This agronomy researcher is testing the timing and efficacy of an application of fungicide or nutrients on hail-damaged crops.

When you have a crop that’s been seriously damaged by hail, conventional wisdom says there’s no way back. If you have hail insurance, you’ll be filing a claim. If you don’t, you’re out of luck.

Even so, growers might have heard something different through the agronomic grapevine: hailed-out crops brought back from the brink by a timely application of a fungicide or crop nutrients. Ken Coles thinks there may be reasons for it to work, at least partially.

“If you’ve got damaged tissue, there’s a chance for infection,” said Coles, General Manager with Farming Smarter, an independent applied research organization based in southern Alberta. “The theory is that a fungicide could potentially protect that damaged tissue so it doesn’t get worse through infection. There are growth-regulating properties in fungicides as well.”

Given the high stakes – the value of the crop and the cost of such applications – Coles wanted to study these claims. In 2015, with funding from Alberta Pulse Growers and others, he began a four-year project to investigate whether these so-called recovery products lived up to their billing.

Device simulates hail on demand

In his research, Coles uses an ingenious invention – a round-linked dog chain with rotating drums mounted on the front-end loader of a tractor – to simulate the effects of hail. First, he uses the device to beat-up plots planted with pulses, cereals and oilseed crops at different times in the growing season. Then, he applies crop nutrients or fungicide and observes the effect of these inputs. Field peas are a major focus of this research product.

“In 2016 and 2017, we noticed that of all the crops, peas are the most susceptible to hail damage,” Coles said. “Peas just have really soft tissue.”

Coles reports that his research so far indicates yield loss due to hail is correlated to the stage of the crop at the time of the hail damage. Early damage had the lowest impact on yield because crops have time to bounce back.

With one year of field work left, Coles hesitates to issue firm recommendations. To this point, however, it appears that broad-based claims of miraculous crop recovery don’t hold water. Coles has seen a slight improvement with early or mid-season applications of nutrients and fungicide. These same applications made later in the season, though, were more likely to add stress to crops, or encourage weed growth. In effect, they could do more harm than good.

The project’s final year of research in 2018 will help Coles dig deeper into questions around applying fungicides and nutrients to hail-damaged crops.

“It looks like both the early- and mid-season timing give a very slight result,” Coles said, “but quantitatively, is it enough to pay for? I don’t think so at this point, but that’s what this last season of data will help us discover.”

Knowing the distribution and severity of this invasive insect would allow growers to make better management decisions and use insecticide only when needed.

How bad will pea leaf weevil be in your 2019 field pea crop? It’s a question that’s hard for growers to answer. First, you need to know whether pea leaf weevil is in the neighborhood. Second, since this pest is only an intermittent problem, you need to know whether an infestation is likely to be mild, medium or severe.

University of Alberta entomologist Maya Evenden developed a pea leaf weevil monitoring trap to help provide these insights.

“The only way we can find pea leaf weevils when they are still at low densities is by using these traps,” Evenden said. “The feeding damage is really hard to find when weevil populations are at low densities. Putting out these traps lets us know where the leading edge of expansion is because the tool monitors low densities of pea leaf weevil.”

Although pea leaf weevil has been mainly a southern Alberta problem, over the past several years, the pest caused considerable damage in Central Alberta and was found in the Peace region for the first time in 2018.

Between 2014 and 2017, Evenden and her team tested different lures and trap designs and landed on what she considered the best design: a basic pitfall trap. To catch the rice-sized adult pea leaf weevils, a cup is dug into the ground and a pheromone lure hangs from the cup’s small roof. A mesh over the mouth of the cup helps avoid capture of non-target organisms.

Trapping this pest is about placement and timing

Now, with two years of new funding from Alberta Pulse Growers and others in place, Evenden’s expanding her work. In Spring 2018, she and her team distributed pea leaf weevil pitfall traps in newly-seeded Alberta pea and faba bean fields. Knowing there is already a problem in the south, Evenden selected trap sites in the north, northeast and northwest parts of the province.

“There are two times of year we can trap pea leaf weevils,” Evenden said. “One is when they move into the fields in the spring, and the other is in the fall when they are moving out of the field to overwinter.”

Evenden hopes to use the spring catch information to compare numbers with adult weevil feeding activity and damage seen in the crops. For the fall trapping, where catch numbers are typically much higher, the data can help her estimate pea leaf weevil numbers the following spring.

Pea leaf weevil monitoring will help map the range of this pest in Alberta and tell pea and faba bean growers how likely it is that the pest will be a problem over the coming year. This would be a key insight for deciding whether or not spring seed treatment is needed.

