The old battle against potato virus Y (PVY) is becoming harder there, noted Tyler MacKenzie, research and development co-ordinator at the Agricultural Certification Services Lab of Potatoes New Brunswick, and it’s a sneaky problem. Infected plants are hard to spot. With the strains the region is dealing with, there often aren’t a lot of above-ground symptoms to warn of a budding issue.

WHY IT MATTERS: Manitoba Agriculture is on the watch for aphid populations, known vectors for PVY, every year.

PVY remains the top cause of mosaic disease in potatoes, bringing down yields and tainting seed stocks, according to Agriculture and Agri-Food Canada. Growers know it by its common signs: stunted growth, vein banding, leaf drop and early death of plants, with infected potato crops often showing dwarfed size and crinkled leaves.

It’s also an insect management problem. The virus hangs out on the mouthparts of aphids who have fed on infected plants, spreading through a field. It doesn’t take much PVY in a field for seed potatoes to be rejected, resources published by AAFC note.

Necrotic strains like PVYntn have made the problem worse, according to research by MacKenzie and other potato virologists with the Agricultural Certification Services Lab.

These strains cause brownish necrotic rings in tubers while producing minimal leaf symptoms.

Research from potato commodity groups shows that the newer strains of the virus spread faster than older varieties, affecting more plants even when individual impacts were lower. The strains also cause severe tuber necrosis in susceptible varieties.

The problem has grown as New Brunswick’s potato industry consolidated, attendees heard. The number of seed growers has declined, while more operations mix seed production with processing crops.

“In recent years, you can see that the exclusive seed growers … managed to keep their PVY levels low, but the mixed growers really lost control of their PVY,” MacKenzie said.

Why management matters

But the data also showed growers using strict management practices kept infection rates low even during severe aphid years.

The virus can overwinter in tubers left in the field and is easily transmitted during seed cutting operations, or when poor handling causes tissue damage. Aphids, especially the green peach aphid, are the primary mode of transmission. Alternative host plants include other members of the nightshade, goosefoot and legume families.

The most effective control measure is using clean seed.

Fields planted with seed containing around two per cent PVY had five times the failure rate in bad years compared to cleaner seed, MacKenzie said.

Oil sprays as an aphid control also reduced infection rates. Growers applying at least two litres per acre of mineral oil weekly saw infection rates drop by half or a third compared to those using lower concentrations, research showed. Combined with strategic insecticide use and monitoring through aphid alert programs, these tools help growers control the disease, attendees heard.

The post Potato growers beware new PVY strains appeared first on Manitoba Co-operator.

A new mobile app in development at the University of Saskatchewan promises to identify field insects instantly, map local populations and deliver management advice.

WHY IT MATTERS: Tracking pests and beneficial insects in real time could help farmers make quicker, better-informed pest management decisions and cut unnecessary pesticide use.

The app, called IPPM Now, is expected to combine artificial intelligence (AI), geospatial data and entomology expertise to turn a smartphone photo into real-time agronomic insight. Its developers say it recognizes both harmful and beneficial insects.

Farmers could therefore learn not only what insect they’re dealing with, but whether pressure has reached economic thresholds and what conservation steps might protect beneficial species.

“It will be super useful for farmers, agronomists and scientists scouting insect pests,” says project lead Teresa Aguiar, a PhD student at the University of Saskatchewan. “Scouting takes a lot of time, and the information from researchers, agronomists and farmers is often disconnected.”

From photo to field map

Each image submitted through the app is tagged to a rural municipality, not to an exact GPS point, to protect user privacy. Those records build a colour-coded map that shows where pests, pollinators and biocontrol insects are active.

“We want a practical tool that integrates insect identification, spatial reference, data collection and management recommendations in one platform to make decisions with all the variables involved in pest management,” Aguiar says.

Smart traps and sweep-net scouting

Alongside the app, Insect Track Solutions, the Saskatoon-based startup commercializing the project, is testing a smart trap that photographs insects and uploads images to the same AI model used by the app, identifying and counting adult insects automatically.

Because sticky cards only capture flying adults, Aguiar’s team also designed a simple, low-tech workaround for ground or juvenile stages.

