per cent of the provincial acreage has been harvested.

Winter wheat
An early soybean harvest for some has provided an opportunity to plant wheat into very nice conditions with emergence occurring in less than a week. A reminder that a proper planting depth of one inch is extremely important and planting too shallow is often the cause of stand issues the following spring as a result of frost heave and winterkill. Regardless of planting date, seed placed starter fertilizer provides an additional eight bu/ac of grain yield. Seedling Canada fleabane, which in many cases is glyphosate resistant, has already emerged, and there is an opportunity to apply Eragon pre-plant or pre-emergence to manage this problematic weed. Otherwise, a post-emergence herbicide application will be necessary to control Canada fleabane in winter wheat. If chess (aka cheat grass) or downy brome has been a problem in your cereal fields in the past, there are now two options to deal with these grassy weed species. The first is called Focus and must be applied pre-plant or pre-emergence to the wheat crop (and before weed emergence), while the second is called Simplicity and can be applied post-emergence to both crop and weed in the spring.


Corn
A very small amount of corn has been harvested although grain moisture is dryer than it is normally at this time of year, prompting some producers to start taking off high-moisture corn especially when rain has delayed soybean harvest. A significant number of producers and agronomists have noticed western bean cutworm (WBC) damage in mature cobs. When damage is significant, consider harvesting early to stop mould growth. Adjust your combine to discard lightweight mouldy kernels and dry mouldy corn as soon as possible. Normally hot, dry conditions are not good environmental conditions for ear mould fungi like Fusarium graminearum (Gibberella), and Fusarium verticillioides. However, rains or humid conditions along with hybrid susceptibility, incomplete pollination, and cob damage by WBC has resulted in pockets of infection in some areas of the province that could result in mycotoxins being produced, especially deoxynivalenol (DON or vomitoxin). Growers should be assessing fields for ear mould infection and harvest fields first with 10 per cent or more ear mould.


Edible beans
Harvest progress ranges anywhere from 50 to 80 per cent done. The least amount of harvest progress has been made with Adzuki beans since they mature later than other market classes, while significantly more progress has been made harvesting cranberry and white beans. As with many crops in 2016, dry conditions have impacted grain yield. Harvest yield reports have been variable with the larger seeded coloured beans yielding average to below average. While white bean yield reports have been average to below average. Overall bean quality has been good with seed size being somewhat smaller than normal.
Published in Harvesting
In Saskatchewan, leaf blotch disease complex has become more prevalent in oat fields in recent years, but very little is known about the impact of these diseases on oat production. In infected fields, oat yield and grain quality, including test weights, are often reduced, which can impact milling quality and reduce returns.
Published in Diseases
Over the past 15 years, ergot has shifted from being a sporadic, localized problem to a widespread disease issue for Prairie cereal growers. As a result, ergot research has become a rising priority for researchers and producer-driven research funding agencies. A key part of the current research focuses on developing crop varieties that are less susceptible to ergot.
Published in Diseases
Last week Prime Minister Justin Trudeau and Chinese Premier Li Keqiang announced stable canola trade between Canada and China will continue through 2020. Under the agreement, canola trade can occur according to terms in place in August 2016, and measures to manage the risk of blackleg disease in canola will be based on science.
Published in Canola
An international research team has identified two genes which could help protect barley against powdery mildew attack.

Led by the University of Adelaide in Australia and the Leibniz-Institute of Plant Genetics and Crop Plant Research (IPK) in Germany, the research will give plant-breeders new targets for developing lines of barley with resistance to powdery mildew.

The two genes, HvGsl6 and HvCslD2, were shown to be associated with accumulation of callose and cellulose respectively. These two polysaccharides play an important role in blocking the penetration of the plant cell wall by the powdery mildew fungus.

Published in two separate papers in the journal New Phytologist, the researchers showed that by "silencing" these genes, there was lower accumulation of callose and cellulose in the plant cell walls, and higher susceptibility of barley plants to the fungus. Conversely, over-expressing HvCslD2 enhanced the resistance in barley.

"Powdery mildew is a significant disease of barley wherever it is grown around the world, and resistance to the fungicide most commonly used to control it has been recently observed," said Alan Little, a senior research scientist at the University of Adelaide, with the ARC Centre of Excellence in Plant Cell Walls in the School of Agriculture, Food and Wine, in a press release.

"If we can develop barley with improved resistance to powdery mildew, it will help barley producers increase yields and maintain high quality."

In the plant and pathogen co-evolutionary battleground, host plants have evolved a wide range of defence strategies against attacking pathogens.

One of the earliest observed defence responses is the formation of cell-wall thickenings called papillae at the site of fungal infection. They physically block the fungus from penetrating the plant cells.

In barley, the papillae contain callose and cellulose as well as other polysaccharides, but the genes involved in accumulation of these carbohydrates in the cell wall have not been identified.

"Our results show that these novel genes are interesting targets for improving cell-wall penetration resistance in barley and maybe other cereals against fungal intruders," said Patrick Schweizer, head of the Pathogen-Stress Genomics Laboratory at IPK.

"Now we can use these genes to identify molecular markers for breeding enhanced resistance into modern barley."

The two papers can be read online here and here
Published in Genetics/Traits
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