“When we found them in the Peace, I was disappointed for growers, but the fact that we detected them at such a low level meant our monitoring is working,” Evenden said. “It would be great to be able to disseminate this kind of information to growers ahead of time. The research has also indicated that we might be on the verge of developing tools that use pheromone cues in control. It’s a big contribution.”

Looking at herbicide issues, disease pressures and crop nutrients, this researcher is helping to give growers the tools to increase production to meet anticipated new demand.

Alberta faba bean growers will remember the record 100,000-acre crop in 2015. Since then, acreage has generally hovered between 30,000 acres (the figure for 2017) and 50,000 acres.

Despite this lower pace of plantings, faba beans could be the sleeping giant of the province’s pulse sector. As new fractionation plants come on stream, they’ll be looking for pulses, and faba beans will be high on the list.

“These fractionation plants opening across the Prairies will have an impact on faba bean production because this bean fractions very well,” said Robyne Bowness Davidson, Pulse Research Scientist with Alberta Agriculture and Forestry.

In 2016, she began two projects – funded initially by the Alberta Crop Industry Development Fund, and later by Alberta Pulse Growers – to examine and improve the faba bean grower’s agronomic toolkit. Both projects wrap-up next spring.

Studying herbicide residue, chocolate spot and crop nutrients 

More and more growers are applying weed control earlier in the season – either before planting or before emergence. Two years of work by Bowness Davidson has shown that faba bean crops can be critically sensitive to mistimed herbicide application and herbicide residue.

“At two of our four locations, we saw significant impact where pre-seed herbicides were sprayed too close to faba bean emergence,” she said. “This impact included lack of emergence, curling, yellowing and stunting. In one location, we also saw two wheat herbicides sprayed in 2016 that had a negative impact on the 2017 faba bean crop.”

Chocolate spot, a faba bean disease seen worldwide, is another agronomic issue on Bowness Davidson’s radar. Although not yet a significant problem in Alberta, she feels that day is coming.

“Chocolate spot has the potential to be a very devastating disease,” said Bowness Davidson. “In 2018, we’re looking at six different fungicides in varying degrees of registration. If chocolate spot shows up in the future, we’ll have tools in the toolbox that work.”

The third area Bowness Davidson has studied relates to nutrients. Despite having one growing season of project fieldwork remaining, she’s seen enough to urge caution in this area. With micro-nutrients like boron or macro-nutrients like potassium and sulphur, Bowness Davidson advises that supplemental applications only help if the soil is deficient to begin with.

“Two years of research showed no response with the micros in any of our locations,” she said. “But, the micros weren’t limited there in the first place, and most farms don’t struggle with micro-nutrient deficiencies. Research into macro-nutrients (Phosphorus, Potassium, Sulfur) has shown some response in a couple of locations where initial levels were marginal.”

Bowness Davidson is confident her research in the areas of herbicide use, chocolate spot and crop nutrition in faba beans will help farmers be ready to increase production when demand growth occurs.

“It’s an area we’re still working on, and have a bit to learn,” she said. “Sometime in the next three to five years, I think faba beans will rebound. When they go up again, we’ll definitely have some answers.”

With extreme lodging, it can take as much as five days to harvest a quarter-section of peas. A four-year project examined two possible ways to boost standability: inter-row seeding and PGRs.

Why is it that some farmers who can grow peas don’t grow peas? For many, the answer is that the crop frequently lodges and can be extremely time-consuming to harvest.

Research that helps improve standability, therefore, has tremendous value for pea growers and the industry. Between 2014 and 2018, Alberta Agriculture and Forestry Agronomy Research Scientist Sheri Strydhorst carefully examined two ideas for their potential to improve the standability and harvestability of field peas.

Inter-row seeding can help

Some Alberta farmers have reportedly improved their pea standability through the resourceful technique of seeding peas into standing wheat stubble. In concept, the sturdy wheat stubble props up the peas.

Strydhorst tried this idea at three sites in the central and Peace regions of Alberta by inter-row seeding peas into 8-inch and 12-inch wheat stubble. A check treatment had no wheat stubble.

“When there was lodging, stubble did improve standability about a quarter of the time,” Strydhorst said. “What surprised us was the other positive benefits we got, including reduced days to maturity and larger seed size.”

At the field level, growers can implement this low-cost practice to improve field pea standability fairly easily. By seeding in the same direction as the standing stubble, keeping the stubble tall and using the nudge feature on their GPS, about 70% to 90% of plants will be ‘accidentally’ inter-row seeded.

Value of plant growth regulators doubtful

The other idea Strydhorst has been testing is whether applying plant growth regulators (PGRs) would improve standability in pea crops. While Strydhorst gave the inter-row seeding idea a qualified yes, her ruling on PGRs was not so enthusiastic.