“To solve this problem, make a sweep and then put that sweep in a ziplock bag with a white background and take a picture of that ziplock bag using our mobile app,” she says. The model can then identify and count nymphs and instars in the sample, giving a fuller picture of population levels.

What the app can do today

The prototype version already supports canola and wheat and recognizes 10 key insect groups common to the Prairies. Pests include lygus, flea beetles, grasshoppers and weevils; beneficials include lacewings, lady beetles, hoverflies, bumblebees and honeybees. The app draws on field data and photo libraries, including data and images supplied by Manitoba entomologist John Gavloski, to keep improving its accuracy toward species-level ID.

Future updates will broaden crop coverage and add weather and growth-stage links to help predict pest risk or pollinator timing.

Beta testers wanted

Before IPPM Now officially launches this spring, developers are inviting farmers, agronomists and crop scouts to test it out. Beta users will get early access, provide feedback on design and function, and can volunteer to host free smart-trap trials in 2025.

Aguiar says user input will guide the final version.

“We are sending beta testing invitations. If you’re interested, we can put the app in your phone early access to give us feedback and help us to shape the app and get it ready for next season.”

Farmers and agronomists interested in early testing or hosting field validation sites can contact Insect Track Solutions Inc. via email.

The post AI app promises Prairie farmers better insect scouting appeared first on Manitoba Co-operator.

Renaissance BioScience has developed a distinct RNAi technology that interferes with biological processes in a pest.

WHY IT MATTERS: Flea beetles are a perennial battle for canola producers — one that has been relatively starved for novel tools to add to the tool box.

In early September, Renaissance announced that the federal government is providing $830,000 to fund a $1.65 million project, which is called Eco-Friendly Precision: Innovation RNAi Encapsidation for Flea Beetle Control.

The project name is complicated, but the goal is simple.

“This project aims to provide canola farmers with a cost-effective, sustainable alternative to chemical pesticides,” Renaissance said in a press release.

“Once developed and approved, this made-in-Canada biocontrol innovation will be commercially available to farmers worldwide, offering a powerful new tool to protect yields, cut costs and align with the global shift toward eco-friendly agriculture.”

Flea beetles are the most damaging pest for canola growers on the Prairies. The insects can devour an entire field of emerging canola plants in May or early June. Farmers rely on insecticides coated on canola seeds and foliar sprays of insecticides to control the beetles.

Many companies around the globe, including Renaissance, have been looking at RNAi as a solution to pest control in crop production.

RNA interference is a biological process that regulates gene expression. It interferes with messenger RNA that carry genetic instructions for critical functions, such as making new proteins.

The interference can turn off genes and reduce the levels of specific proteins, which a pest needs to survive.

The big advantage of RNAi is it’s highly specific. It harms the crop pest rather than other species.

Scientists and innovators know that it’s effective, but the difficulty has been delivering the RNAi molecule in a cheap and effective manner.

Yeast of burden

Renaissance is using yeast to deliver the RNAi to the pest.

“The yeast acts as a ‘suitcase’ to protect the fragile bioactive in the environment, allowing the RNAi yeast to be sprayed in solution onto plant leaves like a conventional pesticide,” John Rusnik, Renaissance’s chief scientific officer, told Agribusiness Global in April.

The idea is that the flea beetle would chew on the leaves of a canola plant and consume the RNAi yeast.

Then, the RNAi gets into the gut of the beetle, switching off specific genes and killing the pest.

Renaissance has already been testing this technology on the Colorado potato beetle, an annoying pest for potato growers around the world.

In 2023, the Pest Management Regulatory Agency approved field studies of the yeast-based RNAi on the Colorado potato beetle.

“Independent bench-top laboratory testing on the RNAi technology… (had) a 98 per cent mortality rate that delivered excellent protection for potato plant defoliation,” says a Renaissance press release.

Last September, the Vancouver company was recognized for its unique pest control technology. AgTech Breakthrough, a market intelligence firm, awarded Renaissance with the Crop Protection Solution of the Year.

Renaissance will work on its flea beetle project until 2028, partially funded by Agriculture Canada and the Sustainable Canadian Agriculture Partnership.

“This made-in-Canada solution will protect canola yields, open new opportunities across the value chain and support economic growth in our rural communities,” said federal Agriculture Minister Heath MacDonald.

For now, the agri-tech company is focusing its efforts on “leaf munching pests.”