“We tested three different active ingredients using different rates and in different combinations,” she said. “Often it felt like we were spraying water. That’s how ineffective it was.”

Strydhorst would not recommend PGRs for field peas because using them showed no consistent improvement in height, standability, yield or seed size. In fact, if the pea crop was under stress due to heat or drought, PGRs actually reduced yield.

Although her research showed that CDC Meadow responded slightly better to PGRs than AAC Lacombe, Strydhorst indicated further investigation may be needed to identify pea cultivars that might be more responsive to PGRs.

Strydhorst can relate to the frustration growers feel with pea standability. In her research plots, in fact, moderate to severe lodging occurred about 63% of the time. That’s a challenge that needs solving in order for Alberta’s pea growers and the industry to thrive.

“It’s a terrible headache when you have your pea crop go down,” Strydhorst said. “I’m not sure PGRs are the solution, but we do need to put significant agronomic effort into finding a solution for standability. Breeding will help but breeding alone isn’t the answer.”

The confirmed presence of chocolate spot in Saskatchewan is adding urgency to the search for knowledge about how this disease could occur under Alberta conditions.

Maybe not today, maybe not tomorrow, but it won’t be too many years before chocolate spot is a significant issue for faba bean production in Alberta.

It’s a disease associated with potentially serious yield losses, based on the experience of growers in places such as Australia and Egypt.

Syama Chatterton, a Lethbridge-based Plant Pathologist with Agriculture and Agri-Food Canada, is in the second year of a three-year research study on chocolate spot.

How can you study a disease we don’t have much of yet? Throughout the 2017 growing season, Chatterton and her team of co-op students took greenhouse-grown ‘trap plants’ out to the field every Monday and Thursday for about nine weeks, hoping to attract chocolate spot.

“It’s a lot of work moving plants in and out of the greenhouse every few days,” Chatterton said. “For the most part, it was very successful. Bringing the plants back into the greenhouse was a nice way to monitor spore activity and determine when those infection periods are.”

 Understanding chocolate spot before it becomes a threat

Chatterton’s research is taking place in Lethbridge and Lacombe, monitoring the progression of the disease under different regional conditions. She reports that moving plants back and forth between field and greenhouse, while laborious, yielded important insights. Slowly but surely, Chatterton is assembling a data set that can help pinpoint when infectious periods might occur.

“We weren’t necessarily expecting to see disease risk toward the end of June, but in Lethbridge we surprisingly saw infection periods fairly early in the season,” she said. “While infection peaked at the end of June, then declined because it was so dry in Lethbridge, we saw an opposite pattern in Lacombe. There, no early disease peaks, but it slowly increased toward the end of the season.”

For 2018 and 2019, Chatterton and her team will be back indoors. They’ll be augmenting their field data with greenhouse-controlled environmental studies to see how chocolate spot responds to factors such as humidity and temperature. This could ultimately provide growers with a kind of early warning system.

“We’re matching some of the things we’re seeing outside,” Chatterton said, “like weather conditions and environmental variables that lead to disease and taking it into the greenhouse to determine exactly what the humidity and temperature conditions are that lead to infection.”

Given that chocolate spot is the number-one disease of faba beans worldwide, and Saskatchewan is already dealing with it, Alberta can expect a visit sooner or later.

Chatterton hopes that the information generated by this project will help faba bean growers get out ahead of the disease.

“Seeing chocolate spot in Saskatchewan is a good indication that we are going to have problems in Alberta,” she said. “This project is really important for getting a handle on a disease before we start seeing a problem.”

In 2012, scientists discovered that pea root rot caused by Aphanomyces was present on the Prairies. This project began to build a defensive toolkit for pea growers.

Pea growers in Western Canada have battled root rot in recent years. Until relatively recently, it was believed most of this disease was associated with the causal agent Fusarium.

According to Bruce Gossen, 2012 brought a game-changing development.

“At that time, there had been reports and observations indicating increasing problems associated with root rot in pea,” said Gossen, Principal Research Scientist with Agriculture and Agri-Food Canada in Saskatoon. “There was lots of Fusarium causing root rot but Dr. Sabine Banniza at the University of Saskatchewan demonstrated that we should also be looking at Aphanomyces.”

In 2013, with funding from Growing Forward 2, Gossen and a team of western Canadian plant disease specialists began a five-year project to build a knowledge base for root rot.

Start from the basics

When a pea or lentil plant shows signs of root rot, how do you know what caused it: Fusarium, Aphanomyces or another agent entirely? The project’s first order of business was coming up with reliable molecular assessments of the pathogen(s) causing the disease.