“We are fine-tuning our technology to make it suitable for pests that devastate fruit, vegetable, grain and oilseed crops.”

The post RNAi research looks for genetic-level flea beetle control appeared first on Manitoba Co-operator.

Some species will eat each other. If food is scarce, they might reverse molt to become smaller and harder to starve. They’ll go after grain crops, potatoes, onions, carrots, strawberries or almost any other field crop. Their tendency to feast on germinating seeds and young shoots under the soil can be mistaken for other issues that cause poor emergence.

Once in a field, the farmer might fight them for over a decade. Foliar insecticides don’t work.

Welcome to the problem of wireworms.

Why it matters: Wireworms are resilient and adaptable, and neonicotinoid seed treatments provide only limited protection.

Wireworms are larvae of the family of insects known as click beetles, named for the sound they make when placed on their backs.

“We’ve basically got about 100 species of click beetles in Manitoba, but there’s really just a couple of them that are pest wireworms here in the Prairies,” Manitoba Agriculture entomologist John Gavloski said during a May 8 webinar on the pest.

Manitoba has a relative advantage when it comes to wireworms. Local types are less aggressive compared to those in Saskatchewan, British Columbia and Atlantic Canada.

The most common species in this province is a small, pale-yellow worm called Hypnoidus bicolour (lined click beetle), which spends two to three years in the soil before developing into an adult. Producers to the west, particularly in Saskatchewan, face the larger, orange-hued prairie grain wireworm, which consumes more feed per worm and can live from four to 11 years in the soil.

“The 11 years would only be if they didn’t have a lot of food,” Gavloski said. “If they have good food, in four or five years they turn into an adult.”

[RELATED] Farmtario: Cimegra label expansion to help control potato beetles

A third species, Aelosus mellillus (flat wireworm), may also be a problem. That type feeds at the soil surface and cuts stems off rather than boring in and shredding them, Manitoba Agriculture’s website states.

A lineup of western Canadian pests, published by Agriculture and Agri-Food Canada in 2019, also notes western wireworm, wheat wireworm and dusky wireworm as pest species.

Not all wireworms limit themselves to plants. One survey out of Prince Edward Island illustrated predatory behaviour, Gavloski noted. That included the problematic prairie grain wireworm.

“The prairie grain wireworm is an opportunistic predator. If it does come across insect larvae or even other wireworms, it will eat them. It’s been known to cannibalize other prairie grain wireworms that are smaller than them.”

Few tools

Wireworm habits make them hard to control. The feeding damage happens at the larval stage, when they live completely underground, out of reach of sprayed pesticides.

Farmers instead must rely on seed treatments. Neonicotinoid treatments containing thiamethoxam, imidacloprid or clothianidin offer some protection, but they are more of a deterrent than true control.

“They don’t feed well when the plants are getting established (with those treatments), but the wireworms don’t necessarily die off in big numbers,” Gavloski said.

Because neonics don’t reduce populations, wireworms could develop resistance if those products are overused.

Farmers got a different tool in 2021, when BASF’s group 30 broflanilide-based products hit the Canadian market. Terraxa 4 is a fungicide-insecticide combo for cereals, while Cimegra is tagged for in-furrow wireworm control in potatoes, as well as foliar use against Colorado potato beetle.

Those products target the nervous system of wireworms and kill them.

Scientists are also working with a fungus called Metarhizium anispoliae, which can kill wireworms and could be a future microbial insecticide.

Scouting

Producers should dig into bare patches they might otherwise ascribe to poor germination to see if they have a problem, Gavloski advised.

In other infestations, the crop will come up, but stems will appear shredded from wireworm feeding underground. In cereals, a plant’s centre leaves may be yellowed or wilted. Hollowed out seeds are another sign.

Overly hot or dry soil will send the worms deeper.

“The soil is moist this time of year and they’re probably close to the soil surface, but as the soil heats up and dries out a bit later in summer, they do move much deeper and get much trickier to find,” said Gavloski.

In late summer, they will return close to the soil surface.

Producers should also be careful with identification. Wireworms can be mistaken for cutworms or for stiletto fly larvae, the latter of which is farmers’ friend.

“Stiletto fly larvae are actually predators of other insects in the soil, such as wireworms,” Gavloski said. “So, if it’s pale white and not yellowish or orange, it could be a stiletto fly larva. Those are the good guys.”

Some producers try to bait wireworms out of the soil with potatoes, oats or presoaked corn and wheat mixtures. Manitoba Agriculture recommends baits be buried 7.5-10 centimetres deep and checked a week to 10 days later.

Baiting isn’t a guarantee that wireworms will show themselves, Gavloski said.

“The way wireworms find their food is they follow carbon dioxide trails in the soil. Early in the season, when there’s not a lot of carbon dioxide sources, you will get them coming for your potatoes or bait balls.

“But once you’ve had a lot of stuff in the field with roots, it competes with big traps.”

Manitoba Agriculture recommends seeding into warm, moist soil to encourage crops to germinate quickly and develop beyond the most vulnerable growth stages.

The post Wireworms a persistent insect pest on the Prairies appeared first on Manitoba Co-operator.

The Manitoba Crop Alliance noted the allowance in a press release July 28.

“The need for an emergency use registration was identified in the wake of the re-evaluation of lambda-cyhalothrin product use in Canada, which left a void in lygus bug control in confection sunflowers,” the farm groups said in the release.

“This insect pest is a serious economic threat to human consumption market confection sunflowers.”

The 2021 federal decision to ban lambda-cy on certain crops, including sunflowers and any grains bound for livestock feed came into effect this spring.

Carbine is a recently introduced selective pesticide meant to combat aphids in pulse crops, but it has also been shown to be effective against lygus bugs.

“Carbine was chosen because it’s a more selective product and it’s easier on bees and natural enemies,” said Manitoba Agriculture entomologist John Gavloski.

The pesticide will kill some sap-feeding insects. It will not kill chewing insect pests of sunflower seeds, such as banded sunflower moths or larvae of seed weevils.

Lygus bugs feed on developing sunflower seeds, which can cause a physical scar on the bare seed, according to the Manitoba Crop Alliance. Typically, a kernel will have only one spot, on the blunt or distal end, but will take on a bitter taste.

According to Manitoba Agriculture, lygus bugs are capable of damaging 30 to 35 seeds per head per adult.

Because the damage noticeably changes the taste of the seed, sunflower processors have strict regulations that allow only 0.5 per cent damage in their physical product. With those exacting standards, the economic threshold for lygus bugs on sunflowers is low, about one bug per nine heads.

In research trials, damage to sunflower heads was approximately twice as severe when infestations occurred at late bud and early bloom stages compared to stages when heads were fully flowered. This means lygus bug management should be started prior to or at the beginning of blooming.

Farmers are also urged to monitor until flowering is completed to reduce the incidence of kernel brown spot damage.

Lygus bugs have been noted in recent provincial crop pest updates. Manitoba Agriculture has noted an increase in levels in canola plants in the Austin area, but Gavloski says the reason for the emergency use registration of Carbine wasn’t out of any immediate concern of a widespread infestation in sunflowers. It’s just a precaution.

“We just needed something to be used on confectionary sunflowers should an economic outbreak of lygus bugs occur,” he said.

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“Towards the end of May, we experienced unforeseen and unprecedented volume declines in three out of our four operating regions, as our channel partners rapidly reduced inventory levels,” CEO Mark Douglas said in a statement.

The regions hit were North America, Latin America, and Europe, the Middle East and Africa (EMEA).

The stock, down over 23 per cent this year, was trading 8.4 per cent lower at $95.45 in morning trade (all figures US$).

The company reduced its full-year revenue forecast range to $5.2 billion to $5.4 billion, from $6.08 billion to $6.22 billion.

At midpoint, it also expects second-quarter revenue to be lower by about 30 per cent compared to its previous outlook.

In the prior quarter, FMC’s sales took a hit due to drought in southern Brazil and Argentina, lower demand in EMEA and channel inventory management in India.

Credit Suisse analysts lowered their full-year profit estimate for the company by 14 per cent to $6.57 per share to reflect ongoing inventory destocking.

Philadelphia-based FMC, which sells insecticides and herbicides, added on Monday that its adjusted core profit for the second quarter is expected to be between $185 million and $195 million, nearly 50 per cent down from its earlier expectation.