“We needed to develop identification techniques using molecular biology so we could go in and determine which species was causing problems in this pea field,” Gossen said. “Aphanomyces is hard to culture, so there was lots of effort just to do that.”

Next up, the team needed to determine just how widespread Aphanomyces root rot was. The news wasn’t good. Aphanomyces was found at high levels in virtually every region.

What about commercially available seed treatments and soil amendments as a way to manage Aphanomyces root rot? Gossen and team tested them all, but didn’t find the breakthrough that growers might hope for.

“There is a good mix of seed treatments that are useful on other pathogens,” Gossen said, “but we found nothing that was effective enough against Aphanomyces.”

Perhaps plant breeding offered a way forward. If some pea cultivars had some degree of genetic resistance to Aphanomyces, that could offer a long-term answer. Dr. Bob Conner (AAFC, Morden) and his group have had success identifying cultivars with less susceptibility to root rot in general than the rest of the available cultivars. They also identified lines with some specific resistance to Aphanomyces. The team developed molecular markers to give breeders a head start, which provides an avenue for the next stage of Aphanomyces research.

Once scientists learned of the widespread presence of Aphanomyces as a causal agent of root rot on pea and lentil, the push was on to find answers. This project established the foundation for a longer-term Aphanomyces defense. One thing’s for sure. Aphanomyces is now a fact of life for scientists, agronomists and pea growers.

“We were surprised by how widespread the Aphanomyces pathogen is,” Gossen said. “Recently, we’ve made progress on identifying fields at risk. Dr. Syama Chatterton (AAFC, Lethbridge) is developing a decision support system for growers that would recommend a break between susceptible crops for fields with a high risk of severe root rot.”

Project at a glance

Project title:                Pea root rot: distribution, genetic variability, resistance and management

Project lead:                Bruce Gossen, Agriculture and Agri-Food Canada

Total value of project: $1,757,400

Start date:                   April 1, 2013

Completion date:        March 30, 2018

Three years of producer-funded research enabled the development of a semiochemical-baited trap to monitor pea leaf weevil in the prairie provinces.

Pea leaf weevil is a tiny insect that punches far above its weight in terms of potential impact on crop yield. The size of a grain of rice, this non-native invasive insect has emerged in recent years as a threat to Alberta’s most-planted pulse crop.

Complicating growers’ pea leaf weevil defense is the fact that this insect appears intermittently. Some years it’s a significant problem, while in others it’s just a minor inconvenience.

What if pea growers had a way to determine whether next year’s pea leaf weevil activity was likely to be problematic?

University of Alberta entomologist Maya Evenden spent three years working on just such a solution. With support from Alberta Pulse Growers, via the Alberta Crop Industry Development Fund, Evenden has developed the tools for a pea leaf weevil monitoring system.

Two naturally occurring chemicals as bait

“There are two times in the life cycle of pea leaf weevil where you can monitor adult activity,” Evenden said. “You can do it in the spring when adult weevils come into the field and in the fall when the next generation of adults leave the field in search of overwintering locations. You can use traps in the fall to check them when they go to overwinter. That would tell you whether or not you needed to use an insecticide seed treatment the following spring.”

As Evenden explains, her pea leaf weevil monitoring traps required some type of bait to attract weevils. She used two different types of semiochemicals, or information-bearing chemicals: an aggregation pheromones and volatile chemicals emitted by pea plants.

Over three years of field studies, Evenden used a variety of trap configurations, and various combinations and doses of aggregation pheromone and/or volatile chemicals as bait.  Many field trapping studies were conducted in commercial field pea crops during three field seasons to optimize the best bait and trap type to attract and retain weevils.

In addition, Evenden’s team conducted a painstaking mark-recapture experiment over two years that involved the collection of approximately 20,000 weevils from pea fields. Of these, 10,000 were marked with a spot of nail polish on the thorax. The marked weevils were released at eight different distances from the traps to test the traps’ effective radius. As very few marked weevils were trapped in this experiment, more work is needed to establish how many traps might be needed, given the size of a field, for monitoring of pea leaf weevil populations.

After three years of field work led by Evenden, there is now a practical tool for monitoring pea leaf weevil. Evenden’s work with this insect will continue. Building on knowledge gained in the monitoring project, she’s now working to determine the extent of pea leaf weevil in the province.

“We’ve learned a lot about the chemical ecology of weevils and are now tracking it all over Alberta to get a field-scale reading of where pea leaf weevil is,” Evenden said.

Project at a glance

Project title:                Development of semiochemical-based monitoring of the pea leaf weevil

Project lead:                Maya Evenden, University of Alberta

Total value of project: $135,993

Start date:                   April 1, 2013

Completion date:        October 31, 2016