Its adjusted earnings before interest, taxes, depreciation, and amortization (EBITDA) for the year is now expected to be between $1.3 billion and $1.4 billion, compared with an earlier forecast of $1.5 billion to $1.56 billion.

— Reporting for Reuters by Sourasis Bose in Bangalore.

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Now, research by the Prairie Agricultural Machinery Institute (PAMI) along with the College of Agriculture at the University of Saskatchewan and Agrimetrix in Saskatoon is asking, ‘Can we make them more aerodynamic?’

Why it matters: Spray placement is already a complex equation of wind and other weather conditions, but how does air disturbance from the sprayer itself factor in? 

It comes down to air disturbance from the sprayer.

It’s simple to assume that a boom with nozzles pointed straight down is going to put that spray onto the crop or the soil. Under the best of conditions, this is true, but nature rarely provides the best of conditions. 

“Drift is not beneficial. We want to concentrate the spray in the area that it is desired and not have it go anywhere else,” said Lorne Grieger, PAMI’s director of technical sales. “When you’re looking at the sprayer, how it’s physically put together in terms of the structure and how it’s operated, we want to understand how that impacts the potential for spray drift.”

If you’ve ever watered a garden patch by putting your thumb over the end of the hose, you have an idea of how hard it is to get an even spray exactly where you want it. You’ll have droplets of all sizes going in several different directions. Some spots will get more water than others.

A hose nozzle from the local hardware store will do a better job of even coverage and give you options ranging from a long jet of water to a fine mist. Still, it may be confounded by a sudden breeze that can misdirect the stream. 

In the garden, this isn’t a serious problem. With a pesticide, it certainly can be.

You don’t want anything drifting across the road to do damage in a neighbouring field. You want to account for every drop.

Measuring disturbance

The PAMI team’s work started with a computer simulator to get a broad idea of where drops might go during application.

“We used a tool called Computational Fluid Dynamics, which is a computer simulation of air flows,” Grieger said. “Then we coupled that with the equipment to understand what the impacts or implications are with using the physical structure of a high-clearance sprayer.”

Modelling a moving sprayer is more complex than you might think. It’s a solid object moving through the air while it dispenses a liquid out the back from a long boom. As it moves, it sets up small eddies and whorls within the air. To make it even more complicated, that air is moving too. This can have all kinds of influences on where the spray goes.

“Part of the simulation process is simplifying… a very complex type of system,” Grieger said. “This allows us to break it down into something that can be modelled and can be solved.”

The computer separates the equipment into its component parts: the tractor, the tank and the boom. The software can calculate how air would move around the different shapes and how it would probably act in very specific locations.

Researchers can then tweak some of the inputs such as ground speed or wind direction and come up with a good idea of how the air will behave around the sprayer and how it will affect the spray itself. 

Once satisfied with the data, it was time to test the model in the real world.

“We did simulation work looking at a self-propelled sprayer operating in the field.” Grieger said.

Grieger’s team mounted several small anemometers — sensors to measure both the direction and speed of the air at several points behind the sprayer and around the boom.

“The intent of using the anemometers was to understand how laminar or how turbulent the air would be at various locations behind the sprayer and the boom itself,” Grieger said. “We wanted to understand the direction of the air. Is it going straight or is it going to the side? Or it also may be going up.”

That last option, he noted, would certainly have the potential for extra drift.

Laminar flow is a layer of air moving from one point to another, very much like the air flowing from a furnace vent. Under ideal circumstances, it will flow straight and unimpeded along the floor. Staying with the vent analogy, when the dog walks into the warm stream, curls up and lies down, there is suddenly an uneven obstacle that the air has to move around. The dog is now a source turbulent flow. If he’s lying on his back with his legs in the air, the effect is even greater, since the strange shape can cause the air to move in strange directions.

That sleeping dog is a simpler obstruction than a sprayer moving across the field. 

“The combinations of the physical components can impact what you see behind the unit itself,” Grieger said.

If there’s a slight breeze blowing, it may be a laminar flow straight over the square cab, but it starts to move in all kinds of directions as it meets the less regularly shaped tank, tires or the boom, with all its hoses and superstructure. These are the eddies that wind up slipping under the nozzles, thus influencing drift.

There were a few takeaways from the work, some of which echoed standard advice from spray experts. Grieger’s team noted lower drift potential in lower boom heights and slower ground speeds, although a caveat on that last point noted that varying conditions mean there is no perfect speed setting for spraying.

The other thing they found, however, was that the aerodynamic efficiency of the boom was affected by the width of the tractor portion of the machine. Nozzles closer to the end of the boom were less affected by turbulence caused by the machine in the middle.

Impact

What Grieger’s work was really developing was research methods for analyzing the engineering of future farm equipment. The ideas generated by this kind of research could contribute to the development of better simulation software and better design and operation of equipment like sprayers.

“This is the first step in terms of overall understanding. What does it look like in the field when you’re using a high-clearance sprayer? What does it do to your spray drift potential?” Grieger said. “And then, once you have the data, you can use that as a benchmark for making any adjustments or changes to the implement.”

The post The aerodynamics of crop spraying appeared first on Manitoba Co-operator.

Oregon-based processor Grain Millers, whose Canadian operations include its oat mill at Yorkton, Sask., said in a memo Tuesday to growers that the Canadian National Millers Association has asked all member businesses to advise growers of their lambda-cy policies.

The move comes after a 2021 re-evaluation decision by Health Canada’s Pest Management Regulatory Agency (PMRA) took effect at the end of April this year, prohibiting the use of lambda-cy on some crops altogether and the use of any lambda-cy-treated crops as livestock feed.

“Now, while most of you are growing your oats for human consumption, the issue lies in the byproducts that are produced in the milling process,” Grain Millers’ Yorkton procurement manager, Scott Shiels, said in the memo.

“For us, that is primarily the oat hulls, and screenings, which are almost exclusively sold into the feed market.”

Thus, he said, the company is “being forced to prohibit the use of lambda-cyhalothrin on any oats being sold to Grain Millers.”

From now on, he said, “prior to delivering any oats in the future,” growers will be required to sign a delivery affidavit which will include a statement to that effect.

Lambda-cy products currently registered in Canada for use in oats include Syngenta’s Matador and Warrior and Adama’s Zivata against grasshoppers, and Adama’s Silencer against armyworm.

Since April 29, however, those products’ labels all specifically prohibit their use on any crops that may be destined for feed, including crop screenings or other byproducts or aftermath. Treated fields also cannot be grazed by livestock, nor cut for hay or forage.

Among other prohibited products, Grain Millers’ memo also names Karate — a Syngenta insecticide in markets outside Canada — and Saber, a pour-on and ear-tag insecticide registered in Canada to protect cattle against insect pests.

Since late April, grain grower organizations have warned that because any crop entering the grain handling system is eligible for use as livestock feed, the use of lambda-cy “poses a risk of becoming an off-label use.”

Grower groups since then have also advised farmers to discuss any potential related market risk issues directly with their grain buyers. — Glacier FarmMedia Network

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The weevils are small and difficult to see. The farmer often doesn’t know they’re in the field until they find nicks in the leaves of their crop. By that time, it’s too late for the sprayer. The eggs have hatched and the larvae are down in the soil.

“The larvae do the economic damage, so for control to be effective, you have to target that stage,” said University of Alberta doctoral student Maggie MacDonald, but “because [the larvae are] so safe inside those root nodules, there really isn’t a good way to target them.”

Why it matters: The pest was first found in Manitoba in 2019. Since then, reports have spread from the northwest region to southwest and parts of central Manitoba.

This makes pea leaf weevil a good candidate for biological control provided by some kind of predatory insect that can meet the weevil on its own ground. Researchers are searching for a natural enemy that will either take out the adults when they arrive in the field, eat their eggs before they hatch or go after larvae in the soil.

There’s one in particular that’s caught attention: a ground beetle with the Latin name Pterostichus melanarius (P. melanarius).

“Most ground beetles are generalist predators that are known to eat slugs and other insects,” said Agriculture and Agri-Food Canada entomologist Meghan Vankosky. “They’ll go after the eggs, the larvae, the pupae, the adults, and then there are groups within the ground beetles that are known to eat weed seeds, so there’s a lot of interest in ground beetles for biological control of pests.”

Non-picky eaters

The beetle of interest against pea leaf weevil is plentiful in Western Canada, despite being an import itself. It’s a European species that likely landed on North America’s East Coast in the 1920s as a passenger within the soil they used as ship ballast.

“When they took out the ballast, they would put the dirt onto the land and the beetles would disperse,” MacDonald said. “And then on the West Coast, it was introduced much later through nurseries. The beetles were found in plants shipped from Asia and Europe… It’s interesting because when you talk about natural enemies, people always talk about native natural enemies.”

Traps set for ground beetles in western Canadian fields showed P. melanarius were common. Since they were already plentiful in fields, it made sense to look closer at what they were eating and whether they could be a useful biological control species.

“They’re kind of like the garbage cans of the agro-ecosystem. They’ll eat almost anything and their larvae are also predatory,” MacDonald said

But do they eat pea leaf weevils? If so, are they eating adults, larvae or pupae? Those were difficult questions to answer since the adult weevils are so small and the larvae and pupae were in soil where observation was difficult.

To tease out answers, MacDonald set beetles up in a captive lab situation and found that P. melanarius will eat the adult weevils.

“The beetles are starved so they’re hungry, so it makes sense that they’re eating them,” MacDonald said. “So, they have the ability to kill them and eat them, but you can’t really compare laboratory experiments to the field.”

Real-world application

It’s one thing to watch two insects in a closed cage. It’s quite another in the great outdoors. How a small beetle interacts with an even smaller weevil is difficult, if not impossible, to observe under natural conditions.

MacDonald’s research has previously examined 40 to 60 sites to gauge distribution of the pest, but also to see what predators show up in those fields.

If P. melanarius is in the same field as the weevil, researchers set pitfall traps to capture as many as they can over a 24-hour period. The researchers then examine beetle stomach contents to see if they’ve eaten pea leaf weevil.

Once again, that’s a daunting task on a subject so small. The best way determine stomach contents is through DNA. If pea leaf weevil DNA is found in the stomachs of P. melanarius, researchers will know they are, in fact, predators of the pest.

“Currently, I’m developing DNA primers and once they’re all tested, I’ll be able to work on my actual samples,” MacDonald said. “I think once we’re able to see what they’re eating in the field and we’re able to quantify that, I think that will help us answer some questions.”

It’s possible that P. melanarius isn’t eating pea leaf weevil at all, and MacDonald says she’s bracing herself for that possibility.

If not, perhaps there is another predator species or maybe several. This kind of work does not always move quickly.

“With integrated pest management, there is never a silver bullet,” MacDonald said. “I think figuring out what P. melanarius is doing in the field will be good, but I think looking at other species that may [target] the eggs will also be useful. Then you can have an idea of the predator complex and the capability of that in the system.”

The post Ground beetle biocontrol against pea leaf weevil appeared first on Manitoba Co-operator.

Among the pests he cited were grasshoppers, flea beetles and pea leaf weevils. 

Tansey said the grasshopper hatch is well underway in Saskatchewan, but recent rains could change how much of a problem they become. 

“We’ve had some rain in the south of the province and we are still waiting to see what… that has done with these grasshopper nests. The moisture can contribute to disease in these animals and contribute to direct mortality,” he said, noting there have been some reports already of crop damage, 

Tansey stressed the need for vigilance with farmers checking their crops and the surrounding areas for signs of grasshoppers and other pests. He said there has been estimates of 50 to 70 grasshopper nymphs per square meter in ditches, which normal rates tend to be around 40. 

There have also been reports of striped and crucifer flea beetles in the province, especially in the central area. 

“We are hearing about damage to seedling canola in the Saskatoon area,” Tansey said, also noting large numbers of striped flea beetles in the province’s northeast. That said, he cautioned there are still few reports to go on at this time and there was still something of a chance the problem might not be as bad as expected. 

“There’s no replacement for getting out and seeing what’s happening,” he said. 

Pea leaf weevils have been reported as well, though it’s still on the early side to fully know how much of a problem they could become this year. 

“There was a pretty dramatic increase in the number of pea leaf weevil numbers in the northeast last year,” he said, noting monitoring just recently started for this year. 

Some farmers recently began spraying for different insect pests in the province, he said, but added that when reports and numbers have firmed up, the province will make the insect situation well known to them. 

— Glen Hallick reports for MarketsFarm from Winnipeg.

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